Structure and Evolution of Winter Cyclones in the Central United States and Their Effects on the Distribution of Precipitation. Part IV: The Evolution of a Drytrough on 8–9 March 1992

Abstract

The structure and evolution of a drytrough (i.e., a surface pressure trough that has characteristics of both a lee trough and a dryline) from the southern Great Plains to the lower Mississippi Valley are described using both observational data and outputs from a mesoscale model. An elevated zone of cold-air advection associated with a cold front aloft interacted with the drytrough over the southern Great Plains to form a structure similar to a warm occlusion. This type of structure figures importantly in a new conceptual model that has been proposed for cyclones in the central United States.