000
FXUS62 KMFL 231404
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1004 AM EDT TUE SEP 23 2008

.UPDATE...
LATEST WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS MID/UPPER TROUGH
AXIS ACROSS NORTH CENTRAL FLORIDA...WITH PERHAPS A WEAK SFC TROUGH
IN VICINITY OF LAKE OKEECHOBEE. A WELL-DEFINED MOISTURE AXIS LIES
ACROSS SOUTH FLORIDA AHEAD OF THESE FEATURES. AS A
RESULT...WIDESPREAD MID/HIGH CLOUDS COVER THE NORTHERN HALF OF THE CWA.

THE OVERNIGHT LAND BREEZE HAS FINALLY GIVEN WAY TO A LIGHT ONSHORE
FLOW ALONG EAST COAST AREAS. AS THIS NE FLOW STRENGTHENS SOME
TODAY...OFFSHORE SHOWERS AS WELL AS A SEA BREEZE OR OTHER WEAK
COASTAL CONVERGENCE BOUNDARY SHOULD MOVE SLOWLY INLAND AND LEAD TO
AN INCREASE IN SHOWER/THUNDERSTORM DEVELOPMENT. ACTIVITY COULD
BECOME FAIRLY WIDESPREAD ESPECIALLY ACROSS THE SOUTHERN HALF OF
THE CWA AS AREAS SOUTH OF ALLIGATOR ALLEY SEE THE MOST HEATING.
THE 12Z MIAMI SOUNDING SUGGESTS DECENT INSTABILITY...BUT SHOWS
ONLY A SLIGHT CHANCE FOR MICROBURSTS GIVEN THE MOSTLY MOIST
ENVIRONMENT. CURRENT FORECAST HAS THIS SCENARIO HANDLED WELL AND
WILL NOT MAKE ANY CHANGES AT THIS TIME.

&&

.MARINE...
ONLY CHANGE TO THE MARINE FORECAST TODAY WAS TO SLIGHTLY INCREASE
THE WINDS OVER THE NORTHERN ATLANTIC WATERS AND LAKE OKEECHOBEE.
GUIDANCE SEEMS TO BE UNDER DOING THE WINDS SLIGHTLY RIGHT NOW...AS
SOME OF THE LAKE TOWERS HAVE BEEN SUSTAINED AROUND 15KTS. GFS
SHOWS AN INCREASE IN WINDS FROM JUST ABOVE THE SFC THROUGH 850MB
THROUGH THE DAY TODAY...SO A SLIGHT INCREASE IN MARINE WINDS SEEMS
PLAUSIBLE. WILL RE-EVALUATE SWELL FORECAST WITH 12Z MODEL CYCLE
AND CURRENT TRENDS...BUT IF CURRENT FORECAST VERIFIES THEN A SMALL
CRAFT ADVISORY MAY BE NEEDED AFTER MIDNIGHT TONIGHT.

UPDATE/MARINE: STRASSBERG

&&

.PREV DISCUSSION... /ISSUED 722 AM EDT TUE SEP 23 2008/

AVIATION...A NW LAND BREEZE WILL GIVE WAY TO THE PREVAILING NE FLOW
AT THE EAST COAST TERMINALS BY 14Z THIS MORNING. NE FLOW WILL
PREVAIL AT KAPF...WITH A POSSIBLE SEA BREEZE THIS AFTERNOON...THOUGH
THIS IS SOMEWHAT UNCERTAIN. TSRA IS A BETTER BET TODAY AT ALL
TERMINALS...BUT STILL...DUE TO THE TIMING UNCERTAINTIES AND THE
UNCERTAINTY IN EXACTLY WHEN A STORM WILL AFFECT A GIVEN
TERMINAL...DECIDED TO KEEP WITH VCTS AND WILL AMEND WITH CONVECTIVE
TRENDS. VFR WILL PREVAIL....BUT IFR WILL BE BRIEFLY POSSIBLE IN TSRA
TODAY. /DG

DISCUSSION...AS THE UPPER RIDGE...EXTENDING FROM THE W GULF OF MEX
THROUGH THE S AND CENTRAL GREAT PLAINS AND OVER THE GREAT LAKES...
BUILDS NE INTO NEW ENGLAND...THE TROUGH OVER THE EASTERN SEA BOARD
AND EXTENDING SW INTO THE S APPALACHIANS...DEEPENS AND MOVES OFF
-SHORE INTO THE ATLC. BY WED...A CLOSED LOW DEVELOPS OFF OF THE
COASTAL CAROLINAS...REMAINING NEARLY STATIONARY THU...THEN RETRO
GRADING W AND OVER THE CAROLINAS THU THROUGH SAT BEFORE THE LOW
WEAKENS AND LIFTS NE SUN INTO MON THOUGH TROUGHINESS REMAINS OVER
THE EASTERN U.S. WITH SOUTHWESTERLY FLOW ALOFT REMAINS OVER S FLA
WITHE ATLC RIDGE PERSISTING TO THE SE OF THE AREAS. CIRCULATION
ABOUT THIS UPPER LOW WILL PULL THE SYSTEM DEVELOPING N OF HISPANIOLA
NORTHWARD...KEEPING THIS SYSTEM WELL E OF S FLA.

AT THE SURFACE...AN INVERTED TROUGH OFF OF THE SE U.S. COAST PRE
-CEDES THE DEVELOPING UPPER TROUGH TO THE NW. THIS TROUGH EXTENDS
SW OVER S FLA AND AS A SURFACE LOW DEVELOPS OVER THE ATLC...THE
TROUGH MOVES THROUGH S FLA TODAY. THIS SURFACE LOW...AS PER LATEST
GFS...PERSISTS OFFSHORE OFF THE CAROLINAS INTO THE EARLY PART OF THE
WEEKEND...THEN GETS ABSORBED INTO THE DEEP SURFACE LOW THAT DEVELOPS
N OF HISPANIOLA TUE WHICH WILL MOVE N TOWARD NEW ENGLAND. AFTER
TODAY...DRIER AND MORE STALE AIR MOVES OVER S FLA WHICH WILL PERSIST
INTO SAT. CHANCES OF RAIN POSSIBLY INCREASE SUN AND MON AS MOISTURE
THAT HAS BEEN SHUNTED TO THE S OF THE AREA BEGINS TO CREEP NORTHWARD
AGAIN.

FOR THE SHORT TERM...TODAY THROUGH THU...HIGH POPS AND SLIGHTLY
COOLER TODAY AS THE SURFACE TROUGH AND E/W COAST SEA BREEZES
INCREASE RAINFALL POTENTIAL AND ENOUGH CLOUDS TO LIMIT HEATING A
LITTLE. TONIGHT DIMINISHING POPS FROM NW TO SE AS TROUGH SLIDES
THROUGH WITH LOWER POPS WED BUT POSSIBLY HIGHER E COAST AS STEERING
WINDS WILL BE WESTERLY. CHANCES FOR RAIN WED NIGHT AND THU MINIMAL
IF AT ALL. WITH SOME MOISTURE TODAY AND WITH SLIGHTLY COOLER
TEMPS...INTERIOR AREAS MAY SEE A LITTLE FOG WED AND THU MORNING.

EXTENDED PERIOD...FRI THROUGH MON...STILL RELATIVELY DRY FRI AND
SAT WITH A GRADUAL INCREASE IN THE CHANCES OF RAIN SUN AND INTO
EARLY NEXT WEEK AS THE CARIBBEAN MOISTURE PULLED N OVER S FLA.
LITTLE CHANGE TO EXTENDED AS LONG RANGE MODELS HAVE WAFFLED A LITTLE
AND HOW SOON AND HOW MUCH THE MOISTURE RETURNS.

MARINE...WINDS SHIFTING NE AS TROUGH SLIDES THROUGH BUT STAYING 10
KTS OR LESS TODAY. WINDS INCREASE TONIGHT AS SURFACE LOW FORMS TO
THE NE BUT ALSO A NE SWELL BEGINS TO IMPACT TLC WATERS. N/NE WINDS
INCREASE TONIGHT INTO WED...POSSIBLY 15 TO 18 KTS BEFORE DECREASING.
SWELLS CONTINUE TO INCREASE AS WELL...UP TO 3 TO 5 FEET. THOUGH
WINDS DECREASE THU AND INTO THE WEEKEND...THE N/NE SWELLS TO PERSIST
..POSSIBLY BECOMING 6 TO 8 FEET IN THE PALM BEACH WATERS WED NIGHT
AND 3 TO 5 FEET CONTINUING TO THE BROWARD/DADE WATERS. SWELLS
DECREASE THU AFTERNOON INTO THE WEEKEND. A SMALL CRAFT ADVISORY WILL
MOST LIKELY BE NEEDED LATE TONIGHT IN THE ATLC FOR SEAS 7 TO 8
FEET...INCREASING TO 9 TO 11 FEET BY EARLY THU BEFORE SEAS SLOWLY
BEGIN TO SUBSIDE TO BELOW ADVISORY CRITERIA SAT. A HIGH SURF
ADVISORY WILL BE NEEDED WED NIGHT AND THU AS THE SURF...ESPECIALLY
PALM BEACH COUNTY...WILL BECOME QUITE ROUGH AS LARGE BREAKERS CAN BE
EXPECTED. THESE HIGHLIGHTS WILL BE HOISTED AS CONDITIONS
DEVELOP.

FIRE WEATHER...NO CONCERNS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  87  74  86  73 / 60 30 20 20
FORT LAUDERDALE  89  75  86  75 / 60 40 20 20
MIAMI            89  76  87  74 / 60 40 30 20
NAPLES           88  72  88  72 / 60 20 10 10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$

LONG TERM...15/JR
SHORT TERM/AVIATION...04/AT