Troy Kimmel Weather

Forecasting Austin and South Central Texas Weather Since 1984

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TK’s Weather Discussion….

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Updated 845am CT – Monday / 12 May 2014

…. Another Round of Thunderstorms.. Some Possibly Severe.. Today into Tonight ….
…. A Flash Flood Watch in Effect Tonight Through Tomorrow Morning ….
…. A Rather Strong Cold Front Moving Through Late Tonight ….

On this Monday morning…. a strong cold front is moving southeastward from central Oklahoma southwestward into west central Texas into southern New Mexico. As a result of this surface weather pattern, our local surface winds are south southeasterly.

In the upper levels of the atmosphere… a counterclockwise rotating trough, or line, of upper air low pressure extends from the central Rockies south southwestward into northern Mexico and the Baja Peninsula. The upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground, are south southwesterly 20 to 30 mph.

As the surface cold front moves southeastward into the area by a little after midnight tonight and the upper air disturbance approaches the area from the west..  atmospheric lift and instability will be maximized. As a result, I expect a round of thunderstorms by later today  into tonight. Based on the latest NWS/Storm Prediction Center outlook, there is a “slight” risk of severe thunderstorms along with the possibility of periods of heavy rain.

The upper level disturbance out west will lag behind the cold front; as a result, rain showers
and even some thunderstorms will continue to “overrun” the much cooler surface air for about 12 to 18 hours (through the day tomorrow into tomorrow night) following the cold frontal passage.

Once the front passes and the upper level trough moves east of the area.. a drier and more stable weather pattern will prevail with a clearing sky and cooler temperatures, especially at night, through the end of the week. Surface high pressure will move east of the area by Friday allowing for a return south southeasterly surface wind by Friday into the weekend with a few clouds returning

Regarding my forecast, my local forecast confidence: My forecast confidence is medium to today into tonight (mainly regarding exact rainfall amounts as well as the potential for stronger, potentially severe, thunderstorms and flash flooding). My forecast confidence for tomorrow into tomorrow night is high to very high… and then is very high for Wednesday through our upcoming weekend.

Have a good Monday…
Meteorologist Troy Kimmel

Contact me:
[email protected]
http://www.facebook.com/troykimmel

TK’s Special Briefing….

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Austin / Travis County and South Central Texas Weather Update #1
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
730am CT – Monday / 12 May 2014

…. Strong Cold Front Due Late Tonight ….
…. Rain Showers and Thunderstorms Expected.. Some Heavy and Possibly Severe ….
…. Flash Flood Watch in Effect for the IH35 Corridor 6pm Tonight Until Noon Tomorrow ….

. Weather Discussion ..
Early this Monday morning, a strong cold front is oriented from eastern Kansas south
southwestward into western Oklahoma and far west Texas /south of Lubbock/ then west
northwestward into eastern/northern New Mexico. In the upper levels of the atmosphere..
a strong/vigorous eastward moving upper level low pressure disturbance and trough
extends south southwestward from western Colorado into northwestern Mexico and the
Baja Peninsula.

As the cold front moves southeastward into the area by a little after midnight tonight and
the upper air disturbance approaches the area from the west..  atmospheric lift and instability
will be maximized. As a result, I expect a round of thunderstorms by later today  into tonight.
There will be a “slight” risk of severe thunderstorms along with the possibility of periods of
heavy rain.

The upper level disturbance out west will lag behind the cold front; as a result, rain showers
and even some thunderstorms will continue to “overrun” the much cooler surface air for about
12 to 18 hours (through the day tomorrow into tomorrow night) following the cold frontal passage.

The NWS Storm Prediction Center has placed most of the local area is a “SLIGHT”
risk area this afternoon 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 late today into tonight and Tuesday are generally expected to be in the
one to two inch range with isolated heavier totals to 3 or more inches possible. Current flash flood
guidance for Travis County… very rough estimates of what it would take to initiate flash flooding
in a given period… is 3.1 inches in a one hour period, 4.0 inches in a three hour period and 5.2
inches for a six hour period. Flash or urban/small stream flooding is going to be a risk in areas
where heavier thunderstorms occur. As well, flash flooding is a possibility, as indicated by the
NWS’ flash flood watch. Remember the NWS slogan, “turn around, don’t drown.”

Bottom line.. let’s be weather aware again today into tonight and Tuesday… first thing this morning,
please check your NOAA/NWS All Hazards Weather Radios to make sure that the radio is in
the “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
early tonight.

I’ll continue to keep you updated.

Troy