SWODY2
SPC AC 131710
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1110 AM CST TUE DEC 13 2011
VALID 141200Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF TX...
...SRN PLAINS...
LATEST SHORT RANGE GUIDANCE SUGGESTS SWRN U.S. UPPER TROUGH WILL BE
FORCED TO EJECT TOWARD THE PLAINS AS UPSTREAM HEIGHTS BEGIN TO FALL
AHEAD OF DIGGING NWRN U.S. SPEED MAX. THIS LEAD FEATURE SHOULD
TRANSLATE DOWNSTREAM IN A POSITIVE-TILT FASHION ULTIMATELY LIMITING
PLAINS CYCLOGENESIS/CONVERGENCE ALONG ADVANCING COLD FRONT. EVEN
SO...STRONG LLJ EARLY IN THE PERIOD WILL PROVE FAVORABLY LOCATED FOR
BOUNDARY LAYER MOISTURE RETURN ACROSS TX WHICH WILL ALLOW SFC DEW
POINTS TO RISE THROUGH THE 60S ACROSS THE WARM SECTOR PRIOR TO COLD
FRONTAL PASSAGE. AT THIS TIME IT APPEARS MID LEVEL LAPSE RATES WILL
BE SUFFICIENTLY STEEP TO SUPPORT ELEVATED THUNDERSTORMS LEADING INTO
THE DAY2 PERIOD AND CONVECTION WILL LIKELY BE ONGOING AT 12Z ACROSS
PORTIONS OF KS/OK INTO NWRN TX. FORECAST SOUNDINGS ACROSS NWRN TX
AT SUNRISE EXHIBIT MUCAPE IN EXCESS OF 1000 J/KG AND THIS MAY BE
ADEQUATE FOR HAIL APPROACHING SEVERE LEVELS. WITH TIME LOW LEVEL
CONVERGENCE WILL WANE ALONG TRAILING COLD FRONT ACROSS TX AS LLJ AND
STRONGER FORCING SHIFT INTO THE MID MS/OH VALLEY REGION. EVEN
SO...MODEST BOUNDARY LAYER HEATING AND WEAK FRONTAL CONVERGENCE
SHOULD ENHANCE THE PROSPECT FOR SFC-BASED CONVECTION...LIKELY
INITIATING JUST WEST OF THE I-35 CORRIDOR WHEN TEMPERATURES WARM
INTO THE UPPER 60S. IF THIS OCCURS AS THE NAM INSINUATES THEN A FEW
WEAK SUPERCELLS ARE POSSIBLE ALONG ADVANCING COLD FRONT...OR PERHAPS
CONVECTION WILL DISPLAY SOME LINEAR CHARACTERISTICS THAT COULD
RESULT IN ISOLATED DAMAGING WIND GUSTS.
FARTHER NORTH...HAVE OPTED TO LOWER THE SEVERE PROBS ACROSS THE MID
MS VALLEY DUE TO THE MEAGER INSTABILITY EXPECTED PRIOR TO FRONTAL
PASSAGE.
..DARROW.. 12/13/2011
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