DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 200649
SWODY2
SPC AC 200648

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1248 AM CST WED NOV 20 2013

VALID 211200Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A SPLIT FLOW REGIME WILL CHARACTERIZE THE SYNOPTIC PATTERN THURSDAY
WITH AN UPPER TROUGH DROPPING SWD ALONG THE WRN U.S. COAST AND
EVENTUALLY BECOMING CUTOFF FROM THE NRN STREAM WHILE EVOLVING INTO A
CLOSED LOW OVER THE SWRN STATES. MEANWHILE...A NRN STREAM TROUGH
WILL MOVE THROUGH THE NRN PLAINS AND UPPER MS VALLEY REGION. AT THE
SFC A POLAR FRONT WILL SURGE SWD INTO THE SRN PLAINS. BY THE END OF
THE PERIOD THIS BOUNDARY IS FORECAST TO EXTEND FROM THE GREAT LAKES
SWWD THROUGH CNTRL AND SWRN TX.

...SRN PLAINS AREA...

SLY WINDS IN WAKE OF RETREATING SFC RIDGE WILL ADVECT 60S BOUNDARY
LAYER DEWPOINTS THROUGH TX WITH LOW 60S POSSIBLE AS FAR NORTH AS OK
THURSDAY AFTERNOON. DESPITE THE POTENTIAL FOR LOW CLOUDS WITHIN THE
MOISTENING WARM SECTOR...AN AXIS OF MODEST INSTABILITY /500-1500
J/KG MUCAPE/ WILL LIKELY DEVELOP DURING THE AFTERNOON. THE GREATER
INSTABILITY IS EXPECTED FROM WCNTRL THROUGH NWRN TX INTO SWRN OK
WHERE ERN FRINGE OF STEEPER LAPSE RATES MAY OVERTAKE WRN EDGE OF THE
MOIST AXIS AND WHERE SOME DIABATIC WARMING MAY OCCUR. A BELT OF
40-50 KT SWLY 500 MB WINDS WILL PERSIST DURING THE DAY ACROSS NRN TX
INTO OK RESULTING IN 40-45 KT EFFECTIVE SHEAR...THOUGH FLOW IN THE
850-600 MB LAYER IS EXPECTED TO WEAKEN AS HEIGHTS RISE IN WAKE OF AN
EJECTING LOW AMPLITUDE SHORTWAVE TROUGH. STORMS WILL LIKELY INITIATE
ALONG AND POSSIBLY JUST AHEAD OF THE SWD ADVANCING COLD FRONT ACROSS
OK AND THEN SWD INTO NWRN-NRN TX DURING THE AFTERNOON AND EVENING.
ORIENTATION OF THE WINDS ALOFT WITH RESPECT TO THE MOTION OF THE
SURGING FRONT SUGGESTS STORMS INITIATING ON THIS BOUNDARY WILL BE
UNDERCUT. SOME OF THE STORMS MAY POSE A THREAT FOR ISOLATED HAIL AND
POSSIBLY GUSTY WINDS. HOWEVER...THE TENDENCY FOR STORMS TO BE
UNDERCUT AND WINDS IN THE 850-600 MB LAYER TO WEAKEN MAY POSE
LIMITING FACTORS FOR A MORE ROBUST SEVERE THREAT.

..DIAL.. 11/20/2013

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