SPC AC 271156
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0556 AM CST FRI FEB 27 2009
VALID 271300Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS
VALLEY AND CENTRAL GULF STATES...
MORNING WATER VAPOR LOOPS SHOW A STRONG SHORTWAVE TROUGH ROTATING
ACROSS THE MID MS AND OH VALLEYS. THIS TROUGH IS HELPING TO
MAINTAIN A LINE OF SHOWERS AND THUNDERSTORMS FROM OH...ACROSS PARTS
OF KY/TN...INTO MS/AR. NORTHERN/EASTERN EXTENT OF CONVECTION IS
MOVING INTO A DRIER AND MORE STABLE ENVIRONMENT. HOWEVER...TRAILING
SOUTHWESTERN END OF LINE WILL MAINTAIN A RISK OF SEVERE STORMS
THROUGH TONIGHT ACROSS PARTS OF THE ARKLATEX INTO MS/AL.
...CENTRAL GULF COAST STATES...
CURRENT LINE OF MARGINALLY SEVERE STORMS OVER KY/TN MAY CONTINUE TO
POSE A RISK OF LOCALLY GUSTY/DAMAGING WINDS EARLY THIS MORNING.
HOWEVER...A GREATER RISK IS EXPECTED TO EVOLVE FARTHER SOUTHWEST
THIS AFTERNOON ACROSS PARTS OF AR/LA. A COMBINATION OF DEWPOINTS IN
THE MID 60S...STEEPER MID LEVEL LAPSE RATES...AND COOL TEMPERATURES
ALOFT WILL RESULT IN AFTERNOON MLCAPE VALUES OVER 1000 J/KG.
ISOLATED THUNDERSTORMS WILL LIKELY DEVELOP BY EARLY/MID AFTERNOON
AND SPREAD EASTWARD INTO MS/AL DURING THE EVENING. FORECAST
SOUNDINGS APPEAR FAVORABLE FOR LARGE /POSSIBLY SGFNT/ HAIL IN
STRONGER CELLS. SUPERCELL STORMS WILL ALSO BE POSSIBLE...LIKELY
CAPABLE OF LOCALLY DAMAGING WINDS AS WELL.
...AR OVERNIGHT...
LATER THIS EVENING...STRONG LOW LEVEL WARM ADVECTION WILL DEVELOP
ACROSS PARTS OF OK/AR AS NEXT UPPER TROUGH APPROACHES. THIS WILL
LIKELY RESULT IN INCREASING COVERAGE OF ELEVATED THUNDERSTORMS
OVERNIGHT. RELATIVELY STEEP LAPSE RATE WILL PROMOTE A RISK OF HAIL
IN STRONGER CELLS...ALTHOUGH ORGANIZED SEVERE STORMS ARE NOT
CURRENTLY ANTICIPATED.
..HART.. 02/27/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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