212
FXUS62 KKEY 120821
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
421 AM EDT FRI JUN 12 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- ISLAND CLOUD LINE FORMATION WILL BE POSSIBLE IN THE LATE MORNING
OR AFTERNOON HOURS THROUGH THE WEEKEND.
- WATERSPOUTS WILL BE POSSIBLE WITH ANY DEVELOPING ISLAND CLOUD
LINE.
- CONDITIONS WILL REMAIN SEASONABLY WARM AND MUGGY, WITH HEAT
INDICES APPROACHING NEAR 100F EACH AFTERNOON THROUGH EARLY NEXT
WEEK.
DISCUSSION
ISSUED AT 421 AM EDT FRI JUN 12 2026
ANYONE IN THE FLORIDA KEYS MAY WAKE UP TO A NEARLY SHOWER FREE
ENVIRONMENT AS SEEN BY BOTH THE KBYX AND KAMX RADARS. GOES EAST
OBSERVATIONS SHOW SKIES ARE NOT ENTIRELY CLOUD FREE ACROSS THE
FLORIDA KEYS. NIGHTTIME MICROPHYSICS SCANS SHOW HIGH ALTITUDE
CIRRUS DEBRIS CLOUD ASSOCIATED WITH A TROPICAL WAVE OVER THE
YUCATAN PENINSULA ARE STREAMING OVER THE LOWER KEYS AND OUR
WESTERN WATERS. MEANWHILE, WIND OBSERVATIONS AT BOTH EYW AND MTH
ARE BOTH BELOW 10 KNOTS. TEMPERATURE MEASUREMENTS AT BIG PINE KEY,
DOWN TO 77F, AND THE KEY WEST WFO, DOWN TO 80 F, INDICATE THE
WINDS ARE LIGHT ENOUGH AND SKIES CLEAR ENOUGH TO SEE RADIATIVE
COOLING ON THE LARGER ISLANDS. THIS DOES NOT MEAN WE WILL SEE A
BREAK FROM THE HUMIDITY. DEW POINTS ALONG THE ISLAND CHAIN ARE
STILL IN THE MID 70S. OVERALL, THE WEATHER PATTERN DEVELOPING OVER
THE FLORIDA KEYS LOOKS MUGGY WITH LIGHT WINDS TODAY.
WHAT LARGE SCALE FEATURES ARE PLAYING A ROLE IN THE CURRENT
WEATHER PATTERN? THE AFOREMENTIONED TROPICAL WAVE WAS ABSORBED
INTO A CENTRAL AMERICAN GYRE OVER SOUTHERN MEXICO AND CENTRAL
AMERICA. ITS ROLE FOR FLORIDA KEYS WEATHER IS THAT IT WILL WEAKEN
NEARBY HIGH PRESSURE SYSTEMS, LEADING TO OUR LIGHT BREEZES, AND
SEND WAVES OF HIGH ALTITUDE ICE CLOUDS ACROSS THE EASTERN GULF.
MEANWHILE, THE ATLANTIC HIGH HAS MOVED FAR TO THE EAST OF BERMUDA.
A STRONGER HIGH PRESSURE SYSTEM OVER THE EASTERN UNITED STATES
COULD BUILD WINDS ACROSS THE KEYS, BUT A SERIES OF LOWS UNLEASHED
MULTIPLE ROUNDS OF SEVERE CONVECTION ACROSS THE MIDWEST WHICH ALSO
WEAKENED THE SOUTHEASTERN US HIGH. THE RESULT IS A RELATIVELY
STAGNANT PATTERN ACROSS THE FLORIDA KEYS. BREEZES ARE LIGHT TO
GENTLE, DIVERGENCE IN THE UPPER ATMOSPHERE IS ELSEWHERE,
SUGGESTING THE WEATHER FOR THE UPCOMING WEEKEND WILL BE DEFINED
BY DIURNAL HEATING CYCLES. THERE IS ONE MORE CAVEAT, A DRY LAYER
IDENTIFIED BY LAST NIGHT'S 00Z SOUNDING BETWEEN 800 AND 650 MB.
NASA FORECAST MODELS THAT FOCUS ON AEROSOLS HIGHLIGHTED A REGION
OF HIGHER THAN NORMAL OPTICAL THICKNESS OVER SOUTH FLORIDA AND THE
KEYS. IT'S POSSIBLE THAT ONE OF THE REASONS SHOWER COVERAGE HAS
BEEN SO SPARSE THE PAST FEW DAYS WAS A LINGERING LAYER OF SAHARAN
DUST.
WHAT DOES THIS MEAN FOR THE UPCOMING WEEKEND AND NEXT WEEK? MODELS
SUGGEST A DRIER PATTERN IS SETTING UP ACROSS THE KEYS. THE CENTRAL
AMERICAN GYRE WILL DIVERT THE MOST MOISTURE-LADEN AIR WEST OF THE
KEYS. MODEL ENSEMBLES SHOW A PRONOUNCED TROUGH FORMING OVER THE
EASTERN UNITED STATES, WHICH WOULD PREVENT THE SOUTHEAST US HIGH
FROM REDEVELOPING AND FRESHENING BREEZES ACROSS THE KEYS. IN THIS
ENVIRONMENT, THE MAIN CONCERNS BECOME CLOUD LINE SHOWERS,
POTENTIAL WATERSPOUTS, AND HEAT RISK. HEAT INDICES NEAR 100 F ARE
POSSIBLE, AND WE ARE NOT EVEN IN THE HOTTEST MONTH OF THE YEAR.
STAY HYDRATED, WATCH CLOUDS OVER THE WATER, AND STAY COOL WHEN
POSSIBLE!
MARINE
ISSUED AT 421 AM EDT FRI JUN 12 2026
NO WATCHES, WARNINGS, OR ADVISORIES ARE IN EFFECT FOR THE FLORIDA
KEYS COASTAL WATERS. FROM SYNOPSIS, HIGH PRESSURE ACROSS THE
SOUTHEASTERN UNITED STATES WEAKENED OVER THE PAST COUPLE OF DAYS
WHILE THE ATLANTIC HIGH MOVED FURTHER EAST. BREEZES SLACKENED TO
LIGHT TO GENTLE EAST SOUTHEASTERLIES AS A RESULT, AND ARE ON TRACK
TO BECOME LIGHT LATER THIS WEEKEND. SHOWER COVERAGE WILL REMAIN
LOW WHILE A LAYER OF DRY AIR LINGERS IN THE LOWER ATMOSPHERE.
AVIATION
(06Z TAFS)
ISSUED AT 421 AM EDT FRI JUN 12 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH FOR THE UPCOMING TAF
PERIOD. NEAR SURFACE WINDS WILL REMAIN EAST TO SOUTHEASTERLY AND
BELOW 10 KNOTS. AN OCCASIONAL SHOWER MAY BE ABLE TO DEVELOP AND
CAUSE MVFR TO IFR CIGS, BUT CONFIDENCE IN TIMING AND LOCATION IS
TOO LOW TO INCLUDE IN THE TAFS.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 89 81 89 81 / 20 10 20 10
MARATHON 89 81 90 81 / 20 10 20 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AJP
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