SWODY1
SPC AC 271618
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1018 AM CST TUE DEC 27 2011
VALID 271630Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE EASTERN
CAROLINAS...
AN INTENSE UPPER TROUGH IS CURRENTLY MOVING ACROSS THE CENTRAL
APPALACHIANS...AND WILL ROTATE INTO NEW ENGLAND TONIGHT. THIS
SYSTEM HAS BECOME NEGATIVELY TILTED AS A 90-100 KNOT MID/UPPER LEVEL
JET ROTATES THROUGH THE BASE OF THE TROUGH AND ACROSS PARTS OF
SC/NC/VA. RAPID SURFACE CYCLOGENESIS IS OCCURRING AHEAD OF THE
SYSTEM OVER THE MOUNTAINS OF SC/NC WHERE 4-5MB/HR SURFACE PRESSURE
FALLS ARE BEING OBSERVED. IN THE WARM SECTOR...VERY STRONG
SOUTHERLY LOW LEVEL WIND FIELDS ARE HELPING TO SCOUR OUT COLD/DRY
SURFACE AIR MASS AND TRANSPORT 50S TO LOWER 60S DEWPOINTS OFF THE
ATLANTIC INTO THE CAROLINAS.
RECENT RADAR TRENDS HAVE SHOWN A NARROW LINE OF LOW-TOPPED
CONVECTION OVER CENTRAL SC. THESE STORMS ARE IN A REGION OF WEAK
CAPE /DEWPOINTS IN THE LOWER 60S AND MUCAPE VALUES OF 100-300 J/KG/.
HOWEVER...FORECAST SOUNDINGS AND VAD PROFILES SHOW VERY STRONG LOW
LEVEL VERTICAL SHEAR PROFILES /3KM SRH OF 500-800 M2/S2/. MESOSCALE
MODELS SUGGEST THAT SCATTERED CONVECTION WILL CONTINUE TO DEVELOP
ACROSS THE WARM SECTOR THROUGH THE AFTERNOON AND EARLY EVENING
BEFORE COLD FRONT SWEEPS OFF THE COAST. IT IS UNCERTAIN WHETHER
SUFFICIENT CAPE WILL DEVELOP FOR ROBUST/SUSTAINED UPDRAFTS.
HOWEVER...IMPRESSIVE VERTICAL SHEAR PROFILES AND FAVORABLE LARGE
SCALE FORCING FOR ASCENT WILL POSE A CONDITIONAL RISK OF
SUPERCELL/BOWING STORM STRUCTURES AND ATTENDANT DAMAGING
WINDS/TORNADOES.
..HART/GARNER.. 12/27/2011
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