Troy Kimmel Weather

Forecasting Austin and South Central Texas Weather Since 1984

Weather Update (915am – Fri/04Sep2020)

ALL / Austin, Travis County and South Central Texas Weather Update #x
Prepared by UT University/Incident Response Meteorologist Troy Kimmel
915am CT – Friday / 04 September 2020

My Observations/Thoughts…
With morning rainfall and our ground increasingly becoming saturated, I’m getting a bit
more concerned with the slow moving rain showers and thunderstorms overhead. In addition
to the NWS/Austin-San Antonio issued Flash Flood WARNING for southern metro Austin..
the NWS/Weather Prediction Center has now voiced their concern as well.. see below..

Remember.. Turn Around, Don’t Drown!

I’m continuing to monitor..
tk

… Authority / NWS Austin-San Antonio …

Image

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
830 AM CDT Fri Sep 4 2020

The National Weather Service in Austin/San Antonio has issued a

* Flash Flood Warning for...
  East Central Hays County in south central Texas...
  South Central Travis County in south central Texas...

* Until 1130 AM CDT.

* At 830 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Doppler radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Austin, Kyle, Buda, Tanglewood Forest, Mustang Ridge, Niederwald, 
  Bear Creek, Onion Creek, Shady Hollow, Manchaca, San Leanna, Hays, 
  Creedmoor and McKinney Falls State Park.


… Authority / NWS Weather Prediction Center / College Park, MD …

 

Mesoscale Precipitation Discussion: #0713
(Issued at 1005 AM EDT Fri Sep 04 2020 )
MPD Selection

Graphic for MPD #0713

Mesoscale Precipitation Discussion 0713
NWS Weather Prediction Center College Park MD
1005 AM EDT Fri Sep 04 2020

Areas affected...central TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 041402Z - 041830Z

SUMMARY...Slow-moving showers and thunderstorms with rainfall
rates up to 2 inches in 3o minutes will continue a flash flood
threat over parts of central TX through 18Z.

DISCUSSION...GOES East water vapor imagery showed a slow moving
mid-level low over the Edwards Plateau with a trough axis
extending northeastward from the low into northeastern TX. Water
vapor imagery also showed higher mid-upper level moisture east of
the trough axis, with dry air to the west. Precipitable water
values from the 12Z RAOBs and GPS sensors ranged from about 1.7 to
2.1 inches along and east of the mid-level trough. Radar imagery
through 1345Z displayed scattered slow moving showers and
thunderstorms near I-35, between Hillsboro and New Braunfels.

While wind shear is weak (850-300 mb mean wind < 10 kt) which will
limit storm organization and longevity, VAD wind plots identified
a slightly enhanced region of southerly 850 mb flow, ranging
between 10-15 kt, located between KDFX and KEWX. This corridor of
enhanced 850 mb flow will help to support training as individual
cells should tend slowly track toward the north while regeneration
occurs on the south side.

Storms have had a history of intense rainfall rates, with several
observations supporting 0.5 inches in 10 minutes, 0.5 to 1 inch in
20 minutes and values approaching 2 inches in 30 minutes from
12-13Z near I-35, south of Austin. Portions of central TX have
seen heavy rain over the past 24-48 hours which may increase the
flash flood threat given the potential for overlap of additional
heavy rain.

Otto

Weather Update – Severe Thunderstorm Risk Increasing for Tomorrow into Tomorrow Night (235pm CT Tues/26May2020)

ALL / Austin, Travis County and South Central Texas Weather Update #10
Prepared by UT University/Incident Response Meteorologist Troy Kimmel
235pm CT – Tuesday / 26 May 2020

… Chances Increasing for Another Round of Severe Thunderstorms Tomorrow into Tomorrow Night …
… Threat of Large Hail, Damaging Straight Line Thunderstorm Wind and a Few Tornadoes …

A trough, or line, of upper level low pressure continues over the central USA. As a smaller low pressure disturbance.. moving east southeastward in the counter clockwise flow around this trough.. moves into our area by tomorrow afternoon into tomorrow night and times with maximum daytime heating, abundant low level moisture and more than adequate atmospheric instability, we’ll see the possibility of a few stronger, potentially severe, thunderstorms along the IH35 corridor.

In the day two severe thunderstorm outlook, the NWS/Storm Prediction Center originally posted for our area, a “marginal” to “slight” risk (levels 1, 2 of 5), then upgraded to a “enhanced” risk (level 3 of 5) at midday today for severe thunderstorms for our area tomorrow into tomorrow night; the main risks being mentioned include large hail, strong/damaging straight line thunderstorm wind and even a few tornadoes.

Dangerous lightning will also be a risk around any thunderstorms.

Day 2 Severe Thunderstorm Outlook (7am Wednesday to 7am Thursday)…
https://www.spc.noaa.gov/public/fema/images/fema06_swody2.png
(Courtesy NWS/Storm Prediction Center)

In addition to the severe thunderstorm threat, we could see some localized nuisance flooding problems as these thunderstorms move through our area. NWS/Weather Prediction Center forecast rainfall amounts are generally an 1 inch or less, so as long as we use common sense and remember to “turn around, don’t drown,” we should be in good shape.

Days 1-3 Rainfall Forecast (7am today through 7am Friday)…
zzzzz
(Courtesy NWS/Weather Prediction Center and NWS/West Gulf River Forecast Center)

Let’s continue to be weather aware and listen for the latest information from the NWS/Austin San Antonio as this next system approaches the area.

I’ll continue to monitor..
tk


Reminders…
I encourage everyone to be weather aware. Know, in advance, the difference between a
NWS issued WATCH, ADVISORY and WARNING.



Always have at least two methods of getting current weather information..
.. follow me AND activate notifications on Twitter .. @troykimmelwx ..
.. have your NWS All Hazards Weather Radio properly set so it can receive and activate
when NWS watches and warnings are issued ..
.. register to receive emergency updates at https://warncentraltexas.org/
.. make sure the WEA alerts are activated in your settings on your smart phone ..
.. go to the NWS Austin-San Antonio website at weather.gov/ewx ..
.. go to http://mesonet.agron.iastate.edu/cgi-bin/afos/retrieve.py?pil=warewx&limit=20&fmt=html
for a chronological text listing (most current at the top but note the page doesn’t auto-refresh, you must refresh page manually) of NWS Austin-San Antonio watches, advisories and warnings..