Alert archive / Texas / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 88, NWS Austin/San Antonio, TX

May 21, 2011Burnet County, Williamson County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 21, 2011, 9:14 PM CDT for Burnet County, Williamson County, Texas. It was in force for 46 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 21, 2011, 9:14 PM CDT (02:14 UTC)
Expired
May 21, 2011, 10:00 PM CDT
In force
46 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon

Counties Burnet County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 56 km from the middle of the area, began a volume at 02:16 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.

What was reported inside it

TimeReportWhereRemark
May 21, 9:24 PM CDTHAIL 11 N Bertram, TX

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 2.2 hours before the alert went out and 240 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 00:00Z on 2011-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3908 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 00:00Z on 2011-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.193958Sfc1 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
3908 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
978 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
188 m²/s²
Significant tornado parameter
3.2
Supercell composite
16.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

161 
WUUS54 KEWX 220214
SVREWX
TXC053-491-220300-
/O.NEW.KEWX.SV.W.0088.110522T0214Z-110522T0300Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
914 PM CDT SAT MAY 21 2011

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL BURNET COUNTY...
  WEST CENTRAL WILLIAMSON COUNTY...

* UNTIL 1000 PM CDT.

* AT 906 PM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE          
  THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL TO BASEBALL SIZE       
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS      
  LOCATED NEAR BERTRAM...AND MOVING EAST AT 15 MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE MAHOMET AND LIBERTY HILL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3081 9787 3062 9791 3067 9813 3085 9808
TIME...MOT...LOC 0213Z 283DEG 14KT 3074 9799

$$
1 follow-up statement
729 
WWUS54 KEWX 220249
SVSEWX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
949 PM CDT SAT MAY 21 2011

TXC053-491-220300-
/O.CON.KEWX.SV.W.0088.000000T0000Z-110522T0300Z/
BURNET TX-WILLIAMSON TX-
949 PM CDT SAT MAY 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT
FOR WEST CENTRAL WILLIAMSON AND EAST CENTRAL BURNET COUNTIES...

AT 943 PM CDT...NWS METEOROLOGISTS CONTINUED TO DETECT A SEVERE 
THUNDERSTORM CAPABLE OF PRODUCING UP TO QUARTER SIZE HAIL...AND 
DAMAGING WINDS UP TO 60 MPH.  THIS STORM WAS LOCATED NEAR 
MAHOMET...OR 8 MILES EAST OF BERTRAM...MOVING EAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS
OF THE INDICATED COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3070 9807 3085 9806 3081 9788 3075 9788
      3069 9790
TIME...MOT...LOC 0249Z 271DEG 16KT 3075 9790

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 21, 7:10 PM CDTSevere Thunderstorm WarningEWXBurnet, Travis, Williamson50 min
May 21, 7:27 PM CDTTornado WarningEWXBurnet, Williamson33 min
May 21, 7:44 PM CDTSevere Thunderstorm WarningEWXBurnet, Williamson46 min
May 21, 7:50 PM CDTSevere Thunderstorm WarningEWXBurnet, Llano40 min
May 21, 7:59 PM CDTTornado WarningEWXBurnet, Williamson31 min
May 21, 8:08 PM CDTAreal Flood AdvisoryEWXBurnet, Williamson112 min
May 21, 8:11 PM CDTTornado WarningEWXBurnet, Llano34 min
May 21, 8:27 PM CDTSevere Thunderstorm WarningEWXWilliamson48 min
May 21, 8:27 PM CDTTornado WarningEWXWilliamson33 min
May 21, 8:32 PM CDTSevere Thunderstorm WarningEWXBurnet43 min
May 21, 8:44 PM CDTTornado WarningEWXBurnet31 min
May 21, 8:59 PM CDTTornado WarningEWXWilliamson31 min

Nearby

Severe Thunderstorm Warnings in Texas, 2011Every severe thunderstorm warning in 2011

Sources

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