Environment and evolution of a cold-frontal mesoscale convective system

Abstract

During the late morning and early afternoon hours convection was present along and within an ~200-km zone in advance of the cold front. In advance of the main precipitation area, a series of nearly parallel rainbands formed from in situ boundary-layer cloud streets. The development and organization of these rainbands was aided by the moderate-to-large CAPE, small convective inhibition, and moderate unidirectional shear at low levels that characterized the preconvective environment over the ~200-km region ahead of the cold front. The discrete eastward progression of convection afforded by the formation of the rainbands in advance of the main precipitation area presents a distinct departure from the propagation characteristics of many previously observed cases and idealized simulations of linearly oriented MCSs, where system propagation depends crucially on periodic regeneration of multicell convection along a storm-induced cold pool. -from Authors