Alert archive / Texas / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 320

May 30, 201225 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 30, 2012, 12:43 AM CDT for 25 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
May 30, 2012, 12:43 AM CDT (05:43 UTC)
Expired
May 30, 2012, 8:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 25 counties

Camp County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Montague County, TX, Morris County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 116 km from the middle of the area, began a volume at 05:43 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
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 30, 12:49 AM CDTSevere Thunderstorm WarningFWDFannin, Grayson29 min
May 30, 1:32 AM CDTSevere Thunderstorm WarningFWDCooke, Grayson58 min
May 30, 2:22 AM CDTSevere Thunderstorm WarningFWDCooke, Denton53 min
May 30, 3:26 AM CDTSevere Thunderstorm WarningFWDCollin35 min
May 30, 4:26 AM CDTSevere Thunderstorm WarningSHVCamp, Franklin, Titus, Upshur, Wood34 min
May 30, 4:32 AM CDTSevere Thunderstorm WarningFWDJack, Wise58 min
May 30, 5:18 AM CDTSevere Thunderstorm WarningFWDParker57 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

Fort Worth, TX (KFWD), launched 00:00Z, 5.7 hours before the alert went out and 93 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, Fort Worth, TX at 00:00Z on 2012-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1364 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, Fort Worth, TX at 00:00Z on 2012-05-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 square meters per square second.193958Sfc1 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
1364 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
2060 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
175 m²/s²
Significant tornado parameter
0.0
Supercell composite
7.6

Open this sounding in Storm Lab

The text

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

134 
WWUS20 KWNS 300541
SEL0
SPC WW 300541
OKZ000-TXZ000-301300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 320
NWS STORM PREDICTION CENTER NORMAN OK
1245 AM CDT WED MAY 30 2012

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

       FAR SOUTHEAST OKLAHOMA
       NORTH-CENTRAL AND NORTHEAST TEXAS

EFFECTIVE THIS WEDNESDAY MORNING FROM 1245 AM UNTIL 800 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 40
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTHWEST
OF FORT WORTH TEXAS TO 55 MILES EAST SOUTHEAST OF PARIS TEXAS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 319...

DISCUSSION...BOWING MCS WITH EMBEDDED SUPERCELL STRUCTURES IS
EXPECTED TO CONTINUE SEWD THROUGH THE RED RIVER VALLEY EARLY THIS
MORNING INTO A VERY WARM AND MOIST AIR MASS IN PLACE ACROSS NRN TX.
AS SUCH...EXPECT THE RISK FOR LARGE HAIL AND DAMAGING WIND GUSTS TO
CONTINUE FOR THE NEXT FEW HOURS PRIOR TO GRADUAL DECAY OF CONVECTIVE
SYSTEM.

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 32030.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 29, 8:54 PM CDTMesoscale DiscussionSPCCollin, Dallas, Denton, Hood, Jack, Johnson and 6 more96 min
May 29, 11:28 PM CDTMesoscale DiscussionSPCCooke, Fannin, Grayson, Lamar, Montague62 min
May 30, 2:43 AM CDTMesoscale DiscussionSPCArcher, Baylor, Camp, Cass, Clay, Collin and 37 more92 min
May 30, 5:07 AM CDTMesoscale DiscussionSPCAnderson, Camp, Cherokee, Collin, Dallas, Denton and 28 more83 min
May 30, 2:58 PM CDTMesoscale DiscussionSPCBriscoe, Childress, Collingsworth, Cottle, Dickens, Donley and 8 more62 min
May 30, 3:38 PM CDTTornado WatchSPCBaylor, Briscoe, Childress, Collingsworth, Cottle, Dickens and 15 more5 hr
May 30, 4:52 PM CDTMesoscale DiscussionSPCBrown, Callahan, Coke, Coleman, Concho, Eastland and 17 more83 min
May 30, 5:11 PM CDTTornado WatchSPCBrown, Burnet, Callahan, Coke, Coleman, Comanche and 27 more6 hr
May 30, 6:13 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Cooke, Denton, Jack and 5 more8 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.