DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 170554
SWODY2
SPC AC 170553

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT THU APR 17 2008

VALID 181200Z - 191200Z

..THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF LA AND SRN
MS...

..SYNOPSIS...
CLOSED LOW AT MID LEVELS -- INITIALLY OVER THE CENTRAL PLAINS...WILL
SHIFT SLOWLY EWD WITH TIME INTO THE LOWER OH VALLEY. MEANWHILE...A
SECOND TROUGH IS FORECAST TO EXPAND/AMPLIFY OVER THE WESTERN CONUS.

AT THE SURFACE...LOW ASSOCIATED WITH THE CENTRAL U.S. CLOSED LOW IS
FORECAST TO SHIFT SLOWLY EWD FROM THE MO VALLEY INTO THE
MIDWEST/LOWER OH VALLEY THROUGH THE PERIOD. TRAILING COLD FRONT --
INITIALLY EXTENDING FROM WRN MO/WRN AR SSWWD ACROSS THE TX COAST --
WILL MOVE EWD ACROSS THE MID AND LOWER MS VALLEY REGION THROUGH THE
FIRST HALF OF THE PERIOD. THE FRONT WILL CONTINUE EWD
OVERNIGHT...AND SHOULD EXTEND FROM THE MID OH VALLEY/MID SOUTH
REGION TO THE WRN FL PANHANDLE BY 19/12Z.

..LA/SRN MS...
THUNDERSTORMS SHOULD BE ONGOING ALONG/INVOF COLD FRONT AT THE START
OF THE PERIOD...FROM MO/WRN AR INTO COASTAL/ERN TX. THIS CONVECTION
WILL SHIFT EWD INTO EARLY AFTERNOON...MOVING OFF THE TX COAST WITH
TIME. MEANWHILE...PRE-FRONTAL PRECIPITATION IS FORECAST TO INCREASE
ACROSS LA/SRN MS...WITHIN WARM SECTOR FEATURING A MOISTENING
BOUNDARY LAYER/WEAK DESTABILIZATION.

WHILE LIMITED INSTABILITY IS FORECAST ACROSS LA/MS DUE TO DEVELOPING
PRE-FRONTAL CLOUDS/PRECIPITATION AND THUS LIMITED HEATING...WIND
FIELD FORECAST TO VEER WITH HEIGHT AND INCREASE TO 40 TO 60 KT FROM
THE WSW AT MID LEVELS WILL RESULT IN SHEAR SUPPORTIVE OF STORM
ORGANIZATION. MAIN THREAT WILL LIKELY BE LOCALLY-GUSTY/DAMAGING
WINDS AND PERHAPS AN ISOLATED TORNADO.

CONVECTION WILL SPREAD EWD WITH TIME...EVENTUALLY INTO AL AND PARTS
OF THE FL PANHANDLE. HOWEVER...WITH THE EXPECTED DIURNAL DECREASE
IN AVAILABLE INSTABILITY...SEVERE THREAT SHOULD SLOWLY WANE
OVERNIGHT.

.GOSS.. 04/17/2008

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