Area Forecast Discussion
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000
FXUS62 KKEY 200846
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
446 AM EDT SAT SEP 20 2014

.DISCUSSION...MID LATITUDE ENERGY IS READILY APPARENT ON WATER VAPOR
IMAGERY...CARVING OUT LOWER HEIGHTS ACROSS THE FLORIDA PANHANDLE AND
THE NORTHEASTERN GULF OF MEXICO. A COMPACT ANTICYCLONE SPINS ACROSS
CENTRAL MEXICO. THE RESULTING UPPER LEVEL STREAMLINES DEPICT A BROAD
SWATH OF DIFFLUENT FLOW FROM NEAR THE YUCATAN TO EAST OF THE
CAROLINAS. AT THE SURFACE...THE LOWEST PRESSURE EXTEND EAST FROM THE
CENTRAL GULF TO EAST OF PALM BEACH...ROUGHLY SIMILAR TO THE LOW LEVEL
VORTICITY ANALYSES FROM CIMSS. SURFACE WINDS ARE LIGHT AND
VARIABLE...BUT WHISPER FROM THE SOUTHEAST. SKIES ARE CLOUDY AND THE
RADAR IS SURPRISINGLY QUIET...EXCEPT FOR A FEW THUNDERSTORMS ACROSS
THE DISTANT FLORIDA STRAITS.

.SHORT TERM (TODAY THROUGH MONDAY)...THE UPPER LEVEL TROUGH ACROSS
THE FLORIDA PANHANDLE WILL STRETCH AND FRACTURE TODAY...THE MAIN CORE
SLIDING EAST...WHILE THE EQUATORWARD PIECES DIVE SOUTH INTO THE
SOUTH-CENTRAL GULF OF MEXICO. THE MAIN CORE WILL RESULT IN
CYCLOGENESIS EAST OF THE ATLANTIC BIGHT...WHILE THE DIVING ENERGY
WILL ENERGIZE THE CONFLUENT FLOW WHICH ARCS FROM NEAR THE YUCATAN TO
SOUTHWESTERN FLORIDA. DESPITE ALL THIS NEARBY ACTION...THE FLORIDA
KEYS WILL REMAIN JUST WITHIN THE ANTICYCLONIC FLOW OF THE SUBTROPICS.
RAIN CHANCES TODAY AND TONIGHT (ADVERTISED AS 60/50 PERCENT) WILL
EMANATE FROM CUBAN OUTFLOWS AND CENTRAL GULF COLD POOLS...BOTH WHICH
ARE UNCERTAIN AT THIS TIME. SKIES WILL REMAIN CLOUDY DUE TO THE
DIFFLUENCE ALOFT ACTING UPON LIKELY CONVECTION ACROSS THE
SOUTHEASTERN GULF. USING ENSEMBLE MEANS AS A GUIDE...THE LOW LEVEL
RIDGE AXIS WILL PUSH NORTH THROUGH THE KEYS SUNDAY NIGHT...OPENING UP
THE EASTERLIES AND MORE NORMAL RAIN CHANCES NEAR 30 PERCENT.

&&

.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...SEVERAL UNDULATIONS WILL
PASS THROUGH THE KEYS THIS COMING WORKWEEK...TIMING WILL BE HARD TO
PIN DOWN. THE FIRST UNDULATION WILL LIKELY MOVE THROUGH MONDAY
NIGHT...INCREASING RAIN CHANCES AND RESULTING IN A SURGE OF WINDS ON
ITS BACKSIDE. THE REMAINDER OF THE FORECAST CALLS FOR A SLOW TREND
DOWN IN RAIN CHANCES...WHICH CONFORMS TO A RETURN TO CLIMATOLOGY.

&&

.MARINE...A WEAK PRESSURE PATTERN ACROSS THE FLORIDA KEYS AND
ADJACENT COASTAL WATERS WILL SUPPORT MOSTLY LIGHT AND VARIABLE
BREEZES THROUGH SUNDAY. A RIDGE WILL BEGIN TO BUILD BACK OVER THE
FLORIDA PENINSULA SUNDAY NIGHT.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL AT THE ISLAND TERMINALS TODAY. THERE
WILL BE A CHANCE FOR MVFR OR LOWER CONDITIONS DUE TO A TROUGH
LOCATED NORTH OF OUR AREA. TIMING IS CURRENTLY QUITE UNCERTAIN.
SURFACE WINDS WILL BE LIGHT...TENDING OUT OF THE SOUTHEAST...TURNING
SOUTHWEST TO WEST.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  85  79  89  80 / 60 50 50 40
MARATHON  86  79  90  80 / 60 50 50 40

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&

$$

PUBLIC/MARINE.........CLR
AVIATION/NOWCASTS.....11
DATA COLLECTION.......CHESSER

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