Alert archive / Texas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 78

March 16, 201226 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Mar 16, 2012, 3:12 PM CDT for 26 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Mar 16, 2012, 3:12 PM CDT (20:12 UTC)
Expired
Mar 16, 2012, 9:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 26 counties

Andrews County, TX, Borden County, TX, Brewster County, TX, Coke County, TX, Crane County, TX, Crockett County, TX, Dawson County, TX, Ector County, TX, Fisher County, TX, Gaines County, TX, Glasscock County, TX, Howard County, TX, Irion County, TX, Martin County, TX, Midland County, TX, Mitchell County, TX, Nolan County, TX, Pecos County, TX, Reagan County, TX, Reeves County, TX, Scurry County, TX, Sterling County, TX, Terrell County, TX, Upton County, TX, Ward County, TX, Winkler County, TX

The radar

The Midland/Odessa radar (KMAF), 22 km from the middle of the area, began a volume at 20:14 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
40%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 16, 4:01 PM CDTSevere Thunderstorm WarningMAFCrane, Pecos59 min
Mar 16, 8:59 PM CDTSevere Thunderstorm WarningMAFBrewster46 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

Midland Regional, TX (KMAF), launched 12:00Z, 8.2 hours before the alert went out and 22 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, Midland Regional, TX at 12:00Z on 2012-03-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 855 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, Midland Regional, TX at 12:00Z on 2012-03-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.19395878Sfc1 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
855 J/kg
Mixed-layer CIN
-253 J/kg
Mixed-layer LCL
1535 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
16 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.7

Open this sounding in Storm Lab

The text

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

158 
WWUS20 KWNS 162013
SEL8
SPC WW 162013
TXZ000-170200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 78
NWS STORM PREDICTION CENTER NORMAN OK
315 PM CDT FRI MAR 16 2012

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

       SOUTHWEST AND WEST CENTRAL TEXAS

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 315 PM UNTIL 900
PM CDT.

HAIL TO 2.5 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 70
STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH OF BIG
SPRING TEXAS TO 45 MILES WEST OF DRYDEN TEXAS.  FOR A COMPLETE
DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE
(WOUS64 KWNS WOU8).

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.

DISCUSSION...THUNDERSTORMS ARE BEGINNING TO DEVELOP NEAR THE DAVIS
MOUNTAINS IN SW TX...AND THIS AREA OF CONVECTION IS EXPECTED TO
EXPAND EWD/NEWD THROUGH THE AFTERNOON IN RESPONSE TO CONTINUED
DAYTIME HEATING AND THE APPROACH OF A WEAK MIDLEVEL TROUGH FROM FAR
W TX/SRN NM.  THE COMBINATION OF MLCAPE AOA 2000 J/KG...EFFECTIVE
BULK SHEAR AOA 40 KT...AND STRAIGHT HODOGRAPHS WILL SUPPORT
SPLITTING SUPERCELLS CAPABLE OF PRODUCING LARGE HAIL AND ISOLATED
DAMAGING WINDS.  THE ERN EXTENT OF THE SEVERE THREAT WILL BE LIMITED
BY THE PERSISTENT STRATUS AND WEAKER INSTABILITY...WHILE THE TORNADO
RISK APPEARS LIMITED BY RELATIVELY WEAK LOW-LEVEL SHEAR.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27020.


...THOMPSON

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 16, 2:44 PM CDTMesoscale DiscussionSPCBorden, Cottle, Crane, Crosby, Dawson, Dickens and 19 more61 min
Mar 16, 3:47 PM CDTSevere Thunderstorm WatchSPCArmstrong, Briscoe, Childress, Collingsworth, Cottle, Crosby and 23 more5 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.