FXUS62 KTBW 020907
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
407 AM EST WED DEC 2 2009
...SLIGHT RISK OF SEVERE WEATHER THROUGH THURSDAY MORNING ALONG WITH
WINDY CONDITIONS ACROSS THE AREA AND A POTENTIAL FOR MINOR COASTAL
FLOODING...
.SHORT TERM (TODAY THROUGH FRIDAY)...A SIGNIFICANT WEATHER SYSTEM
CONTINUES TO UNFOLD OVER THE NORTHERN GULF. UPPER LEVEL ENERGY
WHICH MOVED ACROSS TEXAS HELPED TO STRENGTHEN A DEVELOPING
SURFACE LOW JUST SOUTH OF LOUISIANA. THIS SYSTEM IS CURRENTLY
PRODUCING VERY HEAVY RAINFALL IN PARTS OF SOUTHERN MS/AL AND THE W
FL PANHANDLE. AS THE SYSTEMS LIFTS NEWD THROUGH TOMORROW...THE
ASSOCIATED COLD FRONT WILL PUSH THROUGH THE GULF EN ROUTE TO OUR
AREA.
FOR TODAY...A STRONG PRESSURE GRADIENT WILL BE IN PLACE OVER THE
AREA AS SURFACE HIGH PRESSURE GETS PUSHED OUT INTO THE ATLANTIC BY
THE LOW PRESSURE SYSTEM TRAVELING NEWD. STRONG SOUTHERLY FLOW WILL
BE GREATEST OVER THE GULF WATERS. FORECAST SOUNDINGS INDICATED
STRONG LOW LEVEL FLOW OF AROUND 30KT JUST ABOVE THE SFC THROUGHOUT
MUCH OF THE REGION. WITH THOSE WINDS MIXING DOWN TO THE SFC THIS
AFTERNOON...WINDS SPEEDS COULD INCREASE TO AROUND 20 KT.
THEREFORE...ISSUED A LAKE WIND ADVISORY FOR THE CWA THROUGH THIS
EVENING. OTHER IMPACTS FROM THE WINDS WILL BE COASTAL FLOODING
FROM MANATEE CO NORTHWARD. LATEST GUIDANCE IS TRENDING TOWARDS A
SLIGHTLY WEAKER WIND FIELD SO DID NOT UPGRADE THE COASTAL FLOOD
WATCH TO A WARNING. REGARDLESS...MINOR FLOODING ALONG SOUTH FACING
SHORES WILL REMAIN A POSSIBILITY AS THE WATER LEVEL COULD INCREASE
A COUPLE FEET ABOVE THE FORECASTED TIDES. GFS REMAINS MORE
AGGRESSIVE WITH THIS SYSTEM COMPARED TO THE NAM AND ECMWF. FAVORED
THE NAM DUE ITS CONSISTENCY AND INITIALIZATION. RAINFALL CHANCES
WILL INCREASE THROUGHOUT THE DAY FROM NORTH TO SOUTH AS FRONT
EDGES INTO THE REGION TONIGHT. DYNAMICS CONTINUE TO LOOK MORE
IMPRESSIVE (ESPECIALLY FURTHER NORTH CLOSER TO THE CENTER OF THE
SYSTEM). WITH ENOUGH LIFT AHEAD OF THIS SYSTEM...STORMS WILL HAVE
THE POTENTIAL TO QUICKLY TURN SEVERE WITH THE THREAT OF DAMAGING
WINDS AND FREQUENT LIGHTNING. PLENTY OF SHEAR (0-6 BLK SHR AROUND
45KT AND 0-1 BLK SHR AROUND 25KT) WILL BE AVAILABLE TO SUPPORT
ISOLATED TORNADOES NORTH OF TAMPA BAY.
FOR THURSDAY...THE FRONT IS EXPECTED TO DRIFT SOUTH THROUGH THE
REGION THROUGHOUT THE MORNING HOURS. BUMPED TO POPS TO 80 FROM
HERNANDO SOUTH TO SARASOTA. BY THE MID MORNING/EARLY
AFTERNOON...THE FRONT IS EXPECTED TO GRADUALLY STALL JUST SOUTH OF
THE REGION THE SOUTHERN 1/3 OF THE CWA WILL SEE THE GREATEST
RAINFALL CHANCES THROUGH THE EVENING.
BY FRIDAY...THE SFC BOUNDARY SOUTH OF THE AREA PUSHES BACK NORTH
AND DRAGS UP SOME DEEP MOISTURE. RAINFALL WILL BE LIKELY FROM
TAMPA BAY SWD THROUGH THE END OF THE SHORT TERM.
.LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)...THE BIGGEST FEATURE IN
THE EXTENDED FORECAST IS GOING TO BE OUR NEXT BOUT WITH RAIN THAT
WILL ARRIVE BY FRIDAY. THIS FEATURE WAS NEW ON YESTERDAYS 00Z
MODELS AND TODAYS RUNS HAVE SHOWN GOOD CONTINUITY AND THUS THE
FORECAST HAS BEEN ADJUSTED MORE FIRMLY IN THE DIRECTION OF HIGHER
POPS AND WARMER NIGHTTIME LOWS. THE FRONT THAT WILL CROSS THE AREA
TODAY IS EXPECTED TO SETTLE INTO FAR SOUTHERN FLORIDA BY THURSDAY
EVENING. AT THE SAME TIME A SIGNIFICANT LONGWAVE TROUGH WILL BE
CARVING OUT ACROSS THE UPPER MIDWEST AND INTO THE LOWER
MISSISSIPPI VALLEY. A SHORTWAVE WILL EJECT OUT OF THE SOUTHERN
ROCKIES BY FRIDAY EVENING AND ASSIST IN CYCLOGENESIS ACROSS THE
WESTERN GULF. THIS LOW WILL SLIDE ALONG THE STATIONARY FRONTAL
BOUNDARY AND GENERATE ABUNDANT CLOUDS AND PRECIP ACROSS THE
FORECAST AREA ON FRIDAY AND INTO SATURDAY AS THE H5 TROUGH SLOWLY
KICKS ACROSS THE NORTHERN GULF. THIS SYSTEM SHOULD DEPART THE AREA
BY EARLY SUNDAY. AS FOR CHANGES TO THE EXTENDED...HAVE RAISED
TEMPS IN THE SOUTHERN FORECAST AREA OVER THE WEEKEND AS THAT AREA
WILL BE SOUTH OF THE BOUNDARY WHICH GETS LIFTED NORTH DUE TO WARM
ADVECTION AHEAD OF THE DEVELOPING GULF LOW. NIGHTTIME TEMPS
CONTINUED TO BE WARMED FROM PREVIOUS FORECASTS GIVEN PRECIP AND
CLOUDS. POPS WERE RAISED...ESPECIALLY IN THE FRIDAY NIGHT
TIMEFRAME AS THE GOOD MODEL CONTINUITY LEADS MORE CREDENCE TO THE
WET SOLUTION.
&&
.AVIATION...DISCUSSION FOR 06Z TAFS. VFR CONDITIONS ARE EXPECTED
THIS MORNING AND WINDS WILL INCREASE OUT OF THE SOUTHEAST THIS MORNING
AND BECOME SUSTAINED AT 12 TO 15 KTS WITH GUSTS TO 22 KTS POSSIBLE.
PRECIP SHOULD ARRIVE AFTER 21Z AND THE HEAVIEST RAIN WILL BE DURING
THE 21 TO 03Z TIME FRAME. MVFR CONDITIONS WILL CLOSE OUT THE LAST
SIX HOURS OF THE PERIOD IN REDUCED VSBY DUE TO RAIN AND LOWER CIGS.
&&
.MARINE...HAZARDOUS BOATING CONDITIONS CAN BE EXPECTED AS GULF
WATERS DETERIORATE THROUGHOUT THE DAY. WINDS ACROSS THE GULF WATERS
WILL INCREASE TO OVER 20 KT AS THE PRESSURE GRADIENT TIGHTENS
BETWEEN THE HIGH TO OUR NE AND THE LOW TO OUR WEST. A SMALL CRAFT
ADVISORY WILL BE CARRIED THROUGH THURSDAY MORNING AS BOTH WINDS
AND SEAS INCREASE. THUNDERSTORM ACTIVITY WILL ALSO INCREASE BY
TOMORROW NIGHT AS A COLD FRONT PUSHES SOUTH THROUGH THE WATERS
THROUGH THURSDAY MORNING. THE FRONT STALLS SOUTH OF OUR REGION BY
THURSDAY EVENING BEFORE LIFTING BACK NORTH BY FRIDAY MORNING.
RAINFALL CHANCES WILL AGAIN BE HIGH THROUGH THE BEGINNING OF THE
WEEKEND.
&&
.FIRE WEATHER...NO FIRE WEATHER CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 78 65 74 56 / 60 80 30 50
FMY 82 70 79 62 / 40 70 50 60
GIF 81 65 76 57 / 50 80 30 50
SRQ 80 67 76 56 / 50 80 30 50
BKV 79 60 74 50 / 60 80 20 50
SPG 77 66 74 60 / 60 80 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR CHARLOTTE-CITRUS-DE SOTO-HARDEE-HERNANDO-
HIGHLANDS-HILLSBOROUGH-LEE-LEVY-MANATEE-PASCO-PINELLAS-POLK-
SARASOTA-SUMTER.
COASTAL FLOOD WATCH FROM 10 AM EST THIS MORNING THROUGH THURSDAY
MORNING FOR CITRUS-HERNANDO-HILLSBOROUGH-LEVY-MANATEE-PASCO-
PINELLAS.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR BONITA BEACH TO
ENGLEWOOD OUT 20 NM-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60
NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 TO 60 NM-TARPON SPRINGS TO SUWANNEE
RIVER OUT 20 NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO
60 NM.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR TAMPA BAY WATERS.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...20/BARRON
LONG TERM/AVIATION...35/JOHNSON
