20th Conference on Severe Local Storms

P7.5

WSR-88D mesocyclone characteristics of selected thunderstorms during the Southwest Georgia Tornado Outbreak of 13–14 February 2000

T. J. Turnage, NOAA/NWS, Tallahassee, FL; and R. R. Lee and E. D. Mitchell

On 13-14 February 2000 a series of deadly tornadic thunderstorms moved over southwest Georgia. Ground and aerial surveys revealed well-defined damage tracks from three separate, strong tornadoes, each of which produced fatalities. The first tornado devastated the outskirts of Camilla, and was well-detected by the Tallahassee Florida WSR-88D. Less than an hour later, the WSR-88D detected a comparably strong circulation that followed a track nearly identical to the Camilla tornado. Aerial surveys could not detect damage associated with this second circulation. A separate supercell spawned the second and third tornadoes, which occurred near Meigs and Omega, respectively. The time separation between the end of the Meigs tornado and the beginning of the Omega tornado was estimated to be only 32 minutes.

Archive II data recorded on the Tallahassee WSR-88D during these events will be analyzed, and compared with the locations of the tornado damage tracks to estimate the exact times the tornadoes occurred. The forecast skill of the WSR-88D Tornado Detection Algorithm (TDA) will then be assessed using scoring procedures devised by the WSR-88D Operational Support Facility (OSF). Various settings of Adaptable Parameters for the TDA will be analyzed to determine the optimum configuration of settings for detecting these tornadoes. These optimized settings will then be compared to the default TDA settings.

The implications of using only these events to optimize TDA settings will be discussed. The optimized TDA will then be used to try to resolve a difference between the first circulation that produced the Camilla tornado and the second circulation that didn't produce a tornado over the same area. The ability of the optimized TDA to detect the separate tornadoes that occurred near Meigs and Omega will also be investigated. Finally, the evolution of spectrum width data and radar-derived mesocyclone data will be investigated to determine whether these data sources could provide tornado forecast skill comparable to the optimized TDA.

Poster Session 7, Severe Storm Detection
Thursday, 14 September 2000, 5:00 PM-6:30 PM

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