Alert archive / Texas / Tornado Watches in 2011

Tornado Watch 126

April 10, 201134 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 10, 2011, 11:39 PM CDT for 34 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 10, 2011, 11:39 PM CDT (04:39 UTC)
Expired
Apr 11, 2011, 6:28 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
70 kt
All 34 counties

Anderson County, TX, Bandera County, TX, Bell County, TX, Blanco County, TX, Bosque County, TX, Burnet County, TX, Comal County, TX, Coryell County, TX, Edwards County, TX, Falls County, TX, Freestone County, TX, Gillespie County, TX, Hamilton County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Kendall County, TX, Kerr County, TX, Kimble County, TX, Lampasas County, TX, Leon County, TX, Limestone County, TX, Llano County, TX, Mason County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Navarro County, TX, Real County, TX, Robertson County, TX, San Saba County, TX, Somervell County, TX, Travis County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 117 km from the middle of the area, began a volume at 04:41 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

15 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 10, 11:45 PM CDTSevere Thunderstorm WarningSJTKimble, Mason, Menard45 min
Apr 10, 11:52 PM CDTSevere Thunderstorm WarningFWDComanche, Coryell, Hamilton, Lampasas, Mills53 min
Apr 11, 12:17 AM CDTSevere Thunderstorm WarningSJTKimble43 min
Apr 11, 12:19 AM CDTSevere Thunderstorm WarningSJTMason, San Saba41 min
Apr 11, 12:25 AM CDTTornado WarningFWDHamilton20 min
Apr 11, 12:25 AM CDTTornado WarningSJTMason23 min
Apr 11, 12:28 AM CDTSevere Thunderstorm WarningFWDBosque, Coryell, Hamilton62 min
Apr 11, 12:32 AM CDTSevere Thunderstorm WarningEWXGillespie, Llano28 min
Apr 11, 12:49 AM CDTSevere Thunderstorm WarningFWDHood, Johnson, Somervell41 min
Apr 11, 12:52 AM CDTSevere Thunderstorm WarningEWXGillespie, Llano23 min
Apr 11, 12:55 AM CDTSevere Thunderstorm WarningFWDHill35 min
Apr 11, 1:23 AM CDTSevere Thunderstorm WarningFWDEllis, Hill, Johnson, Navarro51 min
Apr 11, 1:53 AM CDTSevere Thunderstorm WarningFWDHenderson, Kaufman52 min
Apr 11, 4:53 AM CDTSevere Thunderstorm WarningEWXWilliamson26 min
Apr 11, 5:00 AM CDTSevere Thunderstorm WarningEWXBastrop, Lee, Travis, Williamson33 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 4.7 hours before the alert went out and 260 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, Del Rio, TX at 00:00Z on 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 800 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Del Rio, TX at 00:00Z on 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 117 square meters per square second.1939587897Sfc1 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
800 J/kg
Mixed-layer CIN
-89 J/kg
Mixed-layer LCL
3016 m above ground
0-6 km bulk shear
84 kt
0-1 km storm-relative helicity
117 m²/s²
0-3 km storm-relative helicity
336 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.1

Open this sounding in Storm Lab

The text

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

795 
WWUS20 KWNS 110439
SEL6
SPC WW 110439
TXZ000-111000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 126
NWS STORM PREDICTION CENTER NORMAN OK
1140 PM CDT SUN APR 10 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       CENTRAL AND SOUTH CENTRAL TEXAS

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 1140 PM UNTIL
500 AM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE
MILES EAST AND WEST OF A LINE FROM 110 MILES WEST SOUTHWEST OF
AUSTIN TEXAS TO 25 MILES WEST NORTHWEST OF CORSICANA TEXAS.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU6).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

OTHER WATCH INFORMATION...CONTINUE...WW 121...WW 122...WW
123...WW 124...WW 125...

DISCUSSION...CLUSTERS OF INTENSE TSTMS HAVE FORMED THIS EVE OVER
CNTRL TX...AHEAD OF SRN PART OF LARGE SCALE UPR TROUGH THAT IS
MOVING ENE FROM THE TX BIG BEND.  GIVEN STRENGTH OF WIND FIELD AND
INCREASING MOISTURE AVAILABILITY ASSOCIATED WITH 40-50 KT SLY
LLJ...POTENTIAL WILL EXIST FOR ADDITIONAL SUSTAINED
STORMS/SUPERCELLS/LEWPS.  THESE MAY CONTAIN A THREAT FOR
TORNADOES...IN ADDITION TO HIGH WIND/LARGE HAIL...AS THE ACTIVITY
MOVES/DEVELOPS ENEWD THROUGH EARLY MON.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 25040.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 7:02 PM CDTSevere Thunderstorm WatchSPCBosque, Brown, Callahan, Coleman, Collin, Comanche and 41 more8 hr
Apr 10, 9:09 PM CDTMesoscale DiscussionSPCBrown, Callahan, Coleman, Comanche, Concho, Cooke and 21 more66 min
Apr 11, 1:27 AM CDTMesoscale DiscussionSPCAnderson, Bell, Blanco, Bosque, Brown, Burnet and 36 more93 min
Apr 11, 1:49 AM CDTTornado WatchSPCBowie, Camp, Cass, Delta, Franklin, Gregg and 14 more4 hr
Apr 11, 4:19 AM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Gregg, Harrison, Marion and 7 more56 min

Nearby

Tornado Watches in Texas, 2011Every tornado watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.