S44 Tornadic behavior related to land-falling tropical cyclones in the United States

Sunday, 23 January 2011
Jaclyn M. Ritzman, University of Wyoming, Laramie, WY; and D. S. Arndt and M. C. Kruk

The 2004 and 2005 North Atlantic Hurricane Seasons were among the most active and economically devastating for the United States, during which eighteen tropical cyclones (TCs) made landfall. These TCs were analyzed using the International Best Tracks Archive for Climate Stewardship (IBTrACS) and Local Storm Report (LSR) datasets to determine if they produced tornadoes within a preferred quadrant and distance from the center of circulation of the TC. The land-falling TCs were tracked and analyzed through their weakening stages with tornado reports being classified based on the strength of the TC at the time of occurrence. Tornado reports were not included after the TC was classified as extratropical in the IBTrACS dataset. Over half of all tornado reports (415 out of 568) occurred when the TCs were rated at or below Tropical Storm strength. As expected, the northeast (right-front) quadrant was the most dominant area where tornadic activity occurred. In addition, there were three distinct peaks in tornadic activity occurred at distances of 75-100 nm, 175-200 nm, and 325-375 nm from the center of circulation.

Another emphasis of this work used NEXRAD data to determine the best method of identifying potential tornadic storms within land-falling TCs. Three tropical cyclones (Katrina, Rita, and Ivan) were investigated to determine which radar product should be used to diagnose tornadic activity. The most reliable radar product for the three TCs investigated was velocity couplets.

- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner