Alert archive / Texas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 162

April 13, 201214 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 13, 2012, 6:06 PM CDT for 14 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Apr 13, 2012, 6:06 PM CDT (23:06 UTC)
Expired
Apr 14, 2012, 1:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Armstrong County, TX, Briscoe County, TX, Carson County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Donley County, TX, Floyd County, TX, Gray County, TX, Hale County, TX, Hall County, TX, Motley County, TX, Swisher County, TX, Wheeler County, TX

The radar

The Amarillo radar (KAMA), 71 km from the middle of the area, began a volume at 23:07 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
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 13, 6:35 PM CDTSevere Thunderstorm WarningLUBChildress, Hall40 min
Apr 13, 7:10 PM CDTSevere Thunderstorm WarningAMACollingsworth44 min
Apr 13, 7:11 PM CDTSevere Thunderstorm WarningLUBChildress34 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

Amarillo Airport, TX (KAMA), launched 12:00Z, 11.1 hours before the alert went out and 70 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, Amarillo Airport, TX at 12:00Z on 2012-04-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Amarillo Airport, TX at 12:00Z on 2012-04-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -96 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
4062 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-96 m²/s²
0-3 km storm-relative helicity
12 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.

816 
WWUS20 KWNS 132306
SEL2
SPC WW 132306
TXZ000-140600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 162
NWS STORM PREDICTION CENTER NORMAN OK
605 PM CDT FRI APR 13 2012

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

       SOUTHERN AND EASTERN TEXAS PANHANDLE

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 605 PM
UNTIL 100 AM CDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES EAST
NORTHEAST OF AMARILLO TEXAS TO 50 MILES EAST SOUTHEAST OF
PLAINVIEW TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 160...WW 161...

DISCUSSION...TSTMS DEVELOPING ALONG WARM FRONT/DRYLINE RETREATING
NWWD ACROSS REGION ARE DOING SO IN AN ENVIRONMENT CHARACTERIZED BY
MLCAPE OF 2000-2500 J/KG AND 50 KT OF EFFECTIVE BULK SHEAR.  AS
SUCH...POTENTIAL WILL EXIST FOR SUPERCELL EVOLUTION WITH AN
ATTENDANT RISK OF LARGE HAIL AND DAMAGING WINDS.  INCREASING
LOW-LEVEL MOISTURE AND NEAR GROUND SHEAR IS ANTICIPATED ACROSS THE
ERN PNHDL LATER THIS EVENING INTO TONIGHT...SIGNALING A HEIGHTENED
TORNADO RISK.  THUS...CONDITIONS WILL BE MONITORED FOR A POSSIBLE
UPGRADE TO A TORNADO WATCH IN THE 14/00-03Z TIME FRAME.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 25025.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 13, 12:10 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Foard, Hardeman, King and 3 more2 hr
Apr 13, 1:28 PM CDTTornado WatchSPCFoard, Hardeman, Wichita, Wilbarger8 hr
Apr 13, 3:39 PM CDTMesoscale DiscussionSPCHardeman, Wichita, Wilbarger96 min
Apr 13, 5:47 PM CDTMesoscale DiscussionSPCHardeman88 min

Nearby

Severe Thunderstorm Watches in Texas, 2012Every severe thunderstorm watch in 2012

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.