U.S. Department of Commerce
NOAA Technical Reports and Related Materials
Date of this Version
1999
Document Type
Article
Citation
National Weather Digest (December 1999) 23(4): 33-17
Abstract
Probabilities provide a means of quantifying both the likelihood of a particular meteorological event and the degree of certainty in its forecast. In the future, probabilities will likely be issued routinely for the occurrence of severe convective storms. As a prelude to such efforts, this study developed a procedure for estimating probabilities of severe convective storms as applied to a local area. The primary intent is to acquaint local forecasters and potential users with representative probabilities for time and space scales for which forecasts are made. Probabilities of severe convective storm occurrence within local areas near selected cities were computed. The period of record was 1992-1994. For this study, a "local area" was defined as within 30 nautical miles (nm) of the center of a selected city. Cities selected were Kansas City and Saint Louis, Missouri; Indianapolis, Indiana; Minneapolis, Minnesota; and Omaha, Nebraska. The relative frequency of at least one severe convective event while an Outlook and / or Watch were in effect provided an estimate of the local probability associated with that product. A composite model was developed from the combined data from the five local areas. This model reflected local probability associated with Outlooks and Watches and trends relative to the period from issuance to end of valid time. An operational scenario is described in which local probabilities are estimated and grids of probability are constructed.
Comments
United States government work