DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 021647
SWODY2
SPC AC 021646

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1146 AM CDT FRI AUG 02 2013

VALID 031200Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR THE CNTRL HIGH PLAINS...

...SYNOPSIS...
UPPER-LEVEL ANTICYCLONE WILL BE POSITIONED OVER THE SRN HALF OF THE
NATION DURING SATURDAY...WITH A RIDGE EXTENDING NWD FROM THE SRN
HIGH PLAINS INTO THE NRN HIGH PLAINS. BROAD AREA OF CYCLONIC FLOW
ALOFT WILL EXIST OVER THE NERN CONUS...WHILE A POSITIVE TILT UPPER
TROUGH REMAINS ORIENTED FROM SRN BRITISH COLUMBIA TO AREAS OFFSHORE
OF NRN CA. A BELT OF STRONG UPPER-LEVEL FLOW /60+ KT AT 250 MB/ WILL
EMANATE FROM THE WRN TROUGH...TOP THE RIDGE OVER THE NRN
PLAINS...AND THEN EXTEND SEWD INTO THE MID-ATLANTIC REGION. AT THE
SURFACE...HIGH PRESSURE WILL EXIST FROM THE NRN PLAINS INTO THE
UPPER GREAT LAKES. S OF THIS FEATURE...A COLD FRONT WILL EXTEND SWWD
FROM THE NERN CONUS INTO THE CNTRL APPALACHIANS...THEN WWD ACROSS
THE OZARKS AND INTO THE CNTRL HIGH PLAINS...WHERE IT WILL THEN
EXTEND NWD INTO THE NRN HIGH PLAINS.

...CNTRL HIGH PLAINS...
ELY LOW-LEVEL WINDS ALONG AND TO THE COOL SIDE OF A SURFACE COLD
FRONT WILL AID IN MAINTAINING 60S DEWPOINTS OVER WRN KS INTO NERN
CO...AND 40S/50S DEWPOINTS FROM SERN CO TO THE FRONT RANGE. PLUME OF
STEEP MIDLEVEL LAPSE RATES WILL RESIDE OVER THE REGION...AND WHEN
COMBINED WITH THE AVAILABLE BOUNDARY LAYER MOISTURE AND DAYTIME
HEATING...WILL SUPPORT MLCAPE VALUES UP TO 1500 J/KG IN ERN CO...AND
POSSIBLY 2500-3500 J/KG IN WRN KS. BOTH FRONTAL AND OROGRAPHIC
FORCING FOR ASCENT COULD SERVE TO INITIATE STORMS DURING THE
AFTERNOON. LOW-LEVEL ELY WINDS VEERING TO WLY IN THE
MID/UPPER-LEVELS WILL YIELD SHEAR PROFILES SUPPORTIVE OF A FEW
SUPERCELLS AND AN ASSOCIATED RISK FOR LARGE HAIL AND DAMAGING WIND
GUSTS. UPSCALE GROWTH AND AN ISOLATED SEVERE THREAT MAY OCCUR AFTER
DARK AS ACTIVITY SPREADS EWD ALONG THE FRONT OVER KS.

...CNTRL/ERN KS...WRN MO...
HEATING ALONG THE E-W ORIENTED FRONTAL BOUNDARY WILL AID IN BOOSTING
TEMPERATURES INTO THE 80S TO LOW 90S ACROSS CNTRL/ERN KS INTO WRN
MO. SUBSEQUENT BOUNDARY LAYER DESTABILIZATION COMBINED WITH
DEWPOINTS NEAR 70F WILL YIELD MLCAPE VALUES FROM 1500-3000
J/KG...AND FAVOR THE DEVELOPMENT OF THUNDERSTORM CLUSTERS DURING THE
AFTERNOON. VERTICALLY VEERING WIND PROFILES COMBINED WITH THE
MOIST/UNSTABLE ENVIRONMENT WILL SUPPORT A RISK FOR ISOLATED LARGE
HAIL AND DAMAGING WIND GUSTS.

...NRN HIGH PLAINS...
MODEL GUIDANCE INDICATES THE NRN HIGH PLAINS WILL RESIDE BENEATH A
BELT OF 45 KT WLY FLOW AT 500 MB...AND 90 KT AT 250 MB. THE STRONG
WINDS ALOFT COMBINED WITH SELY LOW-LEVEL FLOW WILL YIELD VERY LONG
HODOGRAPHS AND EFFECTIVE BULK SHEAR VALUES NEAR 60 KT.
THUS...ISOLATED SPLITTING SUPERCELLS AND A THREAT OF LARGE HAIL WILL
BE POSSIBLE ALONG A STATIONARY FRONT AS WEAK TO MODERATE BUOYANCY
DEVELOPS DURING THE AFTERNOON IN RESPONSE TO DAYTIME
HEATING/BOUNDARY LAYER DESTABILIZATION.

...MID-ATLANTIC REGION...
MODEST DAYTIME TEMPERATURES COMBINED WITH DEWPOINTS IN THE MID TO
UPPER 60S WILL AID IN MLCAPE VALUES FROM 500-1500 J/KG OVER SRN NJ
SWD INTO NERN NC DURING SATURDAY AFTERNOON. THIS WILL SUPPORT
ISOLATED TO SCATTERED THUNDERSTORM CLUSTERS...SOME OF WHICH COULD
BECOME MARGINALLY SEVERE GIVEN THE PRESENCE OF 0-6 KM BULK SHEAR
NEAR 40 KT. HOWEVER...WEAK LOW AND MIDLEVEL LAPSE RATES ARE EXPECTED
TO PRECLUDE A MORE SUBSTANTIAL SEVERE WEATHER THREAT.

..GARNER.. 08/02/2013

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