SPC AC 230745
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0145 AM CST SAT DEC 23 2006
VALID 251200Z - 261200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN SC/GA AND
MUCH OF FL...
...SYNOPSIS...
AS MENTIONED IN DAY 2 OUTLOOK...SOME UNCERTAINTY WITH RESPECT TO
LARGE SCALE PATTERN EVOLUTION BEGINS TO IMPACT FORECAST CONFIDENCE
FOR CHRISTMAS DAY OVER THE SOUTH. NCEP-SREF MEAN DEPICTS A SURFACE
LOW ASSOCIATED WITH A STRONG SRN LATITUDE UPPER TROUGH NEAR THE WRN
FL PNHDL. MEANWHILE...LATEST DETERMINISTIC GUIDANCE FROM GFS AND
ECMWF PLACE THE SURFACE LOW FARTHER INLAND...PERHAPS OVER AL. DEEP
CONVECTION SHOULD BE ACTIVE NEAR THE LOW AND ALSO OVER THE NERN GULF
ALONG ATTENDANT COLD FRONT. THE COLD FRONT IS EXPECTED TO MOVE EAST
ACROSS FL AND THE SOUTHEAST U.S. COAST THROUGH CHRISTMAS DAY WITH
THE EWD PROGRESSION AND INTENSITY OF THE FRONTAL FORCING BEING
MODULATED BY LARGER SCALE TROUGH AMPLIFICATION AND PHASING EXPECTED
TO OCCUR ACROSS MS/OH VALLEY AREAS THROUGH EARLY TUESDAY.
...GA/SC AND FL...
SIMILARITIES AMONG 00Z GFS/ECMWF AND LATEST GFS ENSEMBLE MEAN IN THE
TIMING OF THE COLD FRONT AND STRENGTH OF LARGE SCALE PHASING LEND
SUPPORT FOR A MORE AMPLIFIED AND ENERGETIC FLOW REGIME OVER THE
SOUTHEAST THROUGH CHRISTMAS DAY. DEGREE OF DESTABILIZATION AHEAD OF
THE FRONT...ACROSS PARTS OF ERN GA/SC AND FL...CONTINUES TO BE
SOMEWHAT PROBLEMATIC GIVEN THE POTENTIAL FOR WEAK LAPSE RATES
DEPICTED IN MODEL SOUNDINGS. HOWEVER...RELATIVELY MOIST PRE-FRONTAL
BOUNDARY LAYER WITH 65-70F DEWPOINTS APPEARS REASONABLE AND SHOULD
SUPPORT AT LEAST MARGINAL SURFACE-BASED CAPE. FORCING ON THE
ADVANCING FRONT SHOULD PROVE SUFFICIENT TO MAINTAIN DEEP CONVECTION
WHICH SHOULD EVOLVE INTO A SQUALL LINE AS FRONTAL FORCING
STRENGTHENS THROUGH THE DAY. THE SQUALL LINE SHOULD CROSS THE SERN
U.S. COAST AND CNTRL FL THROUGH THE LATE AFTERNOON BASED ON
GFS/ECMWF. STRENGTHENING OF DEEP-LAYER WIND FIELDS WILL CONTRIBUTE
TO BOWING LINE SEGMENTS AND/OR SUPERCELLS EMBEDDED WITHIN THE
CONVECTIVE LINE WITH DAMAGING WINDS POSSIBLE.
..CARBIN.. 12/23/2006
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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