SWODY2
SPC AC 120704
DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0104 AM CST WED NOV 12 2008
VALID 131200Z - 141200Z
...NO SVR TSTM AREAS FORECAST...
CORRECTED FOR GENERAL THUNDER GRAPHIC
...SYNOPSIS...
UPPER PATTERN WILL REMAIN IN TRANSITION THURSDAY. MODELS CONTINUE TO
DIFFER ON DETAILS OF THIS EVOLUTION. TWO SIGNIFICANT IMPULSES MOVING
THROUGH THE BROADER SCALE UPPER TROUGH WILL BE OF INTEREST THIS
PERIOD. INITIAL LEAD SHORTWAVE THROUGH WILL DEAMPLIFY AS IT EJECTS
INTO THE MEAN RIDGE POSITION OVER THE MID ATLANTIC REGION EARLY
THURSDAY. FARTHER WEST...MREF ENSEMBLE MEMBERS MAINTAIN A MORE
PROGRESSIVE SRN STREAM UPPER TROUGH OVER THE GULF COASTAL AREA
RATHER THAN CLOSING OFF THIS FEATURE OVER THE WRN GULF AS IN THE
NAM...GFS AND MOST SREF MEMBERS. EARLIER ECMWF RUNS HAVE BEEN
PROGRESSIVE WITH THIS FEATURE. LATEST RUN IS SOMEWHAT LESS
PROGRESSIVE AND HAS TRENDED CLOSER TO THE NAM AND GFS SOLUTIONS.
AT THE SURFACE...A QUASISTATIONARY FRONT WILL EXTEND ALONG THE NRN
GULF THEN NEWD NEAR THE COASTAL CAROLINAS EARLY THURSDAY.
...COASTAL CAROLINAS...
INLAND PENETRATION OF COASTAL FRONT WILL LIKELY BE LIMITED IN PART
BY A WEDGE OF COOLER AIR NEAR THE SURFACE THAT WILL PERSIST EAST OF
THE APPALACHIANS. COLD AIR DAMMING MAY BE FURTHER ENHANCED BY ONSET
OF PRECIPITATION WITHIN DEVELOPING WARM ADVECTION REGIME. STRONGER
LIFT ASSOCIATED WITH THE EJECTING AND DEAMPLIFYING SHORTWAVE TROUGH
WILL LIKELY REMAIN ABOVE A STABLE BOUNDARY LAYER WITH LIMITED
CYCLOGENESIS ALONG THE COASTAL FRONT. NEVERTHELESS...A SMALL WARM
SECTOR COULD ADVANCE INLAND ALONG THE NC AND SC COASTS DURING THE
DAY. DEEP LAYER FLOW AND VERTICAL SHEAR WILL INCREASE IN RESPONSE TO
THE EJECTING WAVE AND CONTRIBUTE TO POTENTIAL FOR ORGANIZED STORMS.
INLAND WARM SECTOR INSTABILITY SHOULD REMAIN MARGINAL DUE TO WEAK
LAPSE RATES...AREAS OF CLOUDS AND PRECIPITATION. SCATTERED
CONVECTION WILL BE POSSIBLE IN WARM SECTOR WHERE VERTICAL SHEAR
WOULD SUPPORT ROTATING STORMS. HOWEVER...THE EXPECTED MARGINAL
THERMODYNAMIC ENVIRONMENT AND UNCERTAINTY REGARDING INLAND ADVANCE
OF COASTAL BOUNDARY PRECLUDES MORE THAN 5% SEVERE PROBABILITIES AT
THIS TIME.
...CNTRL AND NERN GULF COASTAL AREA...
RICHER LOW LEVEL MOISTURE IS EXPECTED TO REMAIN NEAR THE COASTAL
AREAS ALONG AND SOUTH OF WARM FRONT. SEVERE THREAT IN THIS REGION IS
PREDICATED UPON HOW QUICKLY SRN STREAM IMPULSE EJECTS INTO THE CNTRL
GULF. THERE IS SOME CHANCE THAT THIS IMPULSE MAY EJECT INTO GULF
COASTAL AREA LATER THURSDAY NIGHT WITH A CORRESPONDING INCREASE IN
LOW LEVEL WINDS AND NWD PROGRESSION OF WARM FRONT. HOWEVER...LATEST
MODEL TRENDS HAVE BEEN LESS PROGRESSIVE WITH A TENDENCY TO TRY AND
CLOSE OFF THE UPPER LOW OVER THE GULF WHICH WOULD SIGNIFICANTLY
REDUCE ANY SEVERE POTENTIAL. GIVEN THESE UNCERTAINTIES...WILL
INTRODUCE ONLY 5% SEVERE PROBABILITIES AT THIS TIME BUT CONTINUE TO
MONITOR.
..DIAL.. 11/12/2008
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