SPC AC 150450
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM CDT MON MAR 14 2011
VALID 151200Z - 161200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER LOW CENTERED OVER THE MID SOUTH AT THE BEGINNING OF THE
FORECAST PERIOD WILL DEAMPLIFY AS IT LIFTS NEWD ACROSS THE MID
ATLANTIC REGION BY 16/12Z. AS THIS OCCURS...WEAK SURFACE LOW
PRESSURE WILL DEVELOP ALONG A LOW-LEVEL BAROCLINIC ZONE POSITIONED
OVER THE CAROLINAS AND VA...AND SHIFT INTO THE DELMARVA DURING WED
MORNING. FARTHER W...BROAD UPPER TROUGH AND ASSOCIATED SURFACE COLD
FRONT WILL PROGRESS EWD INTO THE PAC NW DURING THE
AFTERNOON...PROVIDING A FAVORABLE ENVIRONMENT FOR THUNDERSTORM
DEVELOPMENT.
...PACIFIC NW...
COLD MIDLEVEL TEMPERATURES /BETWEEN -20 TO -30 C AT 500 MB/ ARE
FORECAST TO STEADILY ADVECT EWD ACROSS THE REGION DURING THE
AFTERNOON AND NIGHT. THIS WILL CONTRIBUTE TO POST FRONTAL
DESTABILIZATION/STEEP LOW TO MIDLEVEL LAPSE RATES AND MLCAPE VALUES
OF SEVERAL HUNDRED J/KG. THUNDERSTORMS ARE EXPECTED TO INCREASE IN
COVERAGE BY MID AFTERNOON...OCCURRING IN AN ENVIRONMENT
CHARACTERIZED BY FAVORABLE VERTICAL WIND SHEAR PROFILES FOR
ORGANIZED THUNDERSTORM DEVELOPMENT. GIVEN THE STRONG SHEAR AND STEEP
LAPSE RATES...A FEW STRONG TO SVR THUNDERSTORMS WILL BE
POSSIBLE...POSING MAINLY A DAMAGING WIND AND MARGINAL HAIL THREAT.
...CAROLINAS AND ERN VA...
LOW TOPPED CONVECTION AND ISOLATED-SCATTERED THUNDERSTORM
DEVELOPMENT IS FORECAST TO OCCUR DURING THE LATE AFTERNOON AND NIGHT
AS INCREASING FORCING FOR ASCENT ACCOMPANYING THE UPPER TROUGH AND
SURFACE COLD FRONT ENTER THE REGION. MODEL FORECAST SOUNDINGS
INDICATE WEAK INSTABILITY WILL BE IN PLACE /MUCAPE VALUES AOB 300 J
PER KG/...SUGGESTING THE SVR WEATHER THREAT WILL BE VERY
CONDITIONAL. HOWEVER...STRONG VEERING WIND PROFILES WOULD SUPPORT
ORGANIZED THUNDERSTORM DEVELOPMENT. IF GREATER DESTABILIZATION
BECOMES APPARENT DURING LATER D1 OUTLOOKS...THEN LOW-END
WIND/TORNADO PROBABILITIES MAY NEED TO BE INTRODUCED.
..GARNER/GOSS.. 03/15/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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