A new climatology of 25-year, 50-year, and 100-year microburst winds

A dataset of potential peak microburst wind speeds across the contiguous United States for a 30-year period (1974-2003) during the summer months of July and August was created using NCDC/FSL 00z rawinsonde data. The Dry Microburst Index, Microburst Day Potential Index and Convective Available Potential Energy were used to define days where microbursts were likely, with the Wind Index producing the potential peak wind speed values. In addition to plotting the mean potential microburst winds speeds for the study period, a type I extreme value distribution was used to calculate 25-year, 50-year, and 100-year potential peak microburst wind gusts.

Results indicate that the majority of the contiguous United States experiences a threat of severe microburst winds (gusts greater than 57 mph) during the months of July and August, with the West Coast and the Northeast not seeing a significant threat. Three regions stood out in the spatial analysis as regions with the most intense microburst winds. These regions--the Southwest, the southern Plains, and the northern Plains--all have the potential of experiencing microburst winds that are stronger than previous non-tornadic wind climatologies have indicated. The results of this study will not only give much needed climatological information to meteorologists, but will aid operational forecasters by giving a greater understanding of the probability and potential of intense microburst winds for a given region.