Dual-Polarization observations of Microbursts Associated with Intense Convection: The 20 July Storm during the MIST Project

Abstract

A detailed case study of the microbrust-producing storm on 20 July 1986 during the MIST Project is presented, together with visual (based on cloud photogrammetry) and radar observations during the life cycle of the storm. In particular, multiparameter radar information is seen to have important implications for operational detection of this wind shear event. Noteworthy is the observation of a small shaft (less than 1 km in horizontal dimensions) of near zero differential reflectivity (ZDR) surrounded by large positive ZDR values in the main precipitation core within a microburst-producing downdraft. This ?ZDRZm-Hole-Hole? implies a strong localized downdraft composed of melting hail.