Alert archive / Texas / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 127, NWS Austin/San Antonio, TX

May 17, 20214 counties in Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 17, 2021, 1:00 PM CDT for 4 counties in Texas. It was in force for 60 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 17, 2021, 1:00 PM CDT (18:00 UTC)
Expired
May 17, 2021, 2:00 PM CDT
In force
60 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Blanco County, TX, Burnet County, TX, Travis County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 69 km from the middle of the area, began a volume at 18:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 6.0 hours before the alert went out and 279 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Fort Worth, TX at 12:00Z on 2021-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2021-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2 J/kg
Mixed-layer CIN
-203 J/kg
Mixed-layer LCL
1295 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

566 
WUUS54 KEWX 171800
SVREWX
TXC031-053-453-491-171900-
/O.NEW.KEWX.SV.W.0127.210517T1800Z-210517T1900Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Austin/San Antonio TX
100 PM CDT Mon May 17 2021

The National Weather Service in Austin San Antonio has issued a

* Severe Thunderstorm Warning for...
  Southwestern Williamson County in south central Texas...
  Western Travis County in south central Texas...
  Northeastern Blanco County in south central Texas...
  South central Burnet County in south central Texas...

* Until 200 PM CDT.

* At 100 PM CDT, a severe thunderstorm was located over Smithwick, or
  8 miles east of Marble Falls, moving southeast at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Austin, Round Rock, Cedar Park, Pflugerville, Anderson Mill,
  Windemere, Leander, Lakeway, Lago Vista, Bee Cave, West Lake Hills,
  Hudson Bend, The Hills, Rollingwood, Spicewood, Barton Creek, Shady
  Hollow, Smithwick, Mansfield Dam and Jonestown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail, damaging winds, and continuous cloud to ground lightning
are occurring with this storm. Move indoors immediately. Lightning is
one of nature's leading killers. Remember, if you can hear thunder,
you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3046 9761 3015 9787 3028 9807 3036 9817
      3035 9818 3043 9830 3069 9813
TIME...MOT...LOC 1800Z 302DEG 26KT 3053 9814 

HAIL...1.00IN
WIND...60MPH
 
$$

PLATT
2 follow-up statements
909 
WWUS54 KEWX 171829
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
129 PM CDT Mon May 17 2021

TXC031-053-171838-
/O.CAN.KEWX.SV.W.0127.000000T0000Z-210517T1900Z/
Blanco TX-Burnet TX-
129 PM CDT Mon May 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN BLANCO AND SOUTH
CENTRAL BURNET COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3046 9761 3015 9787 3028 9807 3036 9816
      3056 9796
TIME...MOT...LOC 1828Z 303DEG 19KT 3042 9799 

$$

TXC453-491-171900-
/O.CON.KEWX.SV.W.0127.000000T0000Z-210517T1900Z/
Williamson TX-Travis TX-
129 PM CDT Mon May 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM CDT
FOR SOUTHWESTERN WILLIAMSON AND WESTERN TRAVIS COUNTIES...

At 128 PM CDT, a severe thunderstorm was located over Lago Vista, or
11 miles west of Anderson Mill, moving southeast at 25 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Austin, Round Rock, Cedar Park, Pflugerville, Anderson Mill,
Windemere, Leander, Lakeway, Lago Vista, Bee Cave, West Lake Hills,
Hudson Bend, The Hills, Rollingwood, Barton Creek, Shady Hollow,
Mansfield Dam, Jonestown, Briarcliff and Point Venture.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

If on or near Lake Travis, get away from the water and move indoors 
or inside a vehicle. remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3046 9761 3015 9787 3028 9807 3036 9816
      3056 9796
TIME...MOT...LOC 1828Z 303DEG 19KT 3042 9799 

HAIL...1.00IN
WIND...60MPH
 
$$

PLATT
045 
WWUS54 KEWX 171852
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
152 PM CDT Mon May 17 2021

TXC453-491-171901-
/O.EXP.KEWX.SV.W.0127.000000T0000Z-210517T1900Z/
Williamson TX-Travis TX-
152 PM CDT Mon May 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WILLIAMSON AND
WESTERN TRAVIS COUNTIES WILL EXPIRE AT 200 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However hail, 
gusty winds and heavy rain are still possible with this thunderstorm.

LAT...LON 3046 9761 3015 9787 3028 9807 3036 9816
      3056 9796
TIME...MOT...LOC 1851Z 302DEG 26KT 3035 9785 

$$

PLATT

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 17, 9:21 AM CDTRiver Flood WarningEWXFrio19 hr
May 17, 11:36 AM CDTSpecial Weather StatementEWXBurnet54 min
May 17, 11:58 AM CDTSpecial Weather StatementEWXBurnet47 min
May 17, 12:05 PM CDTSevere Thunderstorm WarningEWXBurnet, Llano55 min
May 17, 1:53 PM CDTSpecial Weather StatementEWXBastrop, Hays, Travis, Williamson52 min
May 17, 2:34 PM CDTFlash Flood WatchEWXAtascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 19 more55 hr
May 17, 2:37 PM CDTSpecial Weather StatementEWXComal38 min
May 17, 3:16 PM CDTSpecial Weather StatementEWXFayette, Gonzales44 min
May 17, 3:25 PM CDTAreal Flood AdvisoryEWXFayette3 hr
May 17, 3:51 PM CDTSpecial Weather StatementEWXComal39 min
May 17, 3:59 PM CDTSpecial Weather StatementEWXGonzales, Lavaca61 min
May 17, 4:15 PM CDTAreal Flood AdvisoryEWXGonzales, Lavaca2 hr
May 17, 5:05 PM CDTSpecial Weather StatementEWXLavaca40 min
May 17, 6:08 PM CDTSpecial Weather StatementEWXVal Verde52 min
May 17, 6:11 PM CDTSpecial Weather StatementEWXDimmit49 min
May 17, 6:46 PM CDTSpecial Weather StatementEWXDimmit44 min
May 17, 6:48 PM CDTSevere Thunderstorm WarningEWXVal Verde41 min
May 17, 6:50 PM CDTSevere Thunderstorm WarningEWXDimmit25 min

Nearby

Severe Thunderstorm Warnings in Texas, 2021Every severe thunderstorm warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.