Alert archive / Texas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 207

April 29, 201217 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 29, 2012, 10:50 PM CDT for 17 counties in Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 29, 2012, 10:50 PM CDT (03:50 UTC)
Expired
Apr 30, 2012, 3:00 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Bailey County, TX, Borden County, TX, Castro County, TX, Cochran County, TX, Dawson County, TX, Garza County, TX, Hale County, TX, Hockley County, TX, Kent County, TX, Lamb County, TX, Lubbock County, TX, Lynn County, TX, Parmer County, TX, Scurry County, TX, Swisher County, TX, Terry County, TX, Yoakum County, TX

The radar

The Lubbock radar (KLBB), 35 km from the middle of the area, began a volume at 03:51 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
2%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 29, 10:51 PM CDTSevere Thunderstorm WarningLUBCochran, Hockley, Lamb39 min
Apr 29, 10:55 PM CDTSevere Thunderstorm WarningLUBCrosby, Garza50 min
Apr 29, 10:58 PM CDTSevere Thunderstorm WarningLUBLubbock, Lynn, Terry62 min
Apr 29, 11:10 PM CDTSevere Thunderstorm WarningLUBBailey, Lamb50 min
Apr 29, 11:14 PM CDTSevere Thunderstorm WarningLUBSwisher46 min
Apr 29, 11:32 PM CDTSevere Thunderstorm WarningLUBGarza, Lynn58 min
Apr 29, 11:34 PM CDTSevere Thunderstorm WarningLUBSwisher26 min
Apr 29, 11:57 PM CDTSevere Thunderstorm WarningLUBBailey, Lamb48 min
Apr 30, 12:28 AM CDTSevere Thunderstorm WarningLUBGarza, Lynn47 min
Apr 30, 1:07 AM CDTSevere Thunderstorm WarningLUBGarza, Kent53 min
Apr 30, 1:59 AM CDTSevere Thunderstorm WarningLUBKent28 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 00:00Z, 3.8 hours before the alert went out and 158 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 00:00Z on 2012-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 63 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, Amarillo Airport, TX at 00:00Z on 2012-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 108 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
63 J/kg
Mixed-layer CIN
-116 J/kg
Mixed-layer LCL
2070 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

014 
WWUS20 KWNS 300352
SEL7
SPC WW 300352
TXZ000-300800-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 207
NWS STORM PREDICTION CENTER NORMAN OK
1050 PM CDT SUN APR 29 2012

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

       WEST TEXAS

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 1050 PM UNTIL
300 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 45
STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES NORTHWEST OF
PLAINVIEW TEXAS TO 85 MILES SOUTH SOUTHEAST OF LUBBOCK TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU7).

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...THIS SEVERE THUNDERSTORM WATCH REPLACES
SEVERE THUNDERSTORM WATCH NUMBER 204. WATCH NUMBER 204 WILL NOT
BE IN EFFECT AFTER 1050 PM CDT. CONTINUE...WW 203...WW 205...WW
206...

DISCUSSION...GIVEN RELATIVELY WEAK EML CAP ON MAF 00Z
RAOB...TSTMS...INCLUDING SUPERCELLS...MAY PERSIST ANOTHER FEW HOURS
IN ZONE OF SLIGHTLY MOISTENING/STRENGTHENING SSELY LOW LVL FLOW OVER
THE SRN HI PLNS.  MOST UPDRAFTS ARE EXPECTED TO BE LOCATED ATOP
COMPOSITE OUTFLOW FROM EARLIER STORMS AND MAY CONTINUE PRODUCE SVR
HAIL/LOCALLY DMGG WIND AND POSSIBLY A BRIEF TORNADO BEFORE
DEGENERATING INTO A LOOSELY ORGANIZED MCS EARLY MON.

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 550. MEAN STORM
MOTION VECTOR 30020.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 7:23 PM CDTSevere Thunderstorm WatchSPCAndrews, Bailey, Borden, Briscoe, Castro, Cochran and 14 more4 hr
Apr 29, 7:33 PM CDTMesoscale DiscussionSPCCarson, Dallam, Gray, Hansford, Hartley, Hemphill and 8 more87 min
Apr 29, 8:55 PM CDTSevere Thunderstorm WatchSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hemphill and 6 more6 hr
Apr 29, 10:04 PM CDTMesoscale DiscussionSPCArmstrong, Borden, Briscoe, Carson, Castro, Childress and 29 more86 min
Apr 29, 10:31 PM CDTMesoscale DiscussionSPCDallam, Hansford, Lipscomb, Ochiltree, Sherman119 min
Apr 30, 12:38 AM CDTMesoscale DiscussionSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hansford and 9 more37 min
Apr 30, 2:15 AM CDTMesoscale DiscussionSPCBriscoe, Castro, Crosby, Dickens, Floyd, Garza and 5 more30 min
Apr 30, 2:08 PM CDTMesoscale DiscussionSPCCrane, Ector, Midland, Pecos, Terrell, Upton97 min
Apr 30, 2:39 PM CDTSevere Thunderstorm WatchSPCBorden, Brewster, Crane, Dawson, Ector, Howard and 12 more7 hr
Apr 30, 2:58 PM CDTMesoscale DiscussionSPCArmstrong, Bailey, Briscoe, Carson, Castro, Cochran and 21 more62 min
Apr 30, 3:36 PM CDTSevere Thunderstorm WatchSPCArmstrong, Bailey, Briscoe, Carson, Castro, Childress and 35 more7 hr
Apr 30, 5:19 PM CDTMesoscale DiscussionSPCGray, Hemphill, Lipscomb, Ochiltree, Roberts, Wheeler56 min
Apr 30, 5:42 PM CDTTornado WatchSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Donley and 12 more7 hr
Apr 30, 6:11 PM CDTMesoscale DiscussionSPCBaylor, Borden, Callahan, Coke, Coleman, Concho and 48 more2 hr
Apr 30, 6:54 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Callahan, Coke, Coleman, Concho and 33 more6 hr

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.