{"Bibliographic":{"Title":"The Plainfield/Crest Hill tornado, Northern Illinois, August 28, 1990.","Authors":"","Publication date":"1991","Publisher":""},"Administrative":{"Date created":"08-16-2023","Language":"English","Rights":"CC 0","Size":"0000212516"},"Pages":["QC\n955.5\n.U6\nOF\nCOMPUTER\nP53\n1991\nWHERE\nSTATES\nOF\nNatural Disaster Survey Report\nTHE PLAINFIELD/CREST HILL TORNADO\nNorthern Illinois\nAugust 28, 1990\nU.S. DEPARTMENT OF COMMERCE\nNational Oceanic and Atmospheric Administration\nNational Weather Service, Silver Spring, Maryland","ATMOSPHERIC\nNOAA\ncommunication\nDEPARTMENT\nCover: Panoramic photographs of the damage track of Plainfield/Crest Hill\nTornado--provided to NOAA for use in this report by Robert E. Gorsich, M.D.,\nDowners Grove, Illinois.\nTop panel shows path of tornado damage from Plainfield High School (middle left)\nsoutheastward across two subdivisions of the town.\nBottom panel shows path of damage from extreme southeastern Plainfield (middle\nleft) across I-55 through the Crystal Lawns Subdivision and eastward toward\nCrest Hill (middle right).","QC\n955.5\n,166\nAND NOAA ATMOSPHEAIC\nP53\nLIBRARY\n1991\nAPR 2 0 1993\nS.S\nN.O.A.A.\nU.S. Dept. of Commerce\nDEP\nPARTMENT\nOF\nNatural Disaster Survey Report\nTHE PLAINFIELD/CREST HILL TORNADO\nNorthern Illinois\nAugust 28, 1990\nMay 1991\nU.S. DEPARTMENT OF COMMERCE\nRobert A. Mosbacher, Secretary\nLIBRARY\nNational Oceanic and Atmospheric Administration\nDr. John A. Knauss, Administrator\nMAY 2 7 1993\nNational Weather Service\nNOAA CENTRAL LIBRARY\nDr. Elbert W. Friday, Jr., Assistant Administrator\nHeru Commerce\n1315 East West Highway\n2nd Floor, SSMC3, E/OC4\nSilver Spring, MD 20910-3281","PREFACE\nParticipation on a Natural Disaster Survey is both a rewarding and potentially\ntrying experience. Witnessing the personal tragedy caused by a disaster and\nassessing services provided by the National Weather Service are responsibilities\nnot taken lightly. Reports on natural disasters are very important in that they\nprovide needed recommendations on how to improve warning service.\nThe Plainfield/Crest Hill tornado was a particularly difficult disaster to evaluate.\nI wish to express sincere appreciation to the Disaster Survey Team members for\ntheir thorough, professional, and unbiased review of the disaster and for their well\nthought out recommendations for improvements in National Weather Service\nwarning services.\nElbert W. Friday, Jr.\nAssistant Administrator\nfor Weather Services\nMay 1991\nii","FOREWORD\nThis survey report on the tornado which struck northeastern Illinois on August\n28, 1990, was prepared by a National Oceanic and Atmospheric Administration\nDisaster Survey Team following a 4-day visit to the storm site. The report is\nbased upon information gathered by the team through a series of visits to\nNational Weather Service Offices and during interviews with members of other\nagencies, organizations, and state, county, and municipal governments. The team\nthanks the county and municipal officials who took time from urgent disaster\nresponse duties to share their impressions of the event and interpretations of the\neffectiveness of National Weather Service watch and warning products. The team\nwas impressed by the cooperativeness and candor of these officials who were\nworking under conditions of high personal and organizational stress.\nAlthough this document is not intended to chronicle the entire history of the\ntornado-producing thunderstorm system, it does assess the effectiveness of\nNational Weather Service performance and products before and during the period\nof severe thunderstorms in northern Illinois. The report presents a number of\nfindings, followed by related recommendations, based upon the team's survey.\nThe recommendations could lead to more effective severe storm warning and\nforecasting procedures in northern Illinois.\nThe Disaster Survey Team\niii","TABLE OF CONTENTS\nPage\nii\nPreface\niii\nForeword\nvi\nAcronyms\nviii\nThe Disaster Survey Team\nix\nExecutive Summary\nxi\nFindings and Recommendations\n1\nPlainfield/Crest Hill Tornado--The Event and its Impacts\nChapter 1\n13\nMeteorology of the Event\nChapter 2\n27\nWarnings and Forecasts\nChapter 3\n32\nDiscussion of Services\n3.1\n38\nPreparedness, Dissemination, and Response\nChapter 4\n38\nPreparedness--SSC Chicago\n4.1\n41\nPreparedness--External User Groups\n4.2\n42\nMedia Dissemination\n4.3\n43\nUser Response\n4.4\nChronology of Releases Related to the Plainfield/Crest Hill\nAppendix A\nA-1\nTornado\nReleases of the National Severe Storms Forecast Center\nA-1\nA-1\nA-7\nReleases of WSO Rockford\nA-2\nA-13\nReleases of WSMO Marseilles\nA-3\nA-18\nReleases of WSFO Chicago\nA-4\nA-26\nReleases of WSFO Indianapolis\nA-5\niv","TABLE OF CONTENTS (Cont'd)\nPage\nAppendix B\nChronology of Actions/Reports\nB-1\nB-1\nThe Actions/Reports at WSO Rockford\nB-1\nB-2\nThe Actions/Reports at WSFO Chicago\nB-2\nB-3\nThe Communication Log at Marseilles WSMO\nB-5\nB-4\nSpecial Radar Scans of the Storm Taken at Marseilles\nWSMO\nB-7\nB-5\nThe Communication Log at NSSFC\nB-8\nAppendix C\nProduct and Information Dissemination\nC-1\nC-1\nEmergency Service Agencies\nC-1\nC-2\nRadio Stations\nC-3\nC-3\nTelevision Stations\nC-5\nAppendix D\nPreparedness Activities WSFO Chicago\nD-1\nD-1\n1989 Preparedness Talks\nD-1\nD-2\n1990 WPM Appearances\nD-2\nAppendix E\nSummary of Fatalities\nE-1\nE-1\nList of Individuals\nE-1\nE-2\nMap Showing the Locations of the Fatalities\nE-2\nE-3\nMap Showing Locations of Major Damage\nE-3\nAppendix F\nPersons Interviewed and/or Contacted by the Disaster\nSurvey Team\nF-1\nF-1\nNational Weather Service Employees\nF-1\nF-2\nOther Agencies/Institutions\nF-2\nAppendix G\nNWS Staffing for Northern Illinois\nG-1\nAppendix H\nFujita Tornado Intensity Scale\nH-1\nV","ACRONYMS\nConvective Outlook\nAC\nAFOS Data Analysis Program\nADAP\nAlphanumeric Display Module\nADM\nAutomation of Field Operations and Services\nAFOS\nAssociated Press\nAP\nBounded Weak Echo Region\nBWER\nCivil Defense\nCD\nCentral Daylight Time\nCDT\nCentimeter\ncm\nCenter Weather Service Unit\nCWSU\nData Communications Module\nDCM\nDeputy Meteorologist in Charge\nDMIC\nDisaster Survey Team\nDST\nEmergency Services and Disaster Agency\nESDA\nFederal Aviation Administration\nFAA\nGeostationary Operational Environmental Satellite\nGOES\nGeneric WARNing System\nGWARN\nIllinois State Police\nISP\nIllinois State Police Emergency Radio Network System\nISPERNS\nkm\nKilometer\nkts\nKnots\nLaw Enforcement and Dissemination System\nLEADS\nmb\nMillibar\nMeteorologist in Charge\nMIC\nWSMO Marseilles\nMMO\nModel Output Statistics\nMOS\nNational Warning System\nNAWAS\nNext Generation Weather Radar\nNEXRAD\nNested Grid Model\nNGM\nNational Oceanic and Atmospheric Administration\nNOAA\nNational Severe Storms Forecast Center\nNSSFC\nNOAA Weather Radio\nNWR\nNational Weather Service\nNWS\nNOAA Weather Wire Service\nNWWS\nOceanic and Atmospheric Research\nOAR\nOfficial in Charge\nOIC\nvi","ACRONYMS (Cont'd)\nPMO\nPort Meteorological Officer\nPPI\nPlan Position Indicator\nRADID\nRADar Information Display\nRHI\nRange Height Indicator\nRISOP\nRapid Interval Scan OPerations\nSDM\nStation Duty Manual\nSELS\nSEvere Local Storms Unit\nSRWARN\nSouthern Region WARNing System\nUPI\nUnited Press International\nUTC\nCoordinated Universal Time\nVIP\nVideo Integrator Processor\nWER\nWeak Echo Region\nWPM\nWarning Preparedness Meteorologist\nWRIST\nWeather Radar Identification of Severe Thunderstorms\nWSFO\nWeather Service Forecast Office\nWSMO\nWeather Service Meteorological Observatory\nWSO\nWeather Service Office\nWSR\nWeather Service Radar\nWSS\nWeather Service Specialist\nvii","THE DISASTER SURVEY TEAM\nAfter a significant severe weather event, such as a destructive tornado, a Disaster\nSurvey Team (DST) may be assigned by the National Oceanic and Atmospheric\nAdministration (NOAA) to evaluate the roles played by the National Weather\nService (NWS), to provide an objective appraisal of the event, and to make\nrelevant findings and recommendations. Such a team was asked to survey the\nPlainfield/Crest Hill tornado which struck in northeastern Illinois on August 28,\n1990.\nTEAM MEMBERS\nLeader, Robert A. Maddox, Director, National Severe Storms Laboratory,\nOceanic and Atmospheric Research (OAR)\nCoordinator, Linda Kremkau, Program Assistant, Warning and Forecast Branch,\nNWS\nMyron I. Berger, Meteorologist, Warning and Forecast Branch, NWS\nT. Michael Carter, Consultant, Corporate Response Group, Inc.\nRobert Elvander, Meteorologist, Next Generation Weather Radar (NEXRAD),\nJoint Systems Program Office, NWS\nKenneth Howard, Meteorologist, National Severe Storms Laboratory, OAR\nRobert Jacobson, Meteorologist, Marine and Applied Services Branch, NWS\nMichael Looney, Deputy Meteorologist in Charge, Denver, Colorado, NWS\nRichard Przywarty, Area Manager/Meteorologist in Charge, Seattle,\nWashington, NWS\nJay Tebeau, Public Affairs Officer, NOAA Public Affairs\nviii","EXECUTIVE SUMMARY\nThe Event\nOn the afternoon of August 28, 1990, an intense tornado struck Kendall and Will\nCounties in northeastern Illinois. The storm produced severe property damage,\nwhile causing 29 deaths and more than 300 personal injuries. Damage in these\ntwo counties exceeded $160 million, with the tornado's impact being most\ndestructive and deadly from Plainfield to Crest Hill. The severe thunderstorm\nthat produced the tornado also produced large hail and damaging winds along a\nnearly continuous path from west of Rockford, Illinois, to central Indiana. The\nstorm produced severe weather in Illinois for more than 4 hours, making it not\nonly unusually intense but very long-lived.\nAlthough the large-scale meteorological environment did not appear supportive of\nsupercell storms and possible tornadoes because of unfavorable wind shear in low\nlevels, it was characterized by extremely large convective instability. However,\nthe storm, as viewed by conventional weather radar, displayed distinct supercell\ncharacteristics throughout much of its life and produced at least five smaller\ntornadoes prior to the final, and most intense, one which struck Kendall and Will\nCounties. One or two of these occurred early in the storm event and produced\nconfirmed damage near Rockford. A post-event, aerial survey indicates four small\ntornadoes occurred in rapid sequence immediately prior to the major tornado.\nThe weather event which occurred in northeastern Illinois on the afternoon of\nAugust 28 was unusually intense and climatologically very rare, resulting in an\nextreme service challenge to staffs of the National Weather Service offices at\nRockford and Chicago. Between them, these two offices had severe thunderstorm\nwarning responsibility for all of the Illinois counties struck by the storm.\nServices\nThe National Severe Storms Forecast Center, located in Kansas City, Missouri,\nhas responsibility for providing outlooks and watches for possible severe\nthunderstorms and tornadoes across the entire country. The morning outlooks\nconcerning the potential for severe thunderstorms were very accurate. The center\nissued a severe thunderstorm watch just prior to the onset of the event that\nincluded all of northern Illinois. This watch remained in effect at the time of the\nPlainfield/Crest Hill tornado. Although the severe thunderstorm moving across\nix","northeastern Illinois displayed supercell characteristics, staff at the center chose\nnot to reissue this watch to include the threat of tornadoes. The reason was that\nthe storm was isolated, and the tornado threat was being well-covered by local\nwarnings issued at Rockford. Early in the event, the Weather Service Office at\nRockford responded quickly and provided warnings for the second reported\ntornado and other severe weather associated with the thunderstorm. The\nRockford office communicated with staff at the Weather Service Meteorological\nObservatory in Marseilles, Illinois, the site of the relevant network weather radar,\nto determine the storm's intensity and probable track. The office in Rockford\nreceived several very timely reports of a funnel cloud, a tornado touchdown, and\nother associated severe weather from the Illinois State Police, which helped them\nconfirm the serious nature of the storm's threat.\nAs the storm moved into the warning area of the Weather Service Forecast Office\nat Chicago, the severe weather services provided were not as timely or accurate as\nthey might have been. The first two severe thunderstorm warnings issued at\nChicago were for locations that remained to the north and east of the actual path\nof the severe weather. The large hail, damaging winds, and tornadoes in\nsouthwestern Kane, northeastern Kendall, and western Will Counties occurred,\nessentially, without warnings of any type in effect. The last several minutes of\nthe major tornado were covered by a severe thunderstorm warning that included\nwestern Will County.\nDuring the time that the supercell storm was moving through Kane, Kendall, and\nWill Counties, neither the staff at Marseilles nor Chicago recognized severe\nthunderstorm signatures or indicators of the storm's tornadic potential exhibited\nby its radar echo. Few reports of severe weather, none of funnel clouds or\ntornadoes, were received at the Chicago office, contributing to slow recognition of\nthe continuing serious threat this storm posed. The lack of spotter reports and\nlimited flow of information in northeastern Illinois prior to and during the severe\nthunderstorm event, coupled with the failure of radar operators and forecasters to\nrecognize the severe nature of the long-lived supercell thunderstorm, indicates\nthat training and preparedness activities and severe weather program oversight\nhad not been implemented effectively at Chicago during recent years.\nThe Disaster Survey Team feels strongly that careful consideration of the reasons\nwhy, for this particular tornado occurrence, warnings were not as timely or\neffective as they might have been, can lead to long-term improvements in the\nwarning and forecast system. The team has developed an extensive series of\n\"Findings\" and \"Recommendations\" as part of its report of the Natural Disaster\nSurvey. These are presented on the following pages. The body of this document\nprovides detailed and sometimes technical information supporting the team's\nfindings and recommendations.\nX","FINDINGS AND RECOMMENDATIONS\nFinding 1:\nOn August 28, 1990, a climatologically rare and unusually intense tornado\nstruck Kendall and Will Counties in northern Illinois, causing 29 deaths\nand injuries exceeding 300, while producing more than 160 million dollars\nof property damage. (Chapter 1)\nFinding 2:\nThe severe thunderstorm that produced the tornado developed near the\nIllinois/Wisconsin border shortly after 12:00 p.m., Central Daylight Time\n(CDT), and produced nearly continuous severe weather-including large\nhail, strong and damaging winds, and several tornadoes--as it moved\nsoutheastward across northeastern Illinois. The storm remained severe\nas it moved into Indiana during the late afternoon. (Chapter 1)\nFinding 3:\nA number of NWS offices were involved in various aspects of the severe\nweather watch, warning, and radar surveillance programs for the storm\narea on August 28 (i.e., the National Severe Storms Forecast Center\n(NSSFC) in Kansas City, the Weather Service Forecast Office (WSFO)\nChicago, the Weather Service Office (WSO) Rockford, the Weather Service\nMeteorological Observatory (WSMO) Marseilles (MMO), and the Center\nWeather Service Unit (CWSU) Aurora, all in Illinois; WSFO Indianapolis,\nIndiana, observed the severe thunderstorm with its surveillance radar\nand issued products for Indiana, referring to the character of the storm\nthat was moving across northern Illinois). (Chapter 3)\nFinding 4:\nThe large-scale meteorological setting (e.g., approaching surface front and\nmid-level short-wave trough, extreme convective instability) documented\nby the 7:00 a.m., CDT, synoptic observations on August 28 was highly\nxi","conducive to the occurrence of severe thunderstorms. Because of this,\nthe NSSFC upgraded its severe thunderstorm outlook to include a\n\"moderate risk\" for northern Illinois at mid-morning and then issued a\nsevere thunderstorm watch at 1:28 p.m. that covered all of northern\nIllinois, valid through 8:00 p.m., CDT. (Chapter 2)\nFinding 5:\nThe latest numerical model forecasts and standard meteorological\nobservations available in real-time indicated that, based on current\nunderstanding, the vertical wind profile over the western Great Lakes\nRegion would favor the occurrence of multi-cell strong wind and hail-\nproducing thunderstorms rather than tornadic storms on the afternoon of\nAugust 28. (Chapter 2)\nFinding 6:\nRadar data, however, indicated that the tornadic thunderstorm possessed\nboth severe and supercell characteristics (e.g., extreme echo intensities\nand heights, strong leading edge reflectivity gradient, continuous\nmovement to the right of the mean wind that was indicated in Severe\nThunderstorm Watch #691, bounded weak echo region (BWER), distinct\ninflow notch, and intense echo pendant) as it moved across northeastern\nIllinois. (Chapter 2)\nFinding 7:\nGiven the explosive nature of the initial thunderstorm developments,\nstaff of the WSO Rockford, Illinois, responded extremely well to rapidly\nevolving severe weather events on August 28. (Chapter 3)\nFinding 8:\nThe severe weather products issued by WSO Rockford, in addition to\nbeing timely, were consistently well written, included excellent call-to-\naction statements, and provided valuable storm location/motion\ninformation for users. (Chapter 3)\nxii","Finding 9:\nCommunication and coordination among NWS offices and staff could have\nbeen more effective during the period of severe weather. For example,\ninformation provided to the DST by the NSSFC indicates that staff did\nnot discuss with WSFO Chicago forecasters the decision not to reissue\nSevere Thunderstorm Watch #691 as a tornado watch; there was little\ndiscussion among the staffs at WSFO Chicago, WSO Rockford, and WSMO\nMarseilles concerning the character, behavior, and intensity of the severe\nthunderstorm moving across northeastern Illinois; the Automation of\nField Operations and Services (AFOS) Alarm and Alert program at WSFO\nChicago alerted issuances but was not programmed to display severe\nweather products issued by its WSOs and other nearby offices. (Chapters\n3 and 4)\nRecommendations:\nThe NSSFC should make a concerted effort to alert WSFOs if SELS\n(Severe Local Storms unit) forecasters feel that a localized tornadic\nthreat has developed within a severe thunderstorm watch. In situations\nlike this, unusually close coordination is needed to ensure that all\naffected offices are aware of the threat and how it will be dealt with (i.e.,\nvia a new tornado watch or through local warning actions).\nDuring severe weather situations, the WSFO Chicago lead forecaster/\nsevere weather focal point should interact aggressively with affiliated\nWSOs, its CWSU, and other nearby NWS offices to monitor the current\nstatus and anticipated actions regarding severe storms and related\nproducts.\nThe WSFO Chicago should update its AFOS Alarm and Alert program to\ninclude all WSO statements and warnings from Illinois as well as from\nNWS offices in adjoining states.\nFinding 10:\nCritically important information concerning tower operations, controller\nobservations, and the intensity of the severe weather occurrences at the\nFederal Aviation Administration (FAA)-controlled airport in Sugar Grove,\nIllinois, was not conveyed to WSFO Chicago until well after the event.\n(Chapter 3)\nxiii","Recommendation:\nThe NWS, at all levels, should work closely with FAA officials to develop\nprocedures that will ensure rapid, two-way communication of significant\nsevere weather information between the two agencies.\nFinding 11:\nThe WSMO at Marseilles was the primary source of radar information for\nuse at WSO Rockford and WSFO Chicago during the severe weather of\nAugust 28. Staff of the WSMO provided important information\nconcerning the radar-observed character of the severe thunderstorm to\nboth WSO Rockford and WSFO Chicago. (Chapter 3)\nFinding 12:\nEarly in its life, the storm displayed a BWER that was detected by MMO\nstaff and reported to WSO Rockford. (Chapter 3)\nFinding 13:\nAs the severe thunderstorm approached Chicago's area of warning\nresponsibility, the station communication log indicates that MMO passed\nspecific storm structure reports to the WSFO. These reports emphasized\ncore echo locations, storm top heights, and the height to which the\nstorm's Video Integrator Processor (VIP) level 6 echo extended.\nInformation on the storm's movement was transmitted in MMO's radar\nobservations. (Chapter 3)\nFinding 14:\nDuring the period of the development and life of the Plainfield/Crest Hill\ntornado, the storm was moving through an extensive ground clutter\npattern exhibited by the MMO Weather Service Radar (i.e., WSR-74S\nradar, where the numbers indicate year of design and letters denote\nspecial characteristics--S for 10 cm (centimeter) wavelength, C for 5 cm\nwavelength, and D for Doppler). However, it is apparent from the WSR\nPlan Position Indicator (PPI) film that the storm was viewed several\ntimes at elevations above the clutter and a number of Range Height\nIndicator (RHI) scans were accomplished. (Chapters 2 and 3)\nxiv","Recommendation:\nElevated scanning strategies should be used routinely when intense\nstorms are located near the radar. Occasional operation of the radar in\nshort-range mode can provide high-resolution detail and help both the\noperator and WSFO Chicago forecasters identify storm signatures.\nAlthough these procedures may cause some interruptions for external\nusers, the NWS responsibility to use the radar for warnings and\nprotecting life and property should take precedence.\nFinding 15:\nThe WSR PPI film from Marseilles shows that the principal echo\nexhibited severe storm signatures, immediately prior to and during the\ntornado, that are usually associated with supercell thunderstorms and\nmesocyclones. Most of these radar signatures (see Finding 6) were not\ndetected or recognized by staff at either WSMO Marseilles or WSFO\nChicago. (Chapters 2 and 3).\nRecommendation:\nManagement of the WSFO Chicago should work closely with its WSMO at\nMarseilles to ensure that all radar operators are well trained and drilled\nin severe thunderstorm detection procedures and cognizant of severe\nstorm structures and signatures. The same applies for all WSFO Chicago\nforecasters. This training would help ensure more effective use of the\nremote radar's capabilities and provide a common base for improved\ncommunication among the radar operators and forecasters.\nFinding 16:\nThe hotline communication system between WSMO Marseilles and WSFO\nChicago did not function reliably early in the severe weather period. The\nstaff of the WSMO had to call the WSFO on regular phone lines to provide\nradar information. However, regardless of this specific problem, the\ncommunication and coordination between the WSFO and its radar site\ncould have been better. Given the severe weather history and the\nrecognized unusual intensity of this storm, more frequent coordination\ncalls were needed. (Chapter 3)\nXV","Recommendation:\nFormal coordination guidelines should be established between the WSFO\nand WSMO. The WSFO should encourage effective communication and\ninteraction by instituting frequent familiarization and exchange visits\namong the respective staffs.\nFinding 17:\nThe NSSFC upgrade of its severe thunderstorm outlook for northern\nIllinois to a moderate risk at 1500 Coordinated Universal Time (UTC) was\nnot reflected in the products issued by WSFO Chicago prior to the\ninitiation of the severe weather episode. The staff did not issue a \"State\nSevere Storm Outlook.\" The office issued refining statements and\namended zone forecasts after Severe Thunderstorm Watch #691 went into\neffect. (Chapter 3)\nRecommendation:\nDuring the warm season, WSFOs potentially affected by severe\nthunderstorms should issue a morning State Severe Storm Outlook,\ncharacterizing the likelihood for severe weather over their area of\nresponsibility using the NSSFC Convective Outlook (AC) products as\nguidance. State Severe Storm Outlooks should not be considered optional\nfor \"moderate\" and \"high risk\" situations.\nFinding 18:\nThe senior forecaster on duty is the \"supervising meteorologist\" and is\nresponsible for all WSFO Chicago warning and forecast operations,\nincluding severe weather desk staffing and products if a storm event\ndevelops. This procedure was not implemented effectively on August 28.\nResponsibility for severe weather operations was assumed by the\nsupervising meteorologist, i.e., the Deputy Meteorologist in Charge\n(DMIC), with help from an aviation meteorologist and the Meteorologist\nin Charge (MIC). Partly as a result of the direct operations role of senior\nstation management, the public forecaster did not become closely\ninvolved in the decisions being made at the severe weather desk. During\nthe severe weather episode, no single forecaster supervised, monitored,\nand coordinated closely the activities and decision-making processes\nxvi","occurring at the aviation, public service, and the severe weather work\nareas. (Chapter 3)\nRecommendation\nManagement at WSFO Chicago should establish and enforce clear lines of\nauthority and responsibility to be followed during severe weather\noperations. These guidelines should cover specifically situations in which\nsenior station managers may be present in the forecast operations area.\nFinding 19:\nThe WSFO Chicago issued a severe thunderstorm warning at 2:32 p.m.,\nCDT, for northern Kane County as the severe thunderstorm approached\nthe western portion of its warning responsibility area. At 3:23 p.m., CDT,\nWSFO Chicago issued a severe thunderstorm warning for southern Du\nPage County. Then at 3:37 p.m., CDT, another severe thunderstorm\nwarning was issued for northeast Kendall, southern Kane, northern Will\nand southern Du Page Counties.\n(Chapter 3)\nFinding 20:\nAlthough tornado or severe thunderstorm warnings were not issued prior\nto the occurrence of damaging winds, hail, and several tornadoes in\nsouthwestern Kane, northeastern Kendall, and much of northwestern Will\nCounty, severe thunderstorm warnings were in effect for the final few\nminutes (approximately 8 to 10 minutes) of the tornado in Will County.\n(Chapter 3)\nFinding 21:\nMany of the warnings and statements issued by WSFO Chicago contained\ninaccurate or potentially confusing information concerning storm\nlocation, movement, its severe weather history, and counties and towns\nlikely to be in its path. The DST feels that these problems reflect a low\nstate of readiness in the overall severe weather program at WSFO\nChicago. (Chapters 2, 3, and 4)\nxvii","Recommendations:\nIn addition to the radar surveillance training recommended earlier,\nWSFO Chicago should conduct annual severe weather forecasting and\nwarning workshops with attendees, including NWS employees from all\nWSOs, the WSMO, and the CWSU. The WSFO should attempt to draw\nupon local, regional, and national meteorological communities as\nworkshop resources. Emphasis should be given to keeping all staff\ncurrent in advances in severe storm forecasting procedures, e.g., use of\nAFOS Data Analysis Program (ADAP) products, hodograph and sounding\nanalysis, etc.\nManagement at both WSFO Chicago and Central Region should conduct\nreadiness reviews to ensure that national, regional, and local severe\nstorm plans and procedures are well understood by staff and are\nimplemented routinely.\nThe Chicago WSFO should conduct monthly and spot drills to sensitize\nthe staff, local officials, and emergency response managers to proper\nsevere weather watch and warning procedures and responses.\nFinding 22:\nProblems with the map background on the MMO PPI radar display\nmonitor and with the Radar Information Display (RADID) monitor may\nhave contributed to inconsistencies and inaccuracies in the warnings\nissued by WSFO Chicago. (Chapter 3)\nRecommendation:\nThe radar monitors used at WSMO Marseilles and WSFO Chicago should\nbe maintained so that displays are as accurate as is possible. At WSFO\nChicago, both the RADID display and an accurate PPI monitor should be\nsituated to allow easy viewing by the forecaster working at the WSFO\nsevere weather desk.\nxviii","Finding 23:\nBecause of the heavy precipitation and low cloud bases associated with\nthe storm as it crossed Kendall and Will Counties, the visual\nidentification of the major tornado was difficult. (Chapters 2 and 4)\nFinding 24:\nSeveral amateur storm chasers experienced very large hail and strong\nwinds, while observing and filming wall clouds and funnel clouds prior to\nthe touchdown of the principal tornado in Kendall County. However, no\nsevere weather reports were made to NWS offices or to law enforcement\nagencies. (Chapters 2 and 4)\nFinding 25:\nReports of severe weather occurrences between Rockford and Plainfield\nreceived at WSFO Chicago were of large hail and strong or damaging\nwinds. Although the DeKalb Sheriff's Office reported a funnel cloud just\nnorth of DeKalb, this information was not transmitted or conveyed to\nWSFO Chicago by WSO Rockford. (Chapter 3)\nFinding 26:\nThere were few spotter reports received while the storm was moving\nthrough the WSFO Chicago warning area. Reports that were made came\nprincipally from off-duty NWS employees. (Chapters 3 and 4)\nFinding 27:\nMost active severe storm spotter group members in northeastern Illinois\nlive in Chicago or its immediate suburbs, limiting the effectiveness of the\nprogram. Spotter phone listings available at the severe weather desk\nwere not up to date. (Chapter 4)\nRecommendation:\nThe WSFO Chicago needs to invest considerable effort to establish better\norganized, well trained, and broadly distributed severe storm spotter\nxix","groups throughout their entire warning responsibility area. As part of\nthis effort, severe weather desk spotter resource guides need to be\nupdated.\nFinding 28:\nThe Chicago area has a very large user population and is in a geographic\nregion characterized by frequent severe weather events. The office does\nnot have a Warning Preparedness Meteorologist (WPM) position\ndedicated to severe weather coordination and preparedness activities,\nand WPM focal point duties are assigned to one of the staff forecasters.\n(Chapter 4)\nRecommendation:\nThe Chicago WSFO has such a large user population within its warning\narea and such diverse responsibilities that a dedicated WPM position is\nneeded.\nFinding 29:\nThe DST found that there was an overall lack of coordinated,\ncomprehensive, or integrated county-wide procedures or structures in\nplace for preparing for, or dealing with, possible severe weather\noccurrences within the counties struck by the tornado. (Chapter 4)\nRecommendation:\nThe NWS should continue to encourage support of improved and\ncoordinated severe weather preparedness procedures at all levels--state,\ncounty, and municipal. Staff from WSFO Chicago should visit local\nemergency response officials, especially officials having county-wide\nresponsibilities, in each of their warning counties every year, preferably\nnear the start of the severe weather season, to review past and planned\ninteractions and severe weather operations.\nXX","Finding 30:\nLocal officials and emergency managers along with the general\npopulation appear to have given little attention to the severe\nthunderstorm watch and warnings. However, they all indicated that\nhigher awareness and response levels would have been likely in reaction\nto a tornado watch and warnings. (Chapter 4)\nRecommendation:\nStorm spotter training should be provided to these officials so that they\nare aware of the damage potential of straight-line winds and downbursts.\nFinding 31:\nThe statements and warnings issued by WSFO Chicago did not mention\nthe tornado reports associated with the storm in the Rockford area.\nHowever, the severe thunderstorm warnings issued by WSFO Chicago\nincluded a reminder to users that severe thunderstorms can sometimes\nproduce tornadoes unexpectedly. (Chapter 3)\nRecommendation:\nThe importance of conveying the past severe weather history of storms to\ndownstream emergency managers should be emphasized in WSFO\nChicago severe weather drills.\nFinding 32:\nAlthough the principal communication path between the NWS and local\nofficials (the Illinois State Police [ISP] Law Enforcement and\nDissemination System [LEADS]) worked well, some messages were not\nrelayed to all potentially affected districts. The NOAA Weather Wire\nService (NWWS) and NOAA Weather Radio (NWR) appear to be under-\nutilized by local agencies and officials in the area of the tornado.\nThere were few established mechanisms in place to facilitate flow of\ninformation from local officials up to the NWS. (Chapter 4)\nxxi","Recommendation:\nThe Chicago WSFO should routinely review and coordinate with\nappropriate State Police Districts procedures for using the LEADS, the\nIllinois State Police Emergency Radio Network System (ISPERNS), and\nthe National Warning System (NAWAS) to distribute severe weather\ninformation. The office should also work with local officials to encourage\nuse of NWR during threatening weather situations. The importance of\ntwo-way communication between the NWS and state, county, and local\norganizations and officials should be strongly established.\nFinding 33:\nMedia response to the NWS watch and warnings was generally prompt.\nThe severe thunderstorm watch and warnings were distributed primarily\nvia \"crawlers.\" Some stations did convey the messages with live\n\"break-ins.\" (Chapter 4)\nFinding 34:\nMost media outlets in the Chicago area give less emphasis to severe\nthunderstorm products than they do to tornado watches and warnings.\n(Chapter 4)\nFinding 35:\nAlthough most TV and radio stations said they enjoyed a positive working\nrelationship with the NWS, some smaller stations felt that it was difficult\nto get through to WSFO Chicago. Several stations felt that visits and\nsome personal interaction with the staff of the WSFO would be useful.\n(Chapter 4)\nRecommendation:\nManagement at WSFO Chicago should consider conducting an annual\nworkshop or seminar for the media to increase severe weather awareness\nand prepare for the storm season. Visits to some stations may be\nappropriate.\nxxii","Finding 36:\nThe detailed storm survey accomplished immediately after the disaster by\nT. Fujita and D. Stiegler provided invaluable information to the DST\nwhich was not able to begin its work at the site until the Friday\nafternoon following the tornado. This survey occurred only because\nProfessor Fujita was able to obtain financial support for the work from\nthe University of Chicago. (Chapter 1)\nRecommendation:\nBecause of the extreme importance of highly detailed documentation of\nsevere weather occurrences to support the operational implementation of\nthe new WSR-88D radars, the DST feels that NOAA should develop a\ncapability for executing very rapid response storm damage surveys\nduring the 1990s.\nxxiii","CHAPTER 1\nPLAINFIELD/CREST HILL TORNADO--The Event\nand its Impact\nPlainfield and Crest Hill are located in northeastern Illinois approximately 25 miles\nsouthwest of downtown Chicago. Crest Hill is a suburb of Joliet, Illinois; whereas,\nPlainfield is a small community to the west in rural farm country. Both locations\nare within Will County and lie in the warning and forecast responsibility area of\nWSFO Chicago. The maps shown in figure 1.1 cover northern Illinois and indicate\nthe locations of key towns and other features referred to in this report.\nTornadoes occur rather frequently in northeastern Illinois as illustrated by a\ncomposite plot prepared by Professor T. Fujita (see figure 1.2). There have been\n34 previously reported tornadoes in Will County since 1950, and August tornadoes\noccurred in the greater Chicago area in 1956, 1958, 1960, and 1965. The tornado\nthat occurred on August 28, 1990, was unusually intense and has been rated as an\nF-5 tornado by Professor Fujita (see appendix H) putting it in the most intense and\ndestructive category of documented tornadoes. The rare historical nature of the\nevent is emphasized by the fact that since 1950 there has been no documented\nAugust tornado in Illinois that was rated stronger than F-3 on the Fujita scale.\nFurther, this was only the second August tornado to result in fatalities in Illinois\nsince 1916. A tornado at Mattoon Lake, Illinois, killed six persons on August 21,\n1977. (These historical data have been provided by F. Ostby of NSSFC.)\nThe tornado which struck Plainfield and then the Crest Hill area occurred from\napproximately 3:15 to 3:45 p.m., CDT, on Tuesday afternoon, August 28. The\ntornado produced a damage path that was oriented from northwest to southeast,\nagain making it somewhat unusual. Tornadic storms in this part of the country\ntend to track from southwest to northeast during the spring season; however, during\nlate summer, Illinois tornadoes tend to move from the west or northwest in about\nhalf of all cases. The length of the damage track was approximately 16 miles (refer\nto figures 1.3 and 1.4, again provided by Professor Fujita) with the tornado reaching\nF-5 intensity as it approached the western edge of Plainfield. Professor Fujita and\nhis colleague, Duane Stiegler, conducted a comprehensive, aerial photographic\nsurvey along the damage path in Kane, Kendall, and western Will Counties on the\nmorning following the tornado. Fortunately, the University of Chicago provided\n1","funds for this survey. If it had not, the DST would have had little detailed\n\"ground truth\" information on the severe weather since it was not able to visit the\ndisaster scene until the following Friday afternoon and Saturday.\nThe parent severe thunderstorm had produced a wide area of wind and hail\ndamage over DeKalb, Kane, and Kendall Counties prior to the occurrence of the\nprincipal tornado. Four weak and short-lived precursor tornadoes occurred over\nthe open farm country of southwest Kane County. Although the principal tornado\nbegan near Oswego in Kendall County, it did not cause serious injuries until it\nhad moved almost 8 miles to the southeast. Much of the region along the track in\nKendall County is also open farmland. However, heavy damage occurred in the\nWheatland Subdivision, where few persons were at home, as the tornado entered\nWill County.\nFour persons traveling along U.S. Highway 30 just to the west of Plainfield were\nthe storm's first victims. The tornado then produced heavy damage, numerous\ninjuries, and 25 additional fatalities along the remainder of its track with\nPlainfield and the Crest Hill area particularly hard hit. The photographs in\nfigure 1.5 show examples of damage along the tornado track. Additional details\nare provided in appendix E, and a summary of the property damage is shown in\ntable 1 below.\nTABLE 1\nDamage Produced by the Plainfield/Crest Hill Tornado\n(information provided by the Joliet Herald-News)\nDeaths:\n29\nInjuries:\n300+\nHomes destroyed:\n470\nHomes damaged:\n1000+\nTownship\nDamage\nComments\nPlainfield\n$105 Million\n915 homes damaged or\ndestroyed\nWheatland\n$ 5 Million\n64 homes damaged or\ndestroyed\n$ 50 Million\nTroy\nIncludes Crest Hill where\n350 apartment units were\ndestroyed\nTOTAL DAMAGE\n$160+ Million\n2","When the tornado moved southeastward into Plainfield, it destroyed two\nCommonwealth Edison 345,000 volt transmission towers, leaving 65,000 customers\nwithout power. Emergency clean up, repair, and required protective measures\nwere substantial along the entire tornado track.\nAs the tornado moved through Plainfield, it struck the town's high school, the\nPlainfield School District's Administration Center, and St. Mary's Elementary\nSchool, a private institution. The tornado also destroyed the St. Mary Immaculate\nChurch, the church rectory, and its gymnasium in Plainfield. The Grand Prairie\nElementary School in Crest Hill was also destroyed by the tornado. School was\nnot in session; however, the first day of the new fall semester was scheduled for\nAugust 29. Enrollment figures exceed 1,500 students for the Plainfield schools\ndestroyed, and the impacts of this event would likely have been much more\ncatastrophic if it had occurred just one day later.\nThe severe thunderstorm, which produced the tornadoes in Kane, Kendall, and\nWill Counties, first developed shortly after noon along the Illinois/Wisconsin\nborder northwest of Rockford. It rapidly intensified to severe levels and began to\nmove southeastward. One or two tornadoes occurred near Pecatonica and Seward\nin Winnebago County and produced minor damage at about 1:42 p.m., CDT (or\n1842 UTC) near the local State Police District Headquarters. Between 2:00 and\nabout 2:45 p.m., CDT, the storm produced wind damage and particularly large\nhail (up to 2-1/2 inches in diameter) over Rockford, northwest DeKalb County, and\nnorth and east portions of the city of DeKalb. In addition to large hail and wind\ndamage, a funnel cloud was reported just north of DeKalb by the County Sheriff's\nOffice at 2:55 p.m., CDT. As the storm moved across southwestern Kane County,\nwind damage, large hail, and four small tornadoes occurred between about\n2:45 and 3:15 p.m., CDT.\nWhen the storm moved across western portions of Aurora, Illinois, it struck the\ncity's FAA-controlled airport (which is located at Sugar Grove, about 10 miles west\nof downtown Aurora) at about 3:05 p.m., CDT. Tower controllers felt that they\nobserved a \"wall cloud\" moving over the airport immediately before winds gusted\nas high as 80 to 90 mph, and they abandoned the control tower. (A \"wall cloud\" is\na characteristic rotating cloud feature with a lowered base that attends meso-\ncyclone circulations. Mesocyclones typify supercell thunderstorms and indicate\nthat tornadoes are possible.) The damage at the airport in Sugar Grove was\nextensive and the controllers' actions and observations were possibly of critical\nimportance. However, the only report that reached WSFO Chicago was one of\nlarge hail falling at the CWSU at 3:23 p.m., CDT. Information on the extent of\ndamage at Sugar Grove was not received at WSFO Chicago until about 4:30 p.m.,\nCDT.\n3","While the damage was occurring at Sugar Grove (i.e., about 3:05 to 3:10 p.m.,\nCDT) amateur severe storm chasers (a Mr. Paul Sirvatka, who is an instructor at\nthe College of Du Page, and several of his students) observed and photographed a\ndistinct wall cloud and several funnel clouds over and to the northwest of the\nairport. The chasers had earlier observed large hail, very high winds, a wall\ncloud, and funnel clouds south and east of DeKalb. Once again, this critical\nsevere storm information was not reported to the NWS or to law enforcement\nofficials.\nThe principal tornado developed from about 3:10 to 3:15 p.m., CDT, as a very\nstrong gust front (associated with the microburst area shown on figure 1.3)\nwrapped around the south flank of the supercell and interacted with the\nmesocyclone/wall cloud that, as reported to the DST by Sirvatka, was now moving\nacross the Oswego area. The tornadic thunderstorm may have produced several\nmesocyclones during its movement across northern Illinois. These appear to have\ndeveloped on the south to southeast flank of the storm in association with the\nrapid advance of a strong gust front that characterized this region of the storm.\nThis is not an unusual sequence of events for tornadic, supercell storms.\nThe final mesocyclone was the most intense of the series and produced the\ndestructive tornado. The heavy rains and hail that trailed the gust front (golf ball\nto tennis ball-size hail was reported at and west of Joliet by an NWS WSFO\nemployee at 3:40 and 3:45 p.m., CDT) were apparently drawn completely around\nthe circulation of the mesocyclone obscuring the tornado itself. The only post-\nevent report of a funnel cloud by persons along the damage track was from a\nresident of the Crest Hill Apartments. She said she observed several funnels\nswirling around her as the apartments were being destroyed. This would be\nconsistent with the occurrence of a multiple vortex tornado. The damage survey of\nFujita and Stiegler documented suction vortices at several places along the path,\nagain indicative of an intense, multiple vortex tornado.\nAfter the tornado dissipated in northwest Joliet, the parent thunderstorm\ncontinued southeastward and then eastward for the next hour and a half. Along\nthis portion of its track, it produced substantial wind damage both east of Joliet\nand in Kankakee County. At about 5:15 p.m., CDT, the severe thunderstorm\nmoved eastward into Indiana, continuing to produce severe weather. Thus, this\nparticular storm produced nearly continuous severe weather across northern\nIllinois for a period of almost 4-1/2 hours.\n4","BOONE\nJO DAVIESS\nSPTEPHENSON\nWINNEBAGO\nMcHENRY\nLAKE\n1\nROCKFORD\nLAKE MICHIGAN\nIOWA COUNTIES\nIN ILLINOIS ZONE\nCARROLL\nOGLE\n2\nCOOK\nKANE\nDE KALB\nCHICAGO\nCLINTON\nDUPACE\nWHITESIDE\nCEDAR\nLEE\nSCOTT\nKENDALL\nPORTER\nLASALLE\nWILL\nLAKE\nMOLINE\nMUSCATINE\nBUREAU\n*\n4\n5\nMarseilles\nGRUNDY\nROCK ISLAND\nHENRY\nMERCER\nPUTMAN\nKANKAKEE\nSTARK\nKNOX\nWARREN\nLIVINGSTON\nIROQUOIS\nINDIANA\nCOUNTY IN\nPEORIA\nWOODFURD\nILLINOIS\nPEORIA\n6\n7\nZONE\nHENDER-\nSON\nFORD\nFULTON\nMcLEAN\nMcDONOUGH\nTAZEWELL\nVERMILION\nHANCOCK\nCHAMPAIGN\nMASON\nLOGAN\nDEWITT\n10\nSCHUYLER\nMENARD\nPLATT\nMACON\nBROWN\nCASS\nSANGAMON\nDOUGLAS\nMORGAN\nSPRINGFIELD\nEDGAR\nMOULTRIE\n9\nSCOTT\nCHRISTIAN\nPIKE\nCOLES\nGREENE\nSHELBY\nCUMBERLAND\nCLARK\nMACOUPIN\nMONTGOMERY\nPAYETTE\nJASPER\nEFFINGHAM\nJERSEY\nCRAWFORD\nBOND\nRICHLAND\nMADISON\nLAWRENCE\nMARION\n12\nCLAY\nILLINOIS COUNTIES IN\n11\nMISSOURI ZONE 12\nCLINTON\nN\nWABASH\nST CLAIR\nWAYNE\nWASHINGTON\nJEFFERSON\nFD\nMONROE\nWARDS\nWeather Service Office\nWeather Service Forecast Office\n*\n* Weather Service Meteorological Office\nCROSS-HATCHING indicates Chicago WSFO Warning Responsibility Area\nFigure 1.1a Map showing delineation of Illinois forecast zones. Counties for\nwhich WSFO Chicago has warning responsibility are cross-hatched.\n5","N\nPECATONICA\nSEWARD\nROCKFORD\nGENOA\nBURLINGTON\nSYCAMORE\nO'HARE\nAIRPORT\nELGIN\nDeKALB\nLISLE\nAURORA\nSUGAR GROVE\nNAPERVILLE.\nOSWEGO\nPLAINFIELD\nNEW\nJOLIET\nLENOX\n~26 n.m.\nMARSEILLES\nMONEE\nWSMO\n*\nMANTENO\nFigure 1.1b Blowup map of northeastern Illinois. Towns referred to in survey\nreport are indicated. Approximate track of the severe thunderstorm is shown.\n6","ONO LAKE\nWAUKEGAN\nHOUR\n1876 to 1990\nNOV 10,1975\nSEP28,1972\nNORTH CHICAGO\nMcHENRY\no\n10\n15\n20 Miles\nLIBERTYVILLE\no\n5\n10\n20\n30 Kilometers\nMUNDELEIN\nCRYSTAL\nMAUCONDA\nLAKE\nLANE FOREST\nLAKE\nBy T. Theodore Fujita\nlast\nSharidan\nCARY\nDepartment of the Geophyiscal Sciences\nLAKE ZURICH\nMALF DAY\nTHE UNIVERSITY OF CHICAGO\nHIGHLAND PARK\nALGONQUIN\nDECAFIELD\nAugust\nBARRINGTON\nMAY 23,1971\nJUL 14,1974\nOLENGOE\nNORTHBROOK\nWHEELING\nCARPENTERSVILLE\nPALATINE\nJUN 9, 1966\nWINNETKA\nMOVEMENT\nALINGTON\nJUN 17, 1975\nHEIGHTS\nWILMETTE\nC\nAPR2,1956\nROLLING\nARR 6, 1912\nMT PROSPECT\nJUN 19,1972\nMORTON\nEVANSTON\nJUL14,1972\nallowed\nGROVE\nJUL 4, 1985\nMPH\nELGIN\nAPR18,1955\nAU673,1156 JUN16,1973 HOFFMAN\nNILES\nSHAKIE\n40\nJUL.17.1975\nSEP26,1959-\nESTATES\nSTREAMWOOD\nPARK RIDGE\nADH 21,19670\nLINCOLNWOOD\nSCHAUMBURG\nDES\nMPH\nELK GROVE\nPLAINES\nVILLAGE\nAPR 21, 1967\n30\nMAY 25, 1996\nROSELLE\nMAY 26,1959\nCHARE\nMPH\nITASCA\nAIRPORT\nAPR 30 1970\nMONTROSE BEACH\n20\nAUR 21,1967\nENSENVILLE\nSEP 21, 1959\nJUN 20,034\nCLOVERDALE\nAUG 25, 1972\nFRANKLIN\n10\nINCOL PARK\nAPH 14, 1955\nADDISON\nMARK\nJUN 23, 1965\nNORTH\nChicago\nCHARLES\nLAKE\nCROSE\nMAY 6,1876\nFAUG23,1956\n26,1969\nPARK\nOAK\nGENEVA\nELMMURST\nPARK\nNOV12,1965\n1967\nGLEN\nJUN18,1975\nVILLA PARK\nMAYWOOD\nDOR\nELLYN\n@MAY'5,1930\nAPR241073-VHEATOM\nCOMBARG\nDU PAGE\nAPR\n1965\nMEIGS FIELD\n980\nBATAVIA\nP30,1961\nCICERO\nKANE\nNational\nSEP 29,19660\nOAK ROOK\nAccelerator\nMAY 29, 1283\nRIVERSIDE\nBROOKFIELD\nMAR 28, 1920\nDOWNERS\nMAY 21,191A\nSLE\nHINSDALE\nORANGE\nDate of Change\n.\nGROVE\nAPH19,1966\nSUMMIT\nMIDWAY AP\nMAY\n27,1954\nNAPERABLE\nMIC M60\nMARA,\nMAY?7,1954\nPAUG 24,1971\nBRIDGEVIEW\nPARK\nAURORA\nALK 1, 1976\nrinn\nHICKORY\nAPR 7. 1925\nMILLS\nCALUMET PARK\nPARK\nOAK LAWN\n1990\nCOOK\nLob.\nAPR4,1978/WORTH\nLote Columbia\nOSWEGE\nJUN 13, 1976\n28,\nAUG 30, 195A\nMOHOLO\nPALOR FK\nBLACK\nLEMONT\nOCT 17, 1991\nMAY 26, 1955\nISLAND\nROME\nEAST\nJON 1884\nMAY 30, 1980\nJUN\nJUN 24,193H\nCHICAGO\nRIVERDALE\nJUN 15,1984\nKENDALL\nJUN 10,1967\nORLAND PM\nDOLTON\n16 1360\nJUN 23,1962\nJUL 9, 1966\nMAY 18,1926\nCOLUMET\nJULP8,973\nCITY\nGARY\nOAK\nFOREST\nAPR 7,1940\nHARVEY\nPt AIN\nAPR 20, 1984\nJUN 9, 1974\nLOCKPORT\nMANHOND\nPORTAGE\nAPR\nJUN2\nAUG 73,1956\nOCT10,1954\nLANSING\nNOV12,1965\nAPREJOIC\nJUN 130.1977\nAPR 6, 1912\nMAR6,1983\nHOMEWOOD\n: MUNSTER HIGHLAND\nMOBART\nAPR 6, 1972\nJUN 70,074\nNOV13,1951\nAUG 26, 1965\nSHIPPITH\n1984\nMAY 15, 1982\nHIN 30,1977\nJOLIET\nCHICAGO\nNEW LENOX\nJUN 30,1977\nFRANKFORT\n1766\nHEIGHTS\nLAKE\nOMAY 15. 1982\nOVER\nWILL\nFOREST\nSEP22,1980\nDEEP RIVER\nMAY 8, 1988\nMAH nos\nAPR 27, 1984\nMAY 26,1965\nNOV 9, 1984\nCRETE\nSEP22,1961\nMANHALIAN\nMONEE\n\"\nCROWN POINT\nMAY\nAPR 27, 1904\n1963\nJIIN 30,1977\nAPR 3, 1987\nDAIRY 1, 1974\nMAY 27,1955\nMORAS\nGRUNDY\nPLOTOW\nJUN 20,1974\nAPH 1948\nWE RINGION\nTORNADOES\nTORNADOES\nBY MONTH\nBY HOUR\n20 TORNADORS\n20\n10\n10\n0\n0\nJAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC\n0\n2\n4\n6\n8\n10 AM\n2\n4\n6\n8\n10 PM\n2\n4 AM CDT\nProduced and updated by Prof. Ted Fujita, The University of Chicago\nFigure 1.2 Chicago area tornadoes that have occurred since 1876. Figure\nprovided to NOAA by Professor T. Fujita, The University of Chicago.\n7","DE KALB\n1-88\nKANE\nWHEATON\nDU PAGE\n5\n1-88\nNAPERVILLE\nAURORA\n4 Spin-up - Vortices\n6\nTracks of four short-lived\nPrecessor tornadoes\nYORKVILLE\nWILL\nKENDALL\n\"R\"\nOver 30 Suction Vortices\nJOLIET\n1-80\n0\n5\n10 miles\nProduced by Prof. Ted Fujita, The University of Chicago\nAerial Photos on AUG 29 and 30 by Dyane Stiegler\nFigure 1.3 Results of Fujita/Stiegler damage survey from DeKalb to Joliet,\nIllinois. Figure provided to NOAA by Professor Fujita.\n8","DAMAGE MAP\n\"A\"\n3\n3\n3\n3\n3 4 F5\n3\n2\n2\n2\nF2\nQSWEGO\no mile\nI\n2\n3\n4\n5\n6\n7\n8\n^\n^\n3:15 pm CDT\n3:25 pm CDT\nDAMAGE MAP\n\"B\"\nPLAINFIELD\n5\n3\n3\n3\n2\n4\n3\n2444\nCREST HILL\n4X3\nJOLIET\n3\n322,23\n22\n12\nI\n9\n10\n11\n12\n13\n14\n15\n16\n16.4 miles\n^\n^\n3:30 pm CDT\n3:40 pm CDT\nFigure 1.4 Detailed blowup of damage path of the major tornado. The Fujita F-scale\ndamage ratings are indicated along the path as are several locations referred to in the\ntext. Approximate times of the tornado occurrence are indicated along the bottom of the\nfigure. Figure provided to NOAA by Professor Fujita.\n9","Figure 1.5a Suction vortex tracks in corn field near Wheatland Subdivision.\nPhotograph provided to NOAA by Professor Fujita.\nFigure 1.5b Intense damage area (F-5) on a farmstead and corn fields just\nnorthwest of Plainfield. Photograph provided to NOAA by Professor Fujita.\n10","Figure 1.5c Damage near the Plainfield High School.\nPhotograph provided by Robert Jacobson, NWS.\n11","Figure 1.5d Damage to the Crest Hill apartment complex. Photograph provided\nto NOAA by Professor Fujita.\n12","CHAPTER 2\nMETEOROLOGY OF THE EVENT\nThe meteorological analyses presented in this section were developed by the DST\nduring a 3- to 4-month period following the on-site survey. The team has drawn\nupon interpretations of the severe weather setting that were provided by the\nNSSFC. It should be noted that the meteorological analyses and interpretations,\nsince they were done after the fact, make use of all available information. Some of\nthe charts and photographs shown in this section were not available to the staff of\nWSFO Chicago prior to the occurrence of the tornado.\nThe large-scale flow pattern over the United States was dominated by a large\n500 millibar (mb) high that extended essentially from southern California\neastward to North Carolina. This ridge had been flattened over the north-central\nand northeastern United States by a series of short-wave troughs that tracked\nfrom western Canada eastward across the Great Lakes. The Nested Grid Model\n(NGM) 24-hour forecast valid at 7:00 p.m., CDT (note that UTC equals CDT, plus\n5 hours over Illinois) on August 28 (see figure 2.1) indicated that another in this\nseries of short-wave troughs would be approaching the Great Lakes Region on the\nafternoon of August 28. The NGM also indicated that a cold front would be\nmoving southeastward across the Great Lakes states in conjunction with the\nshort-wave trough. The short-wave trough and its accompanying strong upper-\nlevel jetstream were forecast to \"dig\" slightly to the southeast, amplifying the\n500 mb pattern. Thus, the large-scale cold front was expected to push south and\neastward, ending several days of fairly stagnant, hot humid weather in the upper\nMidwest.\nThe evening 850 and 500 mb charts (figure 2.2) at the valid time of the forecast\nmaps show that the NGM handled the large-scale pattern evolution quite well.\nThe 850 mb front stretched from Colorado to Michigan and was just moving into\nnorthern Illinois. There did appear to be a double short-wave trough structure\nwith one trough extending from Hudson Bay southward across Indiana; portions of\nthis feature which affected the United States were very weak. A trailing short-\nwave trough appeared to be located over the upper Midwest. Temperatures at\n500 mb had cooled several degrees over the Great Lakes Region, e.g., the\ntemperature at Peoria, Illinois, had decreased from -4 to -7 degrees Centigrade (C)\nduring the preceding 24 hours. The warm mid-level temperatures had acted to\n13","suppress convection, particularly over Iowa and northern Illinois, on the day\npreceding the tornado. Thus, the strengthening of the large-scale cold front as the\n500 mb trough-ridge pattern amplified, coupled with mid-level erosion of the\ncapping inversion, indicated an increasing potential for thunderstorms along and\nahead of the front.\nIn addition to these aspects of the meteorological setting, the thermodynamic\npotential that had developed over the Great Lakes Region for intense storms was\nsubstantial. The morning upper-air sounding at Peoria, Illinois (figure 2.3a) was\nextremely unstable. The lifted parcel, given a reasonable forecast of afternoon\ntemperature and dewpoint, exhibited lifted indices of -8 at 500 mb, -12 at 300 mb,\nand -10 at 200 mb. Further, the projected area of negative buoyancy below the\nlevel of free convection was not great. Thus, the morning upper-air data indicated\na substantial potential for severe thunderstorm activity had developed in the\nGreat Lakes Region (the Flint, Michigan, upper-air data were slightly more\nunstable than Peoria's).\nThe vertical structure of the upper-air winds, however, was not as favorable for\nsevere storms as were the thermodynamics. The low-level flow was from the west-\nsouthwest to west at only 15 to 25 knots (kts), with a layer of weaker winds\npresent from 700 to 400 mb. At upper levels, winds veered to west-northwesterly\nat 70 kts at 200 mb, indicating substantial shear in the upper troposphere.\nA weak shear environment was present in the lower troposphere. The overall\nsetting thus appeared very favorable for the occurrence of multicell\nthunderstorms, with large hail and damaging winds a definite threat.\nThe evening sounding at Peoria (figure 2.3b) was released a bit more than 2 hours\nafter the tornado but still within the unstable air mass that supported the storm.\nIt shows even greater instability than the morning data indicated and that mid-\nlevel winds had increased in speed substantially. The degree of instability\navailable if a storm with a strong gust front lifted air at the surface directly into\nits updraft is extreme. The morning and afternoon wind hodographs (figure 2.4)\nindicate little potential for tornadic storms (particularly for the afternoon\nsounding) because of the straight-line character of the shear profiles. A rapidly\nveering and strong shear profile below about 3 kilometers (km), i.e., one\ncharacterized by positive helicity, is most favorable for supercell storms and\nmesocyclone formation. But, it is the \"storm relative\" hodograph that is\nphysically important, and these hodographs (also figure 2.4) show more tornadic\npotential. These storm-relative data were derived after the fact using the\nobserved storm motion. However, the Plainfield/Crest Hill thunderstorm did move\nconsistently 30 to 40 degrees to the right of the steering level winds (steering level\nwinds were approximately 280 degrees at 35 kts--see text of Severe Thunderstorm\nWatch #691 in appendix A-1.3) for much of its life. This type of systematic right-\nmovement is a well-known characteristic of supercell thunderstorms.\n14","The life cycle of the thunderstorm, from inception through the tornado occurrence\nat Plainfield/Crest Hill, is illustrated in figure 2.5 through satellite imagery. The\nimagery depicts the rapid growth of the storm from 12:46 to 2:46 p.m., CDT. The\nsatellite data, even in this static display mode, indicate that the Illinois storm is\nmoving more slowly and more toward the south than is the strong storm that had\ndeveloped at the south end of Lake Michigan. Infrared satellite images (not\nshown) of the storm consistently displayed a very pronounced \"warm wake\"\nsignature at the storm top, indicative of a very intense and likely severe\nthunderstorm. The primary storm appears to have interacted with several\nconverging lines of cumulus that the satellite imagery indicates were over north-\ncentral Illinois during the early afternoon. A detailed surface analysis for\n2:00 p.m., CDT (figure 2.6--carefully done after the event) shows that the surface\npatterns present over northern Illinois were very complex. This analysis indicates\nthat a trough, or convergence line, along which some of the cumulus clouds were\naligned, did intersect the storm track.\nAnimated presentations of the imagery, of the type only available at NSSFC in\nreal-time, indicate that the divergent outflow at the storm summit may have been\nrotating cyclonically during the period from about 3:00 to 5:00 p.m., CDT, which\nwould be indicative of very intense cyclonic rotation within the storm's updraft.\nPhotographs of individual frames from the PPI film of the WSR-74S Marseilles\nnetwork radar (MMO is located approximately 26 miles southwest of Plainfield--\nrefer to figure 1.1b) are shown in figure 2.7 and careful, after the fact, scope\ntracings of the PPI reflectivity are shown in figure 2.8. These radar data\nillustrate much of the storm's life and several important aspects of its structure.\nAt 1:46 p.m., CDT (figure 2.7b) the low-level PPI (0.5 degrees elevation throughout\nthis sequence except for the 11 degree scan shown in figure 2.8d) display shows a\nvery intense storm that displays a distinct downwind \"v-notch\" and a strong\nreflectivity gradient along the south flank of the cell. These characteristics are\nboth severe storm indicators. During the period from about 1:00 to 2:30 p.m.,\nCDT, the storm displayed supercell structural characteristics, exhibiting a very\npronounced weak echo region (WER) and at times a distinct BWER. This con-\nclusion is based partly upon examination of Collins Doppler radar data that were\nnot available to WSFO Chicago in real-time (obtained from the United Airlines\nMeteorology Group). However, the radar operators at MMO identified the BWER,\nrecognized its significance, and notified WSO Rockford (see chapter 3 and\nappendix B).\nAround 2:45 p.m., CDT (figures 2.7c and 2.8b) overall echo structures were very\ncomplex and more multi-cellular in character than earlier. However, the principal\necho continued to exhibit the \"v-notch\" signature and a strong reflectivity gradient\non the south side. Interpretation of the display and storm structure at this time is\ncomplicated by the presence of additional cells north and west-northwest of the\n15","principal echo. Further, the echoes are moving into the extensive ground-clutter\npattern of the MMO radar. The radar has detected a very pronounced gust front\nmoving out of the main echo and a trailing boundary along which the secondary\ncells are aligned. The rapid movement (i.e., strength) of the gust front is apparent\non the radar PPI film but is not as obvious when viewed in static displays.\nThe low-level PPI scans taken at 3:02 and 3:12 p.m., CDT (figures 2.8c and e) and\nthe elevated scan taken at 3:05 p.m., CDT (figure 2.8d) illustrate some aspects of\nthe vertical structure of the storm during this period. The 11 degree elevation\nscan captures key features of the reflectivity field at an altitude of approximately\n35,000 feet above the ground, indicating that the storm has a pronounced front\nand right-front flank overhang of extremely strong echo. Thus, the storm\ndisplayed a very pronounced WER, again typifying an intense supercell\nthunderstorm.\nThe severe character of the low-level storm structure at 3:12 p.m., CDT (figure\n2.8e) is quite pronounced, with a distinct right flank appendage of high reflectivity\nand a definite inflow notch in the high reflectivity gradient at the leading edge of\nthe storm. This type echo structure is considered indicative of a supercell with\nprobable low-level mesocyclone. These features are closely correlated with the\ntornado track and indicate that the tornado developed to the left (with respect to\nthe storm's movement) of the high reflectivity appendage and within the inflow\nnotch.\nAbout 3:20 p.m., CDT (figures 2.7d and 2.8f) the principal echo had moved away\nfrom the weaker cells to the northwest and continued to display very distinct\nsupercell characteristics. When viewed with respect to the cell motion, a very\nlarge \"inflow notch\" and right flank extension (appendage) of strong echo\nreflectivity are still present. Although a Kavouras monitor display of NWS radar\ndata has slightly degraded horizontal resolution, the storm structures mentioned\nabove were apparent in a Kavouras display of this particular storm at 3:11 p.m.,\nCDT (see figure 2.9).\nMany of these analyses give some indication of the potential value of the\nobservational and display capabilities that will be available following the\nmodernization of NWS operational observation and analysis/display systems. The\nco-analysis and animated display of WSR-88D (the new Doppler radars being\nprocured by the NEXRAD program) radar data with surface observations and\nrapid-sequence satellite data would, in the opinion of the DST, have indicated\nclearly the unusually severe aspects and tornadic potential of this particular\nstorm.\n16","17","10\n12 520\n141\n13 414\n+01\n397\n368\n+4--01\n11-437\n+01\n16 464\n+01\n144\n11 550\n-01\n+01.\n12\n+00\n18\n16 407\n17\n545\n10 448\n150\n147.\n-05\n15\n+00\n19 472\n12 466\nin\n40+01\n431\n17\n464\n0-00\n030\nUI\n18 554\nD\n+03\\\n22\n514\n15\n01+00\n21\n525\n/181\n-01\n156\n16\n18\n19\n20 463\n-01-\n504\n20\n03\n20\n4\n14 498\n20\n-01\n488\n153\n18\n472\n030\n-01\n488\n15\n+00\n-03\n219\n22V\n-02\n19 515\n494\n030\n16\n543\n24 542\n20 506\n0+02\n21_527\n+00\n249m\n519\n+01\n+00\n514\n-01\n20\n10\n6\n24 518\n-04\n29 523\n25\n21\n120-03\n22 521\n29\n530\n280-01\n02.\n27\n537\n24 521\n22 545\n+00\n19 +00\n,25\n9\n129-01\n34\n16_551\n<26\n526\n33\n522\n22\n98+01\n13. -02\n546\n-02\n541\n30 523\n24 553\n-02\n23\n221\n28\n538\n1X0-01\n546\n547\n1-1\n+00\n17\n6\n20\n-01\n-01\n22 557\n34\n24 543\n22 553\n30 1522\n32\n109-01\nx 510\n515\n3\nR\n201549\n030\n-01\n1248\n-01\n24\n+00\n-03\n030\n-03\n158\n22\n22\n23 542\n554\n151\na\n15 5 + 00\n21 1545\n22\n6\n+00\n01\n30\n24 542\n20 553\n534\n27\n20.\n552\n13G -01\n27 530\n01\n19\n54317\n539\n21\n547\n030\n16 -01,\n+00\n+01\n22\n+00\n85 00\n030\n23 528\n00Z29\n18\n550\n11-01\n22\nLFM\n538\n+00\n19\n535\nM\n-01\nROO\n531\n155\n18\n18 530\n+00\n850 MB\n00Z WED 29 AUG 90\nR23\nFigure 2.2a AFOS 850 mb analysis for 0000 UTC on August 29, 1990 (7:00 p.m., CDT,\non August 28). The position of the large-scale frontal zone at 850 mb has been added.\n578\n570\n-10\n0+02\n564\n09\n22\n577\n10 569\n552\n-10++22\n550\n01\n-21°\n+01\n26\n-07\n574\n564\n15\n13 578\n-15\n09\n+06\n05\n16Q+00\n-10\n14\n11 568\n576\n576\n558\n-15\n581\n100 05\n+03\n137578\n14\nWIT\n578\n14\n5.+02\n567\n578\n+00\n5577\nttn\n40-08\n-12 584\n16\n01/13\n01\nIIII\n579\n-0+04\n11\n583-10\n10-578\n+03\nIII\n14 581\n+04 16\n578\n-04\n-13 57\n4-+303\n13\n+00\n-12\n578\nIIII\n580\n05\n583\n582\n8\n7-06\n3\n10\n++00\n-585\n583\"\nIIII\n582\n18\nUT\n583\n-13\n09 589\n586\n586 13+01\n404\n10P+03\n+03\n10\n-01\n12\n+00\nIII-0\n586\nW\n11\n591\nW-07588\n-03\n08+03\n-07 590\nw\n589\n588\n0-06\nIII\n588\n@+03\n01\n160\n01\nIIII\n591\n-06\n594\n-06\n1-06\n06 590\n+04\n11\n-08\nx +00\n-07 589\n-07 594\n11-08\n595\nIII\n594\nrx\n0+04\n0+03\n-06 596\n0+00\n0+01\n01505\n05\n10+03\n593\n19\n06 594\n19\n-04 595\n+00\n06 595\n-041592 -06) 590\nx\n0+00\nXO+03\n+00\n+02\n596\n-06/591\nx\n596\n595\n190\n-03 595\n-04\n+05 595\n+01\n-06 5941\n-04 / 593\n-05 595\nXQ+01\n-061591\nX 01\n+01\n189+01\n+02\n+01\n03\n59.\n-05)\n593\n594\n588\nX-01\n2000\n+00\n593\n04\n593\n06\n-04\n+01\n59\n-07 593\n04 593\nX-+101\n+01\n03\n89+01\n-06\n09\n588\n04\nX-03\n5500\n+03\n-04_592\n594\n+00\n20\n+02\n+01\n+03\n50 00\n00Z29\n06 590\nLFM\n-05\n589\n6\n-08 589\n7011\n4\n-06 590\n4\n+01\nR01\n+01\n-07 589\n07\n588\n4@\nR22\n14\n05\\589\nR23\n-07-LV\n500 MB\n00Z WED 29 AUG 90\nF+02\n13\nR22\nx\n/\nFigure 2.2b AFOS 500 mb analysis for 0000 UTC on August 29, 1990 (7:00 p.m., CDT,\non August 28). Heavy dashed lines indicate the position of two short-wave troughs over\nsouthern Canada and the northern United States.\n18","-60\n-40\n-80\n-100\n100\n360\n-10\n32\n24\n300\n16\n200\n-12\n300\nw\n-10\n400\n8\n11,\n500\n-7\n600\n5\n12 3 20\n2\n.4\n700\n800\n900\n1000\n1050\n20\n0\n-20\n1200Z\n28 AUG 1990\nPIA\nFigure 2.3a Skew T/log P plot of Peoria, Illinois, upper-air sounding for 1200 UTC (5:00 a.m., CDT) on\nAugust 28, 1990. The shaded area shows the positive buoyancy area for a representative afternoon mixed\nlayer parcel; lifted indices at various levels are also shown for this parcel.\n-40\n-60\nIII\n-80\n-100\n100\n360\nSurface\nParcel\n-12\n32\nAL\n24\n300\n16\n200\nAll\nAll\n-14\n300\nAL\n-13\n400\nW\n-10\n500\n-9\n600\n5\n12 420\n.4\n2\n700\nIr\n800\n900\n1000\n1050\n20\no\n-20\n0000Z\n29 AUG 1990\nPIA\nFigure 2.3b Similar chart for Peoria's 0000 UTC sounding on August 29, 1990 (7:00 p.m., CDT, on August\n28). The shaded area shows the positive buoyancy area for the mixed layer parcel along with lifted indices at\na number of levels. The moist adiabat for the surface lifted index is also indicated.\n19","360°\na\nStorm\nRelative\n850\n500\n700\n850\n500\n700\nActual\nWinds\n15\nStorm\nVelocity\n30\n45 kts\n28/1200\n360°\nb\n850\n700\n500 850\n700\n500\n15\nStorm\nVelocity\n30\n45 kts\n29/0000\nFigure 2.4 Hodographs for observed winds in lower half of troposphere at Peoria, Illinois,\nat (a) 1200 UTC (5:00 a.m., CDT) on August 28, 1990 and at (b) 0000 UTC on August 29,\n1990 (7:00 p.m., CDT, on August 28). Wind speeds are indicated in kts, and velocity\nvector of the supercell thunderstorm is indicated. The actual hodographs are shown by\nthe solid line and the storm-relative hodographs by the dashed lines. Winds at 850, 700,\nand 500 mb levels are indicated. Cross-hatched areas are proportional to positive, storm-\nrelative helicity for layer from the surface to 3 km.\n20","","73\n10\n50\n12\n097\n08\n0\n68 103\n50\n130\n093\n73\n06\n78°\n11\n45\n09\n50\n74,\n115\n51\n80\n66\n058\n14\n36\n63\n138\no\n0\n78\n78\n80\n77\n089\n069\n77\n75\n40\n50\n89\n57\n122\n68\n44\ne\noo\n78\n84\n45\n72\n83\n50\n050\n78°\n41\n79\n83 081\n56\n76\n132\n53\n81\n072\n80\nP\n142\n54\n80\n68\n62\n57\n83\noo\n59\n77\n80\n135\n72\n41\n87\ne\n104\n09\n058\n55\n2\nO\n006\n83\n38\n/\n62\n77\n135\n82\n131\n06\n79\n89\nKoo\n84\n091\n077\n82\n78\n85 096\n5\n000\n57\n62\n61\n2\n75\n63\nU 83\n75\n9\n08\n83\n127\n65\n081\n87\n85\n134\n870101 73\n63\n0\n92\n084\n61\n79\n0\n800\n152\n71\n16\noo\n67\n10\n83\n85\n90.116\n72 G 123\n74\n111\n092\n85\n86\no\n59\n83\n77\n75\nb\n912\n69\n85 G 1131\nR\n101\n91\n74\n71/\n103\n00\n89\n76\n76\n88\n12\n86\n123\n107\n11\n78\n90\n00\n86\n83\n70\n122\n77\nG\n92\n69'\n72\n73\n86 122\n89\n95\n75G\n111\n12\n101\n94\n77\n90\n92/\n11\n101\n80\noo\n120\n88\n92\n74\n80\n84\n76\n109\n74\n00\n95 100\n74\n68\n84\n122\n095\n96\n94\n76\na\n89\n131\n112\nG\n749\n680\n74 D\n95\n67\n126 91 134\noo\n700\n680\n10\n98\n98\n94\n114\n95 131\n112\n97\n75\n47\n61\n095\n68\n120\n72\n@\n095\n104\n96\n119\n00\n99\n95 109\no\n95\n710\n99\n69\n66\n97 0 131\n70\n8\n14\n55\n41\n96\n72\n96Q 43\n99\n132\n62\n132\n109\n64\n74\n98\n8\n104\n96 130\n64\nO\n116\n55\n69\n12\n98\n60\n100\n12\n45\n1900Z\nFigure 2.6 AFOS surface data plotted for 1900 UTC (2:00 p.m., CDT) on August\n28, 1990. A subjective analysis of surface features is overlain. Surface pressure is\nin mb.\n22","a\n90-31\nb\nFigure 2.7 Photographs of the Marseilles, Illinois, WSR-74S radar PPI scope at: (a) 1746\nUTC (2:46 p.m., CDT) and (b) 1846 UTC (1:46 p.m., CDT).\n23","C\nd\nFigure 2.7 (cont'd) Photographs of the Marseilles, Illinois, WSR-74S radar PPI scope at:\n(c) 1946 UTC (2:46 p.m., CDT) and (d) 2021 UTC (3:21 p.m., CDT) on August 28, 1990.\n24","2012\n1927\nRFD\nRFD\na\n70\nORD\nORD\nOakalb\nDe Kalb\nCGX\nCCX\nG\nAurora\nMDW\nMDW\nTornado\nTrack\nJOL\nJOL\nMMO\nMMO\n25 mi\n50\n25 mi\n2021\nf\n1948\nb\nRFD\nRFD\n-\n0\nORD\nORD\no\n31h\nDe Kaib\nCGX\nCGX\nAurora\nMDW\nGust Front\nMDW\n-\n$\nJOL\nJOL\nMMO\nMMO\n25 mi\n25 mi\n2034\n2002\ng\nc\nRFD\nRFD\n3\nORD\nORD\nDe Kalb\nDe\nlb\nCCX\nCGX\nuroro\nAdrore\nO\nMDW\nMDW\n@\nJOL\nJOL\nMMO\nMMO\n25 mi\n50)\n25 mi\n50\n2049\nh\n2005\nd\nRFD\nRFD\nORD\nORDER\nDe Kalb\nDe Kalb\nCGX\nCCX\n10\nG\nMOW\nAMDW\nPhoto\nJOL\nJOL\nMMO\nMMO\n25 mi\n50\n25 mi\n50\nFigure 2.8 Tracings of the reflectivity patterns from the MMO PPI scope film for:\n(a) 1927 UTC (2:27 p.m., CDT); (b) 1948 UTC (2:48 p.m., CDT); (c) 2002 UTC (3:02\np.m., CDT); (d) 2005 UTC (3:05 p.m., CDT); (e) 2012 UTC (3:12 p.m., CDT); (f)\n2021 UTC (3:21 p.m., CDT); (g) 2034 UTC (3:34 p.m., CDT); and (h) 2049 UTC\n(3:49 p.m., CDT). Reflectivity contours for VIP levels 2 through 6 are traced. All\npanels are at 0.5 degrees elevation, except for panel \"d.\" Panel \"d\" is for an\nelevation angle of 11 degrees with all VIP levels 1 through 6 contoured.\n25","RF D\nCGX\nSBN\nMMO\nMLI\nL\n:\nPIA\nLAF\nCMI\nFigure 2.9 Kavouras monitor PPI reflectivity from MMO at 2011 UTC\n(3:11 p.m., CDT) as it appeared on a Kavouras remote display at NSSFC,\nwhere the data were digitally recorded. Original color photograph of this\ndisplay was provided to the DST by Professor Fujita.\n26","CHAPTER 3\nWARNINGS AND FORECASTS\nThe potential for severe thunderstorm activity over the Great Lakes region had\nbeen monitored closely by NSSFC during the 2 days preceding August 28. The\nNSSFC Convective Outlook issued at 2:00 a.m., CDT, on August 28 (see figure 3.1)\nindicated a slight risk for severe thunderstorms over a large portion of the\nnortheastern United States, including northern portions of Illinois. The zone\nforecasts for Illinois that were issued at 4:00 a.m. and updated at 10:00 a.m., CDT,\nfocused on the cooling and drying that would follow the passage of the cold front\nand upon the increased chances for thunderstorms accompanying the front during\nthe afternoon and evening. For example, the 4:00 a.m., CDT, WSFO Chicago zone\nforecast had increased the probabilities for thunderstorms and measurable\nprecipitation to 40 percent (while MOS (model output statistics) guidance\ncontinued to indicate 20 percent levels of probability).\nThe NSSFC Convective Outlook was updated at 10:00 a.m., CDT (1500 UTC) to\nindicate a substantially increased severe thunderstorm threat from western New\nYork to northern Illinois, i.e., a \"moderate risk\" for severe thunderstorms. The\ndiscussion accompanying the outlook map (see appendix A and figure 3.1)\nemphasized the extreme instability present in the moderate risk area and noted\nthe weakening of the mid-level cap that would allow easier development of storms.\nAlthough northern Illinois was now in a moderate risk situation, the WSFO\nChicago staff choose not to issue a special \"State Severe Storm Outlook.\" The\ndecision not to issue a \"State Severe Storm Outlook\" after the mid-morning\nNSSFC upgrade to moderate risk for northern Illinois reflected the fact that the\nnew morning zone forecasts had just been released. These zone forecasts,\nhowever, did not mention any risk of severe thunderstorms for northern Illinois.\nBecause of the perceived strong likelihood of widespread severe thunderstorm\nactivity, the NSSFC requested special rapid interval scan operations (RISOP)\nGOES (Geostationary Operational Environmental Satellite) imagery beginning at\n11:30 a.m., CDT. The high-frequency RISOP imagery is not accessible to field\nWSFOs.\n27","Between 12:40 and 1:28 p.m., CDT, the MMO radar indicated rapidly intensifying\nstorms over extreme northern Illinois. The staff at WSO Rockford responded\nquickly, indicating a local sensitivity to the significant nature of the severe storm\nthreat highlighted in the NSSFC morning update. Rockford issued special\nweather statements at 1:12 p.m. and 1:26 p.m., CDT, noting the strong nature of\nthe developing storms. These statements keyed on the immediate possibility of\nheavy rains, small hail, and strong gusty winds, particularly in Boone County and\nthe city of Rockford.\nThe NSSFC issued Severe Thunderstorm Watch #691 at 1:28 p.m., CDT (1828\nUTC) for portions of northern Illinois, southern Lake Michigan, and northwest\nIndiana. The watch was valid from when issued until 8:00 p.m., CDT (0100 UTC)\nand the descriptive text emphasized that extreme instability was present, that a\nstrong upper-tropospheric jet was over the area, and that rapid development of\nsevere thunderstorms was expected in northern Illinois and northwestern Indiana.\nVery shortly after the watch was issued (1:32 p.m., CDT) the MMO radar site\ncalled WSO Rockford to report that the radar indicated a BWER just north of\nRockford. Only 3 minutes later, a funnel cloud occurrence (1:35 p.m., CDT)\nfollowed by a tornado touchdown (1:37 p.m., CDT) just south of Pecatonica (about\n15 miles west of Rockford) were both reported to WSO Rockford by the ISP. In\nresponse, WSO Rockford issued a tornado warning (1:39 p.m., CDT) for southern\nWinnebago, southern Boone, and northern DeKalb Counties. The storm was\nidentified as moving to the southeast. The warning contained specific community\nnames that might be affected and excellent \"call-to-action\" statements. The final\nsentence emphasized that \"This is a serious situation your life may depend on\nhow quickly you respond to this tornado warning!\"\nTwo more reports were received from District 16 State Police Headquarters at\n1:40 and 1:42 p.m., CDT, that a tornado was on the ground at Seward, Winnebago\nCounty. Seward was within the specified tornado warning area. Within minutes,\nthe State Police also reported that there was confirmed damage with this storm.\nBecause there was no post-storm survey, it is not clear whether there were\nactually two separate tornado occurrences west of Rockford. The WSO Rockford\nissued another tornado warning; this time for Ogle County. Excellent call-to-\naction statements were again included; however, the relationship of this new\nwarning to the previous one, which remained in effect, was not made clear.\nInformation provided to the DST by NSSFC indicates that special SELS analyses\nand RISOP imagery led their staff to be concerned that the northern Illinois\nthunderstorm was a right-moving, supercell storm with tornadic potential. Rather\nthan reissuing the severe thunderstorm watch, SELS decided that the local offices\nhad the situation well in hand, i.e., the rapid response of WSO Rockford and the\n28","issuance of the tornado warnings. However, SELS did not discuss the reasons for\nthis decision directly with WSFO Chicago.\nThe WSFO Chicago issued a special weather statement at 2:00 p.m., CDT, providing\nfurther geographic refinements to the area affected by WW#691. This statement\ncarried day, date, and time information in the header but was missing the month\n(AFOS alphanumeric display module--ADM) problems may have contributed to\nheader problems on all of the severe weather statements issued at Chicago during\nthe remainder of the afternoon). The statement described a line of thunderstorms\nmoving into and through northeastern Illinois. The storms were anticipated in the\nmetropolitan Chicago area between 2:00 and 6:00 p.m., CDT. The statement did not\nrefer to any of the warnings or reports that had been issued by WSO Rockford.\nDuring the next hour, WSO Rockford continued to issue multiple severe thunder-\nstorm warnings and statements as the storm moved southeastward (see appendices A\nand B). The WSO continued to receive reports of marble to golf ball-size hail\nand storm damage from Winnebago and DeKalb Counties. At 2:55 p.m., CDT, WSO\nRockford received a report of numerous instances of wind and crop damage from the\nDeKalb County Sheriff that also noted that golf ball-size hail and a funnel cloud\nhad been observed 1-1/2 miles north of DeKalb, moving to the southeast. The\ninformation concerning the funnel cloud sighting was not included on any products\nissued by WSO Rockford and was apparently not relayed to WSFO Chicago.\nThe WSFO Chicago updated the local forecast at 2:17 p.m. and the zone forecasts at\n2:27 p.m., CDT, in response to the watch. These new forecasts highlighted the\npossibility that some thunderstorms might produce large hail and damaging winds.\nAt 2:20 p.m., CDT, Indianapolis issued a special weather statement that included\nsome discussion of the severe storm reports that had been mentioned in the severe\nweather statements issued by WSO Rockford.\nThe Chicago WSFO issued a severe thunderstorm warning at 2:32 p.m., CDT (1932\nUTC) for northern Kane County that would be valid until 3:30 p.m., CDT. The\nwarning included names of specific communities that could be affected by the storm\nalong with the prophetic reminder to \"Remember severe thunderstorms can and\noccasionally do produce a tornado with little or no advance warning... so be on the\nlookout.\" Although no mention was made of the earlier reports of tornadoes with this\nstorm, the fact that it had produced 1-1/2-inch hail as it passed through Rockford was\nhighlighted. The storm was noted as being located 25 miles southeast of Rockford;\nhowever, it was stated that \"This storm is moving to the east at 25 miles an hour.\"\nThe severe thunderstorm was actually moving to the southeast (as had been correctly\nnoted in previously issued WSO Rockford severe weather products and the 2:30 p.m.,\nCDT, MMO radar report) and at about 2:45 p.m., CDT, it moved into southwestern\nKane County. No warnings were issued for this part of Kane County until 3:37 p.m.,\nCDT.\n29","The Marseilles office initiated a call (at 2:34 p.m., CDT) to the Chicago WSFO to\nalert them that the storm near Genoa in DeKalb County was a VIP level 6 and\nhad tops indicated to 55,000 ft. The WSFO then contacted ISP District 2 to solicit\npossible severe weather and damage reports. At 2:50 p.m., CDT, the WSFO\nissued a severe weather statement noting that 1-inch hail had just been reported\nin extreme western Kane County. This statement correctly noted that the storm\nwas moving to the southeast.\nThe 2:50 p.m., CDT, severe weather statement carried a header indicating that it\nwas issued on \"Sat Jun 30 1990.\" All additional severe weather statements issued\nby WSFO Chicago for the storm carried this same erroneous header; however, this\nproblem appears not to have created any confusion as users were likely focusing\non the content of the messages.\nThe Marseilles office initiated another call to the WSFO Chicago lead forecaster\nat 2:54 p.m., CDT (1954 UTC) to alert them that storm tops were 60,000 ft.,\n4-5 miles east of DeKalb, and that the VIP 6 level echo extended upward to\n40,000 ft. At 3:15 p.m., CDT, the WSFO Chicago lead forecaster called MMO to\nask for the exact location of the center of the VIP 6 echo. Staff at WSMO\nMarseilles responded that the storm top was now 65,000 ft., and the VIP 6 was\nlocated near Aurora (see appendix B). There were no further communication\ninterchanges between the staffs at MMO and at WSFO Chicago for the next hour\nand twenty-six minutes.\nThe MIC of the CWSU called WSFO Chicago at 3:20 p.m., CDT (2020 UTC) and\nreported 1-1/4-inch hail at the CWSU in Aurora. He was apparently not aware of\nthe possible wall cloud observed at the airport, nor of the very strong measured\nwind gusts, nor of the fact that the control tower had been abandoned.\nThe WSFO Chicago issued its second severe thunderstorm warning at 3:23 p.m.,\nCDT, for southern Du Page County valid until 4:30 p.m., CDT (2130 UTC). This\nwarning was similar to the first in that it again reminded users that severe\nthunderstorms can produce tornadoes with little warning. The warning\nhighlighted tree damage that had occurred west of Aurora and that the storm had\nproduced 1-1/2-inch hail at Rockford and 3/4-inch hail at Aurora. The warning\nalso noted that the severe thunderstorm was located near Aurora and moving\ntoward the southeast at 25 mph. Naperville and Lisle were identified as towns\nthat should be affected by this storm. This warning was internally inconsistent\nsince these towns are directly east of Aurora. Southern Du Page County is located\nnortheast to east-southeast of Aurora.\nThe WSO Rockford issued a severe weather statement at 3:35 p.m., CDT, noting\nthat all the severe thunderstorm warnings for north-central Illinois had expired\nand were no longer in effect. At this same time, WSFO Chicago was issuing new\n30","warnings for counties in northeastern Illinois and Severe Thunderstorm Watch\n#691 remained in effect. Thus, information that was possibly confusing and\ncontradictory was being broadcast across the general area, e.g., messages from\nboth Chicago and Rockford go to some of the same ISP District Headquarters in\nnorthern Illinois.\nThe WSFO Chicago issued a new severe thunderstorm warning at 3:37 p.m., CDT\n(2037 UTC). This warning (issued 14 minutes after the warning for southern Du\nPage County) was for northeast Kendall, southern Kane, northern Will, and\nsouthern Du Page Counties valid until 4:45 p.m., CDT. Thus, at this time there\nwere two warnings in effect simultaneously for southern Du Page County; there\nwas no clarifying language regarding this situation. This warning stated that\nanother severe storm had developed to the west of Aurora and that it had\nproduced nearly 2-inch hail in Aurora. Communities identified as possibly in the\npath of this storm were Bolingbrook, Lockport, Naperville, Oswego, and Aurora.\nThis warning also carried the reminder that severe thunderstorms occasionally\nproduce tornadoes.\nAt 3:37 p.m., CDT, the tornado was approaching northwest Joliet in Will County.\nThus, the severe weather events and tornadoes over southwest Kane, northeast\nKendall, and much of western Will Counties had occurred in a region not covered\nby any type of warnings. These events were within the severe thunderstorm\nwatch area. The last several minutes of the tornado track and the wind damage\neast of Joliet were covered by the 3:37 p.m., CDT, severe thunderstorm warning.\nAt 3:40 p.m., CDT (2040 UTC) the WSFO issued a severe weather statement\nalerting users that winds had overturned a trailer near Oswego at 3:38 p.m., CDT\n(note that the damage had in reality occurred earlier than indicated by a radio\nstation's report) and that golf ball-size hail had been reported near Joliet at\n3:40 p.m., CDT. Between 3:40 and 3:45 p.m., CDT, the WSFO MIC called the Will\nCounty Sheriff's Office twice seeking severe storm reports. Even though the MIC\nidentified himself as an NWS employee, the sheriff's office responded that they\ndidn't have time to talk to the \"media\" and hung up.\nAt 3:45 p.m., CDT, the ISP reported that a tornado had occurred in the Crest Hill\narea. In response to this confirmation, the WSFO issued a tornado warning for\nwest-central Will County at 3:51 p.m. that was valid until 5:00 p.m., CDT (2200\nUTC). This warning carried excellent call-to-action statements and identified the\ntown of New Lenox as possibly being in the path of the tornado. The tornado had\ndissipated by the time this warning was issued; however, the storm continued to\nproduce substantial wind damage as it moved to the southeast of Joliet.\nA severe weather statement was issued at 3:55 p.m., CDT, emphasizing the\nreported tornado at Crest Hill and identifying east Joliet and New Lenox as being\n31","in the storm path. The radar echo was continuing to move southeastward toward\nIndiana, and at 4:23 p.m., CDT, WSFO Indianapolis issued their first severe\nthunderstorm warning for this storm, specifically for Newton and Jasper Counties.\nAs damage reports continued being received and as the storm continued\nsoutheastward, WSFO Chicago issued a new severe thunderstorm warning at\n4:31 p.m., CDT, for eastern Kankakee County. This warning provided substantial\ninformation about the severe weather history of the storm (2-inch hail, damaging\nwinds, tornado at Crest Hill, and a funnel cloud near Bourbonnais) and alerted\nthe communities of Kankakee, Manteno, Momence, and St. Anne that they were\nlikely to be affected. Also at this time (4:35 p.m., CDT) a severe weather\nstatement canceled the tornado warning for west-central Will County. This severe\nweather statement included the somewhat contradictory sentences: \"The storm\nproducing the tornado has moved to the southeast and is now located over east\nKankakee County. A Severe Thunderstorm Warning is in effect until 5:30 p.m. for\neast Kankakee County.\"\nAt 4:41 p.m., CDT, WSFO Chicago called the MMO radar operator to ask if there\nwas a hook on the VIP 6 storm. The operator replied that there had not appeared\nto be any through the past hour, but he would watch the storm closely. He also\nreported that the storm was located in northeast Kankakee County. However,\n3 minutes later the MMO operator called the WSFO to report a hook echo south of\nBeecher along the Will and Kankakee County line. In response to this, a new\ntornado warning was issued at 4:50 p.m., CDT, for southwest Lake County,\nIndiana, by WSFO Chicago. Although there were no call-to-action statements in\nthis message, it did identify several towns in the path of the storm. At 5:15 p.m.,\nCDT, WSFO Chicago canceled both the severe thunderstorm warning for eastern\nKankakee County and the tornado warning for southwestern Lake County since\nthe storm had moved into Indianapolis' area of responsibility.\nThe WSFO Indianapolis issued a tornado warning for northern Newton County at\n4:51 p.m., CDT, referencing the MMO hook echo observation. All further actions\nregarding this storm occurred within the area of responsibility of WSFO\nIndianapolis.\n3.1 Discussion of Services\nThe NSSFC in Kansas City correctly identified the increasing severe thunder-\nstorm threat that was developing over the Great Lakes Region and noted the\nextreme instability present. The 1500 UTC updated outlook was particularly\naccurate in its identification of the region where the threat had reached moderate\nlevels. During the afternoon of August 28, severe storms affected an area that\nstretched all the way from Illinois eastward to the Atlantic Seaboard. NSSFC\nissued three tornado watches and eleven severe thunderstorm watches during the\n32","day. The center received 255 reports of severe weather events, only 10 of which\nwere reported as tornadoes. Thus, August 28 proved to be an unusually active\nlate summer severe weather day.\nWatch #691 was issued as a \"Severe Thunderstorm\" watch primarily because of\nthe low-level wind shear characteristics of the large-scale environment over\nnorthern Illinois. The thunderstorm situation appeared to favor the occurrence of\ndamaging wind storms and hail rather than tornadoes. When the storm over\nnorthern Illinois was identified as dangerous and potentially tornadic, NSSFC\ndecided not to reissue #691 as a tornado watch. The staff at NSSFC felt that the\nsituation was being handled well locally. The DST feels that this information, if it\nhad been discussed with the severe weather desk forecaster at Chicago, might\nhave affected the decision-making process for the next several critical hours.\nThe storm posed particularly serious problems for WSO Rockford during the early\nafternoon since it developed explosively within Rockford's area of responsibility.\nThe WSO Rockford responded rapidly and very effectively. There appeared to\nhave been useful interaction between the MMO radar site and WSO Rockford,\nparticularly from 12:56 to 1:43 p.m., CDT. However, there was apparently little\ncommunication between the Chicago and Rockford offices. (Note that staffing\nlevels at the Illinois offices followed NWS standard practices, and actual duty\nhours worked on August 28 are shown in appendix G.) The WSFO Chicago AFOS\nAlarm and Alert program was not set to display severe weather products issued by\nits WSOs, and this may have contributed to delayed recognition at the WSFO of\nhow rapidly the severe storm threat was evolving.\nThe storm also posed interpretation problems for the radar operators at Marseilles\nand the forecasters at Chicago since it spent a large portion of its life within the\nextended ground clutter pattern of the radar. The storm was apparently\nexamined carefully in the vertical when it was at long ranges, i.e., the timely\nidentification of the BWER and the interaction with Rockford helping the WSO\nrespond very quickly and appropriately. As the storm approached the Chicago\nwarning area and the ground clutter, the situation became much more complex.\nThe major storm developed rapidly southeastward, while two intense but much\nsmaller cells lagged behind to the north and northwest. However, a number of\nspecial scans and RHIs were taken during this critical period (see appendix B-4).\nThere were several important radar indicators of the dangerous character of the\nprimary storm, discussed earlier in chapter 2, as it moved across portions of Kane\nand Kendall Counties. (Both Chicago and Marseilles have static monitors as well\nas animated RADID displays.) These radar signatures were not identified in real-\ntime at either Marseilles or Chicago. Frame-by-frame review of the MMO film\nindicates that two elevated scans and a number of RHI scans were made before\nand during the principal tornado (again, refer to appendix B-4 for details).\n33","The DST feels that the full capabilities of the WSR-74S radar were not utilized\nduring this critical period, i.e., while the storm was moving through Kane and\nKendall Counties. Although the PPI character of the storm was viewed\noccasionally at elevations above the clutter, systematic scanning of the echo at\nelevations above 0.5 degrees was apparently not done. Similarly, there are no\nclear indications that the weather radar identification of severe thunderstorms\n(WRIST) procedures were employed. The WSFO did not request any special\nscanning of the principal storm cell. These facts may reflect local operating\napproaches to minimize impacts on external, dial-up users of the Marseilles radar\ndata. The physical separation of the radar and its operators from the WSFO\nexacerbates any communication, radar control, and interpretation problems.\nAlthough several calls were made from MMO to WSFO Chicago as the severe\nthunderstorm was moving into its area of responsibility, no further phone calls\nwere initiated to the WSFO during an extended period from 2:54 p.m. until\n4:44 p.m., CDT. The reasons for this lack of communication and interaction\nbetween Marseilles staff and their WSFO are not clear. Nearby surveillance radar\nsites observed the very severe character of the radar echo of the principal storm\n(e.g., Moline, Illinois, and South Bend, Indiana) but also did not communicate\ntheir observations to WSMO Marseilles or WSFO Chicago.\nFinally, the Marseilles WSR-74S radar was fitted with an experimental Doppler\ncapability in 1983. On the afternoon of August 28, the high resolution fast fourier\ntransform processor was inoperative, having been returned to the manufacturer\nfor repairs (note that this processor is virtually a one-of-a-kind unit with no spares\navailable). The lower resolution pulse pair processor was operating; however, even\nthough the major gust front was progressing almost directly toward MMO, no\nvelocities of any significance were detected. In discussing this particular Doppler\nupgrade with NOAA staff involved in its initial installation and evaluation, the\nDST concluded that the pulse pair processor at MMO has probably never\nfunctioned properly. The Doppler capabilities available at MMO on August 28\nwere very crude and operating in a degraded mode; comparisons with the WSR-\n88D radar are inappropriate.\nThe Chicago office, while not having to react to a rapid thunderstorm development\ndirectly in its responsibility area, did have problems in responding to the severe\nweather in a timely fashion. We have already noted that there was a low level of\ncommunication and direct interaction between key NWS offices. There was also\nvery little timely spotter or damage information available to WSFO Chicago as the\nstorm moved through its warning area. These are important aspects of the event,\nand they impacted the decision-making process at WSFO Chicago.\nDuring severe weather episodes, the most senior forecaster, termed the\n\"supervising forecaster,\" on duty is responsible for determining the staffing of\n34","the severe weather desk. This forecaster is also responsible for overseeing and\ncoordinating all warning and forecast activities during the shift. The DST\ninterviews with WSFO Chicago staff indicate that these procedures were not fully\nimplemented on August 28. The supervising forecaster, the DMIC, assumed\nresponsibility for the severe weather desk--with assistance from an aviation\nmeteorologist and the MIC. Because of the presence and direct involvement of\nsenior station management, the forecaster at the public service desk did not\nbecome closely involved in the activities, products, and decision-making processes\noccurring at the severe weather desk. The DST feels that effective coordination\namong all the meteorologists at work at the WSFO did not occur during the\ncritical period from 1:30 to 4:00 p.m., CDT.\nThe first two warnings issued by the WSFO were for areas located to the north\nand east of the actual storm track. A long period of time elapsed between the\nissuance of the warning for northern Kane County and the warning 51 minutes\nlater for southern Du Page County. During this period, the principal thunder-\nstorm echo was moving rapidly through southwestern Kane County, northeastern\nKendall County, and into western Will County (refer to chapter 2). Some of the\nproducts issued, while correctly noting where the storm was located, gave\nincorrect storm movements or highlighted locations threatened that were not\nconsistent with the stated storm movement. There were equipment factors that\nmay have contributed to the apparent confusion concerning where the storm was\nand where it was moving. Several hardware and systems problems had to be\ndealt with by the WSFO staff during the period of intense thunderstorms. These\nare described below.\nThe WSFO had been experiencing database storage problems with AFOS\nand was running \"modify\" to correct them. This procedure requires AFOS\nto operate in data communications module (DCM)-degrade mode. The office\nreturned to dual computer operation prior to issuing the watch redefining\nstatement (i.e., before 2:00 p.m., CDT).\nPrior to 3:00 p.m., CDT, the bell pager on the telephone \"hotline\" to MMO\nwas not functioning. Commercial lines were used for communicating with\nMMO. The bell pager began to function again after 3:00 p.m., CDT.\nAfter issuance of the 3:37 p.m., CDT, severe thunderstorm warning, the\nADM, being used for message composition, became \"flaky\"--primarily\ndropping lines of text in product display and in message-composition\npreformat. During preparation of the 3:51 p.m., CDT, tornado warning\nmessage, the console became unusable, and another ADM was used for\ngeneric warning system (GWARN) preparation.\n35","There are three different radar monitors available in the forecast operations\narea. The Kavouras display was working normally and displayed the low-\nlevel radar echoes accurately. However, the direct monitor display of the\nMarseilles radar PPI scope had a systematic northeastward displacement\n(5 to 7 miles) of the echoes relative to their true location. This is apparently\na software problem that has been present since the equipment was installed\nin 1983. The staff of the WSFO is aware of this problem, and it has been\ndealt with via subjective, visual adjustments. This MMO monitor is the one\nmost accessible to the severe weather desk and, in the midst of the hectic\nactivities of the afternoon of August 28, may have contributed to the\nwarning problems already discussed.\nFinally, the public service desk forecaster stated that the RADID monitor\nwas randomly picking up \"out-of-sequence\" PPIs, making it very difficult to\nfollow the storm's movement.\n36","120\n110\n100\n50\nSLGT\n30\nCNVTV OTLK\nISSUED 28AUG90 0700Z\nVALID 281200 291200Z\nFIKE\n110\n940-CNVTV OTLK DAY1 V12ZTu28AU90\n120\n110\n100\n50\n40\nMDT\nSLGT\n30\non\nCNVTV OTLK\nISSUED 28AUG90 1500Z\nVALID 281500 291200Z\nHALES\n110\n940CNVTV OTLK DAY1 V15ZTu28AU90\n120\nX\n110\n100\nYR NO DA ISSUED VALID EXPIRE RCSTR HFT WLAT MLONG BLAT ELONG T ut CHLD FCSTR\nmiz\n4123\n9032 4136 8611 11 70\n591\n90\n$28\n1228\n1300\n1900\nse\nJud 691 SEVERE TSTM ILSIN LN(2819002 290100Z\nAXIS. .70 STATUTE MILES NORTH AND SOUTH OF LINE\nIL/ 10SE SBN/SOUTH BEND INT\nssu\nFigure 3.1 Map plots of the NSSFC convective outlooks issued at 0700 UTC (2:00 a.m., CDT) in the\nupper panel, issued at 1500 UTC (10:00 a.m., CDT) in middle panel and of the area covered by Severe\nThunderstorm Watch #691 in bottom panel.\n37","CHAPTER 4\nPREPAREDNESS, DISSEMINATION, AND RESPONSE\nThe Chicago WSFO is directly responsible for severe weather warnings, weather\npreparedness, and warning coordination for 13 counties in northeastern Illinois\nand 2 counties in northwestern Indiana. The population of this area exceeds\n7 million, making this one of the largest severe weather responsibilities in the\nNWS. Preparedness efforts at the Chicago office generally are directed at active\nuser and emergency preparedness/disaster response group meetings to foster\nsevere weather awareness and to accomplish training of severe thunderstorm\nspotters.\n4.1 Preparedness--WSFO Chicago\nPrior to 1990, WSFO Chicago local station severe weather drill procedures were\nhandled very informally; a new and more formal drill approach has been initiated\nduring the past year. There was a Spring 1990 severe weather program drill\nconducted at the office during March of 1990. The NWS requires at least an\nannual severe weather program drill at every WSFO. Also, there were June 1990\ndrills on using GWARN and July 1990 drills on GWARN and the Southern Region\nWarning System (SRWARN). There were no August drills. Reviews of the station\nduty manual (SDM) by forecaster staff had not occurred systematically during\neither 1989 or 1990.\nPreparedness activities within the NWS, in general, are designed to focus on three\nprimary activities: hazard awareness, severe weather spotter training, and\nwarning coordination with emergency service agencies and the media. These\nactivities are discussed for WSFO Chicago and northeastern Illinois in the\nfollowing subsections and in section 4.2.\n4.1a Hazard Awareness\nThe NWS has produced a number of slide presentations for use by local offices in\npresentations on the hazards posed by severe thunderstorms, tornadoes, flash\nfloods, winter storms, etc. These presentations are designed for general audiences,\ni.e., civic groups, neighborhood associations, schools, etc. These presentations are\n38","not technical and are given to increase public awareness of weather hazards and\nof protective actions which can be taken to prevent deaths and injuries.\nThe WSFO Chicago assigns these activities to the Port Meteorological Officer\n(PMO) and the WPM focal point forecaster. Because of lack of available time and\nthe higher priority of spotter training and warning coordination activities, many\nNWS offices have essentially handed much of this responsibility over to other\ngroups, e.g., local emergency management officials or local media meteorologists.\n4.1b Severe Weather Spotter Training\nGiven the limited ability of existing NWS technology to detect and monitor the\npresence and intensity of severe weather phenomena, e.g., the inability of existing\nradars to detect directly the existence of a tornado, it is essential that remote-\nsensing observations be supplemented with ground truth observations of trained\npersonnel. Thus, an important preparedness activity for NWS offices is\nconducting severe weather spotter training for a variety of groups.\nThe WSFO Chicago has been very active in conducting such training sessions--\nrefer to appendix D for details. The sessions given have been typically to law\nenforcement, civil defense, and fire departments and to amateur radio groups.\nThese presentations do reflect principally responses to requests for talks. Since\nthe office does not have a staff position dedicated to preparedness activities, it was\nnot able to develop an aggressive and proactive spotter and warning coordination\nprogram. The severe storm spotter network in the Chicago area, the Chicagoland\nSkywarn Association, is coordinated, and essentially maintained, by a single ham\noperators' radio club. Inquiries from potential storm spotters are routinely\nreferred to the radio operators group.\nWhile the DST was visiting WSFO Chicago, several members examined a storm\nspotter notebook maintained at the severe weather desk. They found that some of\nthe numbers listed were no longer in service and that, generally, the spotter\ninformation was not current. It appears that the last substantial update of the\nspotter notebook had been made in 1979. Thus, the entire storm spotter program\nat WSFO Chicago relies heavily upon the efforts of the ham network. This aspect\nof the severe weather program may be reflected by the fact that most of the calls\nregarding severe weather on August 28 were actually initiated by off-duty\nemployees of the NWS.\nHowever, as will be noted in the next section, the training of groups on how to\nrecognize severe weather phenomena is only one component of an effective spotter\nprogram. Equally important is the development of an integrated system to ensure\nthat spotters are activated prior to the onset of severe storms and that reliable\nmeans exist to relay their observations to the NWS. The DST found no evidence\n39","of the existence of such an integrated system in the counties impacted by the\ntornado. In the three counties in which interviews were conducted, no spotters\nhad been activated and no reports of severe weather were relayed to WSFO\nChicago. Despite the fact that 11 severe weather awareness talks and/or spotter\ntraining sessions were held in Kane and Will Counties during 1989 and 1990, an\neffective severe weather spotter system did not result.\n4.1c Warning Coordination and Dissemination\nThe most important preparedness activity of the NWS is warning coordination\nwith local emergency service agencies and the media. Evidence of this importance\nis the fact that in the modernized and restructured Weather Service each office\nwill have a position dedicated to these activities. While the activities discussed in\nthe two preceding sections essentially involve giving prepared presentations and\nfielding related questions, warning coordination requires much more interaction\nand discussion.\nThe purpose of warning coordination activities is to ensure that there is full\nunderstanding between NWS and local officials and media of how severe weather\nevents will be handled. This activity should consist of regular discussions\nconcerning how the NWS forecasts and detects severe weather, what products the\nNWS issues to indicate the potential or occurrence of severe weather, how these\nproducts are disseminated from the NWS, how these products are further\ndisseminated by users who receive them, how local officials and the media should\nuse these products, what types of \"ground truth\" events are important to the\nNWS, how reports of these severe weather events are relayed to the NWS, etc. In\ncontrast to the two previous activities, the DST found no evidence that WSFO\nChicago had engaged in warning coordination activities with officials in the area\nimpacted by the tornado.\nThe ISP plays a pivotal role in the dissemination of severe weather warnings to\ncounty and municipal law enforcement agencies. The ISP is thus in an ideal\nposition to collect and relay severe weather reports from the numerous law\nenforcement agencies in northeastern Illinois. Both ISP district offices visited by\nmembers of the DST indicated that they had never been visited by, nor discussed\nwarning coordination issues with, anyone from WSFO Chicago. Likewise, county\nofficials in Kane, Kendall, and Will Counties stated to the DST that they had not\nhad any direct contact with NWS personnel for the past year or two. These\nofficials did not know what procedures they should use to relay severe weather\nreports to WSFO Chicago. One official did not know how to call WSFO Chicago\nand another indicated that he was not aware of any need to relay such reports on\nto the Chicago WSFO.\n40","4.2 Preparedness--External User Groups\nThe general response given to various members of the DST by external groups was\nthat responses taken after the issuance of severe thunderstorm watches are\nminimal. Local emergency response groups and officials agreed that tornado\nwatches and tornado warnings are the NWS products that are likely to evoke\npreparedness actives. None of the three counties in the Chicago area of\nresponsibility that were seriously affected by the storm (i.e., Kane, Kendall, and\nWill) appear to have organized storm spotter groups. Officials in these counties\ndepend heavily upon information from law enforcement units. Some specific\ndetails of local preparedness activities follow.\nThe ham radio spotter group, \"Chicagoland Skywarn Association,\" activates\nwhenever watches and warnings are issued by the NWS. The group monitors\ndaily weather conditions and sometimes anticipates being needed so that they are\nready to activate immediately. The group has a radio located at the WSFO and\nwill man this station if requested by the WSFO staff. This position was not\nmanned on August 28. The group maintains telephone contact with the WSFO if\nthe radio is not manned. Members of the group appear to be well trained and\nmotivated; however, they are clearly most easily available outside of normal\nworking hours. Although the group has a substantial membership, most members\nlive in Chicago or the near suburbs. Few Chicagoland Skywarn Association\nmembers live in the far western suburbs or in the counties affected by the storm\non August 28.\nKane County relies upon road crews and building inspectors for storm reports\nduring normal working hours and has about 26 volunteer employees for reporting\nat other times. The sheriff's deputies and local police are expected to alert the\ndispatchers if they experience or observe severe weather. The county has no plan\nfor strategically deploying storm spotters. The Chicago WPM focal point\nforecaster spoke to three groups in Kane County during 1990. The annual\nprogram at the Fermilab is the largest severe weather awareness meeting of the\nyear in the Chicago area.\nKane County subscribes to a private meteorological service to obtain weather\ninformation. Through this service, the Emergency Services and Disaster Agency\n(ESDA) director monitors images from the NWS MMO radar. The director also\nmonitors NWR reports and spotter reports and makes telephone calls to WSO\nRockford to keep current on threatening weather conditions. Each municipal\ngovernment within the county appears to act somewhat autonomously with regard\nto severe weather.\nKendall County also has no formal, active storm spotter program; spotter training\ndoes not seem to have a high priority in the county. Several ham operators in the\n41","county occasionally provide storm reports. There is an active spotter group in\nSandwich, Illinois (DeKalb County) and their reports are monitored by the\nKendall County ESDA director. County and local law enforcement officials are\nexpected to be more alert to weather conditions during watches and warnings, but\nthe county has no procedures for positioning units strategically. The ESDA\ndirector is a part-time position; however, the incumbent is a member of the county\nsheriff's department. Most sirens in Kendall County can be sounded either locally\nor by the ESDA director. There were no severe weather awareness interactions\nbetween the NWS and groups in Kendall County during 1990.\nWill County has no organized storm spotter effort and relies upon law enforcement\nagencies, similar to the other two counties. The sounding of sirens is a local\nresponsibility in Will County. Unfortunately, the Will County Sheriff's Office,\nperhaps because of lack of past interactions, confused the NWS with the media\nand refused to talk to the MIC immediately following the tornado.\nAll of the above information indicates an overall lack of coordinated,\ncomprehensive, or integrated county-wide procedures or structures for preparing\nfor or dealing with possible severe weather situations. The emphasis has clearly\nbeen upon emergency and disaster response functions, rather than preparedness,\nin the counties affected by the tornado.\n4.3 Media Dissemination\nThe severe weather watch and warning information messages generated by the\nChicago and Rockford NWS Offices appear to have been well disseminated during\nthe afternoon of August 28. However, representatives from most media outlets in\nthe Chicago area stated that they give less emphasis to severe thunderstorm\nproducts than they do to tornado watches and warnings.\nThose media outlets relying on NWR and NWWS appear to have used them\neffectively (refer to appendices C-2 and C-3). Three of the five 50,000 watt\nChicago radio stations subscribe to the NWWS. Similarly, two Rockford TV\nstations and three Chicago TV stations subscribe to the service. Because of the\ncost of NWWS, it is often not used by smaller media outlets, e.g., none of the radio\nstations in Joliet subscribe. Except for WIFR-TV in Rockford, there were no\ncomplaints about NWWS service on August 28. This station complained that\ninformation flows much too slowly over the Contel system of distribution for\nNWWS.\nThe severe storms of August 28 occurred within the service area of two NWR\nstations operated in northern Illinois by the NWS. The transmitter for the station\nprogrammed by WSO Rockford is located 25 miles southwest of Rockford, near\nOregon, Illinois. The transmitter for the station programmed by WSFO Chicago is\n42","located on the Sears Tower in downtown Chicago. Of all the media outlets\ncontacted, only two Joliet radio stations used NWR as a primary source of severe\nweather information. Several other stations do use NWR as a backup.\nMedia representatives were contacted at nine TV stations (five in Chicago, three\nin Rockford, and one in Joliet). The television stations generally broadcast the\nNWS severe weather watches and warnings promptly. All of the TV stations\nresponded by at least airing crawlers, and some said that they had cut in with live\nreports. Most of the stations felt that they had a good working relationship with\nthe NWS and that NWS personnel were cooperative when contacted for\ninformation and interviews. Additional details are provided in appendix C.\nThe DST contacted nine radio stations. Four of these were in Joliet and the other\nfive were 50,000 watt outlets in Chicago. All stations except for two Joliet outlets\nbroadcast Severe Thunderstorm Watch #691. All stations but one broadcast the\nwarnings that were issued. However, three of the Joliet stations lost power\nshortly after they broadcast the 3:37 p.m., CDT, severe thunderstorm warning; the\nother station in Joliet lost power before this warning could be broadcast. Again,\nsee appendix C for additional details.\n4.4 User Response\nBecause the county ESDAs take little action in response to a severe thunderstorm\nwatch and because there were no severe thunderstorm or tornado warnings issued\nfor the affected counties prior to the tornado, there is little to report regarding\nuser response. Most officials with whom we talked felt that the storm had \"struck\nwithout warning\" and emphasized that their groups would have responded in\nsome way to a tornado watch or warning. The ESDA directors of the three\naffected counties were generally unaware of the critical need for storm information\nto flow from their counties to the NWS. Thus, most of the actual storm reports\nreceived at the WSFO came from off-duty employees or from the ISP.\nPublic education on storm awareness and personal protective actions to be taken if\na tornado occurs appear to have been quite successful. Tornado safety week\nactivities and Plainfield High School's extensive safety drills proved lifesaving in a\nnumber of instances. This is likely the reason for a relatively low death toll from\na large area of very great destruction. Several people saved lives by having family\nmembers and children take refuge in interior bathrooms. A teacher at Plainfield\nHigh instinctively fell into the protective position practiced in the safety drills and\nreceived only cuts and bruises.\n43","APPENDIX A\nCHRONOLOGY OF RELEASES RELATED TO THE\nPLAINFIELD/CREST HILL TORNADO\nThe following are the products issued by several Illinois National Weather Service offices\nand the National Severe Storms Forecast Center on the August 28, 1990. Each release is\nreproduced exactly as it was disseminated. Releases from the Indianapolis WSFO which\ndiscussed the severe weather in Illinois are also reproduced here.\nA-1: Releases of the National Severe Storms Forecast Center\nA-1.1: Convective Outlook\nOF PA/NY EWD ACRS THE SRN\nGRTLKSINTO THE MID MS VLY. SFC\nCHISWODY1:\nDEWPNTS IN THE 70S AND LIFTED\nINDICES BTWN MINUS 8 AND MINUS 10\nACUS1 KMKC 280614\nARE LKLY ACRS THIS RGN. EXPC SVR\nMKC AC 280700\nTSTMS TO DVLP ALG AND AHD OF\nCDFNT FM MI SWWD ACRS SRN WI/NRN\nCONVECTIVE OUTLOOK REF AFOS\nIL/NWRN IND DURG THE AFTN HRS\nNMCGPH94O\nWITH ACTVTY MOVG RAPIDLY ESEWD\nINTO OH/WRN PA/WRN NY UNDER STG\nVALID 281200 - 291200Z\nWNWLY FLOW ALF. ISOLD SVR TSTMS\nMAY DVLP AS FAR W AS ERN IA/NERN\nREF WW 687 TIL 08Z AND WW 688 TIL\nMO HOWEVER EXPC WRM MID LVL\n09Z.\nTEMPS TO LIMIT SVR TSTM POTENTIAL\nFURTHER W ALG CDFNT OVR\nTHERE IS A SLGT RISK OF SVR TSTMS\nMO/IA/SERN NEB/NERN KS.\nMAINLY THIS AFTN AND EVE TO THE\nRGT OF A LN FM ORF 50 S EKN CVG\nMCC CURRENTLY OVR SERN\nBMG 50 S UIN IRK OTM MSN\nMI/ONTARIO/WRN NY XPCD TO SLOLY\nOSC...CONT..A GFL 20 N BOS.\nWKN. OUTFLOW BNDRY LEFT BHND BY\nMCC MAY SERVE TO FOCUS LOW LVL\nGEN TSTMS FCST TO THE RGT OF A LN\nCNVGNC FM NY/PA/WV EWD TO SRN\nFM 40 N 4OM DLS MFR CEC CONT. S\nNEW ENG AND THE MID ATLC STATES.\nIPL IPL SGU 4HV MTJ ALS ROW 80 W\nDIFFLUENT UPR FLOW WL ENHANCE\nMRF CONT. 20 SSE DRT ACT SHV MEI\nUVV ACRS THIS AREA. ISOLD SVR\nMGM SAV CONT HAT TRI CKV SGF\nTSTMS FCST TO DVLP INVOF BNDRYS\nEMP GRI HON MSP MQT 20 NE MQT.\nOVR NY/PA/NRN WV AND MOVE ESEWD\nTWD THE ATLC CST. CIRRUS SHIELD\nUPR LVL FLOW FCST TO BCM WNWLY\nFM MCC MAY LMT DEGREE OF INSTBY\nACRS THE GRTLKS AND THE NRN AND\nACRS NY/SRN NEW ENG HOWEVER\nMID ATLC STATES AS UPR RIDGE\nEXPC SUF INSTBY FOR ISOLD SVR TSTM\nBUILDS WWD INTO THE ROCKIES. STG\nDVLPMT.\nBAND OF MID LVL WINDS FCST ACRS\nTHE LWR GRTLKS WITH 500 MB WINDS\nFIKE.. 08/28/90\nBTWN 40 AND 50 KTS. AMS WL BE\nMOIST AND VRY UNSTBL FM WRN SXNS\nA-1","OF NGT SEWD INTO LWR MO VLY\nMKC AC 281500\nWHERE STG MID LVL COOLING AND\nINCRG MID LVL NWLY FLOW WILL BE\nCONVECTIVE OUTLOOK REF AFOS\nOCCURRING. QUICK LOOK AT NEW LFM\nNMCGPH94O\nHAS VORT MAX DROPPING SEWD THRU\nPLAINS THIS AFTN AND TNGT WHICH\nVALID 281500 - 291200Z\nCOULD RESULT IN MORE ACTIVE SVR\nTHERE IS A MDT RISK OF SVR TSTMS\nTHAN FCSTD THRU PLAINS BUT WILL\nTHIS AFTN AND TNGT OVR PTNS OF\nWAIT FOR NEW NGM BEFORE\nNRN IL SRN MI. NRN IN NRN OH.\nUPGRADING.\nAND W PA. AND WRN NY. THIS\nINCLUDES AREA TO RT OF LN FM ART\nHALES.. 08/28/90\nELM PIT CMH IND SPI BRL MLI RFD 30\nNE MBS.\nCHISWODY1:\nTHERE IS A SLGT RISK OF SVR TSTMS\nACUS1 KMKC 281836\nSURROUNDING THE MDT AREA TO RT\nMKC AC 281900\nOF LN FM BTV POU CXY MGW EVV VIH\nGVW GRI VTN PIR HON ALO GRB PLN.\nCONVECTIVE OUTLOOK REF AFOX\nNMCGPH94O\nGNL TSTMS TO RT OF LN FM HAT TRI\nSGF RSL LBF 4MC BIS STC RHI\nVALID 281900 291200Z\nMQT CONT DRT ACT SHV MGM\nNBC CONT IPL EED CDC 4HV MTJ ALS\nREF WW 689 TIL 00Z. WW 690/691 TIL\n50 W MRF. CONT N 40M YKM RDM\n01Z AND WW 692 TIL 02Z.\nCEC.\nTHERE IS A MDT RISK OF SVR TSTMS\nSIG CHGS UNDERWAY IN LRG SCALE\nTHIS AFTN AND TNGT OVR PTNS OF\nFLOW OVR CNTR/ERN U.S. WITH STG\nNRN/CNTRL IL SRN MI .NRN/CNTRL\nWLYS ACRS TOP OF PLAINS HI TO TURN\nIND NRN/CNTRL OH N AND W PA\nMORE NWLY BRINGING HGT FALLS AND\nMUCH OF NRN MO. SRN HLF IA AND\nMID LVL CD ADVCN WITH IT. THIS\nERN NEB. THIS INCLUDES THE AREA\nWILL MAKE FOR MORE EFFECTIVE\nTO THE RT OF A LN FM 10 N PBG ALB\nRELEASE OF VERY UNSTBL AMS STILL\nAVP AOO ZZV HUF STJ LNK OLU OFK\nPOSITIONED AHD OF WK CD FNT FM\nSUX CID RFD 20 NE MBS.\nNRN MI TO NEB. SNDGS THIS AM HV\nVERY IMPRESSIVE POS AREAS WITH\nTHERE IS A SLGT RISK OF SVR TSTMS\nFNT MOST UNSTBL WITH A MINUS 14 LI.\nSURROUNDING THE MDT AREA TO RT\nWITH LWR LVL FLOW BCMG WLY AND\nOF LN FM 60 NNE MPV HVN NEL HGR\nRATHER WK. FOCUSING OF INITIAL\nEVV VIH TOP BBW 10 SW RAP 10 NW RAP\nDVLPMNT STILL SOMEWHAT IN DOUBT.\nABR 20 N RWF LNR MTW PLN.\nA FAST MVG S/WV TRF IS EVIDENT OVR\nUPR MS VLY AND SHLD PROVIDE SM\nGNL TSTMS TO RT OF LN FM HAT TRI\nUVV IN WEAKLY CNVGNT FNTL ZN. SVR\nSGFRSL LBF 4MC BIS STC RHI\nTSTMS SHLD DVLP DURG AFTN NR AND\nMQT CONT DRT ACT SHV MGM\nAHD OF FNT OVR LWR GRT LAKES AND\nNBC CONT IPL EED CDC 4HV MTJ ALS\nMV RPDLY ESEWD THRU NRN OH VLY\n50 W MRF CONT 40 N 40M YKM RDM\nAND ERN GRT LAKES WITH AN MCC\nCEC.\nLIKELY. OTR DVLPMNT EXPCD IN\nINCRGLY NWLY FLOW OVR PLAINS ALG\nSVR TSTMS HV RPDLY FORMED IN SVRL\nAND N OF FNT WHERE POOLING OF\nAREAS FM WRN SD THRU NRN IL. AMS\nVERY HI DPTS AND UPSLOPE WILL AID\nIS EXTRMLY UNSTBL FM CNTRL IA\nSVR TSTM DVLPMNT. MINUS 8 LI AT\nTHRU LWR MI AS SFC DWPTS RMN IN\nRAP AT 12Z REFELCTS THIS PNTL\nTHE LOW/MID 70S AND MID LVL TEMPS\nINSTBLTY. STMS COULD CONT MUCH\nBGN TO COOL IN RESP TO SHRTWV\nA-2","TROFS DROPPING SEWD INTO THE RGN.\nSELS MESOSCALE DISCUSSION FOR SE\nSVR CELL NR RFD IS RPDLY INCRG IN\nWI/NRN IL/NW IN. CONCERNING.\nSIZE ALG FNTL BNDRY WITH STG\nSEVERE THUNDERSTORM POTENTIAL\nTSTMS ALSO DVLPG OVR NRN IND.\nTSTMS ARE DVLPG RPDLY ALG SFC\nEXPC ORGANIZED BAND OF SVR TSTMS\nCDFNT NR THE IL/WI BDR N/NW OF RFD.\nTO EVENTUALLY DVLP. PSBLY INTO A\nAMS IS XTRMLY UNSTBL AHD FNT AND\nDERECHO. AND CONT MOVG RPDLY\nINCRG MID LVL WIND FIELD WILL\nESEWD ACRS NRN IL/NRN IND AND NRN\nENHANCE VERT SHEAR PROFILE AND\nOH THIS AFTN.\nINCR SVR POTENTIAL. XPC TSTM TO\nCONT INTSFYG AND BECOME SVR DURG\nSHRTWV TROF MOVG ESEWD ACRS\nTHE NEXT HR WITH GREATEST\nGRTLKS THIS AFTN/EVE IS EXPCD TO\nTHREAT ACRS NRN IL/NW IN THRU 21Z.\nENHNC UVV OVR EXTRMLY UNSTBL\nISOLD CELLS MAY REACH SVR LVLS\nAMS OVR MI AND RESULT IN RPD SVR\nALG/SE OF A JVL/MKE LN ALTHO THESE\nTSTM DVLPMT. STRENGTH OF MID LVL\nSTMS WILL MOVE OUT OF WI BTWN\nWIND FIELD AND DEGREE OF INSTBY\n19-1930Z. PRIND WW WILL BE NEEDED\nSUGS ISOLD TORNADOES ARE PSBL OVR\nSHORTLY ACRS NRN IL/NW IN.\nTHIS AREA.\nSAMMLER.. 08/28/90\nANOTHER SHRTWV TROF MOVG RPDLY\nSEWD ACRS THE NRN PLAINS THIS\nA-1.3: Watch\nAFTN IS BEST DEPICTED BY 12HR NGM.\nSVR TSTMS ALREADY DVLPG IN RESP\nNote: NSSFC issued many other\nTO THIS SYS OVR SD WHERE STG\nwatches for the central and eastern\nMID/UPR LVL FLOW IS RPDLY\nUnited States that are not reproduced\nSHEARING TOPS OFF CNVTN. EXPC\nhere. Severe Thunderstorm Watch #691\nTHIS ACTVTY TO CONT SVR AND DVLP\nwas the only watch that affected\nESEWD INTO E-W MOIST AXIS WHICH\nnorthern Illinois during the afternoon of\nEXTDS FM CNTRL NEB THRU CNTRL IA.\nAugust 28, 1990.\nALTHOUGH AMS IS VERY UNSTBL IT IS\nCURRENTLY CAPPED OVR THIS AREA\nBUT PROGS FCST STG COOLING ALOFT\nMKCSEL1\nMOVG INTO THIS RGN WHICH WILL\nALLOW FOR RPD DVLPMT OF SVR\nWWUS9 KMKC 281828\nSTORMS BY EVE.\nMKC WW 281828\nILZ000-INZ000-LMZ000-290100\nRPD TSTM DVLPMT FM LK HURON EWD\nACRS SE ONTARIO IS EXPCD TO CONT\nBULLETIN - IMMEDIATE BROADCAST\nAND RCH SVR LIMITS BEFORE RCHG\nREQUESTED\nNRN LK ERIE LK ONTARIO. AND WRN\nSEVERE THUNDERSTORM WATCH\nNY. AMS HAS RPDLY DSTBLZD OVR\nNUMBER 691\nPA/NY THIS AFTN AND CONDTIONS ARE\nNATIONAL WEATHER SERVICE KANSAS\nNOW FVRBL FOR DVLPMT OF AN MCS\nCITY MO\nOR DERECHO OF MOV ACRS MUCH OF\n128 PM CDT TUE AUG 28 1990\nNY AND PA LT THIS AFTN AND EVE.\n.A.. THE NATIONAL SEVERE STORMS\n..July.. 08/28/90\nFORECAST CENTER HAS ISSUED A\nSEVERE THUNDERSTORM WATCH FOR\nA-1.2: Mesoscale Discussion\nNORTHERN AND PARTS OF\nCENTRAL ILLINOIS\n..JULY.. 08/28/90\nPORTIONS OF NORTHWEST\nINDIANA\n:419,0849 424,0904 404,0905\nAND PARTS OF SOUTHERN LAKE\n400,0854:ACUS3 KMKC 28180\nMICHIGAN\nMKC MCD 281810\nA-3","EFFECTIVE THIS TUESDAY AFTERNOON\nC.. A FEW SVR TSTMS WITH HAIL SFC\nAND EVENING UNTIL 800 PM CDT.\nAND ALF TO 3 IN. EXTRM TURBC AND\nSFC WND GUSTS TO 70 KNOTS. A FEW\nLARGE HAIL DANGEROUS LIGHTNING\nCBS WITH MAX TOPS TO 550. MEAN\nAND DAMAGING THUNDERSTORM\nWIND VECTOR 28035.\nWINDS ARE POSSIBLE IN THESE AREAS.\nD... TSTMS DVLPG RPDLY ALG CD FNT\nREMEMBER A SEVERE\nN/IL BDR. WITH AMS XTRNY UNSTBL\nTHUNDERSTORM WATCH MEANS\nAND STG JET ACRS AREA STMS SHLD\nCONDITIONS ARE FAVORABLE FOR\nBCM RPDLY SVR AS THEY MV/DVLP\nSEVERE THUNDERSTORMS IN AND\nESEWD INTO NRN IL/NWRN IN.\nCLOSE TO THE WATCH AREA. PERSONS\nIN THESE AREA SHOULD BE ON THE\nE....OTR TSTMS.. CONT WW 689 690.\nLOOKOUT FOR THREATENING\nWEATHER CONDITIONS AND LISTEN\nHALES\nFOR LATER STATEMENTS AND\nPOSSIBLE WARNINGS.\n$$\nA-4","A-1.4: Tornado and Severe Thunderstorm Reports\nWWU560 KMKC 291038\nNSSFC TORNADO AND SEVERE THUNDERSTORM REPORTS\nPRELIMINARY LIST-INTERNAL DISSEMINATION ONLY\nFOR 06CST TUE AUG 28 1990 THRU 06CST WED AUG 291990\nREMARKS\n(CST)TIME\nEVENT\nLOCATION\n( )\n28/1240\nNR PECATONICA IL\n(14 WNW RFD)\n*TORN\n2\nTREES DOWN CARS LIFTED OFF GROUND.\nRFD/TOR\n4230 8935\n28/1430\nPLAINFIELD IL\n(29 ENE MMO)\n(WS# 691)\n31\n*TORN\n15 DEAD 350 INJ HIGH SCHOOL AND MANY HOMES DSTDCHI/LSR\n4160 8820\n(30 ENE MMO)\n(WS# 691)\n28/1445\n15\n*TORN\nCREST HILL IL\n11 DEAD APT COMPLEX HIT MANY INJURIES CHI/TOR\n4156 8815\n28/1605\n43 WSW DETROIT MI\n(15 SW ARB)\n(WT# 689)\n67\n*TORN\nDTW/LSR\n4206 8396\nBRIEF TORNDAO TOUCHDOWN.\n(WTN 689)\n28/1610\nDUNDEE MI (19 SSE ARB)\n68\n*TORN\nDTW/LSR\n4195 8365\n28/1045\n13 SW SAULT STE MARIE MI\n(11 SW SSM)\n( )\n9\nA175\nSSM/LSR\n4635 8455\n28/1045\n13 SW SAULT STE MARIE MI\n(11 SW SSM)\n( )\n10\nWNDG\nSSM/LSR\n4635 8455\n28/1055\n12 SSE SAULT STE MARIE MI\n(12 SE SSM)\n( )\n8\nA100\nSSM/LSR\n4631 8421\n(RFD) GTR ROCKFORD ARPT IL\n(WS# 691)\n28/1310\n4\nA250\nALSO GOLFBALL HAIL IN SOUTHEAST ROCKFORD.\nRFD/LSR\n4220 8910\n(WS# 691)\n28/1315\nSRN SOUTH BEND IN\n(4 ESE SBN)\n5\nWBDG\n$SBN/SVS\n4166 8625\nBLDG DMGD POWER LINES DOWN\n(WS# 691)\n28/1318\n5 S SOUTH BEND IN\n(8 SSE SBN)\n53\nWNDG\n1 DEAD 1 INJ HOUSE UNDER CONSTR. COLLAPSED.\nSBN/LSR\n4158 8625\nNAPPANEE IN\n(23 SE SBN)\n(WS# 692)\n28/1340\n7\nWNDG\nSBN/SVR\n4145 8600\nLRG TREES DOWN\n(WS# 692)\n28/1345\nGOSHEN IN (26 ESE SBN)\n55\nG 50\nALSO.; .LARGE TREE DOWN ON HOUSE 8 SE GOSHEN.\nSBN/LSR\n4158 8583\n(WS# 691)\n281350\nNR SYCAMORE IL\n(26 SE RFD)\n6\nA100\nCHI/SVS\n4198 8868\n(WS# 691)\n28/1354\n1 N DEKALB IL\n(24 SE RFD)\n20\nA175\nRFD/LSR\n4195 8875\n28/1400\nAURORA IL\n(33 NE MMO)\n(WS# 691)\n12\nA 75\n$CHI/SVR\n4176 8831\n10 SSW SOUTH BEND IN (12 S SBN)\n(WS# 691)\n28/1407\n56\nWNDG\nSBN/LSR\n4151 8633\nTREES AND POWER LINES DOWN.\n5 5 NAPPANEE IN (28 SE SBN)\n(WS# 692)\n281411\n57\nWNDG\nSBN/LSR\n4136 8600\nTREES AND POWER LINES DOWN.\n(WS# 691)\n28/1420\nDEKALB IL (25 SE RFD)\n11\nWNDG\nRFD/SVS\n4193 8875\nTREES/POWER LINES DOWN\nAURORA IL (33 NE MMO)\n(WS# 691)\n28/1427\n28\nA125\nCHI/LSR\n4176 8831\n(WS# 691)\n28/1427\nAURORA IL (33 NE MMO)\n29\nWNDG\nCHI/LSR\n4176 8831\nLARGE TREE LIMBS DOWN.\n(WS# 691)\n28/1438\nNR OSWEGO IL (27 NE MMO)\n13\nWNDG\nCHI/SVS\n4168 8835\nTRAILER FLIPPED OVR\n(WS# 691)\n28/1440\nSYCAMORE IL (26 SE RFD)\n30\nWNDG\nCHI/LSR\n4198 8868\nTREES DOWN.\n(32 ENE MMO)\n(WS# 691)\n28/1445\nNR JOLIET IL\n14\nA250\nCHI/LSR\n4153 8810\n(WS# 692)\n28/1448\n3 SE GOSBEN IN\n(29 ESE SBN)\n58\nA100\nSBN/LSR\n4155 8578\n(WS# 691)\n28/1527\n5 5 DEMOTTE IN\n(50 NNW LAF)\n19\nA175\nIND/SVS\n4111 8720\n(W54 691)\n28/1530\nAURORA IL\n(33 NE MMO)\n16\nA200\nRPTS OF MANY CARS DMGD\n(WS# 691)\n28/1530\n(33 NE MMO)\n41\nWNDG\nAURORA IL\nAPRXLY 14 AIRCRAFT OVERTURNED OR\nCHI/LSR\n4176 8831\nDMGD HANGARS DSTRYD.\n(WT# 689)\n28/1535\nNR ADRIAN MI (25 NNW TOL)\n18\nA 75\nDTW/SVR\n4190 8403\n(WT# 689)\n28/1545\nLENAWEE CO MI\n(26 NNW TOL)\n66\nWNDG\nLRG TREES UPROOTED AND PWR LNS DWN.\nDTW/LSR\n4190 8406\nA-5","(17 W TOL)\n93\nWNDG\nFULTON CO OH\n(WS# 692)\n28/1605\nTREES DWN.\nCLE/SVS\n4161 8413\n21\nA 88\nJASPER CO IN\n(42 NNW LAF)\n(WS# 691)\n28/1610\nRPTD NR JELLYSTONE PARK NRN JASPER CO.\nIND/SVR\n4101 8710\nMONROE CO MI\n(22 SSW DTW)\n69\nA 75\n(WT# 689)\n28/1615\nDTW/LSR\n4190 8345\n70\nG 52\nMONROE CO MI\n(22 SSW DTW)\n(WT# 689)\n28/1615\nDTW/LSR\n4190 8345\n71\nA 75\nLENAWEE CO MI\n(26 NNW TOL)\n(WT# 689)\n28/1615\nDTW/LSR\n4190 8406\n72\nG 52\nLENAWEE CO MI\n(26 NNW TOL)\n(WT# 689)\n28/1615\nDTW/LSR\n4190 8406\n54\nA150\nBRIDGMAN MI\n(14 SSW BEH)\n(WS# 691)\n28/1623\nSBN/LSR\n4193 8655\n17\nA100\n6 NE COLUMBIA CITY IN\n(20 NNW FWA)\n(WS# 692)\n28/1630\nFWA/SVS\n4123 8538\n23\nWNDG\nMONON IN\n(30 N LAF)\n(WS# 691)\n28/1633\nTREES DOWN.\nIND/SVS\n4086 8686\n74\nA100\nREDFORD MI\n(13 NNE DTW)\n(WT# 689)\n28/1645\nDTW/LSR\n4241 8328\n24\nWNDG\nROYAL CENTER IN\n(38 NE LAF)\n(WS# 691)\n28/1652\nTREES AND POWER LINES DOWN.\nIND/SVS\n4086 8650\n25\nWNDG\nLOGANSPORT IN\n(37 NE LAF)\n(WS# 691)\n28/1652\nIND/SVS\n4075 8635\n26\nA 88\n1 E CAMDEN IN\n(25 ENE LAF)\n(WS# 691)\n28/1703\nIND/SVS\n4061 8651\n73\nWNDG\n25 SW DETROIT MI\n(14 SSW DTW)\n(WT# 689)\n28/1738\nLRG TREES UPROOTED.\nDTW/LSR\n4203 8346\n92\nG 52\nANSONIA OH\n(30 NW DAY)\n(WS# 692)\n28/1820\nDAY/SVR\n4021 8463\n63\nG 83\nDARKE CO OH\n(26 NW DAY)\n(WS# 692)\n28/1830\nCLE/SVS\n4014 8460\n81\nA150\n1 N SUMMITVILLE IN\n(14 WNW MIE)\n(WS# 692)\n28/1900\nND/SVR\n4035 8563\n64\nA 88\nKOKOMO IN\n(41 WNW MIE)\n(WS# 692)\n28/1910\nIND/SVR\n4048 8613\n62\nWNDG\nSPRINGFIELD ARPT OH\n(20 ESE DAY)\n(WS# 698)\n28/1916\nTWO-FOOT TREES SNAPPED IN HALF.\nCLE/SVS\n3983 8383\n61\nA 75\nNR CONNERSVILLE IN (43 SSE MIE)\n(WS# 696)\n28/1947\nIND/SVS\n3964 8513\n40\nA175\nANDERSON IN\n(18 SW MIE)\n(WS# 696)\n28/2012\nIND/SVS\n4010 8568\n33\nA 75\nMIDDLETOWN IN\n(15 SSW MIE)\n(WS# 696)\n28/2013\nIND/SVS\n4005 8553\n34\nWNDG\nMIDDLETOWN IN\n(15 SSW MIE)\n(WS# 696)\n28/2020\nTREES DOWN.\nIND/SVS\n4005 8553\n79\nWNDG\nERN HAMILTON CO IN\n(26 NNE IND)\n(WS# 696)\n28/2037\nNMRS TREES DWN.\nIND/SVR\n4006 8605\n80\nWNDG\nRUSHVILLE IN\n(43 S MIE)\n(WS# 696)\n28/2100\nNMRS TREES DWN. TREE DWN ON POLICE CAR.\nIND/SVS\n3961 8545\n77\nWNDG\nNRN HANCOCK CO IN\n(28 ENE IND)\n(WS# 696)\n28/2128\nTREES DWN.\nIND/SVS\n3981 8576\n78\nWNDG\nSRN FAYETTE CO IN\n(43 SSE MIE)\n(WS# 696)\n28/2133\nSVRL TREES UPROOTED.\nIND/SVS\n3964 8516\n76\nA 75\nNR FISHERS IN (22 NE IND)\n(WS# 696)\n28/2145\nIND/SVS\n3996 8601\n75\nA 75\nSE HENRY CO IN\n(21 5 MIE)\n(WS# 696)\n28/2220\nIND/SVS\n3993 8536\nA-6","A-2: Releases of WSO Rockford\nA-2.1: Warnings and Statements\nOF THE CITY OF ROCKFORD MOVING\nTOWARDS THE EAST AT 30 MPH. THIS\nSTORM WILL BRING BRIEF HEAVY\nNNNNZCZC CHISPSRFD\nRAINFALL ALONG WITH STRONG GUSTY\nETTAA00 KRFD 281812 COR\nWINDS AND SMALL HAIL. THE STORM\nILZ001-002-281900-\nWILL MOVE THROUGH THE\nNORHTERRN PORTIONS OF THE CITY OF\nSPECIAL WEATHER STATEMENT\nROCKFORD INTO BOONE COUNTY BY 2\nNATIONAL WEATHER SERVICE\nPM.\nROCKFORD IL\n105 PM CDT TUE AUG 28 1990\nPERSONS IN OR NEAR NEAR THOSE\nAREAS SHOULD BE ON ALERT RAPIDLY\n..TUNDERSTORMS DEVELOP OVER\nCHANGING CONDITIONS.\nEXTREME NORTHERN ILLINOIS..\nLIBRIZZI\nAT 1 PM A CLUSTER OF STRONG\nATT:ISP...1..16..2\nTHUNDERSTORMS HAVE DEVELOPED\nRAPIDLY OVER EXTREME NORTHERN\nILLINOIS. THE STORMS WERE LOCATED\nNNNNZCZC CHITORRFD\nNORTH OF A LINE FORM ORANGEVILLE\nE:IL,MI:TTAA00 KRFD 281839\nTO DURAND TO ROCKTON NEAR THE\nILC201-007-037-281930\nILLINOIS WISCONSIN BORDERS THEY\nWERE WERE MOVING TO THE EAST\nBULLETIN -- IMMEDIATE BROADCAST\nSOUTHEAST AT 30 MPH.\nREQUESTED/EBS ACTIVATION\nREQUESTED\nBREIF HEAVY RAINFALL STRONG\nTORNADO WARNING\nGUSTY WINDS AND SMALL HAIL CAN BE\nNATIONAL WEATHER SERVICE\nEXPECTED WITH THESE STORMS.\nROCKFORD IL\nPERSONS NEAR THOSE AREAS SHOULD\n139 PM CDT TUE AUG 28 1990\nBE ON ALERRT FOR RAPIDLY\nCHANGING CONDITIONS.\nTHE NATIONAL WEATHER SERVICE HAS\nISSUED A TORNADO WARNING\nLIBRIZZI\nEFFECTIVE UNTIL 230 PM CDT FOR\nATT:ISP 1..16..2\nPEOPLE IN THE FOLLOWING COUNTIES\nIN THE NORTH CENTRAL PART OF\nNNNNZCZC CHISPSRFD\nILLINOIS SOUTHERN WINNEBAGO\nETTAA00 KRFD 281826\nSOUTHERN BOONE NORTHERN\nILZ001-002-281900-\nDEKALB\nSPECIAL WEATHER STATEMENT\nAT 140 CDT THIS AFTERNOON A\nNATIONAL WEATHER SERVICE\nTORNADO WAS REPORTED ON THE\nROCKFORD IL\nGROUND NEAR PECATONICA ILLINOIS\n125 PM CDT TUE AUG 28 1990\nIN WEST WINNEBAGO COUNTY ABOUT\n15 MILES WEST OF ROCKFORD IT WAS\nSTRONG THUNDERSTORM OVER\nMOVING SOUTHEAST.\nEXTREME NORTHERN ILLINOIS.\nSOME COMMUNITIES THAT WILL BE\nAT 120 PM RADAR INDICATED A STRONG\nAFFECTED BY THIS TORNADO...\nTHUNDERSTORM JUST SOUTH OF\nROCKFORD LOVES PARK MACHESNEY\nDURAND ABOUT 20 MILES NORTHWEST\nPARK ...BELLEVIDERE AND DEKALB\nA-7","PERSONS IN THE PATH OF THIS\nFARM MACHINERY AND MOBILE HOMES\nDANGEROUS STORM TAKE COVER\nFOR REINFORCED BUILDING. IF\nIMMEDIATELY IN A BASEMENT OR\nOUT-OF-DOORS GO TO A REINFORCED\nSMALL CENTRAL INTERIOR ROOM ON\nSHELTER OR DITCH... CULVERT OR\nTHE LOWEST FLOOR. ABANDON CARS\nRAVINE. THIS IS A SERIOUS\nFARM MACHINERY AND MOBILE HOMES\nSITUATION. YOUR LIFE MAY DEPEND\nFOR REINFORCED BUILDING. IF\nON HOW QUICKLY YOU RESPOND TO\nOUT-OF-DOORS GO TO A REINFORCED\nTHIS TORNADO WARNING!\nSHELTER OR DITCH. CULVERT OR\nRAVINE. THIS IS A SERIOUS\nATTN: ISP DIST 1..2..16 FIELDS\nSITUATION. YOUR LIFE MAY DEPEND\nON HOW QUICKLY YOU RESPOND TO\nTHIS TORNADO WARNING!\nNNNNZCZC CHISVSRFD\nETTAA00 KRFD 281919\nATTN: ISP DIST 1..2..16\nFIELDS\nILZALL-281945-\nSEVERE WEATHER STATEMENT\nNNNNZCZC CHITORRFD\nNATIONAL WEATHER SERVICE\nETTAA00 KRFD 281902 COR\nROCKFORD IL\nILC141-281930-\n215 PM CDT TUE AUG 28 1990\nBULLETIN -- IMMEDIATE BROADCAST\nA TORNADO WARNING REMAINS IN\nREQUESTED/EBS ACTIVATION\nEFFECT TILL 230 CDT FOR THE\nREQUESTED TORNADO WARNING\nFOLLOWING ILLINOIS COUNTIES\n.CORRECTED FOR TIME\nEASTERN OGLE SOUTHERN BOONE\nNATIONAL WEATHER SERVICE\nAND NORTHERN DEKALB.\nROCKFORD IL\n157 PM CDT TUE AUG 28 1990\n.THE TORNADO WARNING HAS BEEN\nCANCELED FOR WINNEBAGO AND\nTHE NATIONAL WEATHER SERVICE HAS\nWESTERN OGLE COUNTIES AS OF 215\nISSUED A TORNADO WARNING\nCDT THIS AFTERNOON.\nEFFECTIVE UNTIL 230 PM CDT FOR\nPEOPLE IN THE FOLLOWING COUNTY\nAT 215 CDT THIS AFTERNOON A\nPOSSIBLE TORNADO WAS LOCATED\nIN THE NORTH CENTRAL PART OF\nALONG THE NORTHEAST OGLE/\nILLINOIS\nNORTHWEST DEKALB COUNTY LINE\nOGLE\nMOVING TOWARD THE SOUTHEAST.\nTHIS IS ABOUT 15 MILES SOUTHEAST\nAT 158 PM CDT A FUNNEL CLOUD WAS\nOF ROCKFORD ILLINOIS.\nREPORTED HEADED TOWARD BYRON IN\nOGLE COUNTY ILLINOIS ABOUT 15\nBETWEEN 130 AND 215 CDT THIS\nMILES SOUTHWEST OF ROCKFORD\nAFTERNOON NUMEROUS REPORTS OF\nILLINOIS.\nDAMAGE DUE TO A TORNADO WAS\nREPORTED IN WINNEBAGO\nSOME COMMUNITIES THAT WILL BE\nCOUNTY MAINLY WEST OF ROCKFORD\nAFFECTED BY THIS TORNADO.\nIN ADDITION LARGE HAIL IN EXCESS\nBYRON AND OREGON.\nOF ONE INCH IN DIAMETER WAS\nREPORTED THROUGHOUT SOUTHERN\nPERSONS IN THE PATH OF THIS\nWINNEBAGO NORTHERN\nDANGEROUS STORM TAKE COVER\nOGLE ..SOUTHERN BOONE AND\nIMMEDIATELY IN A BASEMENT OR\nNORTHERN DEKALB COUNTY.\nSMALL CENTRAL INTERIOR ROOM ON\nTHE LOWEST FLOOR. ABANDON CARS\nA-8","TORNADO WITH LITTLE OR NO\nPERSONS STILL IN THE WARNED\nADVANCE WARNING SO BE ALERT!\nCOUNTIES SHOULD REMAIN IN\nSHELTER.\nATTN: ISP DIST 1..2..16\nFIELDS\nATTN: ISP 1..2..16\nFIELDS\nNNNNZCZC CHISVSRFD\nETTAA000 KRFD 281946\nE:IL,MI:TTAA00 KRFD 281929\nILZALL-282015-\nILCO37-282000-\nSEVERE WEATHER STATEMENT\nBULLETIN -- IMMEDIATE BROADCAST\nNATIONAL WEATHER SERVICE\nREQUESTED\nROCKFORD IL\nSEVERE THUNDERSTORM WARNING\n245 PM CDT TUE AUG 28 1990\nNATIONAL WEATHER SERVICE\nROCKFORD IL\nA SEVERE THUNDERSTORM WARNING\n229 PM CDT TUE AUG 28 1990\nREMAINS IN EFFECT FOR NORTHERN\nDEKALB COUNTY ILLINOIS TILL 3 CDT\nTHE NATIONAL WEATHER SERVICE HAS\nTHIS AFTERNOON\nISSUED A SEVERE THUNDERSTORM\nWARNING EFFECTIVE UNTIL 300 PM\nAT 245 CDT THIS AFTERNOON A SEVERE\nCDT FOR PEOPLE IN THE FOLLOWING\nTHUNDERSTORM PRODUCING HAIL IN\nCOUNTY\nEXCESS OF ONE INCH IN DIAMETER\nCOVERED ALL OF THE NORTHERN\nIN THE NORTH CENTRAL PART OF\nHALF OF DEKALB COUNTY. THIS\nILLINOIS\nWOULD BE FROM 20 TO 35 MILES\nNORTHERN DEKALB\nSOUTHEAST OF ROCKDFORD ILLINOIS.\nIT WAS MOVING EAST SOUTHEAST AT 25\nTHIS AFTERNOON AT 230 CDT A SEVERE\nTHUNDERSTORM WAS LOCATED IN\nMPH.\nNORTHWEST DEKALB COUNTY NEAR\nELSEWHERE THIS SAME\nKIRKLAND ABOUT 20 MILES\nTHUNDERSTORM COMPLEX EXTENDED\nSOUTHEAST OF ROCKFORD ILLINOIS.\nBACK WEST INTO EXTREME EASTERN\nIT WAS MOVING EAST SOUTHEAST AT 25\nOGLE COUNTY JUST NORTH OF\nMPH AND WAS PRODUCING HAIL IN\nROCKHELLE ILLINOIS. THE STORMS\nEXCESS OF ONE INCH IN DIAMETER.\nLOCATED IN OGLE COUNTY WILL\nPRODUCE SMALLLER HAIL WITH BRIEF\nSOME COMMUNITIES THAT WILL BE\nVERY HEAVY RAINS AND STRONG\nAFFECTED BY THIS SEVERE\nGUSTY WINDS.\nTHUNDERSTORM.. GENOA AND\nDEKALB.\nPERSONS IN DEKALB COUNTY SHOULD\nREMAIN IN SHELTER TILL THESE\nIF YOU ARE IN AN AREA THREATENED\nSTORMS PASS OR LATER STATEMENTS\nBY THE STROM.. GO TO A REINFORCED\nOR POSSIBLY NEW WARNINGS ARE\nSHELTER. SEVERE THUNDERSTORMS\nCAN PRODUCE WINDS OF 60 MPH OR\nISSUED.\nGREATER. LARGE HAIL.. DANGEROUS\nATTN: ISP 1..2..16\nFIELDS\nLIGHTNING AND HEAVY RAIN THAT\nCAN QUICKLY FLOOD A LOW LYING\nAREA.\nNNNNZCZC CHISVRRFD\nE:IL,MI:TTAA00 KRFD 281958\nREMEMBER SEVERE\nTHUNDERSTORMS CAN AND\nILC037-282030-\nOCCASIONALLY DO PRODUCE A\nA-9","BULLETIN - IMMEDIATE BROADCAST\nNNNN>##<A<\nREQUESTED\n<ZCZC CHISVSRFD\nSEVERE THUNDERSTORM WARNING\nETTAA00 KRFD 282002\nNATIONAL WEATHER SERVICE\nILZALL-282045-\nROCKFORD IL\n258 PM CDT TUE AUG 28 190\nSEVERE WEATHER STATEMENT\nNATIONAL WEATHER SERVICE\nTHE NATIONAL WEATHER SERVICE HAS\nROCKFORD IL\nISSUED A SEVERE THUNDERSTORM\n320 PM CDT TUE AUG 28 1990\nWARNING EFFECTIVE UNTIL 330 PM\nCDT FOR PEOPLE IN THE FOLLOWING\nA SEVERE THUNDERSTORM WARNING\nCOUNT\nREMAINS IN EFFECT FOR THE SOUTH\nIN THE NORTH CENTRAL PART OF\nHALF OF DEKALB COUNTY ILLINOIS\nILLINOIS\nTILL 330 CDT THIS AFTERNOON..\nSOUTHERN DEKALB\nA THUNDERSTORM WITH LARGE HAIL\nTHIS AFTERNOON AT 300 CDT A SEVERE\nWAS STILL LOCATED OVER THE\nTHUNDERSTORM PRODUCING HAIL IN\nCENTRAL PORTION OF DEKALB COUNTY\nEXCESS OF ONE INCH IN\nAT 320 CDT THIS AFTERNOON. THE\nDIAMETER WAS LOCATED OVER THE\nSHERIFFS OFFICE IN DEKALB\nCITY OF DEKALB DEKALB COUNTY\nREPORTED POWER LINES AND TREES\nILLINOIS. IT WAS MOVING TO THE\nDOWN AT 315 CDT THIS AFTERNOON.\nSOUTHEAST AT 20 TO 25 MPH. THIS\nTHE STORM WAS MOVING ALMOST DUE\nWARNING IS FROM THE CITY OF\nEAST AT 25 MPH.\nDEKALB ON THROUGH THE SOUTH END\nOF THE COUNTY.\nTHIS MOVEMENT MEANS THE AREA\nMOST LIKELY TO BE EFFECTED BY THE\nSOME COMMUNITIES THAT WILL BE\nSTORM WOULD BE THE EXTREME\nAFFECTED BY THIS SEVERE\nEASTERN PORTIONS OF THE SOUTH\nTHUNDERSTORM DEKALB\nHALF OF DEKALB COUNTY NEAR THE\nHINCKLEY AND SANDWICH.\nKANE AND KENDALL COUNTY LINES.\nIF YOU ARE IN AN AREA THREATENED\nPERSONS IN DEKALB COUNTY\nBY THE STORM GO TO A\nESPECIALLY DEKALB AND HINCKLEY\nREINFORECED SHELTER. SEVERE\nSHOULD REMAIN IN SHELTER TILL\nTHUNDERSTORMS CAN PRODUCE\nTHIS STORM PASSES ON EAST OF THE\nWINDS OF 60 MPH OR GREATER..\nCOUNTY.\nLARGE HAIL DANGEROUS LIGHTNING\nAND HEAVY RAIN THAT CAN QUICKLY\nATTN: ISP 1..2..16\nFIELDS\nFLOOD A LOW LYING AREA.\nREMEMBER SEVERE\nNNNN>A##<A<\nTHUNDERSTORMS CAN AND\n<ZCZC CHISVSRFD\nOCCASIONALLY DO PRODUCE A\nETTAA00 KRFD 282038\nTORNADO WITH LITTLE OR NO\nILZALL-282100-\nADVANCE WARNING SO BE ALERT!\nSEVERE WEATHER STATEMENT\nNATIONAL WEATHER SERVICE\nATTN: ISP 1..2..16\nFIELDS\nROCKFORD IL\n335 PM CDT TUE AUG 28 1990\nA-10","ALL SEVERE THUNDERSTORM\nNNNN>##<A<\nWARNINGS HAVE EXPIRED IN NORTH\n<ZCZC CHISPSRFD\nETTAA00 KRFD 290138 COR\nCENTRAL ILLINOIS THIS AFTERNOON\nILZ001-002-290200-\nAT 335 CDT\nSPECIAL WEATHER STATEMENT\nRADAR AT 335 CDT THIS AFTERNOON\nWAS SHOWING ALL SEVERE STORM\nCORRECTED\nNATIONAL WEATHER SERVICE\nACTIVITY EAST OF THE NORTH\nCENTRAL PORTIONS OF ILLINOIS. AS A\nROCKFORD IL\n830 CDT TUE AUG 28 1990\nRESULT ALL WARNINGS HAVE EITHER\nBEEN CANCELED OR EXPIRED.\nSEVERE THUNDERSTORM WATCH FOR\nNORTHERN ILLINOIS CANCELLED.\nTHE STORMS OVER NORTHEAST\nILLINOIS WERE STILL MOVING TO THE\nTHE SEVERE THUNDERSTORM WATCH\nSOUTHEAST AT 25 MPH AWAY FROM\nFOR NORTHERN ILLINOIS WAS\nNORTH CENTRAL ILLINOIS.\nCANCELLED THIS EVENING.\nTHUNDERSTORMS HAD MOVED INTO\nHOWEVER A SEVERE THUNDERSTORM\nWATCH WILL REMAIN IN EFFECT TILL 8\nCENTRAL ILLINOIS.\nCDT THIS EVENING FOR ALL OF\nTHE STORMS WERE IN ADVANCE OF A\nNORTHERN ILLINOIS. THIS IS DUE TO A\nSOUTHWARD MOVING COLD FRONT\nCOLD FRONT STILL LOCATED THROUGH\nWHICH HAD MOVED THROUGH THE\nSOUTHERN WISCONSIN. THIS FRONT\nSTATELINE AREA AT 700 PM CDT.\nMAY VERY WELL PRODUCE ADDITIONAL\nSEVERE THUNDERSTORMS LATER THIS\nPETROVICH\nEVENING.\nREPEATING.. ALL SEVERE\nTHUNDERSTORM WARNINGS FOR\nNORTH CENTRAL ILLINOIS HAVE\nEITHER EXPIRED OR BEEN CANCELED.\nATTN: ISP 1..2..16\nFIELDS\nA-11","A-2.2: Storm Report\n<ZCZC CHILSRRFD\nETTAA00 KRFD 282155\nSTORM REPORT DATA FROM WW 691\nNATIONAL WEATHER SERVICE ROCKFORD IL\n455 PM CDT TUE AUG 28 1990\nTIME CDT\nEVENT\nFUNNEL CLOUD REPORTED BY THE ILLINOIS STATE POLICE AT THE\n135 PM CDT\nSTATE POLICE HEADQUARTERS SOUTH OF PECATONICA ILLINOIS.\n(15 W RFD) WINNEBAGO COUNTY\nTORNADO ON THE GROUND NEAR STATE POLICE HEADQUARTERS.\n142 PM\nMOVEMENT TO THE SOUTH. (15 W RFD) ALSO TORNADO REPORTED\nAT SEWARD. WINNEBAGO CO. (15 W RFD)\n145 PM\nSTATE POLICE REPORTED CARS RAISED OFF THE GROUND.. TREES\nDOWN AND CEMETARY STONES LIFTED OFF THE GROUND NEAR\nPOLICE HEADQUARTERS. (15 W RFD) WINNEBAGO COUNTY.\n205 PM\nFUNNEL CLOUD REPORTEED BY STATE POLICE IN WEST ROCKFORD\nILLINOIS AT MONTAGUE ROAD. WINNEBAGO COUNTY.\n208 PM\nGOLF BALL SIZE HAIL IN SOUTHEAST ROCKFORD ILLINOIS ON SANDY\nHOLLOW ROAD. WINNEBAGO COUNTY.\n210 PM\n21/2 INCH IN DIAMETER HAIL ON THE EASTERN PART OF THE\nGREATER ROCKFORD AIRPORT. REPORTED BY AIRPORT EMPLOYEES.\nWINNEBAGO COUNTY.\n230 PM\nMARBLE SIZE HAIL IN NORTHWEST DEKALB COUNTY. REPORTED BY\nDEKALB COUNTY SHERIFF. (15 SE RFD)\n254 PM\nJUST NORTH OF THE CITY OF DEKALB ILLINOIS IN DEKALB COUNTY.\nGOLF BALL SIZE HAIL. TREE DAMAGE AND CROP DAMAGE. SAME\nDAMAGE AT 11/2 MILES NORTH OF DEKALB. REPORTED BY DEKALB\nCOUNTY SHERIFF. (25 SE RFD)\n308 PM\n3/4 INCH IN DIAMETER HAIL REPORTED AT NORTHERN ILLINOIS\nUNIVERSITY IN DEKALB. REPORTED BY RADIO STATION. DEKALB\nCOUNTY. (25 SE RFD)\nHELGERSON/FIELDS/LIBRIZZI\nA-12","A-3: Releases of WSMO Marseilles\nCHIRNSMMO:\nA-3.1: Radar Summary\nTTAA00 KMMO 282037\nCHIRNSMMO:\nRADAR SUMMARY\nTTAA00 KMMO 281940\nNATIONAL WEATHER SERVICE\nMARSEILLES IL\nRADAR SUMMARY\n330 PM CDT TUE AUG 28 1990\nNATIONAL WEATHER SERVICE\nMARSEILLES IL\nA SERVERE THUNDERSTORM WATCH\n230 CDT TUE AUG 28 1990\nIS IN EFFECT FOR NORTHERN AND\nPARTS OF CENTRAL ILLINOIS.\nA SERVERE THUNDERSTORM WATCH\nPORTIONS OF NORTHWEST INDIANA\nIS IN EFFECT FOR NORTHERN AND\nAND PARTS OF SOUTHERN LAKE\nPARTS OF CENTRAL ILLINOIS.\nMICHIGAN THIS TUESDAY AFTERNOON\nPORTIONS OF NORTHWEST INDIANA\nAND EVENING UNTIL 800 PM CDT...\nAND PARTS OF SOUTHERN LAKE\nMICHIGAN THIS TUESDAY AFTERNOON\nAT 330 PM CDT AN AREA OF\nAND EVENING UNTIL 800 PM CDT...\nNUMEROUS THUNDERSTORMS SOME\nSEVERE WAS DETECTED OVER NORTH\nAT 230 PM CDT. A SEVERE\nCENTRAL AND NORTHEAST ILLINOIS..\nTHUNDER-STORM WAS DETECTED OVER\nSOUTH OF A LINE FROM 10 MILES WEST\nNORTH CENTRAL ILLINOIS 18 MILES\nOF DEKALB TO OHARE AND EAST OF\nEAST SOUTHEAST OF ROCKFORD\nA LINE FROM 10 MILES WEST OF\nDEKALB TO 20 MILES NORTHEAST OF\nMOVEMENT WAS SOUTHEAST AT 25\nMARSEILLES.\nMILES AN HOUR.\nTHE STRONGEST STORMS WERE\nTHIS STORM WAS PART OF A 20 MILE\nLOCATED NEAR YORKVILLE.\nWIDE BAND OF NUMEROUS\nTHUNDER-STORMS. MANY WITH HEAVY\nMOVEMENT WAS SOUTHEAST AT 40\nRAIN AND HAIL THAT WAS OCCURRING\nMILES AN HOUR.\nACROSS NORTH CENTRAL AND\nNORTHEAST ILLINOIS ALSO THE\nALSO THUNDERSTORMS WERE\nEXTREME SOUTH-EAST CORNER OF\nSCATTERED OVER PARTS OF SOUTHERN\nWISCONSIN.. CENTERED ALONG A LINE\nLAKE MICHIGAN 25 TO 35 MILES EAST\nFROM 15 MILES WEST OF ROCKFORD\nOF RACINE.\nTO WOODSTOCK. TO KENOSHA.\nMOVEMENT WAS SOUTHEAST AT 35\nMOVEMENT WAS SOUTHEAST AT 30\nMILES AN HOUR.\nMILES AN HOUR.\nISOLATED THUNDERSTORMS HAD\nELSEWHERE AN AREA OF NUMEROUS\nDEVELOPED OVER CENTRAL\nTHUNDERSTORMS A FEW WITH VERY\nILLINOIS BETWEEN BLOOMINGTON\nHEAVY RAIN WAS LOCATED OVER\nAND 40 MILES EAST OF BLOOMINGTON.\nNORH CENTRAL INDIANA IN THE\nSOUTH BEND AREA.\nMOVEMENT WAS SOUTHEAST AT 35\nMILES AN HOUR.\nMOVEMENT WAS SOUTHEAST AT\nBAALKE\n30MILES AN HOUR.\nBAALKE\nA-13","CHIRNSMMO:\nRAIN WERE DETECTED OVER\nTTAA00 KMMO 282140\nNORTHEAST AND EAST CENTRAL\nILLINOIS NORTHWEST AND NORTH\nRADAR SUMMARY\nCENTRAL INDIANA SOUTH LAKE\nNATIONAL WEATHER SERVICE\nMICHIGAN AND SOUTHWEST LOWER\nMARSEILLES IL\nMICHIGAN EAST OF A LINE FROM 10\n430 PM CDT TUE AUG 28 1990\nMILES WEST OF OHARE AIRPORT TO 10\nMILES EAST OF MARSEILLES TO 25\nA SERVERE THUNDERSTORM WATCH\nMILES SOUTHWEST OF KANKAKEE.\nIS IN EFFECT FOR NORTHERN AND\nPARTS OF CENTRAL ILLINOIS\nTHE STRONGEST STORMS WERE\nPORTIONS OF NORTHWEST INDIANA\nLOCATED 35 MILES NORTH OF\nAND PARTS OF SOUTHERN LAKE\nLAFAYETTE.\nMICHIGAN THIS TUESDAY AFTERNOON\nAND EVENING UNTIL 800 PM CDT.\nMOVEMENT WAS SOUTHEAST AT 40\nMILES AN HOUR.\nAT 430 CDT AN AREA OF NUMEROUS\nJENSEN\nTHUNDERSTORMS SOME SEVERE WAS\nDETECTED OVER NORTHEAST AND\nEAST CENTRAL ILLINOIS EXTREME\nCHIRNSMMO:\nNORTHWEST INDIANA AND SOUTH\nTTAA00 KMMO 282339\nLAKE MICHIGAN EAST OF A LINE\nFROM NEAR DUPAGE AIRPORT NEAR\nRADAR SUMMARY\nAURORA 30 MILES WEST OF\nNATIONAL WEATHER SERVICE\nKANKAKEE TO 20 MILES NORTH OF\nMARSEILLES IL\nDANVILLE.\n630 PM CDT TUE AUG 28 1990\nTHE STRONGEST STORMS WERE\nA SEVERE THUNDERSTORM WATCH IS\nLOCATED 10 MILES SOUTHWEST OF\nIN EFFECT FOR NORTHERN AND PARTS\nCHICAGO HEIGHTS.\nOF CENTRAL ILLINOIS PORTIONS OF\nNORTHWEST INDIANA AND PARTS OF\nMOVEMENT WAS SOUTHEAST AT 40\nSOUTHERN LAKE MICHIGAN THIS\nMILES AN HOUR.\nTUESDAY AFTERNOON AND EVENING\nJENSEN\nUNTIL 800 PM CDT.\nAT 630 PM CDT SCATTERED\nCHIRNSMMO:\nTHUNDERSTORMS WITH VERY HEAVY\nTTAA00 KMMO 282236\nRAIN WERE DETECTED OVER\nNORTHEAST ILLINOIS.\nRADAR SUMMARY\nNORTHWEST NORTH CENTRAL AND\nNATIONAL WEATHER SERVICE\nWEST CENTRAL INDIANA SOUTH LAKE\nMARSEILLES IL\nMICHIGAN AND SOU; WEST LOWER\n530 PM CDT TUE AUG 28 1990\nMICHIGAN EAST OF A LINE FROM\nNEAR MIDWAY AIRPORT TO 20 MILES\nA SEVERE THUNDERSTORM WATCH IS\nSOUTHWEST OF LAFAYETTE.\nIN EFFECT FOR NORTHERN AND PARTS\nOF CENTRAL ILLINOIS PORTIONS OF\nALSO AN ISOLATED THUNDERSTORM\nNORTHWEST INDIANA AND PARTS OF\nWITH VERY HEAVY RAIN WAS\nSOUTHERN LAKE MICHIGAN THIS\nDETECTED OVER NORTH CENTRAL\nTUESDAY AFTERNOON AND EVENING\nILLINOIS. 15 MILES SOUTHWEST OF\nUNTIL 800 PM CDT.\nMARSEILLES.\nAT 530 PM CDT SCATTERED\nTHUNDERSTORMS WITH VERY HEAVY\nA-14","A-3.2: Radar Coded Message\nMOVEMENT WAS SOUTHEAST AT 30\nMILES AN HOUR.\nJENSEN\nCHIROBMMO:\nTTAA00 KMMO 280427\nIMMO 0425 AREA 5TRWU 43/200 60/250\nCHIRNSMMO:\n20W AO110 C3225\nTTAA00 KMMO 290038\n^EQ9988=\nRADAR SUMMARY\nNATIONAL WEATHER SERVICE\nCHIROBMMO:\nTTAA00 KMMO 280526\nMARSEILLES IL\nIMMO 0525 CELL TRWU 61/240 D13 C3220\n730 PM CDT TUE AUG 28 1990\n^ET98=\nA SEVERE THUNDERSTORM WATCH IS\nIN EFFECT FOR PORTIONS OF CENTRAL\nCHIROBMMO:\nAND EASTERN ILLINOIS AND PARTS OF\nTTAA00 KMMO 280626\nCENTRAL AND SOUTHERN INDIANA\nIMMO 0625 CELLS TRWU 50/185 D14 54/199\nTHIS TUESDAY NIGHT AND WEDNESDAY\nD6 MOVMT C2920\nMORNING UNTIL 100 AM CDT.\n^FQ999=\nAT 730 PM CDT WIDELY SCATTERED\nCHIROBMMO:\nTHUNDERSTORMS VERY HEAVY\nTTAA00 KMMO 280726\nRAIN WERE DETECTED OVER PARTS OF\nIMMO 0725 PPINE=\nNORTH CENTRAL AND EAST CENTRAL\nILLINOIS NEAR MARSEILLES AND 30\nMILES NORTHEAST OF BLOOMINGTON.\nCHIROBMMO:\nTTAA00 KMMO 280826\nALSO ISOLATED\nIMMO 0825 PPINE=\nTHUNDERSTORMS AND LIGHT RAIN\nSHOWERS., WERE DETECTED OVER\nNORTHWEST AND WEST CENTRAL\nCHIROBMMO:\nTTAA00 KMMO 280927\nINDIANA EAST OF A LINE FROM 10\nIMMO 0925 CELL TRWU/NEW 301/240 D5\nMILES SOUTHWEST OF MICHIGAN\n^JC9=\nCITY TO 20 MILES SOUTH OF\nLAFAYETTE.\nCHIROBMMO\nMOVEMENT WAS SOUTHEAST AT 35\nTTAA00 KMMO 281026\nMILES AN HOUR.\nIMMO 1025 PPINE=\nJENSEN\nCHIROBMMO:\nTTAA00 KMMO 281126\nIMMO 1125 PPINE=\nCHIROBMMO:\nTTAA00 KMMO 281227\nIMMO 1225 PPINE=\nCHIROBMMO:\nTTAA00 KMMO 281326\nIMMO 13255 PPINE=\nA-15","CHIROBMMO:\nCHIROBMMO:\nTTAA00 KMMO 281426\nTTAA00 KMMO 282133\nIMMO 1425 PPINE=\nIMMO 2130 SPL CELL TRWXX/NC 94/40 D9\nC3135 MT 600 PIA TROP 446 TORNADO\nRPRTD 3N JOLIET 282045\nCHIROBMMO:\nAREA 3TRWX/+ 352/65 75/230 93/205 158/70\nTTAA00 KMMO 281526\nC3125 MT 550 AT 59/93 AREA 3TRWX/+\nIMMO 1525 AREA 4RW/NEW 263/125 234/80\n352/65 75/230 93/205 158/70 C3125 MT 550\n30W C2720 MT 250 AT 261/114\nAT 59/93\n^OI222 PJ2=\n^JP5 JU9 KO2115999 LN562 MN333 NP3=\nCHIROBMMO:\nCHIROBMMO:\nTTAA00 KMMO 281626\nTTAA00 KMMO 282144\nIMMO 1625 AREA 4RW/NC 268/100 218/65\nIMMO 2143 SPL HOOK 93/50=\n33W C2725 MT 270 AT 228/57\n^NK2 OK12=\nCHIROBMMO:\nTTAA00 KMMO 282230\nCHIROBMMO:\nIMMO 2228 SPL AREA 4TRWX/NC 11/50\nTTAA00 KMMO 281726\n77/215 100/200 172/35 C3230 MT 570 AT\nIMMO 1725 AREA 1RW/NC 58/170 213/130\n105/84 TOP 470 AT 92/30 PIA TROP 446\n262/150 C2720 MT 260 AT 61/110\n^JP440009 KO3321999 LO5214 MN2435=\n^IQ2 NK2 OI22 PI101 RK2=\nCHIROBMMO:\nCHIROBMMO:\nTTAA00 KMMO 282333\nTTAA00 KMMO 281828\nIMMO 2330 SPL CELL TRWXX/+ 233/15 D11\nIMMO 1825 SPL CELL TRWX/NEW 338/65\nC3225 MT 570 PSBL A VIP 6 TO 300 VIP\nD12 MT 500 PIA TROP 446\n5 TO 400 PIA TROP 446\nAREA 3TRW++/+ 314/140 68/170 215/100\nAREA 3TRWX/NC 52/50 69/130 100/160\nC2820 MT 400 AT 359/68\n136/100 C3230 MT 550 AT 120/119 CVRG\n^JL330012 KI23250003 NL2 OL2 PL2=\nDCRG\n^KO212 LQ109 MM6002009 NQ45=\nCHIROBMMO:\nTTAA00 KMMO 281930\nCHIROBMMO:\nIMMO 1925 SPL CELL TRWXX/+ 349/45 D12\nTTAA00 KMMO 290028\nC3120 MT 520 PIA TROP 446 TORNADO\nIMMO 0025 SPL AREA 1TRWX/NC 351/35\nRPRTD 15 W RFD 281902\n93/210 116/210 189/70 C3230 MT 410 AT\nLN 7TRW++/NEW 33/105 322/55 20W C3125\n173/30 PIA TROP 483 PTLY TRWU\nMT 450 AT 31/94\n^KQ1 MM35 MS999 NN4 NS89 OP1=\nAREA 2TRW++/NC 32/120 92/200 202/90\n294/145 C2925 MT 500 AT 84/113\n^IN42 IT9 JM34000309 KK16300034 LH1\nCHIROBMMO:\nNN2 PM1=\nTTAA00 KMMO 290131\nIMMO 0129 SPL AREA 2TRW+/- 295/90\n100/190 133/210 260/115 C3125 MT 460 AT\nCHIROBMMO:\n268/71 PIA TROP 483 APRNT TRWX AT\nTTAA00 KMMO 282028\n114/135\nIMMO 2025 SPL CELL TRWXX/NC 27/29 D8\n^MM302012899 NJ33 NT9 OT99 PR9=\nC3135 MT 650 AT 27/29 PIA TROP 446\nAREA 3TRW+/- 53/190 89/210 196/95 335/60\nC3030 MT 430 AT 45/90\n^IO21 JS999 KM52000199 LM46 LS9 NO1\nON21=\nA-16","CHIROBMMO:\nCHIROBMMO:\nTTAA00 KMMO 290434\nTTAA00 KMMO 290235\nIMMO 0429 SPL AREA 6TRWX/NEW 272/160\nIMMO 0230 SPL CELL TRWX/NC 250/50 D13\n275/70 28W C2925 MT 580 AT 272/114 PIA\nC3125 MT 540 PIA TROP 483 VIP 5 TO 260\nTROP 483 VIP 5 TO 300\nAREA 1TRW+/NC 309/140 100/200 130/220\nAREA 2TRW+/NC 309/160 42/110 122/220\n265/100 C3125 MT 380 AT 119/109 APRNT\n169/120 C2925 MT 340 AT 38/56\nTRWX AT 120/145\nMOST TOPS BLO 270 TRWU SE PTN\n^KH102 LS9 MT99 NK45 NR398 OV9=\n^JI1220212 KJ23123 MK1 NG9354 NT99 002\nOU9=\nCHIROBMMO:\nTTAA00 KMMO 290334\nIMMO 0330 AREA 4THRW+/NEW 304/120\n36/70 63W C2930 MT 390 AT 345/57 CELL\nTRW+/- 221/58 D18 C3125 MT 310\nAREA 2TRWU 112/130 125/205 60W C3230\n^JL12 KI2323 NS999 OL3 OT999=\nA-17","A-4: Releases of WSFO Chicago\nA-4.1: State Forecast Discussions\nFNT. CANT SAY FOR SURE HOW FAST\nCDFNT WILL MOV ACRS ST BUT TMP\nFCSTS HV GRDL COOLNG OVR NXT TWO\nTTAA00 KCH1 280918\nDAYS AS A 2NDRY FNT MOVS INTO THE\nST.\nAPRCHG CDFNT PROGGD TO ABT A\nCHI/BRL LINE BY 00Z, THEN CONTD\n.IL...NONE\nSLOLY SEWRD TO SRN TIP OF STA WED\nAFTN. SIGNIFICANTLY COOLER AND\nWILLIAMS\nDRIER AIR SEVERAL HRS BHND FNT,\nHWVR.\nA-4.2: Zone Forecasts\nUPR WV AND PVA ALSO LAG 6-12 HRS\nBHND FNT, WHICH SGGSTS DVLPMNT\nOF SECONDARY CDFNT AND/OR POST\nTTAA00 KCHI 280912\nFNTL TSTMS. WIL THRFR RETAIN TSTM\nILLINOIS ZONE FORECASTS\nTHREAT AFT FROPA AT ANY GIVEN\nNATIONAL WEATHER SERVICE CHICAGO\nPOINT.\nIL\nILZ003-281500-\nHV RAISED TDA/S XPCTD MAX TEMPS A\nILLINOIS ZONE 3\nLTL ABV GUIDANCE IN LITE OF YTDA/S\n4 00 AM CDT TUE AUG 28 1990\nUPSTREAM HIGHS.\n.TODAY. PARTLY SUNNY HOT AND\nHUMID. A 40 PERCENT CHANCE OF\n.IL NONE\nTHUNDERSTORMS BY EVENING. HIGH\nIN THE LOWER OR MIDDLE 90S.\nKOENEMAN\nSOUTHWEST WINDS 10 TO 20 MPH\nBECOMING NORTHWEST TOWARD\nEVENING.\nTTAA00 KCH1 281440\n.TONIGHT. A 40 PERCENT CHANCE OF\nXTRAPLTN PUTS CD FNT CHI-MLI LN\nEVENING THUNDERSTORMS. THEN\nJUST BFR 00Z. FNT CONTINUES SWD\nPARTLY CLOUDY TURNING COOLER\nTHRU EVENING. WND SHFTS WIT FNT\nAND LESS HUMID. LOW IN THE MIDDLE\nBUT COOLR DRIER AIR ABT 6-8 HRS\n60S. NORTHWEST WINDS ABOUT 10\nBHND FNT.\nMPH.\nWEDNESDAY. MOSTLY SUNNY.\nAMS AHD OF FNT VRY JUCY >70 DWPTS\nCOOLER AND LESS HUMID. HIGH IN\nAND UNSTBL WITH CLDR AIR TDA AT H5\nTHE LOWER 04 MIDDLE 80S.\nAND K INDX INTO 30S. SUM SHWRS HV\n$$\nBRKN OUT OVR W CTNRL IL THS AM\nKOENEMAN\nAND ON SWIS SHOW TO BE PART OF A\nBRDR PCPN AREA XTNDG WWD INTO\nCNTR IA.\nTTAA00 KCHI 281500\nADJSMTS TO ZNS FOR FNT PSN AND RW.\nILLINOIS ZONE FORECASTS\nNATIONAL WEATHER SERVICE CHICAGO\n..NONE\nIL\nILZ003-282100-\nSOMREK\nILLINOIS ZONE 3\n10 00 AM CDT TUE AUG 28 1990\n.THIS AFTERNOON HOT AND HUMID.\nTTAA00 KCH1 282002\nMOSTLY SUNNY WITH A 40 PERCENT\nCHANCE OF THUNDERSTORMS. HIGH\nSCT TSTMS NR AND AHD OF CDFNT.\nIN THE LOWER OR MIDDLE 90S.\nSHD TRICKL DWN THE ST WITH THE\nSOUTHWEST WINDS 10 TO 20 MPH\nA-18","BECOMING NORTHWEST BY LATE\n.THIS EVENING HOT AND HUMID WITH\nAFTERNOON.\nSCATTERED SHOWERS AND\n.TONIGHT A 40 PERCENT CHANCE OF\nTHUNDERSTORMS. SOME\nEVENING THUNDERSTORMS. THEN\nTHUNDERSTORMS MAY PRODUCE\nPARTLY CLOUDY TURNING COOLER\nHEAVY RAINFALL LARGE HAIL AND\nAND LESS HUMID. LOW IN THE MIDDLE\nWIND GUSTS ABOVE 40 MPH. HIGH IN\n60S. NORTHWEST WINDS ABOUT 10\nTHE LOWER OR MIDDLE 90S.\nMPH.\n.TONIGHT PARTLY CLOUDY. TURNING\nWEDNESDAY. MOSTLY SUNNY.\nCOOLER AND LESS HUMID. LOW IN\nCOOLER AND LESS HUMID. HIGH IN\nTHE MIDDLE 60S. NORTHWEST WINDS\nTHE LOWER OR MIDDLE 80S.\n10 TO 15 MPH\n$$\nWEDNESDAY. MOSTLY SUNNY.\nSOMREK\nCOOLER AND LESS HUMID. HIGH IN\nTHE LOWER OR MIDDLE 80S. WINDS\nBECOMING LIGHT AND VARIABLE.\nTTAA00 KCHI 281927 AMD\nWEDNESDAY NIGHT. FAIR. COOLER.\nILLINOIS ZONE FORECASTS UPDATED\nLOW AROUND 60.\nNATIONAL WEATHER SERVICE CHICAGO\n.THURSDAY MOSTLY SUNNY. HIGH IN\nIL\nTHE LOWER OR MIDDLE 80S.\nILZ003-282100-\n$$\nILLINOIS ZONE 3 UPDATED\nWILLIAMS\n2 30 PM CDT TUE AUG 28 1990\nSEVERE THUNDERSTORM WATCH\nTHIS AFTERNOON AND EARLY\nTTAA00 KCHI 282105\nEVENING THIS AFTERNOON HOT\nILLINOIS ZONE FORECASTS\nAND HUMID WITH SCATTERED\nNATIONAL WEATHER SERVICE CHICAGO\nSHOWERS AND THUNDERSTORMS.\nIL\nSOME THUNDERSTORMS MAY PRODUCE\nILZ003-290200-\nLARGE HAIL AND DAMAGING WINDS.\nILLINOIS ZONE 3\nHIGH IN THE LOWER OR MIDDLE 90S.\n4 00 PM CDT TUE AUG 28 1990\nSOUTHWEST WINDS 10 TO 20 MPH\nSEVERE THUNDERSTORM WATCH\nBECOMING NORTHWEST.\nTHROUGH THIS EVENING.\n.TONIGHT. SHOWERS AND\n.THIS EVENING... HOT AND HUMID WITH\nTHUNDERSTORMS ENDING THEN\nSCATTERED SHOWERS AND\nPARTLY CLOUDY.U TURNING COOLER\nTHUNDERSTORMS. SOME\nAND LESS HUMID. LOW IN THE MIDDLE\nTHUNDERSTORMS MAY PRODUCE\n60S. NORTHWEST WINDS ABOUT 10\nHEAVY RAINFALL.. LARGE HAIL AND\nWIND GUSTS ABOVE 40 MPH. HIGH IN\nMPH.\nWEDNESDAY. MOSTLY SUNNY.\nTHE LOWER OR MIDDLE 90S.\nCOOLER AND LESS HUMID. HIGH IN\n.TONIGHT PARTLY CLOUDY. TURNING\nTHE LOWER OR MIDDLE 80S.\nCOOLER AND LESS HUMID. LOW IN\n$$\nTHE MIDDLE 60S. NORTHWEST WINDS\nSOMREK\n10 TO 15 MPH.\nWEDNESDAY... MOSTLY SUNNY.\nCOOLER AND LESS HUMID. HIGH IN\nTTAA00 KCHI 282104\nTHE LOWER OR MIDDLE 80S. WINDS\nILLINOIS ZONE FORECASTS\nBECOMING LIGHT AND VARIABLE.\nNATIONAL WEATHER SERVICE CHICAGO\nWEDNESDAY NIGHT... FAIR. COOLER.\nLOW AROUND 60.\nIL\n.THURSDAY MOSTLY SUNNY. HIGH IN\nILZ003-290200-\nILLINOIS ZONE 3\nTHE LOWER OR MIDDLE 80S.\n$$\n4 00 PM CDT TUE AUG 28 1990\nSEVERE THUNDERSTORM WATCH\nWILLIAMS\nTHROUGH THIS EVENING.\nA-19",".THURSDAY. MOSTLY SUNNY. HIGH IN\nILZ003-290200-\nILLINOIS ZONE 3\nTHE LOWER OR MIDDLE 80S.\n4 PM CDT TUE AUG 28 1990\nWILLIAMS\nSEVERE THUNDERSTORM WATCH\nTHROUGH THIS EVENING..\n.THIS EVENING.. HOT AND HUMID WITH\nA-4.3: Warnings and Statements\nSCATTERED SHOWERS AND\nTHUNDERSTORMS. SOME\n<ZCZC CHISPSCHI\nTHUNDERSTORMS MAY PRODUCE\nETTAA00 KCHI 281901\nHEAVY RAINFALL LARGE HAIL AND\nILZ003-201200-\nWIND GUSTS ABOVE 40 MPH. HIGH IN\nTHE LOWER OR MIDDLE 90S.\nSPECIAL WEATHER STATEMENT\n.TONIGHT PARTLY CLOUDY. TURNING\nNATIONAL WEATHER SERVICE CHICAGO\nCOOLER AND LESS HUMID. LOW IN\nIL\nTHE MIDDLE 60S. NORTHWEST WINDS\n2 00 PM CDT TUE 28 1990\n10 TO 15 MPH.\nWEDNESDAY. MOSTLY SUNNY.\nA SEVERE THUNDERSTORM WATCH HAS\nCOOLER AND LESS HUMID. HIGH IN\nBEEN POSTED FOR NORTHERN ILLINOIS\nTHE LOWER OR MIDDLE 80S. WINDS\nINCLUDING THE CHICAGO AREA FOR\nBECOMING LIGHT AND VARIABLE.\nTHIS AFTERNOON AND EARLY\nWEDNESDAY NIGHT... FAIR. COOLER.\nEVENING.\nLOW AROUND 60.\n.THURSDAY. MOSTLY SUNNY. HIGH IN\nA COLD FRONT MOVING SOUTH FROM\nTHE LOWER OR MIDDLE 80S.\nWISCONSIN HAS FORCED\n$$\nTHUNDERSTORMS TO DEVELOP IN\nWILLIAMS\nSOUTHERN WISCONSIN AND NORTHERN\nILLINOIS. AT 2 PM THE\nTHUNDERSTORMS WERE LOCATED IN A\nTTAA00 KCHI 282116 COR\nLINE FROM JUST SOUTH OF\nILLINOIS ZONE FORECASTS\nMILWAUKEE TO JUST WEST OF\nNATIONAL WEATHER SERVICE CHICAGO\nROCKFORD AND HAD ENTERED THE\nIL\nEXTREME NORTH AND NORTHEST\n00 PM CDT TUE AUG 28 1990\nPORTIONS OF THE CHICAGO SUBURBAN\nILZ003-290200-\nAREAS.\nILLINOIS ZONE 3 CORRECTION TO THIS\nEVENING\nTHE LINE OF THUNDERSTORMS ARE\n4 00 PM CDT TUE AUG 28 1990\nSLIPPING SOUTHEAST AND WILL MOVE\nSEVERE THUNDERSTORM WATCH\nACROSS THE CHICAGO AREA BETWEEN\nTHROUGH THIS EVENING\n2 AND 6 PM. SOME OF THE\n.THIS EVENING.. HOT AND HUMID WITH\nTHUNDERSTORMS MAY BE SEVERE AND\nSCATTERED SHOWERS AND\nPRODUCE STRONG WINDS AND LARGE\nTHUNDERSTORMS. SOME\nHAIL.\nTHUNDERSTORMS MAY PRODUCE\nHEAVY RAINFALL LARGE HAIL AND\nBE ALERT FOR RAPIDLY CHANGING\nWIND GUSTS ABOVE 40 MPH.\nAND THREATENING WEATHER AND BE\n.TONIGHT PARTLY CLOUDY. TURNING\nPREPARED TO SEEK SHELTER AS\nCOOLER AND LESS HUMID. LOW IN\nNECESSARY.\nTHE MIDDLE 60S. NORTHWEST WINDS\n10 TO 15 MPH.\nSOMREK\nWEDNESDAY. MOSTLY SUNNY.\nCOOLER AND LESS HUMID. HIGH IN\nTHE LOWER OR MIDDLE 80S. WINDS\n<ZCZC CHILFPCHI\nBECOMING LIGHT AND VARIABLE.\nETTAA00 KCHI 281917 AMD\nILZ003-282100-\nA-20","CHICAGO METROPOLITAN FORECAST\nAT 2 25PM CDT A SEVERE\nUPDATED\nTHUNDERSTORM WAS LOCATED IN THE\nNATIONAL WEATHER SERVICE CHICAGO\nNORTHWEST CORNER OF DEKALB\nIL\nCOUNTY OR 25 MILES SOUTHEAST OF\n2 10 PM CDT TUE AUG 28 1990\nROCKFORD. THIS STORM IS MOVING TO\nTHE EAST AT 25 MILES AN HOUR. THE\nSEVERE THUNDERSTORM WATCH\nSTORM SHOULD MOVE INTO NORTHERN\nTHIS AFTERNOON AND EARLY\nKANE COUNTY IN THE NEXT HOUR\nEVENING.\nPOSSIBLY PRODUCING STRONG WINDS\nAND LARGE HAIL.\n.THIS AFTERNOON HOT AND HUMID\nWITH SCATTERED SHOWERS AND\nAS THIS STORM PASSED THROUGH\nTHUNDERSTORMS. SOME\nROCKFORD ONE AND ONE-HALF INCH\nTHUNDERSTORMS MAY PRODUCE\nHAIL FELL. RESIDENTS OF KANE\nLARGE HAIL AND DAMAGING WINDS.\nCOUNTY SHOULD PREPARE FOR THIS\nHIGH IN THE LOWER OR MIDDLE 90S.\nSTORM IMMEDIATELY. SOME CITIES IN\nSOUTHWEST WINDS 10 TO 20 MPH\nKANE COUNTY AFFECTED BY THE\nBECOMING NORTHWEST BY LATE\nSTORM INCLUDE\nAFTERNOON.\nGENEVA BURLINGTON ELGIN ST\n.TONIGHT. SHOWERS AND\nCHARLES AND MAPLE PARK.\nTHUNDERSTORMS ENDING THEN\nPARTLY CLOUDY. TURNING COOLER\nREMEMBER. SEVERE THUNDERSTORMS\nAND LESS HUMID. LOW IN THE MIDDLE\nCAN AND OCCASIONALLY DO PRODUCE\n60S. NORTHWEST WINDS ABOUT 10\nA TORNADO WITH LITTLE OR NO\nMPH.\nADVANCE WARNING SO BE ON THE\nWEDNESDAY. MOSTLY SUNNY.\nLOOKOUT.\nCOOLER AND LESS HUMID. HIGH IN\nTHE LOWER OR MIDDLE 80S.\nBRUMER\n15\n$$\nSOMREK\nCHISVSCHI\nTTAA00 KCHI 281952\nZCZC CHISVRCHI\nILZ003-282030-\nETTAA00 KCHI 281932\nILC089-282030-\nSEVERE WEATHER STATEMENT\nNATIONAL WEATHER SERVICE CHICAGO\nBULLETIN - IMMEDIATE BROADCAST\nIL\nREQUESTED\n2 50 PM CDT SAT JUN 30 1990\nSEVERE THUNDERSTORM WARNING\nNATIONAL WEATHER SERVICE CHICAGO\nAT 2 50 PM ONE INCH HAIL HAS BEEN\nIL\nREPORTED EAST OF SYCAMORE IN\n232 PM CDT TUE AUG 28 1990\nEXTREME WESTERN KANE COUNTY.\nTHE HAIL IS ASSOCIATED WITH A\nTHE NATIONAL WEATHER SERVICE HAS\nTHUNDERSTORM MOVING SOUTHEAST\nISSUED A SEVERE THUNDERSTORM\nACROSS KANE COUNTY. THE STORM\nWARNING EFFECTIVE UNTIL 330 PM\nWILL AFFECT THE AREAS AROUND ST.\nCDT FOR PEOPLE IN THE FOLLOWING\nCHARLES AND GENEVA.\nCOUNTY\nBE ALERT FOR THREATENING\nIN THE NORTHEAST PART OF\nWEATHER AND BE PREPARED TO TAKE\nILLINOIS\nSHELTER IF NECESSARY\nNORTHERN KANE\nA-21","ZCZC CHISVRCHI\nZCZC CHISVRCHI\nETTAA00 KCHI 282037\nETTAA00 KCHI 282023\nILC093-089-197-043-282145\nILC043-282130-\nBULLETIN -- IMMEDIATE BROADCAST\nBULLETIN -- IMMEDIATE BROADCAST\nREQUESTED\nREQUESTED\nSEVERE THUNDERSTORM WARNING\nSEVERE THUNDERSTORM WARNING\nNATIONAL WEATHER SERVICE CHICAGO\nNATIONAL WEATHER SERVICE CHICAGO\nIL\nIL\n337 PM CDT TUE AUG 28 1990\n323 PM CDT TUE AUG 28 1990\nTHE NATIONAL WEATHER SERVICE HAS\nTHE NATIONAL WEATHER SERVICE HAS\nISSUED A SEVERE THUNDERSTORM\nISSUED A SEVERE THUNDERSTORM\nWARNING EFFECTIVE UNTIL 445 PM\nWARNING EFFECTIVE UNTIL 430 PM\nCDT FOR PEOPLE IN THE FOLLOWING\nCDT FOR PEOPLE IN THE FOLLOWING\nCOUNTIES\nCOUNTY\nIN THE NORTHEAST PART OF\nIN THE NORTHEAST PART OF\nILLINOIS\nILLINOIS\nNORTHEAST KENDALL\nSOUTHERN DU-PAGE\nSOUTHERN KANE NORTHERN\nWILL SOUTHERN DU-PAGE\nAT 3 20 PM CDT A SEVERE\nTHUNDERSTORM WAS LOCATED IN\nAT 3 30 PM ANOTHER SEVERE STORM\nSOUTHERN KANE COUNTY NEAR\nHAS DEVELOPED TO THE WEST OF\nAURORA. THIS STORM WAS MOVING TO\nAURORA PRODUCING NEARLY 2 INCH\nTHE SOUTHEAST AT 25 MILES AN HOUR\nHAIL OVER AURORA. THIS STORM WAS\nAND SHOULD ENTER SOUTHERN\nMOVING TO THE SOUTHEAST AT 25\nDUPAGE COUNTY WITHIN THE HOUR.\nMILES AN HOUR AND SHOULD AFFECT\nNAPERVILLE AND LISLE ARE SOME\nSOUTHERN KANE SOUTHERN\nCITIES THAT SHOULD BE AFFECTED.\nDUPAGE NORTHEAST KENDALL. AND\nNORTH WILL COUNTIES AFFECTING\nTREE DAMAGE WAS REPORTED ABOUT\nCOMMUNITIES SUCH AS BOLINGBROOK\n15 MILES WEST OF AURORA AS THE\nLOCKPORT NAPERVILLE OSWEGO...\nSTORM PASSED THROUGH KANE\nND AURORA.\nCOUNTY. THIS SAME STORM\nPRODUCED ONE AND ONE HALF INCH\nRESIDENTS OF THESE COMMUNITIES\nHAIL AT ROCKFORD AND 3/4 INCH HAIL\nSHOULD BE ALERT FOR THE APPROACH\nAT AURORA.\nOF THIS STORM THAT MAY POSSIBLY\nBRING VERY STRONG WINDS AND\nRESIDENTS OF SOUTH DUPAGE COUNTY\nLARGE HAIL.\nSHOULD ALSO BE PREPARED FOR\nSTRONG GUSTY WINDS AND LARGE\nREMEMBER SEVERE THUNDERSTORMS\nHAIL AS THIS STORM APPROACHES.\nCAN AND OCCASIONALLY DO PRODUCE\nA TORNADO WITH LITTLE OR NO\nREMEMBER SEVERE THUNDERSTORMS\nADVANCE WARNING SO BE ON THE\nCAN AND OCCASIONALLY DO PRODUCE\nA TORNADO WITH LITTLE OR NO\nLOOKOUT.\nADVANCE WARNING SO BE ON THE\nBRUMER\nLOOKOUT.\n25 15\nBRUMER\n15\nA-22","CHISVSCHI\nBELOW GROUND IF POSSIBLE.\nTTAA00 KCHI 282044\nOTHERWISE GO TO A SMALL INTERIOR\nILZ003-282130-\nROOM ON THE LOWEST FLOOR\nPOSSIBLE. ABANDON CARS AND\nSEVERE WEATHER STATEMENT\nMOBILE HOMES. TAKE COVER IN A\nNATIONAL WEATHER SERVICE CHICAGO\nREINFORCED BUILDING OR GO TO A\nIL\nDITCH OR CULVERT.\n3 40 PM CDT SAT JUN 30 1990\nSOMREK\nAT 3 38 PM CDT THUNDERSTORM WINDS\nATTN ISP 5\nHAD FLIPPED A TRAILER NEAR OSWEGO\nIN NORTHEAST KENDALL\nCOUNTY ABOUT 10 MILES SOUTH OF\nCHISVSCHI\nAURORA.\nTTAA00 KCHI 282100\nILZ003-282130-\nGOLF BALL SIZE HAIL WAS REPORTED\nAT 3 40 PM NEAR JOLIET IN WILL\nSEVERE WEATHER STATEMENT\nCOUNTY.\nNATIONAL WEATHER SERVICE CHICAGO\nIL\nTHE STORMS PRODUCING THE LARGE\n3 55 PM CDT SAT JUN 30 1990\nHAIL AND STRONG WINDS WAS MOVING\nSOUTHEAST AT 25 MPH.\nA TORNADO WAS REPORTED BY STATE\nPOLRICE AT 3 45PM CDT AT CREST\nHILL. A NORTHERN SUBURB OF JOLIET.\nZCZC CHITORCHI\nFOLLOW-UP REPORTS INDICATE\nETTAA00 KCHI 282051\nINJURIES WITH THE TORNADO.\nILC197-282200-\nTHE TORNADO MOVEMENT IS TO THE\nBULLETIN -- IMMEDIATE BROADCAST\nSOUTHEAST TO THE EAST SIDE OF\nREQUESTED/EBS ACTIVATION\nJOLIET TOWARD NEW LENOX AND\nREQUESTED TORNADO WARNING\nALONG ROUTE 30.\nNATIONAL WEATHER SERVICE CHICAGO\nIL\nIF YOU ARE IN THE PATH OF THIS\n351 PM CDT TUE AUG 28 1990\nSTORM TAKE SHELTER IMMEDIATELY\nTHE NATIONAL WEATHER SERVICE HAS\nSOMREK\nISSUED A TORNADO WARNING\nEFFECTIVE UNTIL 500 PM CDT FOR\nPEOPLE IN THE FOLLOWING COUNTY\nZCZC CHISVRCHI\nETTAA00 KCHI 282131\nIN THE NORTHEAST PART OF\nILC091-282230-\nILLINOIS\nWEST CENTRAL WILL\nBULLETIN -- IMMEDIATE BROADCAST\nREQUESTED\nAT 3 45 PM CDT A TORNADO WAS\nSEVERE THUNDERSTORM WARNING\nREPORTED AT CREST HILL. A\nNATIONAL WEATHER SERVICE CHICAGO\nNORTHERN SUBURB OF JOLIET. THE\nIL\nTORNADO WILL TRACK NORTH AND\n431 PM CDT TUE AUG 28 1990\nEAST OF JOLIET TOWARD NEW LENOX\nFOLLOWING ROUTE 30.\nTHE NATIONAL WEATHER SERVICE HAS\nISSUED A SEVERE THUNDERSTORM\nTHIS IS A DANGEROUS STORM. ACT\nWARNING EFFECTIVE UNTIL 530 PM\nQUICKLY. IF YOU ARE IN THE PATH OF\nCDT FOR PEOPLE IN THE FOLLOWING\nTHIS TORNADO MOVE TO A SHELTER\nCOUNTY\nA-23","BULLETIN -- IMMEDIATE BROADCAST\nIN THE NORTHEAST PART OF\nREQUESTED/EBS ACTIVATION\nILLINOIS\nREQUESTED TORNADO WARNING\nEASTERN KANKAKEE\nNATIONAL WEATHER SERVICE CHICAGO\nAT 4 30 CDT A SEVERE THUNDERSTORM\nIL\n450 PM CDT TUE AUG 28 1990\nWAS MOVING TO THE SOUTHEAST AT 25\nMILES AN HOUR FROM EASTERN WILL\nTHE NATIONAL WEATHER SERVICE HAS\nCOUNTY INTO KANKAKEE COUNTY.\nISSUED A TORNADO WARNING\nEFFECTIVE UNTIL 515 PM CDT FOR\nTHE HISTORY OF THIS STORM\nPEOPLE IN THE FOLLOWING COUNTY\nPRODUCED 2 INCH HAIL DAMAGING\nWINDS A TORNADO AT CREST\nIN THE NORTHWEST PART OF\nHILL AND A FUNNEL CLOUD REPORT\nNEAR BOURBONNAIS. RESIDENTS OF\nINDIANA\nSOUTHWEST LAKE\nKANKAKEE SHOULD PREPARE FOR THE\nAPPROACH OF THIS STORM AND BE ON\nAT 4 45PM CDT RADAR INDICATED A\nTHE LOOK OUT FOR SEVERE WEATHER.\nPOSSIBLE TORNADO NEAR\nBEECHER ABOUT 20 MILES\nSOME OF THE COMMUNITIES AFFECTED\nNORTHEAST OF KANKAKEE JUST WEST\nINCLUDE MANTENO MOMENCE AND\nOF THE INDIANA BORDER.\nST. ANNE.\nTHE STORM IS MOVING SOUTHEAST\nREMEMBER SEVERE THUNDERSTORMS\nAND WILL ENTER SOUTHWEST LAKE\nCAN AND OCCASIONALLY DO PRODUCE\nCOUNTY INDIANA NEAR\nA TORNADO WITH LITTLE OR NO\nLOWELL SHELBY AND SCHNEIDER.\nADVANCE WARNING SO BE ON THE\nLOOKOUT.\nSOMREK\nBRUMER\n21\n<ZCZC CHISVSCHI\nETTAA00 KCHI 282211 COR\nILZ003-282300-\nCHISVSCHI\nTTAA00 KCHI 282135\nSEVERE WEATHER\nILZ003-282230-\nSTATEMENT CORRECTION\nNATIONAL WEATHER SERVICE CHICAGO\nSEVERE WEATHER STATEMENT\nNATIONAL WEATHER SERVICE CHICAGO\nIL\n5 15 PM CDT SAT JUN 30 1990\nIL\n4 30 PM CDT SAT JUN 30 1990\nTHE SEVERE THUNDERSTORM\nWARNING FOR KANKAKEE COUNTY\nTHE TORNADO WARNING FOR WEST\nAND THE TORNADO WARNING FOR\nAND CENTRAL WILL COUNTY IS\nLAKE COUNTY INDIANA HAVE BOTH\nCANCELLED. THE STORM PRODUCING\nBEEN CANCELLED. THE STORM\nTHE TORNADO HAS MOVED TO THE\nASSOCIATED WITH THESE WEATHER\nSOUTHEAST AND IS NOW LOCATED\nEVENTS HAS MOVED SOUTHEAST INTO\nOVER EAST KAKANKEE COUNTY. A\nSEVERE THUNDERSTORM WARNING IS\nNEWTON COUNTY OF INDIANA.\nIN EFFECT UNTIL 5 30 PM FOR EAST\nA FEW FUNNEL CLOUDS WERE\nKANKAKEE COUNTY.\nREPORTED EARLIER IN KANKAKEE\nCOUNTY WITH THE STORM. HOWEVER\nSOMREK\nREPORTS OF SEVERE WEATHER ON THE\nGROUND HAVE NOT MATERIALIZED.\nZCZC CHITORCHI\nBRUMER\nETTAA00 KCHI 282150\nINC089-2822150-\nA-24","A-4.4: Storm Report\nTTAA00 KCHI 290011\nSTORM REPORT DATA FROM WW 691..\nNATIONAL WEATHER SERVICE CHICAGO IL\n600 PM CDT TUE AUG 28 1990\nTIME CDT\nEVENT\n245 PM CDT.\nHEAVY RAIN ONE INCH HAIL HIGH WINDS. REPORTED BY\nSPOTTER IN SYCAMORE IN EASTERN DEKALB COUNTY. (23 SE\nRFD)\n252 PM\nONE HALF INCH HAIL 50 MPH GUST. REPORTED BY SPOTTER\nBETWEEN DEKALB IN DEKALB COUNTY AND I-88.\n255 PM\nTREE DAMAGE AT BIG ROCK IN SOUTHWEST KANE COUNTY.\nREPORTED BY ARTCC AT AURORA.\n317 PM\n35 MPH WIND AND 3/4 INCH HAIL AT ST CHARLES. REPORTED\nBY ARTCC AT AURORA.\n321 PM\nLARGE HAIL AND STRONG WINDS AT SUGAR GROVE IN SOUTH\nKANE COUNTY. REPORTED BY STATE POLICE DISTRICT 2.\n323 PM\n1 1/4 INCH HAIL AT AURORA REPORTED BY ARTCC. KANE\nCOUNTY.\n327 PM\n1 TO 1 1/4 INCH HAIL AT AURORA REPORTED BY WSFO\nEMPLOYEE. KANE COUNTY.\n327 PM\n1/2 TO 3/4 INCH HAIL IN SOUTHWEST CORNER OF AURORA.\nESTIMATED 40 TO 45 MPH WIND LARGE TREE LIMBS DOWN.\nRELAYED REPORTS BY RADIO STATION. KANE COUNTY.\n337 PM\nMOBILE HOME FLIPPED OVER NEAR OSWEGO (15 NW JOT)\nRELAYED REPORT BY RADIO STATION - WMSO. WILL COUNTY.\n340 PM\nGOLF BALL SIZE HAIL AT JOLIET. REPORTED BY WSFO\nEMPLOYEE. WILL COUNTY\n343 PM\n3/4 INCH HAIL AT LOCKPORT. REPORTED BY WSFO EMPLOYEE.\nWILL COUNTY.\n340 PM\n1.25 INCHES OF RAIN IN 20 MINUTES. 3/4 INCH HAIL. TREES\nAND BRANCHES DOWN IN SYCAMORE (23 SE RFD). REPORTED\nBY SPOTTER. DEKALB COUNTY.\n345 PM.\nTENNIS BALL SIZE HAIL JUST WEST OF JOLIET. REPORTED BY\nWSFO EMPLOYEE.\n425 PM\nTORNADO NEAR PLAINFIELD. TWENTY HOMES BADLY\nDAMAGED OR DESTROYED. ONE TO FOUR MILES NORTH OF\nPLAINFIELD. TORNADO STRUCK JOLIET JR COLLEGE DAMAGE\nUNKNOWN. REPORTED BY SPOTTER AT MANHATTEN.\n430 PM\n13 TO 14 AIRCRAFT OVERTURNED OR DAMAGED. POWER OUT.\nTHREE HANGARS DESTROYED. WINDOWS BLOWN OUT OF\nCARS ONE OVERTURNED. ALL AT AURORA AIRPORT.\nREPORTED BY FAA AT AURORA. OCCURRED AROUND 330\nPM RECEIVED LATER.\nA-25","A-5: Releases of WSFO Indianapolis\nShown below are releases of the WSFO Indianapolis that were relevant to the severe\nweather events that occurred over northern Illinois.\nSOME LOCATIONS MAY GET RAINFALL\nA-5.1: Zone Forecasts\nIN EXCESS OF TWO INCHES. THE COLD\nFRONT WILL MOVE SOUTH OF INDIANA\nNNNN>##<A<\nON WEDNESDAY. BEHIND THE FRONT\n<ZCZC INDSWSIN\nCOOLER AND LESS HUMID AIR WILL\nETTAA00 KIND 281610\nMOVE INTO INDIANA. ONLY IN THE\nEXTREME SOUTH WILL TEMPERATURES\nINDIANA WEATHER SUMMARY\nREACH ABOVE 90 DEGREES. THE\nNATIONAL WEATHER SERVICE\nNORTH WILL ONLY HAVE HIGHS\nINDIANAPOLIS IN\nAROUND 80.\n1115 AM EST TUE AUG 28 1990\nHAINES\nHIGH PRESSURE ALONG THE EAST\nCOAST WILL GIVE INDIANA ONE MORE\nA-5.2: Warnings and Statements\nHOT AND UNCOMFORTABLE DAY.\nOVERNIGHT THE AIR CONDITIONERS\nNNNNZCZC INDSPSIND\nDID NOT GET MUCH OF A BREAK AS\nETTAA00 KIND 282027\nLOW TEMPERATURES ONLY DROPPED\nINZ001>006-010-282200-\nINTO THE MIDDLE 60S TO LOWER 70S.\nSPECIAL WEATHER STATEMENT\nTHE HEAT AND HUMIDITY WILL\nNATIONAL WEATHER SERVICE\nCONTINUE TO MOVE INTO INDIANA\nINDIANAPOLIS INDIANA\nTHIS AFTERNOON. BY LATE\n320 PM EST TUE AUG 28 1990\nAFTERNOON TEMPERATURES WILL\nREACH THE LOWER TO MIDDLE 90S.\nTWO SEVERE THUNDERSTORM\nRELATIVE HUMIDITIES WILL ONLY\nWATCHES ARE IN EFFECT FOR\nDECREASE TO THE 50 TO 60 PERCENT\nNORTHERN INDIANA THIS AFTERNOON\nRANGE. THIS WILL MAKE IT VERY\nAND EVENING. THE DIVIDING LINE\nDANGEROUS TO DO ANY HARD WORK\nBETWEEN THESE TWO WATCHES IS\nOUTDOORS. HEAT STROKE WOULD BE\nFROM SOUTH BEND TO 10 MILES SOUTH\nPOSSIBLE IF FREQUENT BREAKS ARE\nOF KOKOMO. THE WESTERN WATCH IS\nNOT TAKEN AND IF YOU DO NOT DRINK\nIN EFFECT UNTIL 800 PM EST THE\nAN ADIQUITE AMOUNT OF LIQUIDES.\nEASTERN WATCH IS IN EFFECT UNTIL\nA COLD FRONT WILL MOVE THROUGH\n900 PM EST.\nINDIANA TONIGHT. THIS WILL BRING A\nAT 315 PM EST RADAR SHOWED\nCHANGE TO THE WEATHER. WITH THE\nTHUNDERSTORMS OVER EXTERME\nAMOUNT OF MOISTURE IN THE AIR\nNORTHERN INDIANA BETWEEN SOUTH\nTHUNDERSTORMS WILL DEVELOP\nBEND AND FORT WAYNE\nALONG THE FRONT. THESE\nTHUNDERSTORMS WILL FIRST MOVE\nTHE WEATHER SERVICE OFFICES AT\nINTO NORTHERN INDIANA LATE THIS\nBOTH SOUTH BEND AND FORT WAYNE\nAFTERNOON. THEY SHOULD NOT MOVE\nHAVE ISSUED SEVERE THUNDERSTORM\nINTO NORTHERN INDIANA LATE THIS\nWARNINGS FOR SOME COUNTIES IN\nAFTERNOON. THEY SHOULD NOT MOVE\nNORTH CENTRAL AND NORTHEAST\nINTO CENTRAL INDIANA UNTIL LATER\nINDIANA. THE WARNING FOR\nTHIS EVENING. A FEW OF THESE\nSOUTHERN ELKHART COUNTY IS IN\nTHUNDERSTORMS MAY BE SEVERE.\nA-26","EFFECT UNTIL 330 PM. ANOTHER\n800 PM EST...THE EASTERN WATCH IS IN\nWARNING IS IN EFFECT UNTIL 330 PM\nEFFECT UNTIL 900 PM EST.\nFOR SOUTHERN LAGRANGE AND NOBLE\nCOUNTIES.\nSOME CITIES INCLUDED IN THE WATCH\nAREAS ARE SOUTH BEND KOKOMO\nTHE THUNDERSTORMS WERE MOVING\nELKART ANGOLA WARSAW FORT\nSOUTHEAST AT 30 TO 35 MILES AN\nWAYNE MUNCIE AND RENSSELAER.\nHOUR.\nAT 400 PM EST RADAR SHOWED\nANOTHER THUNDERSTORM WHICH\nDANGEROUS THUNDERSTORMS 30\nPRODUCED 1 1/2 HAIL IN ROCKFORD\nMILES SOUTH OT DOWNTOWN CHICAGO\nILLINOIS WAS CONTINUING TO MOVE\nAND OTHERS OVER NORTHEAST\nEAST SOUTHEAST AND IS EXPECTED TO\nINDIANA BETWEEN SOUTH BEND AND\nMOVE INTO NORTHWEST INDIANA\nTO THE NORTH OF FORT WAYNE.\nBETWEEN 4 AND 5 PM EST\nTHE STORMS WERE MOVING TO THE\nSOME CITIES INCLUDED ARE\nSOUTHEAST AT 30 MILES AN HOUR.\nKOKOMO ELKHART ANGOLA\nWARSAW FORT WAYNE MARION\nPEOPLE IN THE WATCH AREAS SHOULD\nTIPTON MUNCIE WINCHESTER\nKEEP ABREAST OF THE LATEST\nSOUTH BEND. ROCHERSTER\nWEATHER DEVELOPMENTS AND LISTEN\nLOGANSPORT...VALPARAISO LAPORTE\nFOR POSSIBLE WARNINGS.\nMONTICELLO AND RENSSELAER.\nSTEIGERWALDT\nREMEMBER A WATCH MEANS THAT\nCONDITIONS ARE FAVORABLE FOR\nETTAA00 KIND 282123\nSEVERE WEATHER IN AND CLOSE TO\nINC111-073-282200-\nTHE WATCH AREA. PERSONS IN THESE\nAREAS SHOULD BE ON THE LOOKOUT\nBULLETIN - IMMEDIATE BROADCAST\nFOR THREATENING WEATHER\nREQUESTED\nCONDITIONS AND LISTEN FOR LATER\nSEVERE THUNDERSTORM WARNING\nSTATEMENTS AND POSSIBLE\nNATIONAL WEATHER SERVICE\nWARNINGS.\nINDIANAPOLIS IN\nWJG\n420 PM EST (420 PM CDT) TUE AUG 28\n1990\nNNNNZCZC INDSPSIND\nTHE NATIONAL WEATHER SERVICE IN\nETTAA00 KIND 282106\nINDIANAPOLIS HAS ISSUED A SEVERE\nINZ001>006-010-282210-\nTHUNDERSTORM WARNING EFFECTIVE\nUNTIL 500 PM EST (500 PM CDT) FOR\nSPECIAL WEATHER STATEMENT\nPEOPLE IN THE FOLLOWING\nNATIONAL WEATHER SERVICE\nCOUNTIES.\nINDIANAPOLIS INDIANA\n405 PM EST TUE AUG 28 1990\nIN NORTHWEST INDIANA\nNEWTON\nTWO SEVERE THUNDERSTORM\n.JASPER\nWATCHES CONTINUE IN EFFECT FOR\nNORTHERN INDIANA FOR THIS\nAT 418 PM EST A SEVERE\nAFTERNOON AND EVENING. THE\nTHUNDERSTORM WAS NEARING THE\nDIVIDING LINE BETWEEN THESE TWO\nILLINOIS AND INDIANALINE 35 MILES\nWATCHES IS FROM SOUTH BEND TO 10\nSOUTH OF GARY. THIS STORM\nMILES SOUTH OF KOKOMO. THE\nPRODUCED 2 INCH DIAMETER HAIL IN\nWESTERN WATCH IS IN EFFECT UNTIL\nAURORA ILLINOIS WHICH IS WEST OF\nCHICAGO.\nA-27","ILLINOIS AND INDIANA STATE LINE 35\nANOTHER SEVERE THUNDERSTORM\nMILES SOUTH OF GARY. THIS STORM\nWAS 30 MILES SOUTH OF GARY. GOLF\nPRODUCED 2 INCH DIAMETER HAIL IN\nBALL SIZE HAIL WAS REPORTED WITH\nAURORA ILLINOIS WHICH IS WEST OF\nTHIS STORM AT I-65 AND INDIANA\nSTATE ROAD 10 BY THE PUBLIC AT 416\nCHICAGO.\nPM EST.\nANOTHER SEVERE THUNDERSTORM\nWAS 30 MILES SOUTH OF GARY. GOLF\nTHE STORMS WERE MOVING TO THE\nBALL SIZE HAIL WAS REPORTED WITH\nSOUTHEAST AT 35 MILES AN HOUR.\nTHIS STORM AT I-65 AND INDIANA\nSTATE ROAD 10 BY THE PUBLIC AT 416\nPEOPLE IN THE CITIES OF LAKE\nVILLAGE ENOS KENTS MOROCCO\nPM EST.\nWHEATFIELD AND RENSSELAER\nTHE STORMS WERE MOVING TO THE\nSHOULD REMAIN INDOORS AND AWAY\nSOUTHEAST AT 35 MILES AN HOUR.\nFROM WINDOWS. PEOPLE OUTDOORS\nIN THESE CITIES SHOULD SEEK\nPEOPLE IN THE CITIES OF LAKE\nSHELTER IN A STRONG BUILDINGAS\nVILLAGE ENOS KENTS MOROCCO.\nQUICKLY AS POSSIBLE.\nWHEATFIELD AND RENSSELAER\nSHOULD REMAIN INDOORS AND AWAY\nSEVERE THUNDERSTORMS PRODUCE\nFROM WINDOWS. PEOPLE OUTDOORS\nWINDS OF 58 MILES AN HOUR OR MORE\nIN THESE CITIES SHOULD SEEK\nAND/OR LARGE HAIL 3/4THS INCH IN\nSHELTER IN A STRONG BUILDING AS\nDIAMETER OR GREATER.\nQUICKLY AS POSSIBLE.\nSTEIGERWALDT\nSEVERE THUNDERSTORMS PRODUCE\nWINDS OF 58 MILES AN HOUR OR MORE\nNNNN\nAND/OR LARGE HAIL 3/4 INCH IN\n.BREAK\nDIAMETER OR GREATER.\nZCZC INDSVRIND\nETTAA00 KIND 282135 COR\nSTEIGERWALDT\nCORRECTION FOR LINE LENGTH\nINC111-073-282200-\nBULLETIN - IMMEDIATE BROADCAST\nNNNNZCZC INDSVSIND\nREQUESTED CORRECTION\nSEVERE THUNDERSTORM WARNING\nETTAA00 KIND 282140\nNATIONAL WEATHER SERVICE\nINZ001>006-282200-\nINDIANAPOLIS IN\nSEVERE WEATHER STATEMENT\n420 PM EST (420 PM CDT) TUE AUG 28\nNATIONAL WEATHER SERVICE\n1990\nINDIANAPOLIS IN\nTHE NATIONAL WEATHER SERVICE IN\n439 PM EST TUE AUG 28 1990\nA SEVERE THUNDERSTORM WARNING\nINDIANAPOLIS HAS ISSUED A SEVERE\nTHUNDERSTORM WARNING EFFECTIVE\nIS IN EFFECT FOR NEWTON AND\nJASPER COUNTIES UNTIL 5 PM EST.\nUNTIL 500 PM EST (500 PM CDT) FOR\nPEOPLE IN THE FOLLOWING\nAT 430 PM EST A SEVERE\nCOUNTIES.\nTHUNDERSTORM WAS 5 MILES WEST OF\nMEDARYVILLE OR 35 MILES SOUTHEAST\nIN NORTHWEST INDIANA\nOF GARY. AT 427 PM EST GOLF BALL\nNEWTON\nSIZE HAIL WAS REPORTED WITH THIS\n.JASPER\nSTORM BY THE JASPER COUNTY\nSHERRIFF 5 MILES SOUTH OF\nAT 418 PM EST A SEVERE\nTHUNDERSTORM WAS NEARING THE\nA-28","DEMOTTE. DEMOTTE IS 30 MILES\nPREVIOUSLY PRODUCED A TORNADO IN\nSOUTH OF GARY.\nTHE JOLIET AREA OF ILLINOIS.\nSTEIGERWALDT\nANOTHER SEVERE THUNDERSTORM\nHAD JUST MOVED INTO NEWTON\nCOUNTY BETWEEN LAKE VILLAGE AND\nNNNNZCZC INDSVSIND\nENOS OR 30 MILES SOUTH OF GARY.\nETTAA00 KIND 282206\nTHIS STORM EARLIER PRODUCED A\nINZOO1>006-282230-\nTORNADO NEAR JOLIET ILLINOIS.\nSEVERE WEATHER STATEMENT\nTHESE STORMS WERE MOVING TO THE\n]NATIONAL WEATHER SERVICE\nSOUTHEAST AT 35 MILES AN HOUR.\nINDIANAPOLIS IN\nSTEIGERWALDT\n505 PM EST TUE AUG 28 1990\nA TORNADO WARNING IS IN EFFECT\nNNN\nFOR NORTHERN NEWTON COUNTY IN\n<BREAK\nNORTHWEST INDIANA UNTIL 530 PM\nEST.\nZCZC INDTORIND\nETTAA00 KIND 282153\nTHE NATIONAL WEATHER SERVICE HAS\nINC111-282230-\nNOT RECEIVED NAY REPORTS OF A\nTORNADO WITH THIS STORM IN\nBULLETIN - EBS ACTIVATION\nINDIANA BUT RADAR SHOWED A\nREQUESTED\nPOSSIBLE TORNADO 8 MILES\nTORNADO WARNING\nSOUTHEAST OF LAKE VILLAGE OR 35\nNATIONAL WEATHER SERVICE\nMILES SOUTH OF GARY.\nINDIANAPOLIS IN\n451 PM EST (451 PM CDT) TUE AUG 28\nMOVEMENT WAS SOUTHEAST AT 35\n1990\nMILES AN HOUR.\nTHE NATIONAL WEATHER SERVICE IN\nPEOPLE IN THE CITIES OF\nINDIANAPOLIS HAS ISSUED A TORNADO\nROSELAWN PEMBROKE AND KENTS\nWARNING EFFECTIVE UNTIL 530 PM\nSHOULD REMAIN INDOORS IN AN\nEST (530 PM CDT) FOR PEOPLE IN THE\nINTERIOR ROOM ON THE LOWEST\nFOLLOWING COUNTY.\nFLOOR POSSIBLE UNTIL THIS STORM\nPASSES.\nIN NORTHWEST INDIANA\nSTEIGERWALDT\nNORTHERN NEWTON\nAT 448 PM EST WEATHER RADAR\nINDICATED A POSSIBLE TORNADO ON\nTHE ILLINOIS AND INDIANA STATE\nLINE 5 MILES SOUTHWEST OF\nSCHNEIDER OR 30 MILES SOUTH OF\nGARY.\nMOVEMENT WAS SOUTHEAST AT 35\nMILES AN HOUR.\nPEOPLE IN THE CITIES OF SUMAVA\nRESORTS LAKE VILLAGE THAYER AND\nROSELAWN SHOULD MOVE TO AN\nINTERIOR ROOM OF THE HOME ON THE\nLOWEST FLOOR POSSIBLE. THIS STORM\nA-29","APPENDIX B\nCHRONOLOGY OF ACTIONS/REPORTS\nThe following are the severe weather, telephone, and action logs that were\nmaintained on August 28, 1990, at National Weather Service locations. The logs\nare reproduced fully here.\nB-1: The Actions/Reports at WSO Rockford\nThe following is taken from hand written log from personnel at WSO Rockford August 28.\nNot all actions taken by the staff are noted in this log.\n1:35 PM CDT\nFunnel cloud reported by State Police south of Pecatonica near State Police\nHeadquarters.\n1:37 PM CDT\nTornado on the ground moving south State Police.\nTornado Warning issued for eastern Winnebago, southern Boone and northern\n1:39 PM CDT\nDeKalb Counties. MMO reported cell movement of 29025.\n1:40 PM CDT\nTornado on the ground moving toward Seward State Police.\n1:42 PM CDT Tornado at Seward moving south reported by State Police.\nState Police reports cars carried up to the air, trees down and cemetery stones\n1:50 PM CDT\ncarried aloft.\n1:53 PM CDT Gene Boyt of Sjestron (sp) Construction--Funnel cloud west of Pecatonica--almost\nhit the ground--tail went back up into the cloud.\n2:05 PM CDT\nFunnel Cloud reported west of Rockford Montague RD. No touchdown.\n2:08 PM CDT\nGolf ball hail--Sandy Hollow Road.\n2:20 PM CDT 2-1/2\" diameter hail east of Rockford airport.\nMarble size hail and rain in NW DeKalb reported by DeKalb County sheriff.\n2:30 PM CDT\nNorth of city DeKalb--Damage to crops, tree damage, golf ball-size hail reported by\n2:45 PM CDT\nDeKalb County sheriff.\n2:54 PM CDT\n3/4\" hail at N.I.U. DeKalb.\nGolf ball-size hail, funnel cloud sighted moving southeast 1-1/2 miles north of\n2:55 PM CDT\nDeKalb-reported by DeKalb Co. sheriff--numerous reports of crop and tree\ndamage.\nB-1","B-2: The Actions/Reports at WSFO Chicago\nCHRONOLOGY OF SEVERE WEATHER EVENTS/ACTIONS AT WSFO CHICAGO\nAUGUST 28, 1990\n(all times p.m., CDT)\nSpecial Weather Statement issued as follow-up to Severe Thunderstorm Watch WW691\n2:00\n(NWR: 200-?)\nChicago Metropolitan Forecast updated to include possibility of severe thunderstorms\n2:10\n(NWR: 222-407)\nSevere Thunderstorm Warning issued until 3:30 for northern Kane County (NWR w/tone:\n2:32\n235-253)\nIllinois State Police, district 2, solicited for severe weather report\nOne-inch hail reported in western Kane County east of Sycamore (from ISP, district 2)\n2:45\nSevere Weather Statement issued as follow-up to 232 SVR (NWR: 253-305)\n2:50\nHalf-inch hail and 50 mph winds reported between DeKalb and I-88 in DeKalb County\n2:52\n(from spotter)\nTree damage reported in Big Rode in southwest Kane County (from CWSU ZAU)\n2:55\nThree-quarter inch hail reported at Aurora; 35 mph winds reported at St. Charles (from\n3:17\nESDA center at Melrose Park)\nPea-size hail and strong winds reported at Sugar Grove in Kane County (from ISP,\n3:21\ndistrict 2)\nSevere Thunderstorm Warning issued until 4:30 for southern Du Page County (NWR\n3:23\nw/tone: 325-338)\nOne and one-quarter-inch hail reported at ZAU (from CWSU ZAU)\n3:23\nOne to one and one-quarter-inch hail reported at Aurora (from WSFO employee)\n3:27\nOne-half to three-quarter-inch hail reported over southwest corner of Aurora; winds 40-45\n3:27\nmph; large tree limbs down (from ESDA center at Melrose Park)\nSevere Thunderstorm Warning issued until 4:45 for northeast Kendall, southern Kane,\n3:37\nnorthern Will and southern Du Page counties (NWR w/tone: 338-420)\nMobile home reported flipped near Oswego in Kendall County (from WMAQ radio)\n3:37\nGolf ball-size hail reported near Joliet in Will County (from WSFO employee)\n3:40\nSevere Weather Statement issued as follow-up to 337 SVR\n3:40\nThree-quarter-inch hail reported at Lockport in Will County (from WSFO employee)\n3:43\nTennis ball-size hail reported west of Joliet in Will County (from WSFO employee)\n3:45\nB-2","3:45\nTornado reported at Crest Hill in Will County (from ISP, district 2)\n3:51\nTornado warning issued until 5:00 for west-central Will County (NWR w/tone: 354-435)\nSevere Weather Statement issued as follow-up to 351 TOR (NWR: 401-502)\n3:55\nSevere Thunderstorm Warning issued until 5:30 for eastern Kankakee County (NWR:\n4:31\n433-502)\nSevere Weather Statement issued cancelling 351 TOR (NWR: 453-502)\n4:35\nTornado Warning issued until 515 for southwest Lake (IN) County (NWR: 450-600)\n4:50\nSevere Weather Statement issued cancelling 431 SVR and 450 TOR (NWR: 511-604)\n5:11\nB-3","SEVERE WEATHER LOG FOR ILLINOIS\nMonth Aug 1990\nReporting\nType of\nForm\nWB614-2\nDate\nSent\nDate\nTime\nAgency/Pers\nStorm\nLocation\nRemarks\nDate\nRecd\non\n8/28\n245\nSpotter\nSVRTSTM\nHVY RAIN 1 IN HAIL..HIGH WIND\nSP2\nE.Sycamor\nRS\n9/28\n2:52\nSpotter\nTSTM\nBTWN\nY2\" A 50 MPH more SE\nDKB-188\nDKB-188\n9/28\n255\nARTCC\nWND\nBIG ROCK TREE DAMAGE\n317p\nMelrose\n35 mph St. Charles 3/4A ARR\n9/28\n321\nState Police\nLRG A/STRONG WINDS SUGAR GROVE\n2\nPEA SIZE\n9/28\n323\nFishes\n11/4 A at ARTCC\n9/28\n327\nCollins\n1-11/4 A AURORA-\n8/28\n327pm\nBill Smartz\nHAIL,\n1/2 - 3/4 - INCH HAIL OVER S.W.\nCDT\nWIND\nCORNER OF AURORA EST. 4045 MPH.\nDAMAGE\nWIND; LARGE TREE LIMBS DOWN.\n337\nWMDQ\nMOBIL HOME FLIPPED IN OSWEGO\n3:40\nPaul\nSVR TSTM\nJOT\nGOLF BALL SIZED HAIL AT JOLIETS\nMerzlock\n3:43\nClint\nLockport\n3/4\" HAIL\nSimpeon\n8/28\n3:40 pm\nDan Walts\nDekalb\n1.25\" RAINFALL IN 20 MIN 3/4\" HAIL\nDekalb\nTREES & BRANCHES DOWN IN\nSYSCAMORE\n8/28\nRCVD\nManhatton\nWill CO\nTORNADO\nPLAINFIELD HOMES\n425pm\nSD\nBADLY DAMAGED OR DESTROYED 1-4\nMI NORTH OF PLAINFIELD 127TH ST\nEAST OF HIGHWAY 59 20 HOUSES\nDAMAGED OR DESTROYED, U.S. 30\nCLOSED SW\nOF PLAINFIELD, TOR JOLIET JR\nCOLLEGE. DAMAGE UNKN.\n8/28\nRCVD\nFAA 330 pm\nTORNADO\nARR AIR\n13-14 AFCT OVERTURNED OR\n430\nOR\nPORT\nDAMAGED POWER OUT 3 TRAILERS\nSVRTSTM\nDESTROYED\n8/28\nWINDOWS BLOWN OUT OF CARS 1\nCAR OVERTURNED\n8/28\n345\nPaul MERF\nSVR TSTM\nW JOT\nTENNIS BALL HAIL\n8/28\n605\nBy MMO\nSVRTSTM\nPERU\nDIME TO QUARTER SIZE HAIL\n620\nARTCC\nSVRTSTM\nW.MMO\nMARBLE SIZE HAIL\n135\nSt Police\nGOLF BALL\nCULLON\nFOLLOW UP BROKEN WINDOWS,\nHAIL\nVEHICLES DAMAGED BY HAIL\nB-4","B-3: The Communication Log at Marseilles WSMO\nAugust\n1990\nMonth\nYear\nINITIALS\nDTG (Z)\nTO\nFROM\nSUBJECT\nInfo for Ken\nB\n271812\nCASC\n280000\nTIME\nTime Chk - Clocks ok\nTD\nFurlough info (will call back)\nB\n281312\nREGION\nJAMES\nInfo on furlough\nB\n281320\nR.J.\n281756\nRFD\nAre those trw's nr us?\nVJ\nDon't know for sure\nLVL 5 stm NNW of RFD top 47,000'\nVJ\n281810\nRFD\nAnything new with cell NW of RFD?\nVJ\n281816\nCHI\nTop 48,000'\nBwer N of RFD 5 LVL\nB\n281832\nRFD\nLVL 6 stm top 56,000 ft mvg SE 20-\nW\n281843\nRFD\n25 mph\nCell nr us -- How is it doing?\nVJ\n281855\nSBN\nTop 46,000' LVL 5\nRFD had tornado sighted 15 mi W\nVJ\n281902\nCHI\nof them\nLVL 6 stm nr Genoa in Dekalb. Cty,\nVJ\n281928\nRFD\ntop 55,000'\nVJ\n281934\nCHI\nTold them same as RFD above\n60,000' stm LVL 6 4-5 mi E of DKB\nVJ\n281954\nCHI\nVIP 6 40,000\nMax top 65,000' VIP 6 nr Aurora\nVJ\n282015\nCHI\nDR\n282039\nHONEWOOD\nFAST Poss svr storms 4-7 pm\nCC.\nRNS says storms east of BMI, SPI\nDR\n282039\nPIA\nradar shows nothing. Few\nweakening shwrs now.\n282125\nNORWAY IL\nFCST\nDR\nCITIZEN\nFCST\nDR\n282126\nLASALLE\nNUKE STA.\nB-5","282141\nCHI\nSee any hook on VIP 6 storm? Not\nDR\nreally thru past hour will keep\nclose check. Storm now NE\nKankakee Co.\n282142\nBILL B.\nIn Oswego, major damage rptd\n282144\nCHI\nHotline ok. Hook first time\nDR\nobserved S of Beecher Kankakee/\nWill CO line\n282147\nCHI\nOur monitors shows it further S-E\nDR\nthan Beecher? Storm nr Grant\nPark w/ Appendage extending to\njust SE of Beecher nr stateline.\nFirst appendage seen all day.\n282157\nIND\nStorm in N. Newton Co mvg SE top\nDR\nweakening to 50,000' VIP 5 to\n15,000'\n282204\nCHI\nStorm is now out of S Lake Co.\nDR\nAnother VIP 5 storm nr Joliet\n282340\nCHI\nThe VIP 5 storm nr Joliet has\nDR\nweakened now to LVL 3. New VIP\n5 strm 5 mi W of Peru dev rapidly\nsince 5:30\n282303\nPERU\nRadar shows poss hail spike over\nDR\nPOLICE\nPeru. Any hail reports. Yes.\n223-2157\nQuarter size hail\n282305\nLVL 6 storm LVL 6 to 20,000' over\nDR\nPeru called Peru Police said, dime\nto quarter size hail\n282308\nMMO\nCall Peru police back\nDR\nPOLICE\n282310\nPERU\nLarger size hail than before very\nDR\nPOLICE\nhvy rain.\n282338\nCHI\nLVL 6 storm over Streator picking\nDR\nup in speed now SE at 30-35 mph\nVIP 6 to ~300 will move thru\nPontiac & Odell by 7 am\nB-6","B-4: Special Radar Scans of the Storm Taken at Marseilles WSMO\nThe time and scans taken were derived from the 8 mm film of the PPI scope at Marseilles\nWSMO. Numbers after the RHI denote azimuth angles along which the RHI was\nperformed. Only for the 2005 elevated scan could the actual elevation tilt be determined.\nProcedure\nTime (CDT)\nRHI\n1809\nRHIs and elevated scan\n1955-2000\nRHI\n2002-2003\nElevated scan\n2005\nRHI (37,43,45,49)\n2013\nPower dropout?\n2017\nRHI (8,13,17,28,49,80,81)\n2029\nRHI (54,56)\n2045\nRHI (31,38,52,54,64,70)\n2046\nRHI (25,34,44,55,65,72,83) and elevated scans\n2053-2100\nRHI (46,63,68,82,119)\n2106\nB-7","B-5: The Communication Log at NSSFC\nSELS DAY SHIFT\nLOG OF SIGNIFICANT Ph.\nLLS\nTIME (CDT)\nTO\\FROM\nSUBJECT\n1255\nARB/\n#689\n1310\nFSD/\n#690\n1325\nCHI\n#691\nIND\n1345\nIND\n#692\nCLC\n1350\nPIT/\nNO ON WV\n1530\nBUF\n#693\nALB/PIT\n1540\nOMA\n#694\nSELS SWING SHIFT\nTIME\nTO\\FROM\nSUBJECT\n1700 CDT\nFM CHI\nRadio rpts indc 5 dead, many injured NW & N of JOT\n(Talked to Paul Dailey)\n1705 CDT\nFM ARB\nDiscussed clrg in S LWR MI--prefer -- to keep in counties alg\nand south of bndry as indcd by Stlt (~BEH-FNT LN)\n1730 CDT\nFM CHI\nDiscussed psbl clrg of WW--real cdfnt still N of RFD-ORD\nwith very unstbl ams contg. Prefer not to clr nrn ptn of WW\nattm as path of least regret.\n1815 CDT\nTO ALB\nWW 695 wibis\n1845 CDT\nTO CHI, IND\nWW 696 wibis\n1915 CDT\nTO ALB,\nWW 697 wibis\nPHL,PIT\n1920 CDT\nFM FSD\nOk to clr W of Y26-P05 Ln\nB-8","Primary threat NRN WV pnhdl attm\nFM CRW\n1925 CDT\nWW 698 wibis\nTO CRW,\n1940 CDT\nCLE,PIT\nOK to clr wrn half of WW--we may cancel entire WW at\nFM OMA\n2000 CDT\nzone time\nDiscussed WW 693--Ok to clr nrn ptn\n2020 CDT\nFM BUF\nTO BOS,\nWW 699 wibis\n2120 CDT\nPWM, ALB\nSmall area of W cntrl PA will not be in WW after 03Z\n2135 CDT\nTO PIT\nexpiration of WW 693. Agreed to have PIT Locally extend\nWW of svrl hrs in W cntrl PA as sqln sags swd.\nWW 700 wibis\nTO BOS,\n2145 CDT\nPHL,ALB,\nNYC\nCHH radar indcs tstms rpdly wkng over wrn MA--our 1tg\nFM BOS\n2235 CDT\nconfirms that trend--will cancel WW at 04Z\nWill cancel WWS 695 & 699\nTO ALB,\n2250 CDT\nPWM\nB-9","APPENDIX C\nPRODUCT AND INFORMATION DISSEMINATION\nC-1: Emergency Service Agencies\nWatches, warnings, and severe weather statements are distributed to the various Illinois\ncounty and local emergency officials in several ways. The system is in place so that every\naffected official was notified of watches and warnings affecting his/her area of\nresponsibility. These pathways include:\nLEADS (Law Enforcement and Dissemination System) This is the\nA:\ncommunication system of the Illinois State Troopers. Messages received over the NOAA\nWeather Wire System (NWWS) drop at the state police headquarters in Springfield are\nevaluated by the duty technician, coded by that person as to counties affected, and\nforwarded to the trooper district offices having responsibility for those counties.\ncommunication drops on the LEADS also direct such messages to the various county\nsheriffs' offices, to some municipal police, and to other interested agencies.\nWeather radio (NWR) Only a few emergency offices have these\nB:\nNOAA\ninstalled. Most of the people involved have heard of NWR, however. In some counties,\nspecifically Kane and Kendall, people feel reception deteriorates during bad weather.\nC: NAWAS Personnel at District 2 of the Illinois State Police seemed to do a lot\nmore with this system than did those at District 5 although both offices have it.\nWarnings are not broadcast on NAWAS by District 5. They are broadcast and rebroadcast\nby District 2.\nD: Local radios Both District 2 and District 5 broadcast all watches and warnings\nreceived over LEADS on local radio frequency to their field people. Some of these\nfrequencies are routinely monitored by local sheriffs and other groups.\nE: Ham radios. A very aggressive group (CHICAGOLAND SKYWARN\nASSOCIATION) collocated with the Melrose Park ESDA (Emergency Services and\nDisaster Agency) office has established a ham network through much of the NE Illinois\narea. The head of this group is also the head of the Melrose Park ESDA office. He pays\nfor a NWWS drop out of his own pocket. The SKYWARN people broadcast all watches,\nwarnings, and statements dealing with systems affecting or that possibly could affect NE\nIllinois.\nC-1","F:\nISPERNS (Illinois State Police Emergency Radio Network System) This is a\nstatewide police network connecting all law enforcement agencies. Broadcasts of weather\ninformation on this are sometimes made. However, there seems to be no consistency or\nstandardization as to its use for distributing weather information.\nG:\nWill County has an agreement with Grundy County that Grundy County will\nfax copies of applicable weather messages received. Grundy County has leased a drop on\nthe NWWS.\nC-2","C-2: Radio Stations\nWJCH (FM) - Joliet\nNews director John Rorik said they got the watch and warnings using NOAA Weather\nRadio (NWR). He did not broadcast the watch but indicated he probably would have if it\nwas a tornado watch. He broadcasted the severe thunderstorm warning for Will County\nat 3:37 p.m. but not the tornado warning at 3:51 p.m., CDT, since he lost power.\nWCCQ (FM) - Joliet\nNews director Bob Channick said his station received the watch and warnings from UPI,\nand he uses NWR as a backup. The watch was broadcast. He telephoned SELS directly\nfor additional information and clarification. He cut into programming a number of times\nfor warnings after 3:00 p.m. until he lost power at 3:40 p.m., CDT.\nWJOL (AM) - Joliet\nNews director Randy Bunger said that the station got the watch and warnings from AP.\nNWR is available for backup. He was broadcasting warnings from the Rockford area all\nthe way to Kane County. He couldn't recall the 3:37 p.m. and 3:51 p.m., CDT, warnings\ndue to chaotic emergency conditions accompanying the tornado, in which he lost power.\nWWHN (FM) - Joliet\nOwner Ray Hawkins said he uses NWR. He did not get the watch. He attempted to\nbroadcast the warning at 3:37 p.m., CDT, but lost power. He said he heard the sirens just\nbefore losing power. He indicated that severe thunderstorm watches do not raise as much\nconcern as tornado watches.\nWBBM (AM) - Chicago\nAccording to Georgeann Herbert, the managing editor, they use Accu-weather for\nscheduled weather reports but also have access to AP (Associated Press), UPI (United\nPress International), and NOAA Weather Wire Service for NWS weather information.\nAccu-weather announced the watch over the station shortly after issuance but incorrectly\ncalled it a tornado watch. The station immediately corrected that. They were following\nthe storm all the way from the Rockford area to Joliet and were broadcasting all the\nwarnings. Around 2:00 p.m., CDT, they had a live report form state troopers and other\neyewitnesses to the tornado sighting near Pecatonica. Shortly after the tornado, the\nstation did a telephone interview with WSFO Chicago.\nWGN-AM - Chicago\nStaff meteorologist Roger Triemstra said they got all watch and warning information from\nNWWS. They highlighted the severe weather outlook in the morning. The watch was\nbroadcast at 1:30 p.m. and then they reported on severe weather activity in the Rockford\narea from 1:30 p.m. to 2:00 p.m., CDT. After 2:00 p.m., CDT, they broke into\nprogramming with warning and reports at least 30 times. The station was in contact with\nthe WSMO in Marseilles as the storm progressed.\nC-3","WLS-AM - Chicago\nWayne Messmer of the News Department indicated that they received all watch and\nwarning information through AP. They announced the watch at 2:00 p.m., CDT, and cut\nin on all warnings affecting the Chicago area. Severe weather coverage become\ncontinuous after 3:30 p.m., CDT. The WSFO Chicago was interviewed by telephone\nshortly after the tornado struck.\nWMAQ-AM - Chicago\nNews Director Jim Frank mentioned that sources of weather information are AP and the\nprivate meteorological firm of Murray and Trettel. All watch and warning information\nwas broadcasted as soon as received. Even in routine weather situations they give\nforecasts and observations every few minutes along with expanded reports from Murray\nand Trettel 2 to 3 times an hour (and 4 to 5 times an hour during significant or severe\nweather). Weather coverage was continuous by 3:30 p.m., CDT. The station interviewed\nthe WSFO by telephone.\nWJJD-AM - Chicago\nReese Rickards is public service director. Their weather information source is NWWS and\nthe private meteorological firm of OMNI (at Du Page Co. Airport). Although their news\nand weather reports are primarily a morning operation, their announcers broadcast severe\nweather reports as received.\nC-4","C-3: Television Stations\nROCKFORD, ILLINOIS, TV STATIONS\nWIFR-TV, Ch. 23, CBS affiliate, located in Freeport, IL\nNews Director said station received the Weather Service's severe thunderstorm watches\nand warnings and ran crawls at the bottom of the TV screen to inform the public even\nthough their area was unaffected by the storm.\nWREX-TV, Ch. 13, ABC affiliate\nNews Director Dennis Horton said he first heard about the stormy conditions from a state\ntrooper's police radio. He received the NWS severe thunderstorm watch and warning\nlater and ran crawls across the screen to inform the public.\nWTVO-TV, Ch. 17, NBC affiliate\nNews Director said he received severe thunderstorm watch and warning from UPI wire at\nabout 2 p.m. and ran a slide system and crawls with tone and chirp several times. He\nlater heard the tornado warning from the sheriff's scanner in his office and ran an\nappropriate crawl.\nCHICAGO TV STATIONS\nWCIU-TV, Ch. 26, Univision, Spanish-speaking station\nNews Director received severe thunderstorm watches and warnings and ran crawls to\ninform public.\nWFLD-TV, Ch. 32, Fox affiliate\nNews Director said station received severe thunderstorm watch and warning and ran\nseveral crawls throughout the afternoon. He later got word of the tornado warning from\nRockford WSO through the AP wire and a radio system in the station's weather office. He\ncommented that the information was updated so fast that as soon as the operator would\ntype in one crawl, he'd get another message that would superseded it.\nWGN-TV, Ch. 9, Trinity Broadcasting\nMeteorologist Tom Skilling said his station heard about the severe thunderstorm watch\nand warning through the AP and Weather Wires. Crawls were aired non-stop throughout\nthe afternoon at about 2:15 p.m., CDT. When he heard the tornado warning for southern\nDu Page, Kendall and Will Counties, he ran appropriate crawls at the bottom of the\nscreen. He commented that the warning could've been \"a little stronger.\"\nWMAQ-TV, Ch. 5, NBC affiliate\nMeteorologist John Coleman said he received the severe thunderstorm watches and\nwarnings and ran continuous crawls including county warnings until 3:24 p.m., CDT. The\nstation aired four to six constant updates, including a live cut in at 3:55 p.m., CDT, after\nthe tornado had touched down. His comment was that \"it is quite beyond the Weather\nService's current capability to provide tornado warnings. It would be better if they issued\nsevere thunderstorm watches and warnings and tell citizens that after that they're on\ntheir own.\"\nC-5","APPENDIX D\nPREPAREDNESS ACTIVITIES\nWSFO CHICAGO\nD-1: 1989 Preparedness Talks\nThe list contains all talks related to severe weather and spotter training made in the\ncounties of warning responsibility. However, nine other appearances not relating to\nconvective severe weather also were made.\nWill Co.\nLarson Spotters\nFeb\nCook Co.\nCook County Sheriffs Police\nFeb\nLake/Porter Cos. IN\nSouth Haven Civil Defense\nFeb\nWill Co.\nBolingbrook Amateur Radio Society\nMar\nCook Co.\nLynwood ESDA\nMar\nLake Co.\nBarrington Fire Dept & ESDA\nMar\nMcHenry Co.\nCrystal Lake Radio Amateurs/ESDA\nMar\nKane Co.\nAurora ESDA\nMar\nWill Co.\nJoliet Amateur Radio Society\nMar\nFord Co.\nFord County ESDA\nMar\nIroquois & Livingston Cos. also represented\nCook Co.\nMarkham/Hometown ESDA\nMar\nCook Co.\nMar\nPalos ESDA\nMcHenry Co.\nWAIT Radio (with McHenry Co. ESDA)\nMar\nDu Page Co.\nNaperville ESDA\nMar\nDu Page Co.\nYork Radio Club\nMar\nCook Co.\nPalatine Fire Dept/ESDA\nApr\nWill Co.\nBolingbrook Amateur Radio Society (2nd)\nApr\nCook Co.\nAmateur Radio Emergency Service\nApr\nFermilab/Batavia ESDA Severe Weather Seminar\nKane Co.\nApr\nLake Co.\nLake Co. ESDA (3 separate appearances)\nApr\nCook Co.\nRolling Meadows Amateur Radio Club\nApr\nDu Page Co.\nArgonne Amateur Radio Society\nApr\nCook Co.\nDes Plaines ESDA\nApr\nCook Co.\nMelrose Park Skywarn & ESDA\nApr\nCook Co.\nWGN Radio Severe Weather Seminar\nApr\nGrundy Co.\nGrundy Co. ESDA\nApr\nLake Co.\nWauconda Fire Dept/ESDA\nApr\nCook Co.\nPalatine Fire Dept.\nApr\nDu Page Co.\nIllinois Pilots Assn.\nMay\nAmerican Red Cross-Mid American Chptr.\nCook Co.\nJun\nCook Co.\nColumbia College\nJun\nDu Page Co.\nSuburban Boating Assn.\nJun\nCook Co.\nMelrose Park Skywarn & ESDA (2nd)\nJun\nCook Co.\nMorton Grove ESDA\nJun\nKane Co.\nMoecherville/Aurora Fire Depts/ESDA\nJul\nCook Co.\nWinnetka Public Library System\nJul\nD-1","D-2: 1990 WPM Appearances\nGroup\nApprox Attendance\nPlace\nDate\nCounty\nMorton Grove ESDA\n(40)\nMorton Grove\n2/28\nCook Co.\nAmateur Cross Link Repeater\n(229)\nChicago\n3/03\nCook Co.\n6 Meter Club of Chicago\n(41)\nBrookfield\n3/09\nCook Co.\n*Buffalo Grove Condo Assn.\n(175)\nBuffalo Grove\n3/13\nCook Co.\n*South Shore Marine Assn.\n(30)\nChicago\n3/17\nCook Co.\nWAFAR (amateur radio)\n(30)\nChicago\n3/21\nCook Co.\nDes Plaines ESDA\n(30)\nDes Plaines\n3/28\nCook Co.\nMelrose Park ESDA/Skywarn\n(109)\nMelrose Park\n4/04\nCook Co.\n*WGN Radio Svr Wx Seminar\nChicago\n4/13\nCook Co.\n*Electro Motive\n(280)\nLaGrange\n4/25\nCook Co.\nSouth Suburban Radio Amateurs\n(90)\nCrestwood\n5/15\nCook Co.\nPark Forest Fire Dept/ESDA\n(23)\nPark Forest\n7/20\nCook Co.\nArgonne Amateur Radio Club\n(90)\nArgonne Lab\n3/07\nDu Page Co.\nYork Radio Club\n(65)\nElmhurst\n3/16\nDu Page Co.\nEmergency Radio Service\n(27)\nHanover Park\n3/19\nDu Page Co.\nArgonne Amateur Radio Club\n(31)\nArgonne Lab\n4/03\nDu Page Co.\n*Tellabs\n(8)\nLisle\n4/20\nDu Page Co.\nFord Co. ESDA\n(15)\nPiper City\n3/22\nFord Co.\nalso ESDA from Gilman\nalso ESDA from Forrest\nGrundy Co. ESDA\n(46)\nMorris\n3/23\nIroquois Co.\nIroquois Co. ESDA\nsee Ford Co.\nGrundy Co.\nAurora ESDA\n(8)\nAurora\n3/01\nKane Co.\nFermilab Svr Wx Seminar\n(1400)\nBatavia\n4/14\nKane Co.\nAurora/Moecherville Fire Dept and ESDA\n(55)\nMoecherville\n7/17\nKane Co.\n*American Red Cross\n(15)\nSugar Grove\n8/10\nKane Co.\nLake Co. Emergency Svcs/ESDA\n(25)\nMundelein\n4/02\nLake Co.\nLake Co. ESDA\n(25)\nLibertyville\n4/05\nLake Co.\nWauconda Fire Dept/ESDA\n(41)\nWauconda\n4/15\nLake Co.\nLivingston Co. ESDA\nsee Ford Co.\nLivingston Co.\nCrystal Lake Radio Amateurs\n(35)\nCrystal Lake\n4/17\nMcHenry Co.\nJoliet Amateur Radio society\n(25)\nJoliet\n2/06\nWill Co.\n*Kiwanis of Joliet\n(63)\nJoliet\n4/30\nWill Co.\nNote: All appearances were spotter oriented except those marked \"*\"\nD-2","APPENDIX E\nSUMMARY OF FATALITIES\nE-1: List of Individuals\nSummary of deaths in the Plainfield/Crest Hill tornado, including age, gender and location.\nAge\nSex\nLocation\nAge\nSex\nLocation\nHigh School\nFemale\nAutomobile\n76\nMale\n30\nResidential Area\n69\nMale\nAutomobile\n28\nFemale\n27\nFemale\nResidential Area\n68\nMale\nAutomobile\n67\nFemale\nAutomobile\n26\nMale\nResidential Area\nApartment Complex\nHigh School\n25\nFemale\n55\nFemale\n24\nMale\nApartment Complex\n52\nMale\nAutomobile\n(Automobile)\nApartment Complex\n18\nFemale\n47\nMale\nGrade School\n(Automobile)\nGrade School\n16\nMale\nApartment Complex\n47\nFemale\nResidential Area\nMale\nHigh School\n15\nMale\n43\n(Outside)\nApartment Complex\n41\nMale\nAutomobile\n14\nMale\nApartment Complex\n12\nMale\nApartment Complex\n38\nFemale\nResidential Area\n4\nFemale\nApartment Complex\n37\nMale\nResidential Area\nAutomobile\n3\nFemale\n36\nFemale\n5 weeks\nFemale\nApartment Complex\n32\nMale\nResidential Area\nGrade School\n32\nFemale\nSummary of Totals:\nGender:\nMales = 15\nFemales = 14\n9\nLocations:\nAutomobiles\nHigh School\n3\nGrade School\n2\nApartment Complex\n9\nResidential Area\n6\nE-1","E-2: Map Showing the Locations of the Fatalities\n(From Joliet \"Hearld News\"\nEdited to reflect additional fatalities)\nTHE VICTIMS:\nOn U.S. 30:\nAlice Johnson AGE 30\nAugust 28, 1990\nThomas Thayer\n59\nA trail of death\nPhoumy Senephimmachac\nAGE 36\n143rd St\nThe death toll from Tuesday's tomado\nDirection of\nstarted to mount at 3:30 p.m. on U.S.\n126\ntomado\n30 northwest of Plainfield. By the\n30\ntime the twister left-WIII County, the\ntoll had climbed to more than 20.\nLockport St.\nPlainfield High\nShown here are locations of 24 of the\nSchool:\nvictims when the storm struck. More\nHenry Bergquist\nAGE\nabout the lives of the 27 victims\n30\nStephen Hunt\nAGE 43\nappears in the accompanying article.\nx\nPatricia Skolen AGE 5\nCrystal Lawns\nSt. Mary's Grade School:\n55\nsubdivision:\nHoward Hawes Jr. AGE 47\nCharles Likes AGE 37\nSr. Mary Keenan AGE 47\nRyan Glaser\nGloria Sanchez AGE 32\nAGE 15\nLily Cache subdivision:\nCedarwood\nVirginia Lydon AGE 28\nDrive:\nFrank Riffel AGE 68\nWarwick subdivision:\nAlida Riffel\nJanis Granat AGE 27\nAGE 67\nCaton Farm Rd.\nJames Pullen AGE 32\n30\nCresthill Lakes Apartments:\nLeticia Herrod AGE Thomas Egizio AGE\n14\nTheodore S\nTitlania Brown\nLeslle Egizlo AGE\nAGE\n5 WEEKS\nPatricia Combs 25 AGE\nEddie J. Lee Jr.\nAGE 24\nIngalls Ave\nVicki Egizio\nBrian Strohm\nAGE 38\nAGE 12\nBlac Rd.\njor\nSarah Brower AGE 3\nDied later from injuries\nEric Wilson AGE 16\nJames Niccum AGE 26\nrelated to the tornado:\nGlenwood Ave.\nKent A. Keely AGE 52\nJames Kachel AGE 69\nOne mile\nHEHALD-NE WS/DENISE SMETANA FRIANT\nE-2","E-3: Map Showing Locations of Major Damage\n(From Joliet \"Herald News\")\nAugust 28, 1890\nA trail of death and destruction\nThe final death toll from the storm was 27.\nFederal, state, county and municipal officials still\nare tallying the damages from the devastation.\nBut the latest estimate puts the totals at more\nthan $165 million, excluding cleanup costs, said\nDon Gould, director of the Will County Emergency\nChapins Rd.\nServices and Disaster Agency.\nOne Insurance company also expects to receive\nabout 100 damage claims from crops ruined by\nhall and debris from the storm, said Robert\nMushling, manager of the Will County Farm\nBureau.\nPilcher Rd.\nWHEATLAND PLAINS\nPLAINFIELD\nDestroyed: 12 homes\n59\nDamaged: 50 homes\nDestroyed: 55 homes\n30\nALONG ILLINOIS 59\nEstimated damage: More than\nMajor damage: 55 homes\n$9.2 million\n143rd St.\nMinor damage: 150 homes\nDamaged: Several strip malls\nEstimated damage: More than\nEstimated damage: $3.5 million\n$9.5 million\nDeaths (on U.S. 30): 3\n126\nPEERLESS ESTATES\nLockport St.\nDestroyed: 75 homes\nMajor damage: 26 homes\nPLAINFIELD SCHOOLS\n30\nMinor damage: 122 homes\nDestroyed: High School,\nEstimated damage: $15.4 million\nGrand Prairie Elementary School\nLILY CACHE\nand district administration center\nRenwick Rd\nEstimated damage: $60 million\nDestroyed: 55 homes\nDeaths: 3\nMajor damage: 52 homes\nST. MARY IMMACULATE\nMinor damage: 75 homes\nEstimated damage: $11.5 million\nDamaged: grade school, church,\nDeath: 1\nrectory and convent\nEstimated damage $5 million\n55\nBRIDALWREATH\nDeaths: 3\nJoliet\nDestroyed: 3 homes\nMall\nMajor damage: 14 homes\nMinor damage: 74 homes\nCRYSTAL LAWNS\nEstimated damage: $2.7\nmillion\nDestroyed: 69 homes\n30\nMajor damage: 104 homes\nCaton Farm Rd.\nMinor damage: 220 homes\nEstimated damage: Over $15 million\nThese aress\nDeaths: 2\nWARWICK ESTATES\nsustained\nscattered damage.\nDestroyed: 50 homes\nNo damage\nTheodore St\nMajor damage: 26 homes\nestimates have\nMinor damage: 5 homes\nDied later from\nbeen released.\nEstimated damage: More than $6 million\ninjuries related to\nDeaths: 2\nIngalls\nthe tornado: 3\nBlack\nRd.\nCOLONY WEST\nCRESTHILL LAKES\nDestroyed: 12 townhomes\nDestroyed: 3 buildings\nGlenwood Ave.\nEstimated damage: $2.2 million\n(more than 100 apartments)\nN\nEstimated damage: $5 million\nELIZABETH COURT\nDeaths: 8\nJefferson St.\nDestroyed: 3 apartment buildings\nCEDARWOOD DRIVE\nEstimated damage: $300,000\nDeaths: 2\nOne Mile\nE-3","APPENDIX F\nPERSONS INTERVIEWED AND/OR CONTACTED BY\nTHE DISASTER SURVEY TEAM\nF-1: National Weather Service Employees\nName\nTitle\nLocation\nRobert Somrek\nDMIC\nChicago\nAnthony Williams\nLead Forecaster\nChicago\nRichard Koeneman\nLead Forecaster\nChicago\nRichard Brumer\nAviation Forecaster\nChicago\nPaul Dailey\nMIC\nChicago (phone)\nGregory Dickey\nWeather Service Specialist (WSS)\nChicago\nDon Morrison\nWSS\nChicago\nJohn Jamison\nSupervisory Meteorological Technician\nChicago\nJames Purpura\nForecaster\nChicago\nAl Morrison\nLead Forecaster\nChicago\nJoseph Baalke\nOfficial in Charge (OIC)\nMarseilles WSMO\nViggio Jensen\nIntern\nMarseilles WSMO\nDaniel Riddle\nIntern\nMarseilles WSMO\nRon Fields\nOIC\nRockford WSO\nAllan Fischer\nMIC\nCWSU Aurora\nRon Przybylinski\nLead Forecaster\nIndianapolis (phone)\nTim McClung\nIntern\nSouth Bend (phone)\nJim Meyer\nMIC\nMoline WSO (phone)\nF-1","F-2: Other Agencies/Institutions\nName\nTitle\nLocation\nFAA Tower Controllers\nUnknown\nAurora\nTed Fujita\nProfessor of Meteorology\nUniversity of Chicago\nUnited Airlines\nSteve Gregory\nMeteorologist\nCarl Knable\nMeteorologist\nUnited Airlines\nVillage of Plainfield\nMary Latta\nPresident\nWill County Emergency Services\nDon Gould\nDirector\nand Disaster Preparedness\nKane County Emergency Services\nBill Diamond\nDirector\nand Disaster Preparedness\nJohn Taylor\nDirector\nKendall County Emergency Services\nPat Wilkenson\nCommunications Supervisor\nDistrict 2, Illinois State Police\nMelrose Park Emergency Services\nRobert Hajak\nDirector\nand Public Safety,\nDirector Chicagoland Skywarn\nAssociation\nPhillip Schwartz\nDeputy Director\nsee above\nDiane Larson\nTeacher\nPlainfield High School\nDistrict 5, Illinois State Police\nGene Anderson\nCommunications Supervisor\nPeter Haas\nLt.\nWill County Sheriff's Office\nWill County Sheriff's Office\nEd Mayer\nSgt.\nWayne Perry\nPublisher, \"The Enterprise\"\nPlainfield\nMarx Gibson\nCity Editor, \"Hearld News\"\nJoliet\nCollege of Du Page (phone)\nPaul Sirvatka\nInstructor\nRobert E. Gorsich\nM.D.\nPhotographer\nChris Berry\nWBBM News Director\nChicago (phone)\nGeorgeann Herbert\nWBBM Managing Editor\nChicago (phone)\nJim Frank\nWMAQ News Director\nChicago (phone)\nWayne Messmer\nWLS News\nChicago (phone)\nRoger Triemstra\nWGN Staff Meteorologist\nChicago (phone)\nReese Rickards\nWJJD Public Service Director\nChicago (phone)\nJohn Rorik\nWJCH-FM Station Manager\nJoliet (phone)\nRandy Bunger\nWJOL-AM News Director\nJoliet (phone)\nBob Channick\nWCCQ-FM General Manager\nJoliet (phone)\nPrince Mayne\nWCCQ-FM Program Director\nJoliet (phone)\nRay Hawkins\nWWHN Owner\nJoliet (phone)\nJean Halevi\nWGBO-TV PBS Director\nJoliet (phone)\nDennis Horton\nWREX-TV News Director\nRockford (phone)\nArles Hendershott\nWIFR-TV News Director\nRockford (phone)\nJohn Baumgartner\nWTVO-TV News Director\nRockford (phone)\nTom Skilling\nWGN-TV Staff Meteorologist\nChicago (phone)\nJohn Coleman\nWMAQ-TV Weathercaster\nChicago (phone)\nJim Tillman\nWMAQ-TV Meteorologist\nChicago (phone)\nGreg Caputo\nWFLD-TV News Director\nChicago (phone)\nTom Bomilla\nWLS-TV Meteorologist\nChicago (phone)\nBen Larson\nWCIU-TV News Director\nChicago (phone)\nDon Aguirre\nWCIU-TV News Director\nChicago (phone)\nF-2","APPENDIX G\nNWS STAFFING FOR NORTHERN ILLINOIS\nThree local NWS offices were directly involved in the warnings and forecasts\nprovided to northern Illinois on the afternoon of August 28, 1990. The following is\na list of the stations operational staff levels for that day.\nTotal Operational Staffing:\nWSFO Chicago:\n1 Area Manager/Meteorologist In Charge\n1 Deputy Meteorologist In Charge\n5 Lead/Public Forecasters\n6 Journeymen Level Forecasters\n5 Meteorological Technicians\n1 Supervisory Meteorological Technician\n1 Intern\n1 Service Hydrologist\nWSFO Rockford:\n1 OIC\n4 Meteorological Technicians\n1 Intern\nWSMO Marseilles:\n1 OIC\n3 Interns\n1 Meteorological Technician\nG-1","Staff on Duty August 28, 1990:\nWSFO Chicago:\nPaul Daily (MIC)\n0700-1900\nAdmin/Svr Wx\nRobert Somrek (DMIC)\n0700-1000\nLead/Public\n1000-2000\nAdmin/Svr Wx\nAnthony C. Williams\n0900-1700\nLead/Public\nRichard Brumer\n1000-1400\nAdmin\n1400-1500\nAviation\n1500-1800\nSvr Wx\nJane Hollingsworth\n0600-1400\nAviation\nStephen Kahn\n0900-1600\nAdmin/Hydro\n1600-2100\nSvr Wx\nGregory Dickey\n0600-1400\nObservations\nAllan Randal\n1100-1900\nIntern/Admin\nJames Vermoch\n1500-2300\nAviation\nJim Lebda\n1600-2400\nLead/Public\nDon Morrison\n1400-2200\nObservations\nWSO Rockford:\nRon Fields (OIC)\n0800-1600\nJoe Librizzi (WSS)\n0800-1600\nDale Helgerson\n1000-1800\nWSMO Marseilles:\nJoe Baalke (OIC)\n0800-1600\nViggio Jensen (Intern)\n0800-1600\nDaniel Riddle (Intern)\n~1500-2400\nG-2","APPENDIX H\nFUJITA TORNADO INTENSITY SCALE\nCategory\nDefinition--Effective\n(F0)\nGale tornado (40-72 MPH): Light damage. Some damage to\nchimneys; break branches off trees; push over shallow-rooted trees;\ndamage sign boards.\n(F1)\nModerate tornado (73-112 MPH): Moderate damage. The lower\nlimit is the beginning of hurricane wind speed; peel surface off roofs;\nmobile homes pushed off foundations or overturned; moving autos\npushed off the roads.\n(F2)\nSignificant tornado (113-157 MPH): Considerable damage. Roofs\ntorn off frame houses; mobile homes demolished; boxcars pushed\nover; large trees snapped or uprooted; light-object missiles generated.\n(F3)\nSevere tornado (158-206 MPH): Severe damage. Roofs and some\nwalls torn off well-constructed houses; trains overturned; most trees\nin forest uprooted; heavy cars lifted off ground and thrown.\n(F4)\nDevastating tornado (207-260 MPH): Devastating damage.\nWell-constructed houses leveled; structure with weak foundation\nblown off some distance; cars thrown and large missiles generated.\n(F5)\nIncredible tornado (261-318 MPH): Incredible damage. Strong\nframe houses lifted off foundations and carried considerable distance\nto disintegrate; automobile sized missiles fly through the air in\nexcess of 100 yards; trees debarked; incredible phenomena will occur.\nH-1\n* U.S. G.P.0.:1992-313-153:6052"]}