FXUS62 KTBW 301856
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
156 PM EST MON NOV 30 2009
...POTENTIAL REMAINS FOR SOME SEVERE STORMS AND OTHER HAZARDS...
.SHORT TERM (TONIGHT - WEDNESDAY)...MODELS ARE ALL OVER THE PLACE
WITH THE DETAILS REGARDING THE DEVELOPING SYSTEM IN THE GULF OF
MEXICO ON TUESDAY. NEEDLESS TO SAY...CONFIDENCE IS LOW IN BOTH THE
TIMING OF THE WEATHER AND THE EXTENT OF THE HAZARDS.
FIRST...A BACK DOOR COLD FRONT WILL DROP INTO NORTH FLORIDA
TONIGHT AND MAY HAVE ENOUGH MOISTURE TO SPAWN A FEW SHOWERS NORTH
OF THE TAMPA BAY AREA BEFORE MORNING. THIS FRONT THEN STALLS NEAR
OR JUST NORTH OF TAMPA AND BEGINS TO MOVE NORTH AGAIN ON TUESDAY.
AGAIN... BECAUSE OF LIMITED AVAILABLE MOISTURE...EXPECT JUST A
FEW SHOWERS BUT CERTAINLY MORE CLOUDS FOR MOST OF THE REGION.
THE REMNANT FRONT SHOULD LIFT QUICKLY NORTH OF OUR AREA TUESDAY
NIGHT AS A COMPLEX AREA OF LOW PRESSURE ORGANIZES SOMEWHERE ALONG
THE GULF COAST. THE GFS IS THE STRONGEST AND FASTEST SOLUTION
SHOWING AN INTENSIFYING GALE MOVING INTO LOUISIANA BY WEDNESDAY
MORNING. MEANWHILE...THE 12Z NAM IS FARTHER WEST WITH THE LOW...
WHICH HAS A BIG IMPACT ON THE TIMING OF THE COLD FRONT AND
WEATHER ASSOCIATED WITH IT.
FOR NOW...WE BLENDED THE 12Z GFS WITH LAST NIGHTS 00Z ECMWF. THIS
BRINGS A POTENTIAL SQUALL LINE TO LEVY COUNTY AS EARLY AS SUNSET
WEDNESDAY. FEEL AT THIS TIME ITS BETTER TO REMAIN ON THE FASTER
SIDE OF THE GUIDANCE...WHICH ALLOWS US TO ISSUE SOME COASTAL FLOOD
WATCHES WITH THIS PACKAGE. WILL KEEP WATCH CONFINED TO
HILLSBOROUGH AND PINELLAS COUNTIES NORTHWARD AT THIS TIME.
RIP CURRENT RISK WILL ALSO INCREASE SIGNIFICANTLY AS THE
SOUTHERLY WINDS INCREASE AHEAD OF THE COLD FRONT ON WEDNESDAY.
THE BEST SEVERE THREAT APPEARS TO BE FROM TAMPA BAY NORTHWARD...
STARTING AROUND 7 PM FOR THE NATURE COAST AND MOVING RAPIDLY
SOUTHEAST OVERNIGHT. WE HAVE PLENTY OF SHEAR FOR ORGANIZED SEVERE
STORMS...BUT THE INSTABILITY WILL BE LACKING. STILL...CANT RULE
OUT A FEW STORMS WITH 50 TO 60 KNOT GUSTS AND EVEN A SLIGHT RISK
OF TORNADOES.
.LONG TERM (WEDNESDAY NIGHT - MONDAY)...SHOWERS AND THUNDERSTORMS
WILL BE ONGOING ACROSS THE FORECAST AREA WEDNESDAY NIGHT AND EARLY
THURSDAY AS A COLD FRONT MOVES THROUGH THE REGION. MODEL GUIDANCE
CONTINUES TO SUGGEST THE POSSIBILITY OF SOME STRONG TO SEVERE
STORMS ALONG AND AHEAD OF THE FRONT AS STRONG DYNAMIC
FORCING/ASCENT...A LOW LEVEL 850MB JET IN THE 50-60 KNOT RANGE AND
A HIGHLY SHEARED ENVIRONMENT RESULTS IN FAVORABLE CONDITIONS FOR
SOME ORGANIZED BANDS OR LINES OF CONVECTION AND POSSIBLE ROTATING
STORMS...WITH ISOLATED TORNADOES OR MARINE WATERSPOUTS.
IN ADDITION TO THE SEVERE THREAT A STRONG SOUTH TO SOUTHWEST WIND
FLOW AHEAD OF THE FRONT WILL PRODUCE HAZARDOUS BOATING CONDITIONS
OVER THE ADJACENT GULF WATER WITH LARGE BREAKING WAVES...AND RIP
CURRENTS ALONG AREA BEACHES AND AN INCREASED RISK FOR SOME
COASTAL FLOODING AT TIMES OF HIGH TIDE THROUGH THURSDAY.
ON THURSDAY THE SHOWERS AND STORMS WILL SLOWLY END ACROSS
NORTHERN ZONES...BUT WILL LINGER CENTRAL AND SOUTH AS THE FRONT
MOVES INTO THE SOUTHERN PENINSULA DURING THE DAY. DURING THURSDAY
NIGHT THROUGH EARLY SATURDAY THE 12Z GFS AND 00Z ECMWF SHOW THE
FRONT BECOMING STATIONARY ACROSS THE SOUTHERN PENINSULA AS IT
BECOMES PARALLEL TO THE SOUTHWEST FLOW ALOFT. BOTH THE GFS/ECMWF
SHOW WEAK AREAS OF LOW PRESSURE MOVING NORTHEAST ALONG THE FRONT
THROUGH THE PERIOD...SO WILL DEPICT CONSIDERABLE CLOUDS AND LOW
RAIN CHANCES (POPS 20-30%) ACROSS CENTRAL AND SOUTHERN ZONES
THROUGH THE PERIOD. DRIER AIR WILL FINALLY MOVE INTO THE REGION
LATE SATURDAY AS THE FRONT AND DEEPER MOISTURE EXITS TO THE SOUTH
AS SURFACE HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. PLEASANT
DRY WEATHER IS EXPECTED ON SUNDAY AND MONDAY AS THE SURFACE HIGH
MOVES EAST TOWARD THE MID ATLANTIC REGION WITH THE LOW LEVEL FLOW
VEERING INTO THE NORTHEAST AND EAST. NEAR NORMAL TEMPERATURES AT
THE START OF THE PERIOD WILL FALL TO SLIGHTLY BELOW NORMAL FRIDAY
THROUGH SUNDAY...THEN MODERATE BACK TO NEAR NORMAL EARLY NEXT WEEK
AS THE FLOW BECOMES EASTERLY.
&&
.AVIATION...A PERIOD OF MVFR CEILINGS WITH MAY IMPACT
TAMPA...SAINT PETERSBURG AND SARASOTA TERMINALS BETWEEN 09-18Z ON
TUESDAY AS MOISTURE ASSOCIATED WITH A FRONTAL BOUNDARY MOVING INTO
THE NORTH CENTRAL PENINSULA MOVES INTO THE REGION...OTHERWISE
MAINLY VFR CONDITIONS WITH CEILING HEIGHTS AT OR ABOVE 10KFT ARE
EXPECTED. SURFACE WINDS WILL BECOME LIGHT AND VARIABLE TONIGHT
THROUGH EARLY TUESDAY MORNING THEN WILL BECOME SOUTHEAST AROUND 10
KNOTS TUESDAY AFTERNOON.
&&
.MARINE...THE MAIN FEATURE FOR THIS FORECAST WILL BE THE
DEVELOPING GULF STORM ON TUESDAY. THIS SYSTEM HAS THE POTENTIAL TO
BRING 20 TO 30 KNOT SOUTHERLY WINDS TO OUR WATERS BY
WEDNESDAY...THEN WEST WINDS OF 20 KNOTS BEHIND THE COLD FRONT ON
THURSDAY. SEAS WILL BUILD TO AS HIGH AS 10 FEET...AND THE WESTERLY
WIND SHIFT WILL BRING LARGE SWELLS TO THE COAST DURING THURSDAY.
CONDITIONS WILL IMPROVE GRADUALLY TOWARD THE END OF THE WEEK.
SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR WEDNESDAY NIGHT
BUT WILL HOLD OFF A BIT LONGER IN THE HOPES THAT MODEL GUIDANCE
COMES MORE IN LINE WITH TIMING AND EXTEND OF WINDS AND SEAS.
&&
.FIRE WEATHER...NO FIRE WEATHER CONCERNS OUTSIDE OF STRONG WINDS
AND SOME LIGHTING WITH THE COLD FRONT LATE WEDNESDAY INTO
THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 62 77 65 77 / 10 20 10 50
FMY 60 81 66 81 / 10 10 10 40
GIF 57 77 65 79 / 10 20 10 40
SRQ 60 78 67 77 / 10 20 10 50
BKV 53 76 64 78 / 10 20 10 50
SPG 64 75 67 76 / 10 20 10 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...COASTAL FLOOD WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR CITRUS-HERNANDO-HILLSBOROUGH-LEVY-PASCO-
PINELLAS.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...JILLSON
LONG TERM/AVIATION...MCMICHAEL
