DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 031235
SWODY1
SPC AC 031232

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0733 AM CDT WED OCT 03 2012

VALID 031300Z - 041200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A PROGRESSIVE UPPER-LEVEL PATTERN WILL PREVAIL ACROSS THE NATION
TODAY. OVER THE N-CNTRL CONUS...A STRONG TROUGH AND ASSOCIATED 50-80
KT MIDLEVEL JET STREAK WILL MOVE FROM THE NRN ROCKIES THIS MORNING
TO THE UPPER MS VALLEY BY THE END OF THE FORECAST PERIOD. STRONG
ASCENT AND WEAK ELEVATED INSTABILITY WILL AID IN ISOLATED
THUNDERSTORM DEVELOPMENT FROM ERN MT INTO CNTRL ND THROUGH EARLY
AFTERNOON. MEANWHILE...SURFACE LOW PRESSURE WILL MOVE ACROSS SRN SD
THIS AFTERNOON...AND THEN LIFT NWD ACROSS MN DURING THE NIGHT. AS
THIS OCCURS...A COLD FRONT WILL QUICKLY MOVE SEWD ACROSS THE CNTRL
PLAINS. ASCENT TIED TO THE FRONT AND WEAK ELEVATED BUOYANCY WILL AID
IN ISOLATED THUNDERSTORM DEVELOPMENT FROM NERN CO INTO CNTRL IA.
ELSEWHERE...AN UPPER TROUGH...WHICH HAS BEEN STATIONARY OVER THE
LOWER MS VALLEY DURING THE PAST FEW DAYS...WILL EJECT NEWD INTO THE
OH VALLEY AS THE NRN STREAM TROUGH PROGRESSES EWD. ALONG THE
ATLANTIC COAST...MOIST SLY LOW-LEVEL FLOW WILL AID IN A WEAKLY
UNSTABLE AIRMASS...WHICH WILL SUPPORT SCATTERED SHOWER AND ISOLATED
THUNDERSTORM DEVELOPMENT.

...SERN LA...SRN/CNTRL MS...
COLD MIDLEVEL TEMPERATURES /FROM -12 TO -15 C AT 500 MB/ WILL RESIDE
ACROSS SERN LA AND SRN/CNTRL MS DURING PEAK HEATING...AND WILL AID
IN A MODERATELY STEEP LAPSE RATE ENVIRONMENT OVER THE AREA. WITH
DEWPOINTS IN THE MID 50S TO LOW 60S...MLCAPE VALUES FROM 500-1000
J/KG WILL BE POSSIBLE. THIS INSTABILITY COMBINED WITH 0-6 KM BULK
WIND DIFFERENCE FROM 20-30 KT MAY SUPPORT A MARGINAL THREAT FOR
SMALL HAIL AND GUSTY WINDS WITH ISOLATED THUNDERSTORMS DEVELOPING
DURING THE LATE MORNING AND AFTERNOON.

..GARNER/THOMPSON.. 10/03/2012

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