SPC AC 300546
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1146 PM CST SAT DEC 29 2007
VALID 301200Z - 311200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
SHORT WAVE TROUGH EXPECTED TO BE OVER TX/OK AT 12Z TODAY WILL TRACK
NEWD INTO THE TN VALLEY BY 31/00Z...AS IT PHASES WITH A FEW NRN
STREAM IMPULSES MOVING ESEWD TOWARD THE OH/TN VALLEYS. THE PHASED
TROUGH SHOULD THEN BECOME MORE NEGATIVELY TILTED AS IT MOVES QUICKLY
NEWD ACROSS THE MID ATLANTIC REGION TO SRN NEW ENGLAND TONIGHT. AT
12Z TODAY...A SURFACE BOUNDARY SHOULD EXTEND FROM THE CAROLINAS SWWD
TO SRN AL AND THEN INTO THE NWRN GULF. A SURFACE WAVE LOCATED ALONG
THIS BOUNDARY...INITIALLY OVER THE NORTH CENTRAL GULF OR SRN AL...IS
EXPECTED TO TRACK NEWD INTO NRN GA AND THEN THE CENTRAL CAROLINAS
THIS AFTERNOON. RAPID DEEPENING OF THIS LOW IS THEN FORECAST SUNDAY
NIGHT FROM THE DELMARVA REGION NEWD TO JUST OFF OF CAPE COD WITH
APPROACH OF NEGATIVELY TILT UPPER TROUGH. TRAILING PORTION OF THE
SURFACE BOUNDARY FROM THE LOW WILL EVOLVE INTO A COLD FRONT MOVING
EWD ACROSS SRN AL TO GA/FL PANHANDLE DURING THE FIRST HALF OF THE
FORECAST PERIOD...AND SHOULD EXTEND SWWD ACROSS THE ERN CAROLINAS TO
SRN GA/ERN FL PANHANDLE INTO THE ERN GULF BY EARLY EVENING.
...NERN GULF COAST STATES TO CAROLINAS...
TSTMS...MOSTLY LOCATED ALONG AND N OF THE SURFACE BOUNDARY...ARE
EXPECTED TO BE ONGOING AT 12Z TODAY FROM THE LOWER MS VALLEY INTO
PARTS OF MS TO GA/FL PANHANDLE WITHIN ZONE OF WEAK WAA/ISENTROPIC
ASCENT. MODELS SUGGEST THE STRONGEST FORCING WITH THE PHASING
TROUGHS AND GREATEST HEIGHT FALLS SHOULD REMAIN N OF THE SURFACE
FRONT AND WARM SECTOR. HOWEVER...ASCENT WITHIN ENTRANCE REGION OF
STRENGTHENING MID LEVEL JET ACCOMPANYING THE SRN STREAM TROUGH IS
EXPECTED TO TRANSLATE ENEWD FROM THE LOWER MS VALLEY AT 12Z TO THE
SERN STATES BY EARLY EVENING. THIS ASCENT COMBINED WITH MOISTURE
ADVECTION ALONG STRONG SWLY LLJ ORIENTED PARALLEL TO THE SURFACE
BOUNDARY WILL SUPPORT SUFFICIENT DESTABILIZATION...DESPITE WEAK
LAPSE RATES...FOR ADDITIONAL TSTM DEVELOPMENT THROUGH THE FORECAST
PERIOD. GIVEN DEEP SWLY WIND FIELDS...MODELS SUGGEST THE POTENTIAL
FOR SEVERAL BANDS/LINES OF TSTMS TO DEVELOP ALONG AND EAST OF THE
PROGRESSIVE COLD FRONT/SURFACE LOW INTO THE AFTERNOON/EARLY EVENING.
OVERALL WEAK INSTABILITY IS EXPECTED TO LIMIT THE DEVELOPMENT OF
SEVERE TSTMS. HOWEVER...EFFECTIVE BULK SHEAR OF 35-45 KT AND LOW
LEVEL SPEED SHEAR AND SOME DIRECTIONAL SHEAR SUGGEST THE STRONGER
STORMS MAY BECOME ORGANIZED WITH THE POTENTIAL FOR ISOLATED DAMAGING
WINDS AND/OR A BRIEF TORNADO. IF GREATER INSTABILITY IS EXPECTED
ESPECIALLY INTO PARTS OF ERN GA/CAROLINAS THIS AFTERNOON...THEN
PARTS OF THIS REGION MAY REQUIRE AN UPGRADE TO A CATEGORICAL
OUTLOOK.
..PETERS.. 12/30/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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