FXUS62 KEYW 251408
AFDEYW

FLORIDA KEYS AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1010 AM EDT SUN APR 25 2004

.DISCUSSION...
.OBSERVATIONS/TRENDS...
A SPLENDID MORNING IS IN PROGRESS ACROSS THE FLORIDA KEYS AND 
ADJOINING WATERS. AIR TEMPERATURES HAVE CLIMBED TO NEAR 80F AT MOST 
ISLAND COMMUNITIES...WITH TEMPERATURES IN THE MID-70S AT THE REEF. 
DEWPOINTS ARE NEARLY 5F LOWER THAN 24 HOURS AGO...WITH CURRENT 
READINGS AROUND 66-67F. MODERATE EAST BREEZES PREVAIL ACROSS THE 
ENTIRE SERVICE AREA...UNDER MOSTLY SUNNY TO OCCASIONALLY PARTLY 
CLOUDY SKIES.

THE KEY WEST MORNING SOUNDING REVEALED A VERY "LAYERED" ATMOSPHERE. 
THE UNSTABLE BOUNDARY LAYER WAS TOPPED BY A SHARP SUBSIDENCE 
INVERSION AROUND 4600FT. AN ELEVATED ADIABATIC/MIXED LAYER WAS NOTED 
BETWEEN 7000-10000FT...TOPPED BY A SECOND...BUT WEAKER...INVERSION 
LAYER. A THICK LAYER OF STABLY STRATIFIED AIR WAS THEN INDICATED 
FROM THE SECOND INVERSION UP TO ALMOST 15000FT. IN ADDITION...THERE 
WAS DEEP DRY AIR ALOFT ABOVE THE BOUNDARY LAYER.

.AFTERNOON FORECASTS...
GIVEN THE THERMODYNAMIC STRATIFICATION DESCRIBED ABOVE...IT WILL BE 
DIFFICULT IF NOT IMPOSSIBLE FOR ANY CONVECTION TO INITIATE ACROSS 
THE SERVICE AREA THIS AFTERNOON. THEREFORE...SHOWERS WILL BE REMOVED 
FROM ATLANTIC ZONES.

&&
.MARINE...
A SHIP IN THE GULF STREAM CURRENT 80 NAUTICAL MILES SOUTH-SOUTHEAST 
OF DRY TORTUGAS NATIONAL PARK REPORTED EAST WINDS 18KT...WITH 8-9FT 
SEAS. A QUIKSCAT PASS AROUND 1200 UTC INDICATED WINDS OF 20KT NEAR 
THE VESSEL'S LOCATION...LENDING CREDENCE TO THE VESSEL WIND 
OBSERVATION. OBSERVED SEAS OF 8-9FT IN THE GULF STREAM CURRENT 
CANNOT BE DISPUTED...GIVEN THE OBSERVED WIND SPEEDS...DURATION... 
FETCH...AND PROBABLE CURRENT SPEED. 

THE FIRST PERIOD MARINE FORECAST WILL MAINTAIN STEADY MODERATE EAST 
BREEZES AND 3-5FT SEAS FOR ATLANTIC WATERS SINCE WINDS HAVE COME 
DOWN SINCE SUNRISE...AND A FURTHER WEAKENING OF THE RIDGE TO OUR 
NORTH IS EXPECTED THIS AFTERNOON. THIS IS NOT TO SAY THAT SEAS OF 
6-8FT ARE NOT POSSIBLE IN THE CORE OF THE GULF STREAM CURRENT...AS 
WAS OBSERVED EARLIER...HENCE...THE MAINTENANCE OF THE PHRASE "SEAS 
HIGHER IN THE GULF STREAM".

&&
.AVIATION...
VFR CONDITIONS EXPECTED ALONG THE KMIA-KEYW TWEB ROUTE AND AT BOTH 
KEYS TERMINALS FOR THE REST OF TODAY THROUGH TONIGHT.

&&
.EYW WATCHES/WARNINGS/ADVISORIES...NONE

$$

PUBLIC/MARINE/DIGITAL...K. KASPER
AVIATION/NOWCASTS.......DAIDA