SPC AC 040600
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1200 AM CST FRI DEC 04 2009
VALID 051200Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS SAT ACROSS PARTS OF THE
CNTRL/SRN FLORIDA PENINSULA...
...SYNOPSIS...
MODELS INDICATE THAT A BLOCKING UPPER RIDGE WILL GRADUALLY BUILD
ACROSS THE NORTHEAST PACIFIC/ALASKA/CANADIAN YUKON TERRITORY BETWEEN
NOW AND 12Z SUNDAY. AT THE SAME TIME...TO ITS SOUTHEAST...A COUPLE
OF SIGNIFICANT SHORT WAVE IMPULSES ARE PROGGED TO DIG ACROSS THE
CANADIAN ROCKIES INTO THE PACIFIC NORTHWEST AND GREAT BASIN. THIS
APPEARS LIKELY TO CONTRIBUTE TO A BROADENING OF THE AMPLIFIED
POSITIVELY TILTED TROUGH NOW ENCOMPASSING MUCH OF THE CENTRAL AND
EASTERN U.S...WITH A TENDENCY FOR MID/UPPER FLOW TO TAKE ON A MORE
WEST SOUTHWESTERLY COMPONENT FROM THE WESTERN GULF STATES THROUGH
MUCH OF THE SOUTHEAST. WITHIN THIS REGIME...GUIDANCE INDICATES THAT
A VIGOROUS SHORT WAVE TROUGH WILL LIFT INTO THE EASTERN GULF STATES
BY 12Z SATURDAY...BEFORE CONTINUING ACROSS THE MID/SOUTHERN ATLANTIC
COAST INTO THE WESTERN ATLANTIC BY LATE SATURDAY NIGHT.
THE EVOLVING UPPER PATTERN APPEARS LIKELY TO SUPPORT A DEVELOPING
SURFACE WAVE ALONG A QUASI-STATIONARY FRONT OFF SOUTH ATLANTIC
COASTAL AREAS...ALONG WITH WEAK TO MODERATE DESTABILIZATION ACROSS
THE FLORIDA PENINSULA PRIOR TO FRONTAL PROGRESSION OFF THE SOUTHEAST
FLORIDA COAST AND SOUTH OF THE KEYS. THIS IS EXPECTED TO BE
ACCOMPANIED BY THE RISK FOR THUNDERSTORMS...SOME OF WHICH COULD
BECOME SEVERE.
...FLORIDA PENINSULA...
THE QUASI-STATIONARY FRONTAL ZONE MAY RETREAT NORTHWARD TOWARD THE
CENTRAL PENINSULA BY DAYBREAK SATURDAY...PERHAPS AS FAR AS MELBOURNE
AND AREAS JUST TO THE SOUTH OF TAMPA/ST. PETERSBURG. WHILE STRONGER
LIFT ASSOCIATED WITH THE SOUTHEASTERN TROUGH MAY ALREADY BE IN THE
PROCESS OF LIFTING TO THE NORTH OF THE REGION BY THIS
TIME...LARGE-SCALE FORCING COULD REMAIN SUFFICIENT GIVEN BOUNDARY
LAYER DESTABILIZATION ASSOCIATED WITH WARMING AND MOISTENING THROUGH
MID DAY TO SUPPORT A WINDOW OF OPPORTUNITY FOR THE DEVELOPMENT OF
STRONG/SEVERE STORMS.
IF THIS OCCURS...THIS SEEMS MOST LIKELY TO MANIFEST ITSELF IN THE
FORM OF A SQUALL LINE OR CLUSTER MIGRATING INLAND OFF THE GULF OF
MEXICO ALONG OR JUST AHEAD OF THE FRONT...WITH 40+ KT WESTERLY DEEP
LAYER MEAN FLOW CONTRIBUTING TO THE RISK FOR DAMAGING WIND GUSTS.
HOWEVER...DEPENDING ON THE TIMING OF THE UPPER WAVE...AND ASSOCIATED
VEERING OF THE PRE-FRONTAL LOW-LEVEL FLOW FIELDS... LOW-LEVEL
HODOGRAPHS COULD MAINTAIN SUBSTANTIAL CLOCKWISE CURVATURE SUPPORTIVE
OF ENHANCED TORNADO POTENTIAL IN ANY DISCRETE PRE-FRONTAL STORMS
THROUGH EARLY AFTERNOON.
CONVECTIVE POTENTIAL SEEMS LIKELY TO DIMINISH DURING THE MID TO LATE
AFTERNOON HOURS...PRIOR TO REACHING MIAMI AND ADJACENT SOUTHEAST
COASTAL AREAS...AS LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION
WEAKENS/LIFTS OFF TO THE NORTHEAST.
..KERR.. 12/04/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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