U.S. Department of Commerce


Date of this Version


Document Type



National Weather Digest (December 1999) 23(4): 33-37


United States government work


Summary and Conclusions

A procedure to estimate probabilities of the occurrence of severe convective storms within local areas has been described. Probabilities were based on a simulated climatology and the relative frequency of severe convective events when a selected site was contained within an operational Outlook or Watch. Combined data from five local areas were used to develop a general model for local probabilities within the central and northern Plains region. Attachment of probabilities to specific products placed values within a framework familiar to both forecasters and "end-users." Application of results in an operational scenario demonstrated representative local probabilities and supported production of grids of probabilities.

Reasonable results have been obtained, and concepts of probabilities applicable to local areas have been developed. As such, results of this study support the comprehensive effort currently underway at the SPC to produce a fully operational procedure.