Saturday, April 24, 2010

What Could Have Been .... Wasn't

Conditions were literally ripe for a significant severe weather episode along the I-35 corridor from San Antonio to Austin late yesterday evening/early this morning.  Though there were several severe reports (including a swath from San Antonio through Seguin from stronger cells that rolled through after 1am) what could have been a widespread, damaging episode simply wasn't.  As the old saying goes, we "dodged a bullet" last night/this morning - for sure!

The most interesting storms during the entire event occurred within a consistent band from near Eagle Pass to north of Crystal City.  Several of the cells that developed within this area showed rotation on numerous occasions.  I suspect there were tornado touchdowns in these areas, but due to the very rural and "spotterless" nature of the area, nothing was reported.

These same storms exhibited other classic signs of supercellular organization, including a couple of splits and a tendency to move to the right of the prevailing motion in the area (i.e., they originally started moving Northeast then turned into more of a due East motion over time).

Here is a reflectivity screenshot from the Laughlin AFB (Brackettville, TX) radar shortly after 11pm last night.  The cell immediately Northeast of Eagle Pass was in the process of splitting at the time, while the cell North of Crystal City was showing rotation on the Southwest flank.  (Sorry about the text box, that was a shot I used for a Twitter posting).

Meanwhile, numerous clusters of strong thunderstorms moved Northeast across areas West of I-35 to the West and Northwest of the San Antonio-Austin corridor throughout the late evening.  Between 12 and 1am Saturday morning, much of this activity collapsed and a strong gust front blew Southeast into the Austin-San Antonio areas.  At 12:35 a.m. I measured a 57 knot wind gust here at my home near Kyle (just South of Austin on I-35, at mile marker 217).

I attempted to upload reflectivity and velocity images of the above gust front, but I'm having technical problems right now.  I'll try again later and update this post...have to run right now.

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