Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 421

April 2, 201223 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 6:51 PM CDT for 23 counties in Texas. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Apr 2, 2012, 6:51 PM CDT (23:51 UTC)
Expired
Apr 2, 2012, 7:45 PM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 23 counties

Archer County, TX, Baylor County, TX, Brown County, TX, Callahan County, TX, Clay County, TX, Coleman County, TX, Comanche County, TX, Eastland County, TX, Erath County, TX, Foard County, TX, Haskell County, TX, Jack County, TX, Jones County, TX, Knox County, TX, Palo Pinto County, TX, Runnels County, TX, Shackelford County, TX, Stephens County, TX, Taylor County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 44 km from the middle of the area, began a volume at 23:54 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 11.9 hours before the alert went out and 161 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 12:00Z on 2012-04-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1497 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2012-04-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -170 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
1497 J/kg
Mixed-layer CIN
-102 J/kg
Mixed-layer LCL
582 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-170 m²/s²
0-3 km storm-relative helicity
-79 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.

881 
ACUS11 KWNS 022352
SWOMCD
SPC MCD 022351
TXZ000-030045-

MESOSCALE DISCUSSION 0421
NWS STORM PREDICTION CENTER NORMAN OK
0651 PM CDT MON APR 02 2012

AREAS AFFECTED...TX BIG COUNTRY

CONCERNING...SEVERE THUNDERSTORM WATCH 129...

VALID 022351Z - 030045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 129
CONTINUES.

SEVERE THREAT WILL LIKELY EXTEND S OF THE ORIGINAL WW 129 AND LOCAL
EXTENSION HAS BEEN COORDINATED WITH WFO SJT/FWD. TSTMS WITHIN THIS
REGION SHOULD REMAIN MORE DISCRETE RELATIVE TO FARTHER N IN WW 129
ALONG THE TRAILING INFLUENCE OF THE SHORT WAVE IMPULSE ROTATING NWD
INTO THE TX PANHANDLE. STRONG MID-LEVEL W/SWLYS WILL SUPPORT
EFFECTIVE SHEAR OF 40-50 KT AND PROPAGATION INTO A MORE BUOYANT AIR
MASS FARTHER E WITH ACTIVITY CURRENTLY OCCURRING WITHIN LOWER 50S
SURFACE DEW POINTS. INTENSIFICATION INTO A FEW SUPERCELLS APPEARS
PROBABLE DURING THE EVENING WITH PRIMARY INITIAL RISK OF LARGE HAIL.

..GRAMS.. 04/02/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FWD...OUN...SJT...LUB...

LAT...LON   33989814 32719790 32099806 31629849 31489919 31610007
            32630002 33409997 34009997 34109917 33989814

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 2, 5:16 AM CDTMesoscale DiscussionSPCAustin, Brazoria, Chambers, Colorado, Fayette, Fort Bend and 13 more2 hr
Apr 2, 9:57 AM CDTMesoscale DiscussionSPCAngelina, Hardin, Jasper, Nacogdoches, Newton, Orange and 5 more63 min
Apr 2, 10:10 AM CDTSevere Thunderstorm WatchSPCAngelina, Cherokee, Gregg, Harrison, Jasper, Nacogdoches and 8 more7 hr
Apr 2, 12:15 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Cherokee, Delta, Fannin and 18 more90 min
Apr 2, 12:41 PM CDTSevere Thunderstorm WatchSPCAnderson, Bowie, Camp, Cass, Delta, Fannin and 15 more6 hr
Apr 2, 3:00 PM CDTMesoscale DiscussionSPCBaylor, Childress, Collingsworth, Foard, Hardeman, Hemphill and 7 more2 hr
Apr 2, 3:18 PM CDTMesoscale DiscussionSPCBowie, Delta, Fannin, Franklin, Hopkins, Hunt and 4 more117 min
Apr 2, 3:37 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 28 more7 hr

Nearby

Mesoscale Discussions in Texas, 2012Every mesoscale discussion 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.