MESO: Mesoscale Discussion 2130

ACUS11 KWNS 041709
SWOMCD
SPC MCD 041709
MSZ000-LAZ000-TXZ000-041845-

MESOSCALE DISCUSSION 2130
NWS STORM PREDICTION CENTER NORMAN OK
1109 AM CST TUE DEC 04 2012

AREAS AFFECTED...SERN TX...WRN-NERN LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 041709Z - 041845Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SCATTERED THUNDERSTORM COVERAGE APPEARS LIKELY DURING THE
AFTERNOON FROM SERN TX INTO WRN-NERN LA. ISOLATED THREAT FOR
MARGINALLY SEVERE HAIL AND DAMAGING WIND GUSTS WILL EXIST.
HOWEVER...A WW DOES NOT APPEAR NECESSARY.

DISCUSSION...MIDDAY MESOANALYSIS SHOWS A COLD FRONT EXTENDING S-SWWD
FROM THE ARKLATEX REGION INTO SRN TX. ASCENT SPREADING EWD AHEAD OF
A SHORTWAVE TROUGH LOCATED OVER W TX IS AIDING IN THUNDERSTORM
DEVELOPMENT ALONG THE FRONT IN E-CNTRL TX. AHEAD OF THE FRONT FROM
SERN TX INTO NERN LA...PARTIAL CLEARING HAS ALLOWED TEMPERATURES TO
WARM INTO THE 70S...WHILE DEWPOINTS RESIDE IN THE UPPER 60S. GIVEN
THE PRESENCE OF MIDLEVEL LAPSE RATES FROM 6.5-7.0 C/KM...MODIFIED
12Z RAOBS YIELD MLCAPE VALUES FROM 1000-2000 J/KG. THIS
THERMODYNAMIC ENVIRONMENT COMBINED WITH A CONFLUENT SURFACE FLOW
REGIME WILL FAVOR SCATTERED STORM COVERAGE ALONG AND AHEAD OF THE
FRONT DURING THE AFTERNOON. PRIMARY LIMITING FACTOR FOR GREATER
SEVERE WEATHER POTENTIAL IS WEAK DEEP-LAYER WIND SPEEDS AND SHEAR.
HOWEVER...MODERATE INSTABILITY WITHIN THE AREA OF PARTIAL CLEARING
MAY ALLOW A FEW MULTICELL THUNDERSTORMS TO PULSE UPWARDS IN
INTENSITY AND POSE A THREAT FOR MARGINALLY SEVERE HAIL AND
STRONG/SEVERE WIND GUSTS.

..GARNER/MEAD.. 12/04/2012

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

ATTN...WFO...JAN...LCH...SHV...HGX...

LAT...LON 32289093 31209165 29709385 29459467 29659520 30109547
30809534 31639447 32959228 32289093

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