170
FXUS62 KKEY 031804
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
104 PM EST SAT JAN 3 2026
..NEW AVIATION, PREV DISCUSSION
KEY MESSAGES
-VEERING BREEZES WILL BRING IN A WARMING TREND THROUGH THE REST
OF THE WEEKEND, WITH HIGHS TRENDING TOWARDS THE MID 70S.
-NEAR- NIL RAIN CHANCES ARE EXPECTED THROUGH TONIGHT.
-A WEAK FRONT WILL PUSH THROUGH THE KEYS LATE SUNDAY, BRINGING A
BRIEF SHOT OF SHOWERS.
-TEMPERATURES AND DEW POINTS WILL CHANGE LITTLE BEHIND THE FRONT,
WITH HIGHS GENERALLY IN THE MID TO UPPER 70S FOR THE NEXT WORK
WEEK, ALONG WITH NEAR- NIL RAIN CHANCES ONCE AGAIN.
AVIATION
(18Z TAFS)
ISSUED AT 102 PM EST SAT JAN 3 2026
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE TAF PERIOD.
LIGHT AND VARIABLE BREEZES THIS AFTERNOON ARE EXPECTED TO BECOME
SOUTHWEST TO WEST TONIGHT.
PREV DISCUSSION
ISSUED AT 1012 AM EST SAT JAN 3 2026
IT WAS A COLD TO CHILLY MORNING ACROSS THE FLORIDA KEYS. A
TEXTBOOK RADIATIONAL COOLING SETUP OCCURRED OVERNIGHT AND LASTED
THROUGH SHORTLY AFTER DAYBREAK. TEMPERATURES DROPPED TO THE UPPER
40S ON BIG PINE KEY TO THE LOWER TO MID 60S AT SOME OF THE LESS
SHELTERED LOCATIONS OF THE KEYS. SINCE THEN, TEMPERATURES HAVE
REBOUNDED NICELY. TEMPERATURES ALONG THE ISLAND CHAIN ARE IN THE
UPPER 60S TO LOWER 70S AND DEW POINTS ARE IN THE LOWER TO MID 50S.
GOES 19 TOTAL PRECIPITABLE WATER (TPW) PRODUCTS SHOWS PLENTY OF
DRY AIR REMAINS ACROSS THE KEYS WITH PWAT VALUES RANGING FROM 0.5
TO 0.7 INCHES. KBYX RADAR IS VOID OF ANY SHOWER ACTIVITY AS A
RESULT. SURFACE HIGH PRESSURE IS CENTERED JUST EAST OF SOUTH
FLORIDA. THIS IS PROMOTING MAINLY LIGHT AND VARIABLE BREEZES AT
MARINE PLATFORMS SURROUNDING THE ISLAND CHAIN.
SHORT TERM FORECAST
THE 12Z MORNING SOUNDING SHOWS A MOSTLY DRY PROFILE WITH THE
EXCEPTION OF BETWEEN 900 MB TO 850 MB WHERE SOME LOWER LEVEL
MOISTURE IS PRESENT. THIS CORRESPONDS WELL WITH WHERE THE CLOUD
COVER MAINLY WEST OF THE ISLAND CHAIN IS LOCATED (~4000-5000 FT).
THE PWAT VALUE MEASURED WAS 0.69 INCHES WHICH IS AROUND THE 10TH
PERCENTILE FOR THE DATE. OVERALL, NO CHANGES EXPECTED TO THE
ONGOING FORECAST WITH DRY AIR CONTINUING TO DOMINATE. ENJOY THE
FIRST SATURDAY OF 2026!
MARINE
ISSUED AT 102 PM EST SAT JAN 3 2026
THERE ARE CURRENTLY NO WATCHES, WARNINGS, OR ADVISORIES IN EFFECT
ACROSS THE FLORIDA KEYS COASTAL WATERS. FROM SYNOPSIS, HIGH
PRESSURE CENTERED JUST EAST OF SOUTH FLORIDA WILL MAINTAIN
SOUTHWEST TO WEST BREEZES TONIGHT. A WEAK FRONT WILL PASS THROUGH
THE FLORIDA KEYS MARINE ZONES LATE SUNDAY, ALLOWING BREEZES TO
CLOCK AROUND TO THE NORTHWEST, THEN QUICKLY TO THE NORTHEAST
SUNDAY NIGHT AND MONDAY. AS AN AREA OF HIGH PRESSURE SLIDES
EASTWARD INTO THE CENTRAL NORTH ATLANTIC, LIGHT TO GENTLE
NORTHEAST TO EAST BREEZES WILL GRADUALLY FRESHEN AND VEER TO THE
EAST TO SOUTHEAST BY MID-WEEK.
CLIMATE
ON THIS DAY IN 2017, THE DAILY RECORD HIGH TEMPERATURE OF 88F WAS
RECORDED AT MARATHON. THIS IS ALSO THE WARMEST TEMPERATURE EVER
RECORDED DURING THE MONTH OF JANUARY AT MARATHON. TEMPERATURE
RECORDS FOR MARATHON DATE BACK TO 1950.
PREVIOUS DISCUSSION
ISSUED AT 355 AM EST SAT JAN 3 2026
TONIGHT WAS A TEXTBOOK EXAMPLE OF A RADIATIONAL COOLING EVENT FOR
THE FLORIDA KEYS ISLAND CHAIN. HIGH PRESSURE CENTERED JUST EAST OF
SOUTH FLORIDA CONTINUES TO SUPPORT LIGHT AND VARIABLE WINDS.
COUPLED WITH MAINLY CLEAR SKIES DETECTED BY AVAILABLE GOES-19
NIGHTTIME SATELLITE IMAGERY, MOST OUTGOING LONGWAVE RADIATION FROM
THE SURFACE OF THE LAND MASSES EASILY ESCAPED THE TROPOSPHERE,
ALLOWING TEMPERATURES TO PLUNGE FOR THE FAVORED INTERIOR SPOTS OF
THE LARGER ISLANDS. TEMPERATURES CURRENTLY RANGE FROM THE UPPER
40S IN BIG PINE KEY, TO THE MID 60S SOME OF THE LESS SHELTERED
LOCATIONS. KBYX IS OF COURSE VOID OF ANY METEOROLOGICAL ECHO
RETURNS AT THIS EARLY SATURDAY MORNING HOUR WITH THIS SETUP.
A RATHER ROUTINE FORECAST IN STORE FOR THE NEXT SEVEN DAYS. HIGH
PRESSURE WILL CONTINUE TO SLIDE EASTWARD, AS A WEAK FRONTAL
BOUNDARY CURRENTLY APPROACHING THE GULF COASTLINE DIVES THROUGH
THE FLORIDA PENINSULA BY SUNDAY. FORECAST SOUNDINGS SUGGEST A
BRIEF WINDOW FOR DECENT LOW-LEVEL SUPPORT FOR ASCENT, COUPLED WITH
MODEST BOUNDARY LAYER MOISTENING AHEAD OF THE FRONTAL PASSAGE,
SUPPORTIVE OF AT LEAST A BROKEN LINE OF SHOWERS PUSHING THROUGH
THE ISLAND CHAIN SUNDAY AFTERNOON. WINDS QUICKLY VEERING FROM THE
NORTHWEST TO NORTHEAST IN THE WAKE OF THE FRONT WILL NOT SUPPORT
ANY SIGNIFICANT COOL ADVECTION FOR EARLY NEXT WEEK.
HIGH PRESSURE BUILDING BEHIND THE FRONT WILL SLOWLY SLIDE
EASTWARD INTO THE NORTH ATLANTIC FOR THE EARLY TO LATTER PART OF
NEXT WEEK. BREEZES WILL GRADUALLY CLOCK AROUND TO THE EAST, THEN
TO THE EAST SOUTHEAST AS IT DOES SO, SUPPORTING NEAR OR SLIGHTLY
ABOVE NORMAL TEMPERATURES AND NEAR-NIL RAIN CHANCES. FOR THOSE
LOOKING FOR ANOTHER BLAST OF WINTER IN EARLY 2026, GLOBAL
NUMERICAL WEATHER PREDICTION ENSEMBLE GUIDANCE SUGGESTS THE NEXT
SHOT AT BELOW NUMBER TEMPERATURES FOR THE FLORIDA KEYS IS
UNFORTUNATELY BEYOND THE NEXT SEVEN DAYS.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 64 79 67 77 / 10 10 10 10
MARATHON 62 76 66 75 / 10 10 10 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...MJV
AVIATION/NOWCASTS....MJV
DATA ACQUISITION.....MJV
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