556
FXUS62 KKEY 190333
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1033 PM EST WED DEC 18 2024
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 1035 PM EST WED DEC 18 2024
A MOIST AND SOMEWHAT STILL NIGHT IS UNDERWAY ACROSS THE FLORIDA
KEYS. THE ISLAND CHAIN IS GENERALLY CLEAR OF ANY ORGANIZED CLOUD
COVER AS ONLY A FEW CLUSTERS OF SHALLOW SHOWERS DRIFT LAZILY
THROUGH THE STRAITS OF FLORIDA. MEANWHILE, NIGHTTIME MICROPHYSICS
IMAGERY DEPICTS A LARGE SWATH OF LOW STRATUS EXTENDING FROM THE
BIG BEND OF FLORIDA ALL THE WAY DOWN TO THE WESTERN STRAITS OF
FLORIDA. OBSERVATIONS ALONG THE WEST COAST OF MAINLAND FLORIDA
HAVE CONFIRMED PATCHES OF FOG FORMING AMONG THIS LONG CLOUD DECK
AS IT STREAKS SOUTH TOWARDS OUR OUTER GULF WATERS. BREEZES HAVE
TAKEN ON A NORTHERLY COMPONENT ALONG THE LOWER KEYS WITH EAST TO
SOUTHEAST BREEZES STILL TRANSITIONING ALONG THE MIDDLE AND UPPER
KEYS. THIS WEAKLY CYCLONIC FLOW HAS ALLOWED TEMPERATURES TO
ALREADY APPROACH OBSERVED DEWPOINTS IN THE LOWER 70S MAKING FOR A
MUGGY START TO THE NIGHT.
THE BIG STORY IN THE SHORT TERM IS THE DEVELOPING FOG THREAT AHEAD
OF THE INCOMING COLD FRONT. THIS EVENING'S 00Z SOUNDING DEPICTS A
DECENT SPIKE OF DRY AIR ABOVE 800 MB, BUT RETAINS MOIST LOWER
LEVELS BELOW WITH A PW OF 1.41 INCHES (EASILY SURPASSING THE
HIGHEST RECORDED FOR THIS EVENING). AS A RESULT, ANY SHOWERS ARE
SHALLOW AT BEST. BUT, THIS IS AN ENVIRONMENT CLEARLY PRIMED TO
SUPPORT SOME FOGGY CONDITIONS. IN FACT, IN THE ABSENCE OF GROUND
TRUTH, SATELITTE OBSERVATIONS WOULD SUGGEST ITS ALREADY ONGOING
IN THE WESTERN STRAITS OF FLORIDA AND OUTER GULF WATERS WITH
ANOTHER WAVE APPROACHING THE DISTANT GULF WATERS NORTH OF THE
LOWER KEYS. AS A RESULT, OPTED TO EXTEND THE FOG ADVISORY TO THE
WESTERN STRAITS OF FLORIDA AND REDUCE POPS TO ONLY A SLIGHT CHANCE
FOR THE NIGHT. THE MAIN AREA OF UNCERTAINTY IS HOW FAR SOUTH THIS
FOG WILL ADVECT TOWARDS THE KEYS. THEY'VE BEEN EXCLUDED FOR NOW,
BUT A FEW PATCHES OF LOWER CLOUDS AND SOME AREAS OF FOG DEVELOPING
NEAR THE ISLAND CHAIN OVERNIGHT WOULD NOT BE TOO SURPRISING.
MARINE
ISSUED AT 1035 PM EST WED DEC 18 2024
A DENSE FOG ADVISORY IS IN EFFECT FOR THE DEEP GULF WATERS
INCLUDING THE DRY TORTUGAS AND THE WESTERN STRAITS OF FLORIDA
UNTIL THURSDAY MORNING.
FROM SYNOPSIS, HIGH PRESSURE OVER THE NORTH ATLANTIC WILL
CONTINUE SLIDING FARTHER EAST LOOSENING ITS GRIP ACROSS THE
FLORIDA KEYS. BREEZES WILL FURTHER SLACKEN TONIGHT AND THURSDAY
BECOMING LIGHT TO GENTLE AHEAD OF AN APPROACHING WEAK FRONT.
TONIGHT'S SLOWING BREEZES AND A QUICK REDUCTION OF TEMPERATURES
OVER WARM WATER WILL ALLOW FOR DEVELOPMENT OF PATCHES OF DENSE FOG
ACROSS THE COASTAL WATERS OF THE FLORIDA KEYS FROM TONIGHT INTO
TOMORROW MORNING, ESPECIALLY IN THE OUTER GULF WATERS AND WESTERN
STRAITS OF FLORIDA. THE WEAK FRONT IS ANTICIPATED TO PRESS THROUGH
THE KEYS SOMETIME LATE THURSDAY RESULTING IN FRESHENING NORTHERLY
BREEZES. A SECONDARY FRONT IS EXPECTED TO PRESS THROUGH THE KEYS
LATE FRIDAY REINFORCING THE PREVIOUS FRONT.
AVIATION
(00Z TAFS)
ISSUED AT 1035 PM EST WED DEC 18 2024
WHILE VFR CONDITIONS WILL PREVAIL AT BOTH ISLAND TERMINALS EARLY,
THE DEVELOPMENT OF SEA FOG NORTH OF THE ISLAND CHAIN MAY PUSH INTO
THE KEYS OVERNIGHT. IF SAID FOG MAKES IT TO THE ISLAND CHAIN, MVFR
CONDITIONS ARE PRACTICALLY GUARANTEED SO THEY HAVE BEEN INCLUDED
IN EYW'S TAF WHERE CONDITIONS ARE MOST LIKELY. THAT BEING SAID,
IMPACTS MAY ALSO REACH INTO IFR OR LIFR DEPENDING ON WHERE THE FOG
MOVES AND HOW DENSE IT BECOMES THOSE THIS POSSIBILITY IS STILL OF
LOW CONFIDENCE FOR NOW.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 70 77 69 75 / 20 10 10 0
MARATHON 71 79 69 76 / 20 10 20 0
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...DENSE FOG ADVISORY UNTIL 10 AM EST THURSDAY FOR GMZ033-034-055-
075.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....JAM
DATA ACQUISITION.....DR
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