SPC AC 010659
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CST TUE DEC 01 2009
VALID 021200Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SOUTHEAST
AND THE ATLANTIC COAST STATES...
...SYNOPSIS...
A STRONG SHORT-WAVE TROUGH/UPPER LOW OVER ERN TX AT THE START OF THE
PERIOD IS PROGGED TO SHIFT RAPIDLY NEWD INTO THE NORTHEAST THIS
PERIOD...ON ERN FRINGES OF A MUCH LARGER/DIGGING TROUGH EXPANDING TO
ENCOMPASS MOST OF THE U.S. AND THE ERN 2/3 OF CANADA BY THE END OF
THE PERIOD.
AT THE SURFACE...LOW PRESSURE OVER THE SOUTHEAST WILL UNDERGO
SUBSTANTIAL CYCLOGENESIS...MOVING QUICKLY NNEWD INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE PERIOD. AS A WARM SECTOR SPREADS NWD
ACROSS THE APPALACHIANS/ATLANTIC COAST STATES IN CONJUNCTION WITH
THE LOW...ASSOCIATED SURFACE COLD FRONT WILL BEGIN SWEEPING
EWD...APPROACHING THE ATLANTIC COAST THROUGH THE END OF THE PERIOD
...SOUTHEAST U.S. NEWD TO THE CHESAPEAKE BAY AREA...
WIDESPREAD/POTENTIALLY-SIGNIFICANT SEVERE WEATHER EVENT REMAINS
EVIDENT THIS FORECAST...BEGINNING EARLY IN THE CENTRAL GULF COAST
REGION AND SPREADING EWD/NEWD THROUGH THE PERIOD.
SHOWERS AND STORMS -- AND ISOLATED SEVERE THREAT -- WILL LIKELY BE
ONGOING AT THE START OF THE PERIOD OVER PARTS OF AL AND THE FL
PANHANDLE...WITH CONVECTION TO SPREAD EWD/NEWD WITH TIME AS A
MOISTENING BOUNDARY LAYER SPREADS NWD -- PARTICULARLY E OF THE
APPALACHIANS. WHILE WEAK LAPSE RATES AND WIDESPREAD CLOUD COVER
STREAMING NEWD WILL HINDER APPRECIABLE DESTABILIZATION...INSTABILITY
WILL BE MARGINALLY SUFFICIENT TO SUPPORT ONGOING STORMS -- LIKELY IN
THE FORM OF MULTIPLE BANDS AS WELL AS ISOLATED CELLS.
WHILE GENERAL LACK OF MORE FAVORABLE INSTABILITY WILL LIKELY HINDER
SEVERE POTENTIAL TO SOME DEGREE...FAVORABLE LARGE-SCALE ASCENT WILL
SUPPORT STORM DEVELOPMENT THROUGH THE PERIOD. WITH STORMS ONGOING
WITHIN A VERY FAVORABLE KINEMATIC ENVIRONMENT FEATURING
STRONG/VEERING FLOW WITH HEIGHT...WELL-ORGANIZED CONVECTION --
INCLUDING BOTH BOWS/LEWPS AND SUPERCELLS -- CAN BE EXPECTED. ALONG
WITH THE THREAT FOR DAMAGING WINDS WITH ANY ORGANIZED BANDS OF
STORMS...THE POTENTIAL FOR A FEW STRONG/DAMAGING TORNADOES WILL ALSO
EXIST -- BOTH WITH ISOLATED STORMS AND WITHIN COMPLEX LINE SEGMENTS.
THE THREAT SHOULD CONTINUE OVERNIGHT WITH THE FRONT LIKELY
REMAINING ONSHORE THROUGH THE PERIOD...SPREADING NEWD AS FAR AS ERN
VA AND SWD ACROSS FL LATE.
..GOSS.. 12/01/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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