Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 640

April 30, 201239 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2012, 9:37 PM CDT for 39 counties in Texas. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2012, 9:37 PM CDT (02:37 UTC)
Expired
Apr 30, 2012, 11:30 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
All 39 counties

Bandera County, TX, Baylor County, TX, Brown County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Concho County, TX, Eastland County, TX, Edwards County, TX, Fisher County, TX, Haskell County, TX, Jones County, TX, Kent County, TX, Kerr County, TX, Kimble County, TX, King County, TX, Kinney County, TX, Knox County, TX, Mason County, TX, Maverick County, TX, McCulloch County, TX, Menard County, TX, Mitchell County, TX, Nolan County, TX, Real County, TX, Runnels County, TX, San Saba County, TX, Schleicher County, TX, Scurry County, TX, Shackelford County, TX, Stephens County, TX, Stonewall County, TX, Sutton County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Uvalde County, TX, Young County, TX, Zavala County, TX

The radar

The San Angelo radar (KSJT), 101 km from the middle of the area, began a volume at 02:37 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 nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 2.6 hours before the alert went out and 135 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 00:00Z on 2012-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1868 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 00:00Z on 2012-05-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 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
1868 J/kg
Mixed-layer CIN
-95 J/kg
Mixed-layer LCL
1827 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
0 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.6

Open this sounding in Storm Lab

The text

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

747 
ACUS11 KWNS 010238
SWOMCD
SPC MCD 010237
TXZ000-010430-

MESOSCALE DISCUSSION 0640
NWS STORM PREDICTION CENTER NORMAN OK
0937 PM CDT MON APR 30 2012

AREAS AFFECTED...PORTIONS NWRN/W-CENTRAL/SW TX.

CONCERNING...SEVERE THUNDERSTORM WATCH 210...213...

VALID 010237Z - 010430Z

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

REMAINDER WW 209 HAS BEEN CLEARED.  WRN PORTIONS WW 210 MAY BE
CLEARED BEFORE SCHEDULED 4Z EXPIRATION.  SFC MESOANALYSIS SHOWS
DRYLINE RETREATING NWWD ACROSS TX PANHANDLE AND SOUTH-PLAINS REGION.
WHILE ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG
OUTFLOW-REINFORCED/RETREATING DRYLINE...PROBABILITY OF THIS WILL
DIMINISH WITH TIME AS MLCINH INCREASES.  REMAINING CONVECTION OVER
PORTIONS GARZA/KENT/STONEWALL COUNTIES...AS OF 230Z...REMAINS IN
SOMEWHAT MORE FAVORABLE ENVIRONMENT CHARACTERIZED BY MLCAPE
2000-3000 J/KG AND 35-40 KT EFFECTIVE SHEAR MAGNITUDES...ALTHOUGH
MLCINH WILL INCREASE WITH TIME IN PROSPECTIVE INFLOW REGION.  PRIND
THIS ACTIVITY WILL WEAKEN OR DISSIPATE BY ABOUT 6Z.

SRN PORTIONS W 213 MAY BE CANCELED BEHIND MCS MOVING EWD TOWARD
AREAS BETWEEN DRT-JCT.  THIS COMPLEX STILL MAY POSE ISOLATED
DAMAGING WIND THREAT OVER SRN PORTIONS EDWARDS PLATEAU SWD TO RIO
GRANDE REGION...PERHAPS LINKING WITH ADDITIONAL CONVECTION MOVING
EWD FROM SERRANIAS DEL BURRO REGION OF COAHUILA.  HOWEVER...RADAR
ANIMATIONS INDICATE GUST FRONT HAS SURGED WELL AHEAD OF BAND OF
GREATEST REFLECTIVITY.

..EDWARDS.. 05/01/2012

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

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

LAT...LON   29330123 29840093 30360051 30850070 31960102 33110140
            33810020 33559867 31869858 30909875 29579922 28479995
            28160026 28650053 29140068 29290083 29330123

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 8:55 PM CDTMesoscale DiscussionSPCCollingsworth, Donley, Hemphill, Wheeler65 min
Apr 30, 9:51 PM CDTTornado WatchSPCClay, Wichita, Wilbarger4 hr
Apr 30, 11:28 PM CDTMesoscale DiscussionSPCWichita, Wilbarger92 min
May 1, 5:43 PM CDTMesoscale DiscussionSPCBrewster, Crane, Crockett, Edwards, Kinney, Maverick and 5 more3 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.