Abstract
Conditions leading up to an outbreak of severe hailstorms in northeast Colorado are 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 large hail which was confined to a 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.
