Circulations Associated with a Mature-to-Decaying Midlatitude Mesoscale Convective System. Part I: Surface Features—Heat Bursts and Mesolow Development

Abstract

Abstract This study examines surface features associated with a mature-to-dissipating midlatitude mesoscale convective system that occurred on 23–24 June 1985 during the Oklahoma-Kansas Preliminary Regional Experiment for STORM-Central. The primary data sources include a 400 × 500 km surface mesonetwork on a 50 km grid, rawinsonde observations from 12 supplementary sites in Kansas and Oklahoma and radar measurements from conventional as well as dual-Doppler networks. The mesoscale convective system under investigation developed in an environment with weak vertical shear and had a lifetime of 9–12 h. It consisted in its mature stage of a southward-moving arc-shaped line of deep convective cells with a trailing stratiform precipitation region to the north. Thirty-three percent of the surface rain in the portion of the mesonetwork experiencing storm passage was from the stratiform region. An intense mesoscale downdraft developed beneath the stratiform cloud with a strong mesohigh at the surface. A wake low w...