SWODY1
SPC AC 141223
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0623 AM CST WED DEC 14 2011
VALID 141300Z - 151200Z
...NO SVR TSTM AREAS FORECAST...
A LARGE AND DEEP UPPER TROUGH IS IN PLACE THIS MORNING OVER THE
WESTERN STATES...WITH A STRONG SHORTWAVE TROUGH EVIDENT IN WATER
VAPOR IMAGERY OVER SOUTHEAST CO/EASTERN NM. THIS IMPULSE WILL TRACK
QUICKLY NORTHEASTWARD ACROSS THE CENTRAL PLAINS AND EVENTUALLY INTO
THE GREAT LAKES REGION BY THU MORNING. VERY STRONG SOUTHERLY LOW
LEVEL WINDS ARE CURRENTLY PRESENT ACROSS THE SOUTHERN
PLAINS...RESULTING IN A LARGE AREA OF LOW LEVEL WARM ADVECTION AND
LIFT FROM PARTS OF TX/OK INTO MO/IA. THIS LOW LEVEL JET WILL SHIFT
NORTHEASTWARD THROUGH THE DAY...HELPING TO DRAW MOISTURE NORTHWARD
AND TO DESTABILIZE THE AIR MASS ACROSS MUCH OF THE PLAINS AND MID MS
VALLEY. THE RESULT IS A RATHER LARGE AREA WITH SOME THREAT OF
ISOLATED THUNDERSTORMS THROUGH THIS FORECAST PERIOD.
...OK/KS/MO/AR...
MODEL SOLUTIONS ARE IN STRONG AGREEMENT THAT THE SURFACE LOW OVER
WESTERN KS WILL TRACK INTO IA BY THIS EVENING. AS THIS
OCCURS...STRONG SOUTHERLY LOW LEVEL WINDS WILL OCCUR THROUGHOUT THE
WARM SECTOR OF THE LOW ACROSS MUCH OF OK/KS/MO. LOW LEVEL MOISTURE
IS SLOWLY RETURNING TO THIS REGION WITH DEWPOINTS IN THE MID/UPPER
50S CURRENTLY AS FAR NORTH AS THE KS/OK BORDER. WIDESPREAD CLOUDS
WILL HAMPER INSOLATION AND LIMIT LOW LEVEL LAPSE RATES/
DESTABILIZATION. HOWEVER...FORECAST SOUNDINGS IN THIS REGION SHOW
VERY FAVORABLE LOW LEVEL AND DEEP LAYER VERTICAL SHEAR PROFILES FOR
ORGANIZED THUNDERSTORMS. GIVEN THIS SCENARIO...HAVE EXPANDED LOW
SEVERE PROBABILITIES FARTHER NORTH INTO KS/MO WHERE A STRONG/SEVERE
STORM MIGHT BE POSSIBLE DESPITE THE VERY WEAK CAPE VALUES EXPECTED.
...TX/OK...
THE LOW LEVEL JET AND PRIMARY LARGE SCALE FORCING WILL SHIFT AWAY
FROM THE SOUTHERN PLAINS BY THIS AFTERNOON. AS THIS OCCURS...
COVERAGE AND INTENSITY OF CONVECTION IS EXPECTED TO DIMINISH.
FORECAST SOUNDINGS INDICATE A WARM NOSE AROUND 700MB THAT IS LIKELY
TO LIMIT UPDRAFT STRENGTH IN THE STORMS THAT DO OCCUR ACROSS THIS
REGION. FOR THESE REASONS...HAVE LOWERED SEVERE PROBABILITIES ACROSS
THIS AREA. LATE TONIGHT...A REJUVENATION OF CONVECTION MAY OCCUR
ALONG THE SAGGING COLD FRONT OVER CENTRAL AND SOUTHEAST TX.
HOWEVER...WEAK WIND FIELDS BY THAT TIME SHOULD LIMIT THE SEVERE RISK
WITH THESE STORMS AS WELL.
..HART/GARNER.. 12/14/2011
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