Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 636

April 30, 201254 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2012, 6:11 PM CDT for 54 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 30, 2012, 6:11 PM CDT (23:11 UTC)
Expired
Apr 30, 2012, 8:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 54 counties

Baylor County, TX, Borden County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Concho County, TX, Cottle County, TX, Crane County, TX, Crockett County, TX, Crosby County, TX, Dawson County, TX, Dickens County, TX, Ector County, TX, Edwards County, TX, Fisher County, TX, Floyd County, TX, Foard County, TX, Garza County, TX, Glasscock County, TX, Hale County, TX, Haskell County, TX, Hockley County, TX, Howard County, TX, Irion County, TX, Jones County, TX, Kent County, TX, King County, TX, Kinney County, TX, Knox County, TX, Lubbock County, TX, Lynn County, TX, Martin County, TX, Maverick County, TX, Menard County, TX, Midland County, TX, Mitchell County, TX, Motley County, TX, Nolan County, TX, Reagan County, TX, Runnels County, TX, Schleicher County, TX, Scurry County, TX, Shackelford County, TX, Sterling County, TX, Stonewall County, TX, Sutton County, TX, Taylor County, TX, Terrell County, TX, Terry County, TX, Throckmorton County, TX, Tom Green County, TX, Upton County, TX, Val Verde County, TX, Wilbarger County, TX

The radar

The San Angelo radar (KSJT), 126 km from the middle of the area, began a volume at 23:13 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

Del Rio, TX (KDRT), launched 12:00Z, 11.2 hours before the alert went out and 145 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, Del Rio, TX at 12:00Z on 2012-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2392 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, Del Rio, TX at 12:00Z on 2012-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 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
2392 J/kg
Mixed-layer CIN
-123 J/kg
Mixed-layer LCL
586 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

647 
ACUS11 KWNS 302311
SWOMCD
SPC MCD 302311 
TXZ000-010115-

MESOSCALE DISCUSSION 0636
NWS STORM PREDICTION CENTER NORMAN OK
0611 PM CDT MON APR 30 2012

AREAS AFFECTED...MUCH OF W TX -- FROM SOUTH-PLAINS TO BIG BEND AND
EWD TOWARD LOW ROLLING PLAINS...CONCHO VALLEY AND DRT AREA.

CONCERNING...SEVERE THUNDERSTORM WATCH 209...210...

VALID 302311Z - 010115Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
209...210...CONTINUES.

CLUSTERS AND BANDS OF SVR TSTMS NOW OVER WW AREAS MAY PERSIST
FARTHER E ACROSS PORTIONS NW/W-CENTRAL/SW TX WITH DAMAGING
HAIL/GUSTS BEING PRINCIPAL CONCERNS.  ANOTHER WW MAY BE REQUIRED FOR
SOME PORTIONS OF CORRIDOR FROM SPS-DRT.

SFC MESOANALYSIS SHOWS WAVY DRYLINE OVER WRN PANHANDLE THEN SSEWD TO
JUST S LBB...THEN SSWWD TO NRN FRINGES OF LARGE TSTM COMPLEX BETWEEN
FST AND BIG BEND.  YOUNGER BUT GROWING TSTM BAND...OVER  CAPROCK
REGION E LBB...SHOULD MERGE WITH CONVECTION DEVELOPING TO ITS SW
ACROSS MAF-BPG AREA.  EACH RESULTING MCS SHOULD GROW/DEEPEN ITS COLD
POOL...WHILE FORWARD-PROPAGATING EWD INTO BOUNDARY LAYER
CHARACTERIZED BY FAVORABLE DEWPOINT DEPRESSIONS AND MIXING FOR
MAINTAINING DAMAGING GUST THREAT.  PRE-STORM MLCAPE 2000-3000 J/KG
IS EVIDENT ACROSS MUCH OF THIS AREA...BASED ON MODIFIED RAOBS AND
RUC SOUNDINGS.  STRONGER CINH IS APPARENT AHEAD OF SRN
COMPLEX...WHERE EML BASE WARMTH IS MAXIMIZED IN 700-750 MB LAYER. 
STORM-SCALE FORCED ASCENT ALONG LEADING EDGE OF COLD POOL SHOULD
OVERCOME THAT FOR SOME UNCERTAIN DISTANCE EWD ACROSS SW TX BEFORE
MCS DISSIPATES.  VERTICAL WIND PROFILES ALSO FAVOR POTENTIAL FOR
SUPERCELLS PRODUCING GIANT/DAMAGING HAIL...WHEREVER STORMS CAN
REMAIN RELATIVELY DISCRETE THROUGH MATURE STAGE...WITH 40-50 KT
EFFECTIVE SHEAR MAGNITUDES NEAR CAPROCK.  4.25 INCH STONES ALREADY
REPORTED IN BORDEN COUNTY AROUND 2230Z.

..EDWARDS.. 04/30/2012

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

ATTN...WFO...FWD...OUN...EWX...SJT...LUB...MAF...

LAT...LON   29520278 29920304 30080373 30350277 30940268 31570271
            33570247 34100232 34229958 34159889 32889903 32119909
            30779978 29610028 28270028 28440032 28770052 29110071
            29300086 29520121 29770143 29800189 29770211 29880231
            29750232 29730264 29520278

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 7:23 PM CDTSevere Thunderstorm WatchSPCAndrews, Bailey, Borden, Briscoe, Castro, Cochran and 14 more4 hr
Apr 29, 7:33 PM CDTMesoscale DiscussionSPCCarson, Dallam, Gray, Hansford, Hartley, Hemphill and 8 more87 min
Apr 29, 8:55 PM CDTSevere Thunderstorm WatchSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hemphill and 6 more6 hr
Apr 29, 10:04 PM CDTMesoscale DiscussionSPCArmstrong, Borden, Briscoe, Carson, Castro, Childress and 29 more86 min
Apr 29, 10:31 PM CDTMesoscale DiscussionSPCDallam, Hansford, Lipscomb, Ochiltree, Sherman119 min
Apr 29, 10:50 PM CDTSevere Thunderstorm WatchSPCBailey, Borden, Castro, Cochran, Dawson, Garza and 11 more4 hr
Apr 30, 12:38 AM CDTMesoscale DiscussionSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hansford and 9 more37 min
Apr 30, 2:15 AM CDTMesoscale DiscussionSPCBriscoe, Castro, Crosby, Dickens, Floyd, Garza and 5 more30 min
Apr 30, 2:08 PM CDTMesoscale DiscussionSPCCrane, Ector, Midland, Pecos, Terrell, Upton97 min
Apr 30, 2:39 PM CDTSevere Thunderstorm WatchSPCBorden, Brewster, Crane, Dawson, Ector, Howard and 12 more7 hr
Apr 30, 2:58 PM CDTMesoscale DiscussionSPCArmstrong, Bailey, Briscoe, Carson, Castro, Cochran and 21 more62 min
Apr 30, 3:36 PM CDTSevere Thunderstorm WatchSPCArmstrong, Bailey, Briscoe, Carson, Castro, Childress and 35 more7 hr
Apr 30, 5:19 PM CDTMesoscale DiscussionSPCGray, Hemphill, Lipscomb, Ochiltree, Roberts, Wheeler56 min
Apr 30, 5:42 PM CDTTornado WatchSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Donley and 12 more7 hr
Apr 30, 6:54 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Callahan, Coke, Coleman, Concho and 33 more6 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.