Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 294

March 19, 201253 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 19, 2012, 6:05 PM CDT for 53 counties in Texas. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Mar 19, 2012, 6:05 PM CDT (23:05 UTC)
Expired
Mar 19, 2012, 7:30 PM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 53 counties

Atascosa County, TX, Bandera County, TX, Bastrop County, TX, Bexar County, TX, Blanco County, TX, Bosque County, TX, Burnet County, TX, Caldwell County, TX, Collin County, TX, Comal County, TX, Coryell County, TX, Dallas County, TX, Denton County, TX, DeWitt County, TX, Dimmit County, TX, Edwards County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Frio County, TX, Gillespie County, TX, Gonzales County, TX, Grayson County, TX, Guadalupe County, TX, Hamilton County, TX, Hays County, TX, Hill County, TX, Hood County, TX, Hunt County, TX, Johnson County, TX, Karnes County, TX, Kendall County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, La Salle County, TX, Lampasas County, TX, Lee County, TX, Llano County, TX, Mason County, TX, Medina County, TX, Mills County, TX, Parker County, TX, Real County, TX, Rockwall County, TX, San Saba County, TX, Somervell County, TX, Tarrant County, TX, Travis County, TX, Uvalde County, TX, Williamson County, TX, Wilson County, TX, Zavala County, TX

The radar

The Ft Hood radar (KGRK), 105 km from the middle of the area, began a volume at 23:05 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, 11.1 hours before the alert went out and 255 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 2012-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1782 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 2012-03-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 318 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
1782 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
509 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
318 m²/s²
0-3 km storm-relative helicity
447 m²/s²
Significant tornado parameter
3.3
Supercell composite
17.2

Open this sounding in Storm Lab

The text

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

845 
ACUS11 KWNS 192305
SWOMCD
SPC MCD 192305 
OKZ000-TXZ000-200030-

MESOSCALE DISCUSSION 0294
NWS STORM PREDICTION CENTER NORMAN OK
0605 PM CDT MON MAR 19 2012

AREAS AFFECTED...SCNTRL THROUGH NCNTRL TX

CONCERNING...TORNADO WATCH 85...

VALID 192305Z - 200030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 85 CONTINUES.

GREATEST SEVERE THREAT IS EXPECTED TO PERSIST OVER CNTRL AND SCNTRL
TX PORTION OF TORNADO WATCH 86 THROUGH 01Z. TENDENCY HAS BEEN FOR
STORMS TO DEVELOP FARTHER SOUTH AND A NEW WW WILL BE ISSUED SHORTLY
FOR PORTIONS OF SCNTRL TX. 

LINE OF STORMS FROM NCNTRL THROUGH SCNTRL TX IS MOVING SLOWLY EWD AT
AROUND 15 KT OR LESS. STRONGEST AND MORE DISCRETE STORMS PERSIST
OVER SCNTRL TX NORTHWEST AND WEST OF SAN ANTONIO WHERE THE
ATMOSPHERE REMAINS VERY UNSTABLE WITH MLCAPE FROM 2500-3000 J/KG AND
EFFECTIVE BULK SHEAR FROM 40-50 KT. TREND HAS BEEN FOR STORM TO
INCREASE IN COVERAGE...POSSIBLY IN RESPONSE TO AN IMPULSE MOVING
THROUGH BASE OF UPPER TROUGH. THIS ACTIVITY WILL POSE A THREAT FOR
VERY LARGE HAIL AND TORNADOES INTO THE EVENING AS IT DEVELOPS NEWD.

FARTHER NORTH INTO NCNTRL TX STORMS HAVE BEEN MORE LINEAR IN
NATURE...BUT STILL MAY POSE A THREAT FOR ISOLATED DAMAGING WIND...AN
ISOLATED TORNADO OR TWO AS WELL AS VERY HEAVY RAIN.

..DIAL.. 03/19/2012

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

ATTN...WFO...FWD...OUN...CRP...EWX...SJT...

LAT...LON   30949966 31859855 33589731 33749595 32939612 30959786
            30319689 29179698 28069968 28750015 29170043 29580095
            30949966

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 7:37 PM CDTMesoscale DiscussionSPCChildress, Collingsworth, Cottle, Dickens, Fisher, Foard and 13 more53 min
Mar 18, 9:10 PM CDTMesoscale DiscussionSPCChildress, Collingsworth, Cottle, Crosby, Dickens, Donley and 7 more35 min
Mar 18, 10:09 PM CDTMesoscale DiscussionSPCAndrews, Borden, Crane, Crosby, Dawson, Ector and 13 more96 min
Mar 18, 10:50 PM CDTSevere Thunderstorm WatchSPCAndrews, Borden, Briscoe, Castro, Childress, Coke and 39 more11 hr
Mar 18, 11:23 PM CDTTornado WatchSPCBriscoe, Crosby, Floyd, Garza, Hale, Hall and 6 more4 hr
Mar 18, 11:37 PM CDTMesoscale DiscussionSPCCollingsworth, Donley, Gray, Hemphill, Lipscomb, Ochiltree and 2 more53 min
Mar 19, 1:37 AM CDTMesoscale DiscussionSPCBorden, Childress, Coke, Collingsworth, Cottle, Dickens and 25 more83 min
Mar 19, 1:56 AM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Foard, Hardeman, Knox and 2 more4 hr
Mar 19, 3:34 AM CDTMesoscale DiscussionSPCWilbarger86 min
Mar 19, 4:13 AM CDTMesoscale DiscussionSPCCoke, Fisher, Foard, Glasscock, Haskell, Howard and 16 more92 min
Mar 19, 4:39 AM CDTSevere Thunderstorm WatchSPCCallahan, Coke, Coleman, Concho, Crockett, Fisher and 22 more7 hr
Mar 19, 10:05 AM CDTMesoscale DiscussionSPCClay, Cooke, Grayson, Montague115 min
Mar 19, 10:46 AM CDTMesoscale DiscussionSPCCallahan, Coke, Irion, Jones, Nolan, Runnels and 4 more89 min
Mar 19, 2:15 PM CDTMesoscale DiscussionSPCBosque, Brown, Collin, Comanche, Concho, Cooke and 26 more90 min
Mar 19, 2:39 PM CDTTornado WatchSPCBandera, Blanco, Bosque, Brown, Burnet, Coleman and 42 more7 hr
Mar 19, 6:21 PM CDTTornado WatchSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 26 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.