629
FXUS62 KKEY 311850
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
150 PM EST WED DEC 31 2025
..NEW AVIATION
KEY MESSAGES
-FRESH GENERALLY NORTH BREEZES WILL SLOWLY SLACKEN TODAY
FOLLOWING YESTERDAY MORNING'S COLD FRONT.
-RAIN CHANCES NEAR NIL EXPECTED THROUGH THE END OF THE WEEK.
-COLDEST AIR OF THE SEASON SO FAR HAS ARRIVED! OVERNIGHT LOWS
EXPECTED TO FALL INTO THE UPPER 40S TO NEAR 50 DEGREES IN THE
UPPER KEYS AND MID TO UPPER 50S FOR THE MIDDLE AND LOWER KEYS.
-A SLOW MODERATING TREND IS EXPECTED TO BEGIN ON FRIDAY WITH
TEMPERATURES REBOUNDING INTO THE 70S DURING THE DAY WITH
OVERNIGHT LOWS IN THE 60S.
AVIATION
(18Z TAFS)
ISSUED AT 150 PM EST WED DEC 31 2025
VFR AND DRY CONDITIONS WILL PREVAIL AT BOTH EYW AND MTH FOR THE
REST OF TODAY AND INTO TONIGHT. WINDS WILL BE GENERALLY JUST WEST
OF NORTH AT 10 TO 15 KNOTS WITH OCCASIONAL HIGHER GUSTS AND
GRADUALLY DECREASING THROUGH THE EVENING. AN OVERNIGHT WIND SURGE
MAY OCCUR NUDGING WINDS TO THE NORTH TO NORTHEAST AND UP A FEW
KNOTS, BUT WILL LIKELY SLACKEN FOLLOWING SUNRISE.
MORNING UPDATE
ISSUED AT 1055 AM EST WED DEC 31 2025
A BURST OF WINTER IS HERE IN THE KEYS THIS MORNING! AFTER
YESTERDAY MORNING'S FRONTAL PASSAGE, TEMPERATURES HAVE BEEN
GRADUALLY FALLING INTO TODAY. CURRENTLY, TEMPERATURES RANGE FROM
THE MID 50S AT THE UPPER KEYS TO NEAR 60 IN THE LOWER KEYS. THIS
IS MOSTLY IN PART TO THE MODERATE TO FRESH NORTHERLY BREEZES
DRAINING OFF OF MAINLAND FLORIDA ADVECTING COOLER AIR INTO OUR
AREA. OBSERVATION STATIONS ALONG THE REEF NOTE THAT WINDS HAVE
SLACKENED A TOUCH SINCE LAST NIGHT'S NOCTURNAL SURGE, BUT ARE
STILL BLOWING ENOUGH FOR SMALL CRAFT TO EXERCISE CAUTION.
MEANWHILE, KBYX IS FREE OF PRECIPITABLE ECHOES DESPITE GOES-19
VISIBLE IMAGERY DEPICTING A FIELD OF STRATOCUMULUS PAINTED OVER
THE WESTERN HALF OF OUR WATERS.
OUR POSTFRONTAL PATTERN CONTINUES AS HIGH PRESSURE ESTABLISHES
ITSELF IN THE WESTERN GULF OFF THE COAST OF TEXAS TODAY. AS THIS
SURFACE HIGH CONTINUE TO SHIFT EAST, OUR NORTHERLY BREEZES WILL
GRADUALLY SLACKEN OVER THE NEXT FEW DAYS. THAT BEING SAID, ANOTHER
NOCTURNAL SURGE WILL BE POSSIBLE EARLY TOMORROW MORNING ESPECIALLY
WITH TEMPERATURES STILL LEANING ON THE COOLER SIDE. THIS MORNING'S
KKEY SOUNDING IS ABOUT AS DRY SEASON AS IT GETS DOWN HERE WITH A
PW OF 0.42 INCHES, SINGLE DIGIT SURFACE CAPE, BACKING WIND
PROFILE, AND A POTENT INVERSION AT AROUND 880 MB WITH DRY
MODIFIED CONTINENTAL AIR ALOFT. NEEDLESS TO SAY, POPS ARE TO
REMAIN NEAR NIL FOR THE NEXT FEW DAYS. ANOTHER ROUND OF COOLER
TEMPERATURES IS ON TAP FOR TOMORROW MORNING WITH POSSIBLY SOME
LOWS HITTING THE 45 TO 50 RANGE IN THE UPPER KEYS WHILE THE REST
OF THE ISLAND CHAIN CLAWS AS FAR DOWN THE MID 50S. CONDITIONS WILL
MILD OUT MOVING INTO THE WEEKEND SO ENJOY IT (OR DON'T) WHILE IT
LASTS!
DISCUSSION
ISSUED AT 430 AM EST WED DEC 31 2025
CIMSS PRODUCTS SHOW A DEEP UPPER LEVEL TROUGH ACROSS THE EASTERN
UNITED STATES WITH THIS TROUGH EXTENDING SOUTHWARD ALL THE WAY TO
JAMAICA. AT THE SURFACE, HIGH PRESSURE REMAINS ACROSS SOUTHEAST
TEXAS. FLORIDA AND THE KEYS REMAIN ON THE EASTERN SIDE OF THIS
EXPANSIVE HIGH. THEREFORE, THIS IS PROMOTING MAINLY NORTH BREEZES
NEAR 20 KNOTS AT MARINE PLATFORMS SURROUNDING THE ISLAND CHAIN.
GOES 19 TOTAL PRECIPITABLE WATER (TPW) PRODUCTS SHOWS VAST DRY AIR
ACROSS FLORIDA WITH A DECENT GRADIENT IN THE PWAT VALUES ACROSS
THE KEYS. THE PWAT VALUES RANGE FROM 0.8 INCHES ACROSS THE STRAITS
TO AROUND 0.4 INCHES ACROSS THE NORTHERN AREAS. KBYX RADAR IS NOT
DETECTING ANY SHOWER ACTIVITY AS A RESULT. GOES 19 NIGHTTIME
MICROPHYSICS SHOWS SOME LOW LEVEL CUMULUS CLOUDS ACROSS THE
WESTERN AREAS OF THE KEYS DUE TO THE COLD AIR MOVING OVER THE WARM
WATER SURFACE. THIS CREATES SOME INSTABILITY RESULTING IN SOME
CLOUD FORMATION, SIMILAR TO HOW LAKE-EFFECT DEVELOPS OFF THE GREAT
LAKES WELL TO OUR NORTH. BY THE TIME THIS COLD AIR REACHES THE
SOUTHERN GULF, IT HAS PICKED UP ENOUGH MOISTURE TO PRODUCE CLOUDS.
TEMPERATURES ALONG THE ISLAND CHAIN ARE IN THE LOWER TO MID 50S
FOR THE UPPER KEYS AND NEAR 60 DEGREES FOR THE MIDDLE AND LOWER
KEYS. DEW POINTS HAVE ALSO TUMBLED WITH 30S FOR THE UPPER KEYS AND
MID TO UPPER 40S FOR THE MIDDLE AND LOWER KEYS.
FORECAST
IN THE WAKE OF THE FRONT YESTERDAY, BREEZY CONDITIONS ARE
EXPECTED TO CONTINUE EARLY THIS MORNING. HIGH PRESSURE OVER
SOUTHEAST TEXAS THIS MORNING WILL CONTINUE MOVING TO THE EAST TO
SOUTHEAST THROUGHOUT THE WEEK WHILE SLOWLY WEAKENING. DUE TO THE
SLOW MOVEMENT OF THE HIGH, THE NORTHWEST TO NORTH FLOW WILL LINGER
INTO NEW YEARS DAY/THURSDAY NIGHT BEFORE BREEZES START TO SHIFT
TO THE NORTHEAST. EVEN THOUGH BREEZES SLACKEN A LITTLE BIT TODAY,
A SUBTLER WIND SURGE IS ANTICIPATED TONIGHT INTO NEW YEARS DAY DUE
TO THE MAINLAND NOCTURNAL LAND BREEZE. AS WE APPROACH THE WEEKEND,
THE HIGH WILL MOVE DIRECTLY OVERHEAD WHICH WILL RESULT IN A
PERIOD OF LIGHT TO VARIABLE BREEZES. IN ADDITION, THE COLDEST
TEMPERATURES ARE EXPECTED TO OCCUR TONIGHT JUST IN TIME TO RING IN
2026! OVERNIGHT LOWS INTO NEW YEARS DAY MORNING ARE EXPECTED TO
BE IN THE UPPER 40S FOR THE UPPER KEYS AND MID TO UPPER 50S FOR
THE MIDDLE AND LOWER KEYS. TEMPERATURES WILL START TO SLOWLY
REBOUND BEGINNING FRIDAY WITH HIGHS GETTING BACK TOWARDS 70
DEGREES AND OVERNIGHT LOWS BACK INTO THE 60S. OVER THE WEEKEND,
TEMPERATURES WILL BE BACK TO NEAR NORMAL WHICH IS HIGHS IN THE MID
70S AND OVERNIGHT LOWS IN THE LOWER TO MID 60S. DRY AIR WILL
REMAIN ENTRENCHED ACROSS THE KEYS THROUGH THE PERIOD LEADING TO
NIL RAIN CHANCES THROUGH SATURDAY.
ANOTHER POTENTIALLY REINFORCING/WEAK FRONT MAY PRESS THROUGH THE
KEYS DURING THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK.
HOWEVER, THE TIMING, INTENSITY, AND IF THIS FRONT WILL EVEN PUSH
THROUGH REMAINS TO BE SEEN. STAY TUNED!
MARINE
ISSUED AT 1055 AM EST WED DEC 31 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEYS, BUT SMALL CRAFT SHOULD
EXERCISE CAUTION IN ALL WATERS UNTIL WINDS DECREASE. FROM
SYNOPSIS, MAINLY FRESH NORTHWEST TO NORTH BREEZES WILL SLACKEN
SLOWLY THROUGH THE DAY AS HIGH PRESSURE MOVES EAST TO SOUTHEAST
INTO THE EASTERN GULF. ANOTHER NOCTURNAL WIND SURGE IS EXPECTED
OVERNIGHT INTO TOMORROW MORNING, BUT ONCE THE HIGH MOVES OVERHEAD
TOWARDS THE END OF THE WEEK/WEEKEND BREEZES BECOME LIGHT AND
VARIABLE.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 58 68 61 71 / 0 0 0 0
MARATHON 54 66 58 70 / 0 0 0 0
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....JAM
DATA ACQUISITION.....JAM
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