Tornado Damage Rating Probabilities Derived from WSR-88D Data

Details

• Journal Title:
  Weather and Forecasting
• Personal Author:
  Thompson, Richard L. ; Smith, Bryan T. ; Grams, Jeremy S. ; Dean, Andrew R. ; Picca, Joseph C. ; Cohen, Ariel E. ; Leitman, Elizabeth M. ; Gleason, Aaron M. ; Marsh, Patrick T.
• NOAA Program & Office:
  NWS (National Weather Service) ; NCEP (National Centers for Environmental Prediction) ; SPC (Storm Prediction Center)
• Description:
  Previous work with observations from the NEXRAD (WSR-88D) network in the United States has shown that the probability of damage from a tornado, as represented by EF-scale ratings, increases as low-level rotational velocity increases. This work expands on previous studies by including reported tornadoes from 2014 to 2015, as well as a robust sample of nontornadic severe thunderstorms [≥1-in.- (2.54 cm) diameter hail, thunderstorm wind gusts ≥ 50 kt (25 m s−1), or reported wind damage] with low-level cyclonic rotation. The addition of the nontornadic sample allows the computation of tornado damage rating probabilities across a spectrum of organized severe thunderstorms represented by right-moving supercells and quasi-linear convective systems. Dual-polarization variables are used to ensure proper use of velocity data in the identification of tornadic and nontornadic cases. Tornado damage rating probabilities increase as low-level rotational velocity Vrot increases and circulation diameter decreases. The influence of height above radar level (or range from radar) is less obvious, with a muted tendency for tornado damage rating probabilities to increase as rotation (of the same Vrot magnitude) is observed closer to the ground. Consistent with previous work on gate-to-gate shear signatures such as the tornadic vortex signature, easily identifiable rotation poses a greater tornado risk compared to more nebulous areas of cyclonic azimuthal shear. Additionally, tornado probability distributions vary substantially (for similar sample sizes) when comparing the southeast United States, which has a high density of damage indicators, to the Great Plains, where damage indicators are more sparse.
• Keywords:
  Atmospheric Science
• Source:
  Weather and Forecasting, 32(4), 1509-1528
• DOI:
  https://doi.org/10.1175/waf-d-17-0004.1
• ISSN:
  0882-8156 ; 1520-0434
• Format:
  PDF
• Publisher:
  American Meteorological Society
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Library
• Main Document Checksum:
  urn:sha256:f1cd23b9ea73f24f48a7a74df0e08a13cfcc5f56d0e582dce682da4da9d3b19f
• Download URL:
  https://repository.library.noaa.gov/view/noaa/54858/noaa_54858_DS1.pdf
• File Type:
  [PDF - 6.37 MB ]