[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 031637
SWODY1
SPC AC 031635

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1135 AM CDT MON APR 03 2006

VALID 031630Z - 041200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER NERN GA..NC..SC..AND SOUTH
CENTRAL/SERN VA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SERN STATES INTO THE
UPPER OH VALLEY AND MID ATLANTIC REGION...

...WIDESPREAD SEVERE THUNDERSTORMS EXPECTED THIS AFTERNOON AND
EVENING FROM THE SOUTHERN AND CENTRAL APPALACHIANS INTO THE
CAROLINAS AND VIRGINIA....

...SYNOPSIS...
VIGOROUS UPPER TROUGH EXTENDING FROM THE LOWER GREAT LAKES INTO THE
TN VALLEY IS EXPECTED TO BECOME NEGATIVELY TILTED AS IT MOVES TOWARD
THE CAROLINAS AND VA...AS UPSTREAM LOW OVER NWRN ONTARIO DIGS SEWD.
AT THE SURFACE...PRIMARY LOW OVER THE LOWER LAKES WILL MOVE SLOWLY
EWD WITH SECONDARY CYCLOGENESIS EXPECTED OVER THE DELMARVA REGION
LATE THIS AFTERNOON AS UPPER LEVEL DIVERGENCE INCREASES IN LEFT EXIT
REGION OF MID/UPPER LEVEL JET STREAK MOVING ACROSS THE CAROLINAS. 
SURFACE COLD FRONT FROM LAKE ERIE SWD THROUGH ERN PARTS OF OH/KY/TN
SWWD ACROSS NRN AL AND CENTRAL MS IS FORECAST TO PROGRESS RAPIDLY
EWD...REACHING CENTRAL PARTS OF PA..VA..THE CAROLINAS INTO SWRN GA
AND WWD ALONG THE GULF COAST BY THIS EVENING...AND OFF THE ATLANTIC
COAST TONIGHT.

...SRN APPALACHIANS INTO CAROLINAS AND VIRGINIA...
COMPLEX CONVECTIVE SCENARIO HAS BEEN UNFOLDING THIS MORNING WITH EWD
MOVING BAND OF PRE-FRONTAL CONVECTION FROM ERN VA SWD INTO GA. 
ALTHOUGH ISOLATED STRONG/SEVERE STORMS ARE CONTINUING OVER ERN
NC...MOST OF THIS ACTIVITY HAS DIMINISHED IN INTENSITY WITH THINNING
CLOUDS EVIDENT FROM WRN NC INTO SC AND CENTRAL GA.  ASSOCIATED
OUTFLOW BOUNDARY EXTENDS ACROSS THE ERN CAROLINAS WWD INTO NRN
GA...WITH SC/GA PART OF THE BOUNDARY EXPECTED TO WEAKEN AS SURFACE
WINDS BACK TO A MORE SWLY COMPONENT IN RESPONSE TO ONGOING PRESSURE
FALLS.

12Z SOUNDINGS SHOWED A PLUME OF STEEP MID LEVEL LAPSE RATES
EXTENDING EWD FROM THE LOWER MS VALLEY TO THE SRN ATLANTIC COAST
WHICH IS ENHANCING POTENTIAL INSTABILITY ACROSS THE REGION.  STRONG
INSOLATION IN ADVANCE OF THE AFOREMENTIONED COLD FRONT WILL
CONTRIBUTE TO ADDITIONAL DESTABILIZATION THIS AFTERNOON...WITH
MLCAPE OF 1500 J/KG EXPECTED ALONG AN AXIS FROM GA INTO NC. 
CONVECTION IS DEVELOPING FROM THE UPPER OH VALLEY INTO NERN TN
ATTM...AND DEVELOPING CU FIELD IS EVIDENT SWWD INTO NWRN GA/NRN
AL/CENTRAL MS. AS CAP CONTINUES TO WEAKEN OVER THE SRN APPALACHIANS
REGION...THUNDERSTORMS ARE EXPECTED TO DEVELOP BY EARLY AFTERNOON.

STRONG DEEP LAYER SHEAR ACROSS THE AREA WILL ENHANCE CONVECTIVE
ORGANIZATION AND INTENSITY. STORM COVERAGE WILL LIKELY INCREASE
THROUGH THE MID-LATE AFTERNOON ALONG/AHEAD OF THE FRONT...WITH
POTENTIAL FOR SEVERAL BANDS OF STRONG/SEVERE STORMS WITH EMBEDDED
SUPERCELLS AND BOW SEGMENTS.  REMNANTS OF MORNING OUTFLOW
BOUNDARY/THERMAL GRADIENT ARE EXPECTED TO LIFT SLOWLY NWD FROM NRN
GA ACROSS UPSTATE SC..CENTRAL NC AND EXTREME SERN VA BY LATER THIS
AFTERNOON...PROVIDING AN ADDITIONAL MESOSCALE FOCUS FOR SEVERE
THUNDERSTORMS. A FEW TORNADOES WILL BE POSSIBLE...ESPECIALLY OVER
PARTS OF THE CAROLINAS AND SERN VA WHERE LOW LEVEL SHEAR WILL BE
STRONGEST...ALONG WITH VERY LARGE HAIL AND DAMAGING WIND GUSTS. 
SEVERE THREAT WILL SPREAD EWD TOWARD THE COAST BY THIS EVENING
BEFORE ENDING FROM THE WEST BY 03-06Z.

...UPPER OH VALLEY INTO CENTRAL APPALACHIANS...
A BAND OF STRONG/SEVERE STORMS HAS DEVELOPED JUST AHEAD OF THE COLD
FRONT FROM EXTREME WRN PA INTO ERN KY. THIS ACTIVITY IS  EXPECTED
TO SPREAD EWD IN ADVANCE OF THE STRONG UPPER LOW APPROACHING WRN
LAKE ERIE.  ALTHOUGH MORE EXTENSIVE CLOUDS OVER PA MAY INHIBIT
DIURNAL HEATING/DESTABILIZATION THIS AFTERNOON... STRONG WINDS
IMMEDIATELY ABOVE THE SURFACE WILL AID POTENTIAL FOR DAMAGING WIND
GUSTS THROUGH DOWNWARD TRANSFER OF HORIZONTAL MOMENTUM IN CONVECTIVE
DOWNDRAFTS.  IN ADDITION...THE STRONG LOW LEVEL SHEAR/HELICITY
SUGGESTS POTENTIAL FOR A FEW TORNADOES.  THIS ACTIVITY WILL LIKELY
CONTINUE EWD THROUGH THE AFTERNOON HOURS.

..WEISS/CROSBIE.. 04/03/2006