SWODY1
SPC AC 040515
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1215 AM CDT SUN MAY 04 2008
VALID 041200Z - 051200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
WITH THE LARGE SCALE TROUGH REMAINING CENTERED OVER WESTERN ONTARIO
THROUGH EARLY MONDAY...A SURFACE COLD FRONT IS FORECAST TO EXIT THE
MID ATLANTIC SEABOARD THIS MORNING...WITH THE TRAILING PORTION OF
THE FRONT STALLING FROM THE COASTAL CAROLINAS TO NORTH FL.
OTHERWISE...A SPLIT FLOW REGIME WILL BECOME INCREASINGLY PREVALENT
ACROSS THE WESTERN STATES AS A BROAD UPPER TROUGH BECOMES
ESTABLISHED ACROSS THE SOUTHWEST STATES. AS THIS OCCURS...UPPER
RIDGING IS FORECAST TO DEVELOP ACROSS MUCH OF THE SOUTHERN PLAINS.
WITH THE PREVIOUS COLD FRONT HAVING STALLED ACROSS THE WESTERN GULF
OF MEXICO...BOUNDARY LAYER MOISTURE WILL BEGIN TO GRADUALLY RETURN
WEST-NORTHWESTWARD ACROSS SOUTH TX THIS AFTERNOON/TONIGHT.
...COASTAL CAROLINAS AND EASTERN GA TODAY...
A MOIST/UNSTABLE AIRMASS WILL REMAIN ACROSS THE EASTERN CAROLINAS
AND ADJACENT EASTERN GA AHEAD OF THE WEAKENING/DECELERATING SYNOPTIC
COLD FRONT. WITH THE MID LEVEL TROUGH FORECAST TO CROSS THE REGION
BY LATE MORNING...AND DEVELOPING WESTERLY FLOW ALOFT...LIMITED
CONVERGENCE/DECREASING VERTICAL SHEAR SUGGESTS THE OVERALL SEVERE
RISK SHOULD REMAIN SOMEWHAT MARGINAL/DISORGANIZED TODAY.
NEVERTHELESS...IN THE WAKE OF SOME EARLY MORNING
SHOWERS/THUNDERSTORMS...THE COMBINATION OF THE FRONT/COASTAL SEA
BREEZES SHOULD LEAD TO ADDITIONAL STORM DEVELOPMENT BY EARLY
AFTERNOON. IT APPEARS THAT THE STRONGEST STORMS WILL BE CAPABLE OF
STRONG WIND GUSTS/SEVERE HAIL AMIDST AN ENVIRONMENT CHARACTERIZED BY
25-30 KT OF EFFECTIVE BULK SHEAR WITH STEEP LOW LEVEL LAPSE RATES
AND MLCAPE TO AROUND 1000 J/KG.
...SOUTHWEST TX THIS AFTERNOON/EARLY EVENING...
AS BOUNDARY LAYER MOISTURE BEGINS TO RETURN ACROSS SOUTH
TX...ISOLATED STORMS MAY DEVELOP ALONG THE HIGHER TERRAIN/MOUNTAINS
OF SOUTHWEST TX AND ADJACENT PORTIONS OF NORTHERN MEXICO THIS
AFTERNOON. SCENARIO WILL BE LARGELY DRIVEN BY HEATING/LOW LEVEL
UPSLOPE...ALTHOUGH LATEST NUMERICAL GUIDANCE SUGGESTS A MINOR
SHORTWAVE TROUGH CURRENTLY NEAR BAJA WILL CROSS NORTHERN
MEXICO...REACHING FAR SOUTHWEST TX BY LATE AFTERNOON. IN SPITE OF
MODERATE TO STRONG VERTICAL SHEAR /INCREASING TO 40+ KT/...MODEST
BOUNDARY LAYER MOISTURE /50S F/ AND CAPPING AWAY FROM THE HIGHER
TERRAIN SUGGEST ANY SEVERE THREAT SHOULD REMAIN VERY ISOLATED.
...WESTERN KS/OK PANHANDLE LATE TONIGHT...
ELEVATED MOISTURE RETURN REGIME WILL INCREASE LATE TONIGHT ACROSS
THE CENTRAL/SOUTHERN HIGH PLAINS...SUPPORTED BY THE PROGGED
DEVELOPMENT OF A 40 KT SOUTHERLY LOW LEVEL JET. SUFFICIENT
ISENTROPIC ASCENT/MID LEVEL MOISTENING MAY OCCUR AFTER MIDNIGHT FOR
ISOLATED THUNDERSTORMS ACROSS WESTERN KS AND THE OK PANHANDLE...MOST
LIKELY IN THE 08Z-12Z TIME FRAME. ALTHOUGH FORECAST SOUNDINGS IMPLY
THE POTENTIAL FOR 750-1000 J/KG OF ELEVATED MUCAPE...CONCERNS
REGARDING LARGE SCALE RIDGING/COVERAGE OF LATE NIGHT STORMS
PRECLUDES 5% SEVERE HAIL PROBABILITIES AT THIS TIME.
..GUYER/SMITH.. 05/04/2008
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