Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 436

April 3, 201216 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2012, 4:38 PM CDT for 16 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Apr 3, 2012, 4:38 PM CDT (21:38 UTC)
Expired
Apr 3, 2012, 5:45 PM CDT
In force
67 min
Issued by
the Storm Prediction Center

Counties Austin County, TX, Bastrop County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Fayette County, TX, Grimes County, TX, Hays County, TX, Lee County, TX, Madison County, TX, Milam County, TX, Robertson County, TX, Travis County, TX, Waller County, TX, Washington County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 51 km from the middle of the area, began a volume at 21:37 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, 9.6 hours before the alert went out and 276 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 2012-04-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1939 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 12:00Z on 2012-04-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 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
1939 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
469 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.6
Supercell composite
2.8

Open this sounding in Storm Lab

The text

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

755 
ACUS11 KWNS 032139
SWOMCD
SPC MCD 032138
TXZ000-032245-

MESOSCALE DISCUSSION 0436
NWS STORM PREDICTION CENTER NORMAN OK
0438 PM CDT TUE APR 03 2012

AREAS AFFECTED...PORTIONS OF CNTRL/ERN TX

CONCERNING...TORNADO WATCH 133...135...

VALID 032138Z - 032245Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 133...135...CONTINUES.

MONITORING TSTM DEVELOPMENT W OF AUS AND S OF WW 133/135 FOR AN
ADDITIONAL WW...BUT UNCERTAINTY DOES EXIST IN THE SUSTAINABILITY OF
TSTMS S THE ONGOING WW.

21Z SURFACE ANALYSIS PLACED A COMPOSITE COLD FRONT/OUTFLOW FROM 30 E
DAL TO 10 W AUS. A COUPLE OF TSTMS HAVE FORMED BEHIND THE FRONT
AROUND 25 W AUS...LIKELY AIDED IN DEVELOPMENT BY AN APPARENT GRAVITY
WAVE EMANATING SWD FROM THE MCS OVER NERN TX PER VISIBLE SATELLITE
IMAGERY. A WEAK MESOSCALE CIRCULATION IS ALSO APPARENT IN THE CU
FIELD CLOSER TO THE MIDDLE TX COASTAL PLAIN WHICH IS LIKELY
MITIGATING STRONGER CONVERGENCE ALONG THE FRONT SW OF AUS. ALTHOUGH
THE WARM SECTOR IS STRONGLY UNSTABLE...THE SUSTAINABILITY OF
CONVECTIVE DEVELOPMENT SW OF THE ONGOING WW/S IS UNCERTAIN. SHOULD
TSTMS BE MAINTAINED...PRIMARY RISKS SHOULD BE LARGE HAIL GIVEN
DEEP-LAYER SHEAR VECTOR ROUGHLY PARALLEL TO THE FRONT AND WEAK
LOW-LEVEL SHEAR PER THE GRK VWP.

..GRAMS.. 04/03/2012

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

ATTN...WFO...HGX...FWD...EWX...

LAT...LON   30349802 30999743 31179698 31209625 30839565 30249580
            29689619 29599695 29669800 29949823 30349802

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 2, 7:17 PM CDTMesoscale DiscussionSPCHansford, Hemphill, Hutchinson, Lipscomb, Ochiltree, Roberts58 min
Apr 2, 9:12 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Hardeman, Haskell, Hemphill and 12 more63 min
Apr 2, 10:51 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Jack, Montague, Wichita and 2 more5 hr
Apr 2, 11:45 PM CDTMesoscale DiscussionSPCBrown, Callahan, Coleman, Comanche, Concho, Eastland and 17 more2 hr
Apr 3, 1:14 AM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Jack, Montague and 7 more2 hr
Apr 3, 3:32 AM CDTMesoscale DiscussionSPCArcher, Baylor, Borden, Brown, Callahan, Clay and 24 more88 min
Apr 3, 8:36 AM CDTMesoscale DiscussionSPCArcher, Bell, Blanco, Bosque, Brown, Burnet and 40 more84 min
Apr 3, 9:18 AM CDTSevere Thunderstorm WatchSPCBosque, Clay, Collin, Comanche, Cooke, Coryell and 33 more8 hr
Apr 3, 11:47 AM CDTMesoscale DiscussionSPCBosque, Collin, Cooke, Coryell, Dallas, Delta and 32 more118 min
Apr 3, 12:08 PM CDTTornado WatchSPCAnderson, Bell, Bosque, Collin, Coryell, Dallas and 30 more9 hr
Apr 3, 1:12 PM CDTMesoscale DiscussionSPCBosque, Collin, Dallas, Denton, Ellis, Erath and 16 more93 min
Apr 3, 1:46 PM CDTMesoscale DiscussionSPCCamp, Cass, Cherokee, Franklin, Gregg, Harrison and 9 more89 min
Apr 3, 2:21 PM CDTMesoscale DiscussionSPCLamar, Montague84 min
Apr 3, 2:36 PM CDTTornado WatchSPCAngelina, Bowie, Brazos, Camp, Cass, Cherokee and 23 more7 hr
Apr 3, 3:05 PM CDTMesoscale DiscussionSPCGrayson, Lamar, Red River85 min
Apr 3, 5:00 PM CDTMesoscale DiscussionSPCAnderson, Bowie, Camp, Cass, Delta, Falls and 18 more60 min
Apr 3, 6:53 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Bastrop, Bowie, Brazos, Burleson and 24 more67 min

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.