A dual-polarization investigation of tornado warned cells associated with Hurricane Rita (2005)

Warning operations during hurricane events have been known to be particularly difficult when trying to determine the tornadic potential of cells within hurricane rainbands. The Hurricane Rita (2005) outbreak proved to be an especially challenging event for National Weather Service forecast offices in Mississippi and Alabama. A dual-polarization analysis of three mini-supercells was performed in order to investigate micro-physical processes occurring within the cells. These three tornado warned cells in the Huntsville, AL, CWA were chosen to represent one of each category: tornadic, funnel-producing, non-funnel producing. A comparison among these storms and to previous dual-polarimetric studies of tornadic supercells (non-tropical) was done to discern potential tornadic indicators that would help forecasters in warning operations. It has been found that while standard reflectivity features are quite different in tropical settings than in Midwest outbreaks, dual-polarimetric features are similar in both instances. A distinct separation in K_DP and Z_DR can be seen in the tornadic case in addition to a clear Z_DR arc that has been found in previous dual-polarimetric research. These observations suggest a different size sorting process due to a collapsing updraft and increased vertical wind shear within tornadic storms.