Examination of the Mesoscale Features of the GALE Coastal Front of 24-25 January 1986

Abstract

Abstract The early evolution of a coastal front that formed off the southeast coast of the United States on 24 January 1986 is examined. Satellite and radar imagery together with the intensive surface, upper0air, and aircraft observations available during GALE are combined in an analysis highlighting the low-level mesoscale features associated with the front. The main fonrtal surface appears to form as separate narrow precipitating bands of convection slowly propagate from the east and consolidate near the western edge of the Gulf Stream. The frontal zone to the west is characterized at low levels by alternate axes of convergence and divergence extending roughly parallel to the coast. The role of these semipermanent features in the evolution of the front is discussed and compared with the classical frontal, model. Analysis of the diagnostic frontogenesis terms shows that while confluence reinforces the thermal gradient locally along confluent axes, the differential in diabatic heating, arising principally...