Austin / Travis County and South Central Texas Weather Update #3 – FINAL STATEMENT
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
935pm CT – Thursday / 8 May 2014

tk

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Austin / Travis County and South Central Texas Weather Update #1
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
805am CT – Thursday / 8 May 2014

.. Weather Discussion ..
Early this Thursday morning, a surface low pressure area is over northern Kansas with a
weak cold front extending southward across western Oklahoma and northwest Texas
southwestward into southwest Texas and northern Mexico. A dry line is located to the
east of the front. In the upper levels of the atmosphere, a deep trough.. or line.. of low
pressure extends from southern Canada into Arizona and New Mexico and northern
Mexico.

As both the surface and upper air features move eastward and northeastward today, this
is creating upward lift in the atmosphere across Texas.. especially in the northern parts of
the state where the lift will be maximized. Already this morning, scattered rain and rain
showers are on going across our area. By later today.. scattered to numerous rain showers
and thunderstorms will develop and/or move into the area. Some of these thunderstorms could
be strong and produce periods of heavier beneficial rainfall.

By tonight into Friday as the upper air low pressure area moves off to our northeast and
the weak cold front washes out to our north and west, the best atmospheric dynamics will
move away from our area with the upper air disturbance and our rain chances will diminish
(although not disappearing completely).

One thing to watch today is how efficiently the deck of lower clouds break today.. this could
well be the deciding factor whether severe thunderstorms build/develop this far south.
We need daytime heating to add to the atmospheric instability and help us overcome a warmer,
more stable layer of air above.. if this doesn’t materialize, I think the severe weather risk will
be reduced a little and, as mentioned above, more likely to our north where the atmospheric
dynamics (i.e., lift) are better.

The NWS Storm Prediction Center has placed most of the local area is a “SLIGHT”
risk area today into tonight for severe thunderstorms (see map below) with the primary
hazards locally being larger hail and damaging straight line thunderstorms wind.

For the entire day one outlook and text discussion, see this web page…
http://www.spc.noaa.gov/products/outlook/day1otlk.html

Forecast rainfall amounts today into tomorrow are generally expected to be in the 1 to 2 inch
range.. but isolated heavier totals to 3 or more inches are certainly possible. Current flash flood
guidance for Travis County… very rough estimates of what it would take to initiate flash flooding…
is 3.3 inches in a one hour period, 4.3 inches in a three hour period and 5.6 inches for a six hour
period. My thought is that flash flooding, given the on going drought conditions, is a relatively
small risk. Urban and low water crossing flooding, where heavier rains fall more quickly or
persistently, especially in urban areas and considering the dry parched soils especially west of the
IH corridor, is a hazard today.. but largely, if everyone drives intelligently and remembers the
NWS slogan, “turn around, don’t drown,” this should not be a big issue as I see it at this moment.

Bottom line.. let’s remain weather aware today… please check your NOAA/NWS All Hazards
Weather Radios to make sure that they are in “stand by” mode so that they’ll automatically
alarm if and when the NWS Storm Prediction Center and/or NWS Austin-San Antonio issues
watches and warnings across the area today into tonight.

I’ll continue to keep you updated.

Troy