21st Conf. on Severe Local Storms and 19th Conf. on Weather Analysis and Forecasting/15th Conf. on Numerical Weather Prediction

Thursday, 15 August 2002
Possible Tornadogenesis Mechanism During the 15 November 2001 South Texas Coastal Bend Event
Waylon G. Collins, NOAA/NWS, Corpus Christi, TX
Poster PDF (813.1 kB)
Radar analyses (from a single WSR-88D) was performed of two F1 tornadoes that occurred over the Texas Coastal Bend on 15 November 2001. The tornadoes were associated with storms that possessed at least some supercell characteristics, consistent with the near storm environment. Available radar data suggest that the tornadoes formed via updraft stretching of pre-existing vertical vorticity, followed by additional stretching via downdraft convergence. Evidence suggestive of updraft stretching was available 20-30 minutes in advance of the initial tornado reports for each case. However, data was not available to rule out other tornadogenesis mechanisms, such as those associated with the tilting term.

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