During the evening of March 19, 2012, numerous supercell thunderstorms were observed across portions of the Southern Plains. One of these storms impacted areas just southwest of San Antonio, TX near the towns of Devine, Natalia and Lytle, TX. While further from the radar site (~60 miles from the radar in Austin, TX), the rotation signatures are definitely present on radar. Additionally these signatures and their paths are typical of a supercell thunderstorm that “cycles” – essentially where one area of rotation weakens, and a new area of rotation emerges. Note the time stamps (UTC times) and follow the intersection of the red/green colors along the path as the radar animation progresses. Also, note how the paths curve to the left before weakening, and then a new area of rotation emerges to the right of the old one. This is quite typical of a supercells that cycle.
We’ll learn more in the morning and as tomorrow progresses, but if I was to make an educated guess on the areas potentially impacted, they would be as follows:
- Devine – Northwest side of town
- Natalia – Starting south of town, then going through the southeast portion of town, moving along the east side of town towards the northeast.
- Lytle – Mainly east of town, but also including a portion that crosses over I-35.
Again, the following graphic is a best guess – and does NOT show where an actual tornado traveled, but it may help point towards some areas where storm survey teams might need to start looking. It will be interesting to see how this works out since the storms were so far from the radar site, but we’ll definitely know more tomorrow!
Note: Graphics were created using the National Climate Data Center (NCDC) Weather and Climate Toolkit and Level2 NEXRAD data from the KEWX radar site between 0041 UTC and 0136 UTC on 3/20/2012.