Severe Convective Windstorms over the Northern High Plains of the United States

Abstract

Abstract During the warm seasons (May–September) of 1996–99, Weather Surveillance Radar-1988 Doppler (WSR-88D) data and severe wind reports (either gusts >25 m s–1, or damage-related reports) over the northern High Plains (NHP) of the United States were analyzed in order to document the primary modes of convection responsible for severe winds. It was found that two-thirds of the convectively generated severe wind reports over the NHP were identified as being produced by organized convective structures rather than by isolated downburst or microburst activity. Specifically, at least 29% of all severe wind reports were produced by bow echoes, 20% by squall lines, 9% by supercell thunderstorms, and 7% by other convective systems not organized in a linear fashion. The occurrence of linear convective storm types that typically produce high winds (i.e., squall lines and bow echoes) were also documented over the NHP during the period of study. It was found that 51% of all squall lines and 86% of all bow echoes we...