Detection and Interpretation of Left-Moving Severe Thunderstorms Using the WSR-88D: A Case Study

Abstract

Left-moving supercells, which rotate anticyclonically, are much less common than their right-moving counterparts but are nevertheless capable of producing severe weather. On 26 May 1992, a severe left-moving thunderstorm over east Texas developed within range of the WSR-88D (Weather Surveillance Radar-1988 Doppler) radar at League City, Texas. The evolution of the left-moving thunderstorm, including its split from its parent thunderstorm, is presented using standard WSR-88D products. The storm produced wind damage and large hail, whose presence in the thunderstorm caused a flare echo in the return signal. No automated WSR-88D algorithms exist to detect mesoanticyclones or flares, so the subjective interpretation of these radar signatures as indicators of severe weather can be critical for the proper issuance of warnings for such storms.