Use of Satellite Imagery and Surface Pressure-Gradient Analysis Modified forSloping Terrain to Analyze the Mesoscale Events Preceding the Severe Hailstorms of 2 August 1986

摘要

Conditions leading up to an outbreak of severe hailstorms in northeast Coloradoare examined using satellite and surface data. A persistent mesoscale ridge of surface-high pressure, caused by outflow from a mesoscale-convective system, is seen to coincide with the occurrence of hail which was confined to narrow band extending nearly parallel to the Front Range of the Rocky Mountains. The development of the mesoscale ridge during its most intense stages is documented using a procedure that yields an approximate streamfunction for the surface geostrophic wind. Unlike alternatives over sloping terrain, this method is quick and can be adjusted to minimize the error over a limited portion of the analysis area. Reprints. (jhd)