Tornadic supercells in hurricane katrina: a high-resolution modeling study

Embedded supercells within rainbands located in the northeast quadrant of a landfalling hurricane are not uncommon. While early research efforts focused primarily on the location and timing of these mesoscale events, technological advances in remote sensing have allowed more recent research to focus on analysis of these phenomena within the traditional mid-latitude severe weather framework. However, the dynamics of the tornado itself within the hurricane are still relatively unexplored. This paper investigates the tornado outbreak that occurred in the outer rainband of Hurricane Katrina located over the Alabama-Georgia border from 1800 UTC 29 August 2005 to 0500 UTC 30 August 2005. The University of Wisconsin Nonhydrostatic Modeling System (UW-NMS) was used in a 5-grid configuration, allowing a horizontal resolution of 100m on the innermost grid. The simulation shows that embedded mesocyclones formed within the northeast quadrant of the tropical cyclone, and the evolution of these supercells was influenced by dry air intrusions and wind shear in the middle and lower troposphere respectively. A thorough analysis of these and other influences on the supercells will be presented.