Thursday, 30 October 2008: 5:15 PM
North & Center Ballroom (Hilton DeSoto)
The Serranías del Burro (SdB) mountains make up the northern portion of the Sierra Madre Oriental in northeast Mexico. This region has long been observed to be favorable for supercell thunderstorm development. Many times these supercells cross the Rio Grande into the United States, causing significant damage in Texas. A radar climatology of these storms is presented using the KDFX (Laughlin Air Force Base) WSR-88D radar. The climatology covers the operational lifetime of the KDFX radar from its commissioning in January, 1996, to May, 2007. Supercells were identified using specific radar criteria that required echoes to have a characteristic reflectivity structure, gate-to-gate shear of at least 20 ms-1, and persistence for at least 30 minutes. A serially complete data set was developed that included all clear air days, days with convection, and potential supercell days over the SdB. A partial sample of 92 storms from potential supercell days was investigated. From this sample, 76 supercells were identified, of which 21 crossed into Texas. April and May were the peak months, as 65% of SdB supercells formed during those months, with a secondary peak occurring in October. The median lifetime of SdB supercells was found to be 94 minutes, slightly longer than average supercell duration. These supercells formed almost exclusively between 1900 UTC and 0500 UTC, with the median onset time being 2300 UTC. While future work will expand the dataset and extend the examination of supercell motion and environment, this study provided some initial operational forecast guidelines for the National Weather Service offices serving areas of Texas adjacent to the SdB.
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