379
FXUS62 KKEY 180948
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
448 AM EST THU DEC 18 2025
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
-MODERATE EASTERLY BREEZES WILL SLACKEN AND VEER TOWARDS THE
SOUTHEAST TODAY AS HIGH PRESSURE ALONG THE EASTERN SEABOARD
SLIDES INTO THE NORTH ATLANTIC.
-RAIN CHANCES MODESTLY INCREASE THROUGHOUT TODAY, WITH THUNDER
ALSO POSSIBLE TONIGHT AHEAD OF A WEAK FRONTAL PASSAGE.
-OUTSIDE OF MODESTLY FRESHENED BREEZES, MINIMAL CHANGES TO THE
SEASONABLY WARM CONDITIONS ARE EXPECTED IN THE WAKE OF THE FRONT.
DISCUSSION
ISSUED AT 448 AM EST THU DEC 18 2025
ANOTHER QUIET MORNING IS UNDERWAY ACROSS THE FLORIDA KEYS. KBYX
RADAR IS ONCE AGAIN FREE OF PRECIPITABLE ECHOES IN OUR AREA.
GOES-19 NIGHTTIME MICROPHYSICS IMAGERY SHOWS A MIX BETWEEN PATCHES
OF WESTERLY MOVING FAIR WEATHER CUMULUS IN THE EASTERN STRAITS AND
HIGH CIRRUS STREAKING NORTHEAST ACROSS THE GULF. MODERATE EASTERLY
BREEZES PERSIST ALONG THE REEF HAVING CHANGED VERY LITTLE OVER THE
LAST FEW HOURS. TEMPERATURES ALONG THE ISLAND CHAIN ARE A COUPLE
DEGREES WARMER THAN YESTERDAY AROUND THIS TIME AND RANGE IN THE
LOWER TO MID 70S WITH DEWPOINTS NEAR 70.
SOME CHANGE IN PATTERN IS FORECAST IN THE SHORT TERM. AN ELONGATED
SURFACE HIGH STRETCHING FROM THE SOUTHEAST US INTO THE WESTERN
NORTH ATLANTIC WILL LIFT NORTHEAST AND START LOSING ITS GRIP ON
OUR SENSIBLE WEATHER TODAY. AS A RESULT, EASTERLY BREEZES WILL
GRADUALLY SLACKEN AND VEER TO THE SOUTHEAST THROUGHOUT THE DAY.
WHILE BREEZES WILL BE TURNING TO MORE MOIST SURFACE WIND, A LARGE
POCKET OF DRY AIR STILL EXITS IN THE LOWER TO MID LEVEL JUST
ABOVE THE INVERSION OBSERVED IN OUR 00Z KKEY BALLOON SOUNDING LAST
NIGHT. THUS HAVE OPTED TO KEEP SLIGHT CHANCE POPS TODAY.
TONIGHT COULD GET A LITTLE MORE INTERESTING AS THE LOWER TO MID
LEVEL PROFILE MOISTENS UP. FORECAST SOUNDINGS INDICATE DECENT (FOR
THIS TIME OF YEAR) LOW LEVEL SHEAR AND MODESTLY UNCAPPED
INSTABILITY. THAT BEING SAID, FORCING WILL BE SOMEWHAT NEBULOUS AS
WINDS ARE EXPECTED TO BE ON A DOWNWARD TREND WITH NO APPARENT
SOURCES OF SYNOPTIC LIFT. CAMS DO SUGGEST SOME ISOLATED CONVECTION
MAY FORM DESPITE THESE LIMITING FACTORS, SO HAVE OPTED TO GO WITH
CHANCE POPS AND A SLIGHT CHANCE OF THUNDERSTORMS JUST IN CASE.
OUR SENSIBLE WEATHER PATTERN WILL CONTINUE TO CHANGE THIS WEEKEND
AS A COLD FRONT APPROACHES LATE FRIDAY. BREEZES WILL CLOCK ALL
THE WAY BACK AROUND TO THE NORTH, BUT DUE TO THE WEAK NATURE OF
THE FRONT TEMPERATURES WILL ONLY SEE A FEW DEGREES OF DIFFERENCE
FROM PREVIOUS DAYS. BY THE START OF NEXT WEEK, HIGH PRESSURE WILL
BUILD BACK ALONG THE EAST COAST OF CONUS WITH BREEZY CONDITIONS
DEVELOPING MONDAY AND POSSIBLY BECOMING WINDY INTO TUESDAY. WHILE
THIS SOLUTION HAS BEEN RELATIVELY STABLE, THERE IS STILL PLENTY OF
TIME FOR SOME CHANGES TO THE FORECAST SO STAY TUNED.
MARINE
ISSUED AT 448 AM EST THU DEC 18 2025
NO WATCHES, WARNINGS, OR ADVISORIES ARE CURRENTLY IN EFFECT FOR
THE COASTAL WATERS OF THE FLORIDA KEYS. FROM SYNOPSIS, MODERATE
EAST TO SOUTHEAST BREEZES WILL SLACKEN TODAY AS HIGH PRESSURE
SLIDES FURTHER EASTWARD OFF THE EASTERN SEABOARD INTO THE CENTRAL
NORTH ATLANTIC. A WEAK FRONT WILL PUSH THROUGH THE FLORIDA KEYS
COASTAL WATERS BY THE END OF THE WEEK, WITH MODESTLY FRESHENED
BREEZES EXPECTED FOR THE WEEKEND IN ITS WAKE. ANOTHER HIGH
BUILDING OVER THE EASTERN SEABOARD WILL SUPPORT FRESH TO STRONG
BREEZES FOR EARLY NEXT WEEK.
AVIATION
(06Z TAFS)
ISSUED AT 448 AM EST THU DEC 18 2025
VFR CONDITIONS WILL PREVAIL AT BOTH EYW AND MTH THROUGH THE TAF
PERIOD WITH OCCAISIONAL SCT CLOUDS NEAR FL030. OPTING TO KEEP TAFS
DRY FOR NOW, EVEN WITH A 20 TO 30 PERCENT CHANCE OF RAIN IN THE
FORECAST TODAY. CHANCES FOR SHOWERS PEAK NEAR THE END OF THE CURRENT
TAF PERIOD, SO FUTURE PACKAGES CAN ADDRESS TIMING AND IMPACTS. EAST
TO SOUTHEAST SURFACE WINDS NEAR 10 KNOTS WILL VEER TO THE SOUTH AND
DECREASE TO NEAR 5 KNOTS TONIGHT, BUT CROSSWIND CONCERNS ARE LOW DUE
TO THE LOW MAGNITUDE OF THESE WINDS.
CLIMATE
ON THIS DAY IN 2016, THE DAILY RECORD HIGH TEMPERATURE OF 88F WAS
LAST RECORDED IN MARATHON. TEMPERATURE DATA FOR MARATHON DATES BACK
TO 1950.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 82 73 81 70 / 20 30 20 10
MARATHON 80 73 80 70 / 20 30 20 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...JAM
AVIATION/NOWCASTS....DP
DATA ACQUISITION.....DP
VISIT US ON THE WEB AT WEATHER.GOV/KEY
FOLLOW US ON FACEBOOK AND TWITTER AT:
WWW.FACEBOOK.COM/NWSKEYWEST
WWW.TWITTER.COM/NWSKEYWEST
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page