Alert archive / Texas / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 82, 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, 6:52 PM CDT for Burnet County, Williamson County, Texas. It was in force for 38 min. 2 reports 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, 6:52 PM CDT (23:52 UTC)
Expired: May 21, 2011, 7:30 PM CDT
In force: 38 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), 42 km from the middle of the area, began a volume at 23:56 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

Time	Report	Where	Remark
May 21, 6:54 PM CDT	HAIL 0.88	2 Nnw Florence, TX
May 21, 7:01 PM CDT	HAIL 0.7	4 N Briggs, TX

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 21, 1:45 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 11.9 hours before the alert went out and 222 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 87 J/kg
Mixed-layer CIN: -337 J/kg
Mixed-layer LCL: 1835 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 203 m²/s²
0-3 km storm-relative helicity: 181 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

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

841 
WUUS54 KEWX 212352
SVREWX
TXC053-491-220030-
/O.NEW.KEWX.SV.W.0082.110521T2352Z-110522T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
652 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...
  NORTHWESTERN WILLIAMSON COUNTY...

* UNTIL 730 PM CDT.

* AT 642 PM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE
  THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  BRIGGS...OR 11 MILES NORTHEAST OF BERTRAM...AND MOVING EAST AT 25
  MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE ANDICE...FLORENCE AND
  JARRELL.

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM CDT
SATURDAY EVENING FOR SOUTH CENTRAL TEXAS.

&&

LAT...LON 3092 9783 3089 9764 3086 9758 3075 9758
      3077 9797 3095 9797 3095 9784
TIME...MOT...LOC 2352Z 270DEG 23KT 3086 9786

$$

1 follow-up statement

839 
WWUS54 KEWX 220020
SVSEWX

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

TXC053-491-220030-
/O.CON.KEWX.SV.W.0082.000000T0000Z-110522T0030Z/
BURNET TX-WILLIAMSON TX-
720 PM CDT SAT MAY 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM CDT
FOR NORTHWESTERN WILLIAMSON AND EAST CENTRAL BURNET COUNTIES...

AT 710 PM CDT...NWS METEOROLOGISTS CONTINUED TO DETECT A SEVERE 
THUNDERSTORM CAPABLE OF PRODUCING UP TO GOLF BALL SIZE HAIL...AND 
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR 
BRIGGS...OR 13 MILES NORTHEAST OF BERTRAM...MOVING EAST AT 25 MPH.

THIS STORM ALREADY PRODUCED BASEBALL SIZE HAIL IN BRIGGS AND QUARTER 
SIZE HAIL IN BERTRAM.
SOME LOCATIONS IN THE WARNING AREA INCLUDE FLORENCE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM CDT
SATURDAY EVENING FOR SOUTH CENTRAL TEXAS.

&&

LAT...LON 3092 9783 3085 9778 3080 9777 3076 9776
      3077 9797 3095 9797 3095 9784
TIME...MOT...LOC 0016Z 270DEG 22KT 3086 9785

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 7:49 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Hays, Travis, Williamson	41 min
May 20, 8:04 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Caldwell, Hays, Travis	26 min
May 20, 8:27 PM CDT	Severe Thunderstorm Warning	EWX	Caldwell, Hays, Travis	23 min
May 20, 8:58 PM CDT	Severe Thunderstorm Warning	EWX	Hays, Travis	32 min
May 20, 8:59 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Lee, Travis, Williamson	61 min
May 20, 9:22 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Caldwell, Lee, Travis	38 min
May 20, 10:02 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop, Caldwell	43 min
May 20, 10:32 PM CDT	Severe Thunderstorm Warning	EWX	Caldwell, Guadalupe, Hays	43 min
May 21, 4:58 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Llano, Williamson	47 min
May 21, 5:44 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Williamson	46 min
May 21, 6:00 PM CDT	Areal Flood Advisory	EWX	Burnet, Llano	2 hr
May 21, 6:00 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Llano	45 min
May 21, 6:29 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Williamson	46 min
May 21, 6:59 PM CDT	Tornado Warning	EWX	Burnet	31 min

Nearby

Severe Thunderstorm Warnings in Texas, 2011 Every 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.