FXUS62 KTBW 291903
AFDTBW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
203 PM EST SUN NOV 29 2009
.SHORT TERM (TONIGHT - TUESDAY)...THE SHORT TERM PERIOD WILL
REMAIN ON THE QUIET SIDE. HIGH PRESSURE OVER THE PENINSULA
TONIGHT WILL BEGIN TO MOVE OUT INTO THE ATLANTIC ON MONDAY. A
FAST MOVING UPPER-LEVEL TROUGH WILL MOVE ACROSS THE EAST COAST
MONDAY NIGHT...SUPPORTING A WEAK BACK DOOR COOL FRONT THAT LOSES
STEAM OVER NORTH FLORIDA TUESDAY.
FOR THE MOST PART...ITS GOING TO STAY DRY WITH JUST INCREASING
CLOUDINESS...ESPECIALLY OVER NORTH FLORIDA AS THE BACK DOOR COOL
FRONT DRIFTS SOUTH AND WEAKENS MONDAY NIGHT AND TUESDAY. MOS
GUIDANCE SUGGESTS AT LEAST SOME CHANCE OF SHOWERS ALONG THE
BOUNDARY TUESDAY AFTERNOON...SO WILL SHOW 20 PERCENT RAIN CHANCES
MAINLY NORTH OF BROOKSVILLE.
OTHERWISE...THE WARMING TREND CONTINUES FOR MONDAY WITH HIGHS IN
THE MID 70S NORTH TO NEAR 80 SOUTH. ADDITIONAL CLOUD COVER ALONG
WITH THE EFFECTS FROM THE BACK DOOR COOL FRONT WILL KEEP AFTERNOON
HIGHS IN THE LOWER 70S FOR LEVY COUNTY ON TUESDAY.
.LONG TERM (TUESDAY NIGHT - SUNDAY)...A COMPLEX WEATHER SITUATION
SHAPING UP FOR THE FIRST PART OF THE LONG TERM PERIOD AS A
DEVELOPING LOW PRESSURE AREA OVER THE WESTERN GULF AFFECTS THE
REGION. MODELS TODAY CONTINUE IN FAIR AGREEMENT BUT CONTINUE TO
DIFFER WITH TIMING AND OVERALL TRACK OF THE GULF LOW DURING THE
WEDNESDAY/THURSDAY TIME FRAME. THE GFS CONTINUES TO BE THE FASTEST
IN EJECTING THE CLOSED UPPER LOW OVER TEXAS AND ATTENDANT
DEEPENING SURFACE LOW OVER THE WESTERN GULF NORTHEASTWARD ACROSS
THE NORTHERN GULF REGION AND INTO THE SOUTHEASTERN STATES DURING
WEDNESDAY AND WEDNESDAY NIGHT...THEN UP ALONG THE MID ATLANTIC ON
THURSDAY...WHILE THE ECMWF AND NAM ARE MUCH SLOWER. EVEN THOUGH
THE GFS HAS A BIAS OF EJECTING CLOSED LOWS OUT TOO FAST...PREFER
TO ERR ON THE SIDE OF CAUTION FOR NOW AND CONTINUE TO USE A BLEND
OF THE GFS/ECMWF WITH RESPECT TO MOVEMENT RATHER THAN THROWING OUT
THE FASTER GFS ALTOGETHER...SO WILL KEEP CURRENT TIMING OF
WEATHER/POPS IN THE GRIDS AS IS FOR NOW UNTIL SOME BETTER MODEL
CONTINUITY DEVELOPS...THEN MAKE CHANGES IF NECESSARY.
A STALLED FRONTAL BOUNDARY ACROSS THE NORTH CENTRAL PENINSULA
TUESDAY NIGHT WILL BEGIN TO LIFT BACK TO THE NORTH AS A WARM FRONT
ON WEDNESDAY AS THE AFOREMENTIONED GULF LOW DEEPENS AND BEGINS TO
LIFT NORTHEAST TOWARD THE NORTHERN GULF COAST. INCREASING MOISTURE
WITHIN A DEEP LAYERED SOUTHERLY WIND FLOW AHEAD OF THE LOW MAY
LEAD TO SOME ISOLATED SHOWERS IN THE VICINITY OF THE FRONTAL
BOUNDARY OVER THE NATURE COAST TUESDAY NIGHT WITH OTHER ISOLATED
SHOWERS POSSIBLE IN THE WARM SECTOR SOUTH INTO CENTRAL ZONES WHERE
20 PERCENT POPS WILL BE DEPICTED. DURING WEDNESDAY AND WEDNESDAY
NIGHT A TRAILING COLD FRONT THE GULF LOW WILL APPROACH FROM THE
WEST. THIS FRONT COMBINED WITH STRONG DYNAMICS ALOFT AND
INCREASING LARGE SCALE LIFT WILL LEAD TO INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS (POPS 50-60 PERCENT RANGE) ACROSS THE
FORECAST AREA.
MODEL GUIDANCE CONTINUES TO SUGGEST THE POSSIBILITY OF SOME
STRONG TO SEVERE STORMS LATE WEDNESDAY INTO EARLY THURSDAY.
STRONG DYNAMIC FORCING COMBINED WITH A LOW LEVEL 850MB JET IN THE
50-60 KNOT RANGE AND INCREASING HELICITY VALUES ALL SUGGEST THE
POTENTIAL FOR SOME ORGANIZED SEVERE STORMS WITH THE THREAT OF
TORNADOES AND MARINE WATERSPOUTS. IN ADDITION TO THE SEVERE
THREAT A STRONG SOUTHERLY WIND FLOW AHEAD OF THE FRONT WILL HELP
TO BUILD SEAS OVER THE ADJACENT GULF WATERS WHICH IN TURN WILL
PRODUCE HAZARDOUS BOATING CONDITIONS...LARGE BREAKING WAVES...AND
RIP CURRENTS ALONG AREA BEACHES AND AN INCREASING RISK FOR SOME
COASTAL FLOODING AS WELL AT TIMES OF HIGH TIDE WEDNESDAY THROUGH
EARLY THURSDAY.
ON THURSDAY THE SHOWERS AND STORMS WILL END FROM NORTH TO SOUTH
IN THE MORNING AS THE FRONT EXITS TO THE SOUTH WITH COOLER AND
DRIER AIR ADVECTING INTO THE REGION AS SURFACE HIGH PRESSURE
BUILDS IN FROM THE NORTHWEST. THE HIGH WILL SET UP OVER THE DEEP
SOUTH ON DURING FRIDAY AND SATURDAY WITH DRY PLEASANT WEATHER
EXPECTED. TEMPERATURES WILL START OFF ABOVE NORMAL THEN FALL SOME
5-10 DEGREES BELOW NORMAL THURSDAY THROUGH SATURDAY BEFORE
RETURNING TO NEAR NORMAL ON SUNDAY AS THE HIGH SHIFTS EAST INTO
THE ATLANTIC WITH A RETURN EASTERLY FLOW DEVELOPING. MEX
TEMPERATURE GUIDANCE HAS TRENDED COOLER SO HAVE ADJUSTED MIN/MAX
TEMPERATURES DOWN SLIGHTLY.
&&
.AVIATION...MAY SEE A BRIEF PERIOD OF MVFR VISIBILITIES FROM SOME
PATCHY FOG AFTER 30/09Z EARLY MONDAY MORNING...OTHERWISE VFR
CONDITIONS ARE EXPECTED AT ALL TERMINALS DURING THE NEXT 24 HOURS.
&&
.MARINE...NO PROBLEMS THROUGH TUESDAY...THEN A DEVELOPING SYSTEM
IN THE GULF OF MEXICO PROMISES TO BRING WINDY AND ROUGH
CONDITIONS WEDNESDAY AND THURSDAY. THIS SYSTEM HAS THE POTENTIAL
TO BRING WINDS TO NEAR GALE FORCE ALONG WITH SEAS OF 10 FEET OR
MORE. MARINERS VENTURING OUT THIS WEEK SHOULD CHECK THE LATEST
FORECASTS BEFORE DEPARTING. SLOW IMPROVEMENT IS EXPECTED ON
FRIDAY.
&&
.FIRE WEATHER...ISOLATED POCKETS OF LOW RELATIVE HUMIDITIES ARE
OCCURRING...BUT NO WIDESPREAD RED FLAG CONDITIONS IN OUR AREA YET.
STILL COUNTING ON UNDER 4 HOURS SO NO WARNINGS PLANNED.
NO ADDITIONAL FIRE WEATHER PROBLEMS ANTICIPATED THROUGH THE
WEEK...BUT A PERIOD OF STRONG STORMS WITH PLENTY OF CLOUD TO
GROUND LIGHTNING ALONG WITH STRONG GUSTY WINDS COULD OCCUR
BETWEEN WEDNESDAY AND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 56 77 61 75 / 0 5 10 10
FMY 56 81 60 80 / 0 5 10 10
GIF 53 78 56 76 / 0 5 10 10
SRQ 51 77 60 78 / 0 5 10 10
BKV 40 76 52 75 / 0 5 10 10
SPG 59 75 63 75 / 0 5 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...JILLSON
LONG TERM/AVIATION...MCMICHAEL
