Austin / Travis County and South Central Texas Weather Statement #1
Prepared by UT University/Incident Meteorologist Troy Kimmel
110pm CT – Saturday / 01 April 2017

.. Marginal Severe Thunderstorm Risk Tonight ..
.. Severe Thunderstorm Risk Increases after 3 to 4am Tomorrow Morning and
Continues into Early and Mid Morning Hours for Areas Along and East of
the IH35 Corridor with a Large Hail.. Damaging Straight Line Thunderstorm
Wind Threat.. and an Increasing Tornado Threat..

NWS WATCHES / ADVISORIES / WARNINGS:
There are no current NWS watches, advisories and/or warnings in effect for our IH35
corridor counties..
A severe weather watch is likely for parts of the area beginning after midnight
tonight and continuing into the morning hours tomorrow as atmospheric instability
and lift increases in an increasingly moist air mass just ahead of a vigorous upper air low
pressure area and surface cold front,
Based on current data, the threat of severe thunderstorms should end across the
IH35 corridor by mid and late morning tomorrow.

SYNOPTIC/FORECAST REASONING:
A vigorous upper level low pressure and an associated cold front will move from west to
east across the area in the overnight hours tonight into Sunday morning. Even though it’s
possible we’ll see a few thunderstorms for this afternoon into tonight, there is still some
stability in parts of our atmosphere and the best dynamics (instability and lift) will not arrive
across the IH35 corridor until after midnight tonight and then peak as the system moves
west-to-east overhead in the 3am to 10am hour time period tomorrow morning.
The severe weather risk in this event will primarily be potentially very large hail
as well as damaging straight line thunderstorm winds. In addition, there will be the risk of a
tornado or two locally but the chance of tornadoes will increase by 6am to 9am tomorrow in
areas east of IH35. Based on current data, the risk of a few rather strong tornadoes exists
tomorrow in areas to the east of the IH35 corridor over east and southeast Texas.

THREAT(S) FOR AUSTIN METRO AND IH35 CORRIDOR COUNTIES:
Severe weather threat probability –
Geographic area: Tonight/Overnight.. Areas Along and West of the IH35 corridor
Geographic area: PreDawn and Morning Hours Sunday.. Areas along the IH35 Corridor and Eastward
Time Period: 6pm today to 10am tomorrow
Main severe weather hazards expected: Larger hail.. potential of strong straight line thunderstorm
wind in areas west of the IH35 corridor through midnight tonight. After midnight and especially about
3 to 4am and forward, we’ll see the potential for larger hail and damaging thunderstorm wind as well as a
few tornadoes in areas along and east of the IH35 corridor.
***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: Low
Severe thunderstorm chances: For 4pm today to 3am tomorrow – MARGINAL
Severe thunderstorm chances: For 3 to 4am tomorrow to 10am tomorrow – ENHANCED TO MODERATE
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 marginal risk of large hail.. and strong straight line thunderstorm wind..
threat locally from about 4pm today until about 3am tomorrow morning. By the time we
get to 4 to 5am tomorrow, there are indications that the severe weather risk including
very large hail.. lsrger areas of damaging straight line thunderstorm wind damage..
and potential stronger tornadoes.. will increase rather rapidly in areas along or just to
the east of the IH35 corridor and then move eastward away from our area into southeast
Texas as well as the Brazos Valley and east Texas.
Deadly cloud-to-ground lightning will accompany any thunderstorms that occur over
the next 24 hours.
The thunderstorm/rain chances decreasing after 12 noon tomorrow…

Current KAUS Terminal Aerodrome Forecast (TAF) – Issued 231130Z ..

TUS44 KEWX 011645 AAA
 TAFAUS
 TAF AMD
 KAUS 011645Z 0117/0218 14012G22KT P6SM VCSH SCT025 BKN040
      FM012100 14015G25KT P6SM VCTS BKN035CB
      FM020000 13013KT P6SM BKN040
      FM020300 13010KT P6SM OVC012
      FM020600 13007KT 5SM BR VCSH OVC009
      FM021100 12005KT 4SM -SHRA OVC007
       TEMPO 0212/0216 3SM TSRA OVC005CB=

For Our DAL/DFW Hub Aerodromes ..
Current NWS public forecasts indicates a 30% chance of rain showers and
thunderstorms this afternoon with rain chances increasing to 60% tonight and then
holding at about 80% for tomorrow. The severe thunderstorm threat will include
larger hail.. damaging thunderstorm winds and a tornado or two between now and
about daybreak tomorrow. With thunderstorms lingering for the DAL/DFW
aerodromes tonight into most of the day tomorrow, there is the strong possibility
of delays and diversions from individual aerodromes and the ZFW center air space
especially after 8pm tonight and continue even well into the day on Sunday as this
vigorous upper air low pressure system moves across the area..

For Our HOU/IAH Hub Aerodromes ..
Current NWS public forecasts indicates a 20% chance of rain showers and
thunderstorms for the balance of the day today.. increasing to 40% by late evening
tonight.. then topping out at 80% for most of the day tomorrow. Severe thunderstorms..
some producing very large hail, extensive straight line thunderstorm wind damage as
well as tornadoes (including a few which could be strong) are possible for these
aerodromes after daybreak tomorrow and continuing through much of the day. Indications
are that this will be a dangerous outbreak of severe thunderstorms for the HOU/IAH
aerodromes. As a result, I see it as being almost a certainty that we’ll see extensive
delays and diversions tomorrow during the day from individual aerodromes and the
ZHU center air space as well as this vigorous upper air low pressure system moves
across the area.

Current FAA National Airspace Status

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

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