Area Forecast Discussion
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000
FXUS62 KKEY 041348
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
946 AM EDT MON MAY 4 2015

...WINDY WITH VERY ROUGH SEAS TODAY...

.DISCUSSION...
.CURRENTLY...
ALONG THE ISLAND CHAIN...SKIES ARE MOSTLY CLOUDY WITH TEMPERATURES HOVERING
AROUND 80 DEGREES WITH MOSTLY EAST WINDS OF 20 TO 30 MPH. MEANWHILE...LOCAL
RADARS ARE ONLY DETECTING PATCHES OF LIGHT RAIN ON THE DISTANT FLORIDA STRAITS
BEYOND 20 NM SOUTH OF THE LOWER KEYS...BETWEEN SAND KEY LIGHT AND DRY TORTUGAS.
SURFACE WISE...A FORMIDABLE AND LARGE REGION OF HIGH PRESSURE IS CENTERED
ALONG THE NORTH CAROLINA COAST...WITH A TROUGH OF LOW PRESSURE ALIGNED FROM THE
BAHAMAS SOUTHWESTWARD TO ACROSS WESTERN CUBA AND INTO THE NORTHWEST CARIBBEAN
SEA. ACROSS OUR MARINE DISTRICT...NORTHEAST TO EAST WINDS RANGE FROM 21 TO 26
KNOTS WITH GUSTS OF AROUND 30 KNOTS. OTHERWISE...OUR MORNING SOUNDING REVEALS
MOISTURE CONFINED TO BETWEEN 850 AND 770 MB...WITH SIGNIFICANT DRY AIR BELOW AND
ABOVE. STRONG LOW LEVEL NORTHEAST TO EAST WINDS ARE OVERLAID BY A CHAOTIC
FLOW ABOVE 850 MB. ALSO...A COUPLE OF STABLE LAYERS ARE EVIDENT AT 750 MB AND JUST
ABOVE 700 MB.

.SHORT TERM (REST OF TODAY)...
AN UNUSUALLY DEEP AND EQUATORWARD BROAD TROUGH OF LOW PRESSURE WILL SLOWLY
INTENSIFY IN THE EXTREME SOUTHEAST GULF OF MEXICO AND NORTHWEST CARIBBEAN
SEA. MEANWHILE...A SURFACE TROUGH OF LOW PRESSURE DRAPED FROM BAHAMAS
AND ACROSS THE WESTERN PORTION OF THE ARCHIPELAGO OF CUBA...AND INTO
THE NORTHWEST CARIBBEAN SEA WILL SLOWLY LIFT NORTHWESTWARD...AS A STRENGTHENING
AREA OF HIGH PRESSURE ALONG THE NORTH CAROLINA COAST SLIDES INTO THE
WESTERN ATLANTIC OCEAN LATE TODAY AND TONIGHT. WITH THAT SAID...DESPITE
LARGE SCALE ASCENT SLOWLY INTENSIFYING...THE MAIN LOW LEVEL FORCING ASSOCIATED
WITH THE AFOREMENTIONED TROUGH WILL REMAIN WELL SOUTHEAST WHILE CONSIDERABLE DRY
AIR BELOW 850 MB PERSISTS FOR MOST OF TODAY. HENCE...HAVE ALREADY UPDATED THE
PUBLIC ZONE FORECAST TO REMOVE THUNDER AND TRIM POPS TO LOW CHANCE FOR MID TO
LATE AFTERNOON. HOWEVER...WILL MONITOR ADDITIONAL DATA AND TRENDS TO DECIDE
WHETHER POPS NEED TO BE NUDGED INTO THE ISOLATED RANGE. OTHERWISE...MOSTLY EAST
WINDS OF 20 TO 30 MPH UNDER PARTLY TO MOSTLY CLOUDY SKIES WILL KEEP HIGH
TEMPERATURES IN THE LOWER 80S.

&&

.MARINE...
STRONG NORTHEAST TO EAST WINDS OF 20 TO 30 KNOTS WITH THE HIGHEST WINDS
AND SEAS ON THE FLORIDA STRAITS...AND THE OUTER WATERS OF MAINLAND MONROE
AND IN AND AROUND DRY TORTUGAS WILL PERSIST TODAY AND INTO THIS EVENING.
SUBSEQUENTLY...A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR VERY ROUGH AND
AGITATED WATERS WITH SEAS UP TO 10 FEET IN THE GULF STREAM.

&&

.AVIATION...
CIGS WILL REMAIN VFR THROUGH THIS AFTERNOON AND THROUGH
THIS EVENING...WITH SOME SCATTERED CUMULUS WITH BASES AT FL025-030
AND SCATTERED TO BROKEN CIGS WITH BASES AOA FL050-070. SUSTAINED
WINDS FROM JUST OFF THE SURFACE TO ABOUT 3000 AGL WILL AVERAGE 16 TO
20 KNOTS WITH GUSTS AROUND 25 TO 28 KNOTS FROM 060 DEGREES...VEERING
TO 090 DEGREES BETWEEN 00Z AND 03Z THIS EVENING.

&&

.CLIMATE...
ON THIS DATE IN FLORIDA KEYS WEATHER HISTORY...IN 1977...5.33 INCHES
OF RAIN FELL AT KEY WEST INTERNATIONAL AIRPORT. THIS SET THE DAILY
RECORD FOR MAXIMUM RAINFALL MEASURED IN KEY WEST ON MAY 4TH...A
RECORD WHICH STILL STANDS 38 YEARS LATER. RAINFALL RECORDS AT KEY
WEST DATE BACK TO 1871.


.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY FOR GMZ031>035-042>044-052>055-072>075.

&&

$$

PUBLIC/MARINE/FIRE/CLIMATE/DIGITAL...APA
AVIATION.............................DAF
DATA ACQUISITION.....................EV

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