"The National Meteorological Center has operated for many years on a twice-daily cycle of data collection, processing, and analysis centered on 00 GMT and 12 GMT. This cycle accepts all data judged to be useful from observations taken at or near those times. Until recently, observations taken at other times were not used. With the advent of satellite-borne meteorological sensors, however, new data became available which considerably improved the coverage over previously data-sparse areas. These data are not taken at the standard synoptic times. It thus became necessary to devise ways of assimilating these new data in order that they have an impact on operational numerical weather prediction"--Introduction.

National Weather Service (NWS)

United States