Austin / Travis County and South Central Texas Weather Statement #1
Prepared by UT University/Incident Meteorologist Troy Kimmel
150pm CT – Tuesday / 28 March 2017
.. Marginal to Slight Risk of Severe Thunderstorms Late Tonight into Tomorrow Morning ..
NWS WATCHES / ADVISORIES / WARNINGS:
There are no current NWS watches, advisories and/or warnings in effect for our IH35
corridor counties..
Based on the current NWS/Storm Prediction Center Days 1 and 2 outlooks (and the marginal
to slight risk of severe thunderstorms).. I feel that a severe weather watch is possible for
portions or all of our area between 12 midnight tonight into the morning rush hour tomorrow
morning as the dynamics (atmospheric instability and lift), associated with a passing upper air
low pressure area and surface cold front, increase and peak over our area.
SYNOPTIC/FORECAST REASONING:
A strong upper level low pressure and an associated cold front will move from west to
east across the area in the overnight hours tonight. The best dynamics (instability and lift)
will remain just to our north through northwest and north but will be enough for the primary
risks of larger hail and damaging straight line thunderstorm wind. Given the nature and the
closeness of the dynamics with this system, there is a slim risk of an isolated tornado. One
of the negative factors with this system is the time of day.. with it passing in the middle of the
night it is going to be without the benefit of daytime heating. I still think that the dynamic
nature of the system would be able to compensate for this lack of daytime heating.
Current NWS/Weather Prediction Center rainfall guidance suggests that rainfall should
remain in the 1/2 to 1 1/2 inch range with this progressive system.. given this and the fact that
our soils are not saturated, the risk of flooding is fairly low.
The upper level system and associated weak cold frontal passage should pass west to east of
the area by the 6 to 9am hour tomorrow with the threat of any strong thunderstorms ending quickly
as drier.. more stable air arrives and skies clear midday into afternoon.
THREAT(S) FOR AUSTIN METRO AND IH35 CORRIDOR COUNTIES:
Severe weather threat probability –
Geographic area: All areas of the IH35 corridor of south central Texas
Time Period: 12 midnight to 7am tomorrow morning
Main severe weather hazards expected: Larger hail.. potential of strong straight line thunderstorm
wind; a slim risk of a tornado mainly in areas north through west of the Austin area proper.
***REMEMBER, DANGEROUS CLOUD-TO-GROUND LIGHTNING SHOULD BE EXPECTED
TO OCCUR WITH ANY THUNDERSTORMS THAT DEVELOP OR MOVE INTO OUR AREA***
MY FORECAST CONFIDENCE:
Weather system evolution: Very high
Precipitation chances: Very high
Liquid precipitation (rain) chances: Very high
Thunderstorm/lightning chances: Very high
Flash flood potential: Very low
Severe thunderstorm chances: MARGINAL TO SLIGHT (Main risks being large hail.. straight line thunderstorm wind)
Freezing precipitation (freezing rain/freezing drizzle) chances: None
Frozen precipitation (snow/ice pellets-sleet) chances: None
LATEST OBSERVATIONS AND MY THOUGHTS:
n/a
AVIATION INFORMATION FOR THE AUSTIN/BERGSTROM
INTERNATIONAL AIRPORT (KAUS) AERODROME:
There is a large hail.. and strong straight line thunderstorm wind..
threat from about 12 midnight tonight until 7am early tomorrow morning. Scattered to
numerous rain showers and thunderstorms will affect the AUS aerodrome as the upper
air low pressure storm system and associated weak cold front passes by 7 to 8am.
Deadly cloud-to-ground lightning will accompany thunderstorms.
The thunderstorm/rain chances decreasing after 8 to 9am tomorrow morning…
Current KAUS Terminal Aerodrome Forecast (TAF) – Issued 281721Z ..
FTUS44 KEWX 281721
TAFAUS
TAF
KAUS 281721Z 2818/2924 17017G27KT P6SM BKN035
FM290200 15016KT P6SM BKN018
FM291000 28025G35KT 3SM TSRA BR OVC012CB
FM291200 15005KT P6SM VCSH OVC040
FM291500 19007KT P6SM BKN250=
. For Our DAL/DFW Hub Aerodromes ..
Current NWS public forecasts indicates a 20% chance of rain showers and
thunderstorms this afternoon increasing to 100% after 11pm to 12 midnight tonight.
There will be a severe thunderstorm threat.. including large hail, damaging
thunderstorm winds and a tornado risk for these aerodromes. The threat will end
by 7 to 8am in the morning although the activity will be moving eastward and will
still be east of the aerodromes and will affect airspace in the morning hours. There
is a possibility of delays and diversions from individual aerodromes and the ZFW
center air space overnight into tomorrow morning even though it will be occurring
overhead of the aerodromes in a period of greatly reduced overall/commercial flight
activity in the overnight hours.
For Our HOU/IAH Hub Aerodromes ..
Current NWS public forecasts indicates a 20% chance of rain showers and
thunderstorms by later tonight increasing to 80% for all day tomorrow. There will be
a severe thunderstorm threat.. including large hail, damaging thunderstorm winds
and a tornado risk for these aerodromes for the day tomorrow. Rain chances will
decrease by tomorrow evening for all aerodromes as the upper air system departs to
the northeast. Based on current guidance, there are strong indications of extensive
delays and diversions from individual aerodromes and, for that matter, the ZHU center
air space overall tomorrow into tomorrow night as this storm system moves through the
area. Preparations should be made for this strong possibility.
Current FAA National Airspace Status
CALL TO ACTION:
Please remain “weather aware” and listen for the latest weather statements,
advisories, watches and warnings from the National Weather Service.
Make sure that your NOAA All Hazards Weather Radio is operational and are
set to alarm in case of severe and inclement weather watches and/or warnings.
FOLLOWUP STATEMENTS:
I will continue to keep you informed regarding this severe/inclement weather
event. Any questions, please let me know at tkimmel@austin.utexas.edu
GENERAL WEATHER INFORMATION LINKS:
NWS/Austin-San Antonio Current Statements/Advisory/Watches/Warnings
NWS/Austin-San Antonio Web Page
NWS/Storm Prediction Center (Outlooks)
NWS/Storm Prediction Center (Mesoscale Discussions – Severe Weather & Snow)
NWS/Storm Prediction Center (Severe Thunderstorm/Tornado Watches)
NWS/Weather Prediction Center (Mesoscale Discussions – Heavy Rain & Flooding)
NWS/National Hurricane Center
tk