Austin / Travis County and South Central Texas Weather Update #5 – FINAL
Prepared by UT University/Incident Meteorologist Troy Kimmel
745am CT – Tuesday / 10 April 2017

All NWS Watches Have Been Allowed to Expire for our Overnight Non Event …

Basically, a non-event across the area as the forecast precipitation over our
area never materialized. The cold front that was expected to move down through our
area, producing abundant lift, pulled up stationary to our northwest.
The dying front is what is still triggering the rain shower and thunderstorm activity
to our north around the Temple/Belton/Fort Hood area.

As daytime heating develops, we could still see scattered few rain showers and
thunderstorms develop today but the rain chances are greatly reduced across the
area. Rainfall that does develop will generally produce rainfall of 1/4 inch or less
with heavier totals possible in the coastal plains southeast of Austin.

Sorry for the horrible forecast for the IH35 corridor over the last 24 hours, but
remember that weather forecasting is an imperfect science. This is especially true, in
my opinion, given what I see as over reliance on computer models. Remember, day in
and day out, all weather forecasts still enjoy a pretty high accuracy rate.. but this will not
be the case every time.

This my final statement on this non-event.

tk

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Austin / Travis County and South Central Texas Weather Update #4
Prepared by UT University/Incident Meteorologist Troy Kimmel
240pm CT – Monday / 10 April 2017

Includes Travis and All Surrounding Counties Now Until 11pm…

.. Authority / NWS Storm Prediction Center ..

 

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 139
NWS Storm Prediction Center Norman OK
225 PM CDT Mon Apr 10 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Southwest Arkansas
  Far northwest Louisiana
  Far southeast Oklahoma
  Central and northeast Texas

* Effective this Monday afternoon and evening from 225 PM until
  1100 PM CDT.

* Primary threats include...
  Scattered damaging winds and isolated significant gusts to 75
    mph possible
  Scattered large hail and isolated very large hail events to 3
    inches in diameter possible

SUMMARY...Thunderstorms will become increasingly numerous and likely
widespread by evening as a cold front pushes south-southeast across
the region. Large hail will be most likely initially, transitioning
to mainly damaging winds as one or more lines of storms likely
forms.

The severe thunderstorm watch area is approximately along and 90
statute miles north and south of a line from 80 miles southwest of
Junction TX to 10 miles east southeast of Texarkana AR. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 138...

AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
26025.

...Grams

tk

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Austin / Travis County and South Central Texas Weather Update #3
Prepared by UT University/Incident Meteorologist Troy Kimmel
1225pm CT – Monday / 10 April 2017

Special Attention ABIA Operations
(given possibility of DFW/DAL diverts, etc)

.. Authority / NWS Storm Prediction Center ..

 

Mesoscale Discussion 0476
 NWS Storm Prediction Center Norman OK
 1217 PM CDT Mon Apr 10 2017
 
 Areas affected...Parts of central through northeast Texas and
 adjacent southeast Oklahoma
 
 Concerning...Severe potential...Watch likely 
 
 Valid 101717Z - 101945Z
 
 Probability of Watch Issuance...95 percent
 
 SUMMARY...Thunderstorm development, accompanied by the risk for
 severe hail and locally strong surface gusts, is expected to
 increase across parts of central through northeast Texas (and
 adjacent areas of southeast Oklahoma), including much of the
 Dallas-Fort Worth Metroplex, through 2-4 pm CDT.  A watch will
 likely be needed.
 
 DISCUSSION...Objective analysis suggests inhibition is already
 becoming increasingly negligible for moist boundary layer parcels
 within at least a narrow pre-frontal corridor, from the Edwards
 Plateau region into the Red River vicinity of northeast Texas and
 adjacent southeast Oklahoma.  This appears largely in response to
 insolation, but probably has been aided by at least weak lower/mid
 tropospheric cooling, on the southern fringe of a belt of stronger
 southwesterly mid/upper flow (extending across the south central
 Plains into the Great Lakes region).  This regime appears to be
 characterized by 500 mb winds of 35-40+ kt, and deep layer mean flow
 around 30 kt, though low-level wind fields and shear are rather
 modest.
 
 Models suggest that further weakening of inhibition will allow for
 the initiation and gradual increase in thunderstorm activity through
 the 19-21Z time frame, in the presence of moderately large mixed
 layer CAPE on the order of 2000+ J/kg.  Isolated deep convective
 development may already be underway above/to the cool side of the
 front, west of Sherman TX and north of San Angelo TX.  However, this
 is largely expected to become focused in stronger surface
 convergence near/just ahead of the front.  Additional storm
 development may not be out of the question near a zone of enhanced
 mid-level warm advection, on the northern edge of more strongly
 capping elevated mixed layer air, extending roughly southeast of San
 Angelo TX through the Austin TX vicinity.
 
 The environment appears conducive to severe hail and locally strong
 surface gusts in initial activity, before storm consolidation and
 upscale growth becomes increasingly probable later this afternoon.
 
 ..Kerr/Grams.. 04/10/2017
 
 ...Please see www.spc.noaa.gov for graphic product...
 
 ATTN...WFO...SHV...TSA...HGX...FWD...OUN...EWX...SJT...
 
 LAT...LON   31190003 31649865 32529763 33049739 33489698 34169603
             34329579 33899517 31909622 30789662 30009707 30159809
             30399946 30760076 31190003

 

tk

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Austin / Travis County and South Central Texas Weather Statement #1
Prepared by UT University/Incident Meteorologist Troy Kimmel
800am CT – Monday / 10 April 2017

.. Slight Risk of Severe Thunderstorms and Heavy Rain Later Today
through Tonight ..

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 possible for our area between 3pm today and 3am
tomorrow as an unstable air mass and plenty of low level moisture combines with
a southeastward moving surface cold front to cause widespread rain shower and
thunderstorm activity to increase and peak over our area.

SYNOPTIC/FORECAST REASONING:
A surface cold front will move southeastward into our area later today with an increasingly
moist and unstable air mass in place. As a result, numerous rain showers and thunderstorms
will develop area wide with the potential for a few reports of larger hail as well as damaging
straight line thunderstorm wind. In addition, given the expected weakening of the front
overhead later tonight into early Tuesday, we can expect some periods of heavier rain tonight
to around daybreak Tuesday.

Current NWS/Weather Prediction Center and NWS/West Gulf River Forecast Center
rainfall guidance suggests that area rainfall should average 1 to 3 inches with isolated higher
totals. Urban and small stream flooding along with some flash flooding is possible where the
rainfall is heavier.

Precipitation will decrease by the morning into midday tomorrow as the cold front continues
to weaken and the thunderstorms move into South Texas and to along the Texas coast.

THREAT(S) FOR AUSTIN METRO AND IH35 CORRIDOR COUNTIES:
Severe weather threat probability –
Geographic area: All of our area
Time Period: 3pm today to 3am tomorrow
Main severe weather hazards expected: Larger hail.. potential of strong straight line thunderstorm wind
***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: Moderate
Severe thunderstorm chances: 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 slight large hail and strong straight line thunderstorm wind risk
from about 3pm today until 6am tomorrow morning. Numerous rain
showers and thunderstorms will affect the AUS aerodrome as the weakening
cold front approaches the area and then moves overhead.
Deadly cloud-to-ground lightning will accompany thunderstorms.
The thunderstorm/rain chances will slowly decrease during the morning..
midday into early afternoon hours tomorrow.

Current KAUS Terminal Aerodrome Forecast (TAF) – Issued 101125Z ..

FTUS44 KEWX 101125
 TAFAUS
 TAF
 KAUS 101125Z 1012/1118 15008KT P6SM OVC014
      FM102100 16010KT P6SM TSRA BKN015CB PROB30 1022/1102 4SM TSRA
       OVC010CB
      FM110300 15007KT 4SM -TSRA OVC007CB=

. For Our DAL/DFW Hub Aerodromes ..
Current NWS public forecasts indicates a 60% chance of rain showers and
thunderstorms today through tonight then decreasing to 50% tomorrow. There
is a SLIGHT risk of severe thunderstorms for the aerodromes mainly later today
through about 12 midnight tonight. Larger hail and damaging thunderstorm winds
are the primary risk. There is a very high possibility of delays and diversions from
individual aerodromes and the ZFW center air space this afternoon into tonight
as thunderstorms peak over the area.

For Our HOU/IAH Hub Aerodromes ..
Current NWS public forecasts indicates a 20% chance of rain showers and
thunderstorms today.. increasing to 30% tonight.. then increasing to 50% for
the daytime hours tomorrow. The risk of severe thunderstorms will primarily
remain west through southwest of the upper Texas coast. There is
still a possibility of delays and diversions from individual aerodromes and the
ZHU center air space mainly tomorrow as thunderstorm probabilities peak over
and to the southwest of the area.

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