DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 120507
SWODY2
SPC AC 120505

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1205 AM CDT WED SEP 12 2012

VALID 131200Z - 141200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

SHORTWAVE TROUGH IS FORECAST TO ADVANCE FROM THE NRN PLAINS AT THE
START OF THE PERIOD INTO THE GREAT LAKES BY LATE THURSDAY NIGHT.
FARTHER SOUTH...VORTICITY MAXIMA OVER THE SWRN U.S. WILL SHEAR EWD
INTO THE SRN HIGH PLAINS. ANOTHER WEAK UPPER LOW CIRCULATION SHOULD
PERSIST OVER THE SERN STATES. AT THE SFC...A COLD FRONT WILL EXTEND
FROM GREAT LAKES SWWD INTO THE SRN HIGH PLAINS BY 12Z THURSDAY AND
CONTINUE SLOWLY SEWD DURING THE DAY.

...SWRN THROUGH NCNTRL TX INTO SERN OK...

NEAR SFC WINDS HAVE VEERED TO SELY AND RICHER GULF MOISTURE HAS
RETURNED TO S TX WHERE DEWPOINTS ARE IN THE UPPER 60S TO LOW 70S.
THIS FLOW REGIME WILL PERSIST INTO THURSDAY...LIKELY TRANSPORTING
MID-UPPER 60S DEWPOINTS THROUGH THE REMAINDER OF ERN TX AND SRN OK.
THE MOISTENING BOUNDARY LAYER AND NEWD ADVECTING PLUME OF MID-HIGH
LEVEL SUBTROPICAL MOISTURE WILL RESULT IN A SUBSTANTIAL INCREASE IN
PW FROM SWRN TX THROUGH SRN OK PORTION OF WARM SECTOR. MODEST MID
LEVEL LAPSE RATES ARE EXPECTED...BUT SFC HEATING MAY BOOST MLCAPE TO
1500-2000 J/KG...AND STORMS WILL LIKELY DEVELOP ALONG THE COLD FRONT
AS IT MOVES SWD. WEAK VERTICAL SHEAR WILL PROMOTE MULTICELL STORM
MODES...A FEW OF WHICH MIGHT PRODUCE ISOLATED STRONG WIND GUSTS
WHERE SFC HEATING CAN STEEPEN LOW LEVEL LAPSE RATES. OVERALL THREAT
IS EXPECTED TO REMAIN TOO MARGINAL FOR MORE THAN 5% SEVERE
PROBABILITIES.

...MN INTO WRN WI...

STEEPER LAPSE RATES ASSOCIATED WITH COLD AIR ALOFT ATTENDING THE
PROGRESSIVE VORT MAX AND DIABATIC WARMING OF THE BOUNDARY LAYER
MIGHT CONTRIBUTE TO SUFFICIENT INSTABILITY FOR A FEW THUNDERSTORMS
TO DEVELOP ACROSS A PORTION OF MN INTO WRN WI THURSDAY AFTERNOON.
LIMITED LOW LEVEL MOISTURE AND WEAK INSTABILITY SUGGEST COVERAGE
SHOULD REMAIN SPARSE.

..DIAL.. 09/12/2012

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