Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 369

March 27, 201215 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 27, 2012, 6:55 PM CDT for 15 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Mar 27, 2012, 6:55 PM CDT (23:55 UTC)
Expired
Mar 27, 2012, 8:30 PM CDT
In force
95 min
Issued by
the Storm Prediction Center

Counties Coke County, TX, Crockett County, TX, Edwards County, TX, Glasscock County, TX, Irion County, TX, Kinney County, TX, Mitchell County, TX, Nolan County, TX, Reagan County, TX, Schleicher County, TX, Sterling County, TX, Sutton County, TX, Terrell County, TX, Tom Green County, TX, Val Verde County, TX

The radar

The San Angelo radar (KSJT), 62 km from the middle of the area, began a volume at 23:57 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

Midland Regional, TX (KMAF), launched 12:00Z, 11.9 hours before the alert went out and 156 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, Midland Regional, TX at 12:00Z on 2012-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 946 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, Midland Regional, TX at 12:00Z on 2012-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
946 J/kg
Mixed-layer CIN
-265 J/kg
Mixed-layer LCL
1399 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

300 
ACUS11 KWNS 272356
SWOMCD
SPC MCD 272355
TXZ000-280130-

MESOSCALE DISCUSSION 0369
NWS STORM PREDICTION CENTER NORMAN OK
0655 PM CDT TUE MAR 27 2012

AREAS AFFECTED...PARTS OF THE LOW ROLLING PLAINS...EDWARDS
PLATEAU...AND TRANS-PECOS REGION OF TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 272355Z - 280130Z

A THREAT FOR ISOLATED SVR STORMS WILL EXIST ACROSS PARTS OF THE LOW
ROLLING PLAINS...EDWARDS PLATEAU...AND TRANS-PECOS REGION OF TX THIS
EVENING. A WW IS NOT EXPECTED TO BE REQUIRED.

A SMALL...FORWARD-PROPAGATING MCS THAT DEVELOPED OVER THE
TRANS-PECOS REGION WILL MOVE SEWD OVER SRN SECTIONS OF THE EDWARDS
PLATEAU ADJACENT TO THE RIO GRANDE RIVER THIS EVENING...AND
POTENTIALLY PERSIST INTO THE NIGHT. THIS MCS IS ACCOMPANIED BY A
WELL-DEFINED COLD POOL...WITH PRESSURE RISES IN EXCESS OF 5 MB PER 2
HRS NOTED OVER SWRN TX IN THE WAKE OF THE LEADING CONVECTIVE LINE.
HEAVY RAINFALL...PARTICULARLY AS IT ENTERS RICHER TROPOSPHERIC
MOISTURE CURRENTLY TO ITS EAST PER GPS PW DATA...WILL BE OF
INCREASING CONCERN. WHILE THE FORWARD SPEED OF THE MCS IS EXPECTED
TO REMAIN ONLY MODEST...ISOLATED INSTANCES OF DMGG WIND GUSTS CANNOT
BE RULED OUT OWING TO THE SYSTEM-ENHANCED COLD POOL CIRCULATION.

FARTHER NORTH...CONVECTION WILL BE MORE ISOLATED.
HOWEVER...LOW-LEVEL ASCENT ALONG A DRYLINE ORIENTED NNE-SSW ACROSS
PARTS OF WRN TX HAS BEEN SUFFICIENT FOR THE RECENT DEVELOPMENT OF
ISOLATED CONVECTION OVER PORTIONS OF REAGAN COUNTY. ONE OR TWO
ADDITIONAL STORMS COULD DEVELOP AS HORIZONTAL DENSITY CONTRASTS
ACROSS THE DRYLINE INCREASE IN TANDEM WITH NOCTURNAL COOLING BEFORE
CINH INCREASES SUBSTANTIALLY. MODERATE INSTABILITY EAST OF THE
DRYLINE WILL ALLOW THIS CONVECTION TO PERSIST FOR AT LEAST THE NEXT
HOUR OR TWO. AND...WITH EFFECTIVE BULK SHEAR MAGNITUDES OF 30-35 KT
/ENHANCED MAINLY BY MODERATE HIGH LEVEL FLOW ATOP WEAKER LOW- AND
MID-LEVEL FLOW/...LOCALIZED CONVECTIVE ORGANIZATION WITH ATTENDANT
THREATS OF ISOLATED SVR HAIL/WIND GUSTS MAY OCCUR. THIS ACTIVITY
WILL LIKELY DIMINISH AFTER 02Z OWING TO NOCTURNAL STABILIZATION.

..COHEN.. 03/27/2012

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

ATTN...WFO...EWX...SJT...MAF...

LAT...LON   32510087 32550029 32220003 31740018 30750018 29899981
            29140009 28950070 29360236 29820281 30880235 31600178
            32100144 32510087

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 27, 4:03 PM CDTMesoscale DiscussionSPCBrewster, Terrell87 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.