Mesoscale Discussion 696

Issued

May 6, 2011, 1:41 PM CDT (18:41 UTC)

Expired

May 6, 2011, 3:45 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Counties Coke County, TX, Crane County, TX, Crockett County, TX, Edwards County, TX, Glasscock County, TX, Irion County, TX, Midland County, TX, Pecos County, TX, Reagan County, TX, Schleicher County, TX, Sterling County, TX, Sutton County, TX, Terrell County, TX, Tom Green County, TX, Upton County, TX, Val Verde County, TX, Ward County, TX

The San Angelo radar (KSJT), 134 km from the middle of the area, began a volume at 18:43 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.

792 
ACUS11 KWNS 061841
SWOMCD
SPC MCD 061841 
TXZ000-062045-

MESOSCALE DISCUSSION 0696
NWS STORM PREDICTION CENTER NORMAN OK
0141 PM CDT FRI MAY 06 2011

AREAS AFFECTED...PORTIONS OF SWRN TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 061841Z - 062045Z

WHILE AN ISOLATED SVR STORM OR TWO WILL BE POSSIBLE THIS AFTERNOON
OVER PORTIONS OF SWRN TX...THE ISSUANCE OF A WW IS UNLIKELY.

THE INFLUX OF A PARTIALLY MODIFIED GULF AIR MASS ACROSS PORTIONS OF
SRN TX IS SUPPORTING A FAIRLY WELL-DEFINED MOISTURE GRADIENT ARCING
ENE TO WSW ACROSS THE EDWARDS PLATEAU TOWARD A WEAK MESOLOW 10 W OF
6R6...AND EXTENDING FARTHER SOUTH ALONG THE E-FACING SLOPES OF THE
NRN MEXICO MOUNTAINS. THIS AIR MASS IS CHARACTERIZED BY SFC
DEWPOINTS IN THE UPPER 50S TO LOWER 60S...CAPPED BY AN ELEVATED
MIXED LAYER FEATURING MID-LEVEL LAPSE RATES FROM 8.5 TO 9 C/KM PER
12Z OBSERVED SOUNDINGS. THESE FACTORS ARE SUPPORTING MODERATE
INSTABILITY /MLCAPE VALUES OF 1000 TO 2000 J PER KG/ INVOF THE MOIST
AXIS.

CONVECTIVE INHIBITION HAS BEEN SLOW TO ERODE THUS FAR WITHIN 60 NM
NE OF THE RIO GRANDE RIVER OVER THE EDWARDS PLATEAU...OWING TO
PERSISTENT STRATUS SINCE THE MORNING HOURS. HOWEVER...GREATER
INSOLATION FOUND NEAR A SFC CONFLUENCE AXIS EXTENDING NNW OF THE
AFOREMENTIONED MESOLOW IS SUPPORTING LESS CINH OVER THE NWRN
PERIPHERY OF THE MOIST AXIS -- I.E. OVER ERN PORTIONS OF THE EDWARDS
PLATEAU INTO THE TRANS-PECOS REGION. AS SUCH...RECENT VISIBLE
SATELLITE IMAGERY DEPICTS THE DEVELOPMENT OF A CU FIELD AROUND AND
JUST W OF FORT STOCKTON.

THERE WILL BE THE POTENTIAL FOR ONE OR TWO DEEPER CONVECTIVE PLUMES
TO EVOLVE FROM THE CU FIELD BETWEEN 20Z AND 22Z...AS AFFIRMED BY
RECENT CONVECTION-ALLOWING MODEL GUIDANCE. ANY CONVECTION WILL
LIKELY BE HIGHER BASED INITIALLY WITH THE POTENTIAL FOR GUSTY WINDS.
HOWEVER...AS THE ACTIVITY IS STEERED EWD OVER THE EDWARDS PLATEAU
AND INTERACTS WITH THE RICHER LOW-LEVEL MOISTURE AND GREATER
INSTABILITY...IT WILL HAVE THE POTENTIAL TO STRENGTHEN AND POSSIBLY
BECOME SEVERE POSING THE THREAT FOR DMGG WINDS AND LARGE HAIL. WHILE
THIS POTENTIAL WILL BE SUPPORTED BY NOTABLE DIRECTIONAL SHEAR IN THE
0-3-KM-AGL LAYER PER AREA PROFILER DATA...THE RELATIVELY WEAK
MID-LEVEL FLOW WILL LIKELY TEMPER THE OVERALL SEVERE THREAT.
ADDITIONALLY...WITHOUT ANY SUBSTANTIAL DEEP-LAYER FORCING...THE
COVERAGE OF SVR STORMS IS EXPECTED TO BE ISOLATED...AT MOST. AS
SUCH...A WW IS UNLIKELY.

..COHEN.. 05/06/2011

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

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

LAT...LON   29710172 29770240 30310299 30900330 31630307 32040210
            32200079 31690008 30790009 30010025 29540070 29470124
            29710172

Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011

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.