112
FXUS62 KKEY 191554
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1054 AM EST THU DEC 19 2024
..NEW DISCUSSION, MARINE, AVIATION
DISCUSSION
ISSUED AT 1045 AM EST THU DEC 19 2024
A RARE, DECEMBER DENSE FOG EVENT CONTINUES FOR MOST OF THE LOWER
AND MIDDLE KEYS AS WELL AS THE ADJACENT NEARSHORE COASTAL WATERS
AND THE SOUTHEASTERN GULF OF MEXICO. THIS IS A RESPONSE TO
NORTHERLY BREEZES AND DEW POINTS IN THE UPPER 60S, RIGHT AT THE
ESTIMATED SEA SURFACE TEMPERATURES FOR THE WATERS NORTH AND WEST
OF THE ISLAND CHAIN. KBYX RADAR IMAGERY IS HIGHLIGHTING ISOLATED
SHOWERS IN THE EASTERN STRAITS OF FLORIDA IN A ZONE OF SHALLOW
CONFLUENT FLOW. TEMPERATURES RANGE VASTLY AMONG ISLAND COMMUNITIES,
GENERALLY 70 TO 75 IN THE LOWER AND MIDDLE KEYS, TO THE UPPER 70S
ACROSS THE FOG-FREE UPPER KEYS.
MARINE FOG EVENTS ARE PERHAPS ONE OF THE MOST DIFFICULT FORECAST
CHALLENGES FOR FLORIDA KEYS METEOROLOGISTS. A SUBTLE AMOUNT OF
BOUNDARY LAYER WARMING CAN QUICKLY ERODE THESE EVENTS. ON THE
CONVERSE, FOG CAN REMAIN SOCKED IN FOR MUCH OF THE DAY SHOULD THIS
TURBULENT MIXING BE MINIMIZED. THE CURRENT FORECAST CALLS FOR THE
FOG TO REMAIN IN PLACE THROUGH THE EARLY AFTERNOON, ALTHOUGH WE
WILL CONTINUE TO MONITOR THE LATEST GOES-16 DERIVED MVFR
PROBABILITY PRODUCT TRENDS, UPDATING THE SHORT-FORECAST AS
NEEDED. WE DID ELECT TO NUDGE MAXIMUM TEMPERATURES DOWNWARDS OWED
TO THE LOW STRATUS AND FOG FOR THE LOWER AND MIDDLE KEYS.
OTHERWISE, NO CHANGES PROPOSED AT THIS TIME.
MARINE
ISSUED AT 1045 AM EST THU DEC 19 2024
A DENSE FOG ADVISORY REMAINS IN EFFECT FOR THE COASTAL WATERS
ADJACENT TO THE LOWER AND MIDDLE KEYS, INCLUDING THE BAYSIDE AND
GULFSIDE MARINE ZONES AND WESTERN HAWK CHANNEL, AS WELL AS THE
SOUTHEASTERN GULF OF MEXICO, INCLUDING THE DRY TORTUGAS. THIS FOG
WILL BE SLOW TO BURN OFF, LIKELY LATEST THROUGH AT LEAST THE EARLY
AFTERNOON HOURS. A WEAK FRONT WILL THEN PRESS THROUGH THE KEYS
LATE THIS AFTERNOON OR THIS EVENING RESULTING IN FRESHENING
NORTHERLY BREEZES. A SECONDARY FRONT IS EXPECTED TO PRESS THROUGH
THE KEYS LATE FRIDAY REINFORCING THE PREVIOUS FRONT. IN THE WAKE
OF THE FRONT, STRONG HIGH PRESSURE BUILDS ACROSS THE EASTERN
UNITED STATES RESULTING IN A STRENGTHENING PRESSURE GRADIENT. THIS
PROMOTE FRESHENING NORTHEAST TO EAST BREEZES OVER THE WEEKEND
INTO EARLY NEXT WEEK.
AVIATION
(15Z TAFS)
ISSUED AT 1045 AM EST THU DEC 19 2024
EYW HAS BEEN IN LIFR CONDITIONS WITH FOG AND LOW CLOUDS FOR THE PAST
FEW HOURS, AND THIS IS LIKELY TO CONTINUE AT LEAST INTO THE EARLY
AFTERNOON UNTIL DAYTIME HEATING CAN ERODE THE FOG LAYER. SIMILAR
CONDITIONS HAVE DEVELOPED AT MTH, WHICH IS ON THE EASTERN EDGE OF
THE FOG AND CLOUD FIELD. TIMING FOR IMPROVEMENT TO VFR DEPENDS ON
THE PERSISTENCE OF THE FOG, AS LITTLE OTHER LOW CLOUD COVER IS
EVIDENT IN SATELLITE IMAGERY AND RAIN IS NOT EXPECTED THROUGH THE
REMAINDER OF THE TAF PERIOD. WINDS WILL REMAIN GENERALLY FROM THE N
AT 5 TO 8 KTS THROUGH THE PERIOD.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 75 71 77 64 / 10 0 0 0
MARATHON 77 70 78 62 / 10 0 0 0
KEY WATCHES/WARNINGS/ADVISORIES
FL...DENSE FOG ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR FLZ077-078.
GM...DENSE FOG ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR GMZ032>035-
043-044.
PUBLIC/MARINE/FIRE...BT
AVIATION/NOWCASTS....MJV
DATA ACQUISITION.....MJV
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