SWODY1
SPC AC 191605
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1105 AM CDT FRI OCT 19 2007
VALID 191630Z - 201200Z
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FROM
NY/PA SWD TO THE SE ATLANTIC COAST...
..APPALACHIANS TO THE ATLANTIC COAST TODAY INTO TONIGHT...
A DEEP OCCLUDED LOW OVER LAKE SUPERIOR WILL MOVE NNEWD TOWARD JAMES
BAY WHILE AN ASSOCIATED COLD FRONT /LOCATED FROM CENTRAL AL TO
CENTRAL OH AS OF 15Z/ PROGRESSES EWD ACROSS THE APPALACHIANS LATER
TODAY. THE FRONT IS PRECEDED BY A BROAD LOW-MID LEVEL MOISTURE
PLUME FROM THE SE ATLANTIC STATES INTO NEW ENGLAND. MID LEVEL LAPSE
RATES ARE ALSO LIMITED TO AOB 6 C/KM WITHIN THIS MOISTURE PLUME
BASED ON 12Z SOUNDINGS...WHILE WIDESPREAD CLOUDS WILL KEEP SURFACE
TEMPERATURES IN THE 70S THROUGH THIS AFTERNOON. THE NET RESULT WILL
BE A WARM SECTOR CHARACTERIZED BY MOIST PROFILES AND MLCAPE VALUES
AOB 500 J/KG.
THE STRONGER LOW-LEVEL FLOW AND ASSOCIATED VERTICAL SHEAR WILL
DEVELOP NEWD TOWARD THE NRN CHESAPEAKE/ERN PA/ERN NY AREA THIS
AFTERNOON AS THE PRIMARY MID LEVEL TROUGH LIFTS NNEWD TOWARD WRN
NY/SWRN ONTARIO BY THIS EVENING. VERTICAL SHEAR PROFILES WILL BE
FAVORABLE FOR ORGANIZED SEVERE STORMS...INCLUDING SUPERCELLS AND BOW
ECHOES...BASED ON FORECAST HODOGRAPHS WITH 0-1 KM SRH OF 200-300
M2/S2 AND EFFECTIVE BULK SHEAR IN EXCESS OF 40 KT. ANY PERSISTENT
DISCRETE STORMS IN THE MOIST/WEAKLY UNSTABLE ENVIRONMENT MAY PRODUCE
A TORNADO OR TWO. HOWEVER...THE POOR LAPSE RATES/WEAK INSTABILITY
WILL TEND TO LIMIT THE OVERALL MAGNITUDE OF THIS SEVERE STORM
THREAT...AND THE PRIMARY THREAT SHOULD BE ISOLATED-WIDELY SCATTERED
DAMAGING WINDS WITH THE BAND OF STORMS ALONG THE FRONT.
FARTHER S...STRONGER SURFACE HEATING WILL OCCUR ACROSS N FL AND THE
ERN CAROLINAS IN ADVANCE OF THE PRE-FRONTAL CONVECTION. WIND
PROFILES ARE EXPECTED TO BECOME MORE UNIDIRECTIONAL WITH TIME ACROSS
THIS AREA...WITH ISOLATED DAMAGING WINDS THE MAIN THREAT THIS
AFTERNOON.
.THOMPSON/GRAMS.. 10/19/2007
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