Exploring the possible existence of embedded supercell thunderstorms

A supercell thunderstorm is a thunderstorm consisting of a quasi-steady, rotating updraft, that may exist for several hours. Supercell thunderstorms are almost always associated with some type of severe weather, such as damaging winds, hail or tornadoes. The focus of this research is what are often refer to as “embedded” supercell thunderstorms, or, supercells that purportedly exist within a much larger area of rainfall. This is questioned theoretically because, by definition, a supercell thunderstorm must be able to sustain itself by virtue of its own unique dynamics. Thus, this research attempts to find observational evidence of supercell thunderstorms that are embedded in a larger-scale precipitation system yet still maintain their own unique characteristics.

Potential cases were identified using the Mesoscale Discussions produced daily by the NWS Storm Prediction Center. A keyword search of “embedded supercell thunderstorms” in all Mesoscale Discussions during the period 2007-2008 yielded 31 cases. WSR-88D data for each case were then processed using the Warning Decision Support System-Integrated Information software package. Analysis of general characteristics such as (longevity and extent and existence of precipitation breaks) was first performed. From there, a more detailed analysis of individual storm cells was performed to determine storm intensity, degree of updraft rotation, height, and direction of movement, and therefore determine if the cell had the necessary criteria to be deemed a supercell thunderstorm.