P7.3
Rapid supercell storm and tornado development along a boundary
Kevin B. Laws, University of Alabama, Huntsville, AL; and K. R. Knupp and J. Walters
A very well documented case study involving the interaction of a pre-supercell storm with a well-defined thermal boundary is examined with a variety of data sources. The storm developed on the cold side of the boundary and then intensified upon approaching the boundary from the cold air side. Rapid storm intensification, accompanied by the development of a low-level mesocyclone and tornadogenesis occurred as the storm intersected the boundary. This paper documents the evolution of the boundary and storm using an array of 15 surface stations, the UAH Mobile Integrated Profiling System (MIPS), WSR-88D data, and GOES visible imagery. The boundary was reinforced during the preceding night by evaporative cooling of rain north of the boundary. The boundary receded northward during the morning hours from a location just south of the MIPS. Thus, the MIPS provides a good definition of the boundary structure, and of the boundary layer properties just south of the boundary. The boundary then remained in a quasi-stationary position within a network of surface stations between 1600-1900 UTC. Solar heating south of the boundary reinforced the strong temperature gradient, and the flow around the boundary exhibited increasing cyclonic shear with time. Several minor convective initiation events were associated with the boundary. Despite its sharp contrast and convergent nature, it was not well depicted in GOES visible imagery. In this case there is sufficient surface data to estimate gradients in kinematic and thermodynamic properties over the mesoscale domain where the supercell storm evolved.
Poster Session 7, Convection Initiation
Wednesday, 14 August 2002, 3:00 PM-4:30 PM
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