081
FXUS62 KMFL 071743
AFDMFL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1243 PM EST SAT NOV 7 2009
AVIATION
VERY WINDY CONDITIONS TO CONTINUE THROUGH THE PERIOD AND WILL BE
MAIN IMPACTS. WIND SPEEDS SUSTAINED NEAR 20KT WITH GUSTS 25-30KT
FOR THE REST OF THE AFTERNOON. WINDS SHOULD DROP OFF A FEW MPH
AFTER SUNSET ESPECIALLY INTERIOR TERMINALS BUT KEPT WINDS NEAR UPR
RANGE OF MODEL GUIDANCE DUE TO STRENGTHENING IDA TO THE SOUTH AND
WHATS LIKELY TO BE SLIGHTLY STRONGER THAN FCST PRESSURE GRADIENT.
WINDS TOMORROW WILL GUST OVER 30KT AT TIMES. DRY CONDITIONS
EXPECTED WITH CIGS OF 4-6K FT AT TIMES THRU THE PERIOD.
/STRASSBERG
PREV DISCUSSION
/ISSUED 817 AM EST SAT NOV 7 2009/
PREV DISCUSSION... /ISSUED 459 AM EST SAT NOV 7 2009/
.WINDY WITH STRONG RIP CURRENTS ATLANTIC COAST THROUGH
MONDAY...
DISCUSSION...SURFACE HIGH PRESSURE WILL REMAIN ALIGNED FROM THE
MID ATLANTIC STATES INTO THE WESTERN ATLANTIC. MEANWHILE...TROPICAL
STORM IDA NORTH OF THE HONDURAS COAST IS FORECAST BY NHC TO MOVE
NORTH INTO THE CENTRAL GULF OF MEXICO BY MONDAY. WHAT THIS ENTAILS
LOCALLY IS AN INCREASE IN THE ALREADY STRONG ENE WIND FLOW...AS
THE PRESSURE GRADIENT INCREASES FURTHER. SO IT WILL CONTINUE
WINDY...ESPECIALLY ATLANTIC COAST. FORECAST SOUNDINGS FROM THE
GFS SHOW WINDS IN THE LOWEST FEW THOUSAND FEET IN THE 25-28KT
RANGE TODAY BUT INCREASING INTO THE 30-35 KT RANGE BY SUNDAY
EVENING AND CONTINUING THROUGH MONDAY NIGHT. GIVEN THIS...HAVE
INCREASED WINDS ACROSS THE AREA. BEST ESTIMATE IS THAT GUSTS TO
AROUND 30 MPH WILL PREVAIL TODAY (SIMILAR TO YESTERDAY)...BUT
SUN-MON EXPECT THE GUSTS TO INCREASE TO AROUND 35 MPH...AND
POSSIBLY 40 MPH. SO A WIND ADVISORY MAY BE NEEDED SUN-MON.
THE ATMOSPHERE CONTINUES QUITE DRY. HOWEVER...A GRADUAL MOISTENING
OF THE LOW LEVELS WILL TAKE PLACE TODAY AND SUNDAY.
THEREFORE...HAVE CONTINUED WITH THE POSSIBILITY OF ISOLATED
SHOWERS DEVELOPING AND MOVING IN FROM THE ATLANTIC OCEAN...MAINLY
AFFECTING THE EAST COAST METROPOLITAN AREAS.
THE FORECAST FOR THE EARLY AND MIDDLE PART OF NEXT WEEK WILL ALL
DEPENDS ON THE EXACT PATH T.S. IDA TAKES. THE CURRENT NHC TAKES IDA
INTO THE CENTRAL GULF MONDAY...THEN INTO THE NORTH CENTRAL GULF AND
EVENTUALLY TOWARDS THE EASTERN GULF BY WEDNESDAY WHILE WEAKENING
AND BECOMING EXTRATROPICAL. ON THIS TRACK...THE BULK OF THE
MOISTURE AND ORGANIZED PRECIP/CONVECTION WOULD REMAIN OUT OVER THE
GULF WEST OF SOUTH FL. 07/00Z GFS/ECMWF ARE IN EXCELLENT
AGREEMENT ON KEEPING THE HEAVY RAIN TO THE WEST OF OUR AREA.
THEREFORE...OUR LOW END CHANCE POPS FOR THE EXTENDED FCST CONTINUE
TO LOOK LIKE THE RIGHT WAY TO GO. OF COURSE...IF IDA ENDS UP
TRENDING FURTHER TO THE EAST...THEN THIS WOULD PAINT A MUCH WETTER
PICTURE WITH A HEAVY RAINFALL POTENTIAL.
INCREASING HELICITY TAKES PLACE BY MONDAY...BUT SOUNDING PROFILES
CONTINUE STABLE. HOWEVER...BY MON NIGHT/TUE...INSTABILITY
INCREASES ESPECIALLY ALONG THE GULF COAST...ALONG WITH 0-3KM
HELICITY IN THE 100-150 M2/S2 RANGE. GIVEN CURRENT FCST OF
IDA...THE LOCAL AREA WOULD BE OUTSIDE THE MOST FAVORABLE DISTANCE
FOR TORNADOES. HOWEVER...THIS WOULD BE A TIMEFRAME TO WATCH OUT
FOR THIS POSSIBILITY DUE TO THE HIGHER INSTABILITY AND THE
PRESENCE OF SHEAR. HOWEVER...ON THIS CURRENT TRACK...THIS RISK
LOOKS MINIMAL...BUT AS SAID ABOVE CONCERNING RAIN...THIS WOULD ALL
CHANGE SHOULD THE IDA TRACK FURTHER TO THE EAST THAN CURRENTLY
FORECAST.
GFS/ECWMF ARE ALSO IN AGREEMENT IN HAVING IDA MERGING WITH A
FRONTAL BOUNDARY COMING OUT OF TEXAS BY MIDWEEK...WITH THIS
BOUNDARY EVENTUALLY MOVING SOUTH ACROSS THE FL PENINSULA WED-THU.
STRONG HIGH PRESSURE BUILDS INTO THE MID ATLANTIC...CREATING A
VERY TIGHT PRESSURE GRADIENT JUST NORTH OF THE FRONTAL
BOUNDARY AS IT MOVES SOUTH...CREATING ADDITIONAL MARINE CONCERNS
(SEE MARINE SECTION BELOW). WITH THIS SCENARIO...THE BEST CHANCE
OF RAIN LOCALLY MAY BE MID WEEK ALONG THIS BOUNDARY. MUCH CAN
CHANGE THOUGH SO STAYED WITH LOW END CHANCE POPS THROUGH THE
EXTENDED.
MARINE...THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED THROUGH TUE
MORNING AS WINDS WILL CONTINUE >20 KT...EVEN INCREASING TO 25-30
KT SUN-MON. GUSTS TO GALE FORCE LOOK PLAUSIBLE DURING THIS TIME.
SO VERY HAZARDOUS MARINE CONDITIONS WILL CONTINUE. CONDITIONS LOOK
TO SLOWLY IMPROVE EARLY NEXT WEEK. HOWEVER...WILL HAVE TO WATCH
OUT HOW WINDS BEHIND A POSSIBLE SOUTHWARD MOVING FRONT BY THE
MIDDLE PART OF NEXT WEEK PLAYS OUT...BECAUSE BOTH GFS/ECMWF SHOW
STRONG NE WINDS OFF THE NE/EAST CENTRAL FL COAST WED...SPREADING
INTO OUR PALM BEACH WATERS THU. THIS COULD PRODUCE A LARGE SWELL
BY THURSDAY. WAVEWATCH SHOWS SEAS NEAR 5 METERS OFF EAST CENTRAL FL
EARLY THURSDAY...SPREADING INTO OUR WATERS BY THU AFTERNOON. WE
HAVE PLENTY OF TIME TO SEE IF THIS SCENARIO PLAYS OUT.
FIRE WEATHER...NO CONCERNS.
PRELIMINARY POINT TEMPS/POPS
WEST PALM BEACH 75 83 78 85 / 10 10 10 20
FORT LAUDERDALE 77 84 79 84 / 20 20 20 20
MIAMI 76 83 78 85 / 20 20 30 20
NAPLES 68 87 70 89 / 10 20 30 40
MFL WATCHES/WARNINGS/ADVISORIES
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ610-AMZ630-
AMZ650-AMZ651-AMZ670-AMZ671.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR GMZ656-GMZ657-
GMZ676.
LONG TERM...15/JR
SHORT TERM/AVIATION...65/GS
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