042
FXUS62 KKEY 121729
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
129 PM EDT FRI JUN 12 2026
..NEW DISCUSSION, 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.
AVIATION
(18Z TAFS)
ISSUED AT 125 PM EDT THU JUN 11 2026
DESPITE A THICK CIRRUS DECK BASED AT AROUND FL150, VFR CONDITIONS
WILL PREVAIL AT BOTH ISLAND TERMINALS THROUGH 18Z SATURDAY
AFTERNOON. THE BEST CHANCES FOR AN ISOLATED SHOWER OR
THUNDERSTORM WILL BE ASSOCIATED WITH POSSIBLE ISLAND CLOUD LINE
FORMATION IN THE LATE MORNING OR EARLY AFTERNOON HOURS SATURDAY.
NEAR- SURFACE WINDS WILL LIGHT, GENERALLY OUT OF THE EAST TO
SOUTHEAST, OCCASIONALLY BACKING TO THE NORTHEAST TO EAST.
DISCUSSION
ISSUED AT 421 AM EDT FRI JUN 12 2026
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 1107 AM EDT FRI JUN 12 2026
NO WATCHES, WARNINGS, OR ADVISORIES ARE IN EFFECT FOR THE FLORIDA
KEYS COASTAL WATERS. FROM SYNOPSIS, ELONGATED HIGH PRESSURE
EXTENDING FROM THE SOUTHEAST EASTWARD TO THE WESTERN NORTH
ATLANTIC WILL SUPPORT LIGHT TO GENTLE EAST TO SOUTHEAST BREEZES
TODAY THROUGH SATURDAY, GRADUALLY VEERING TO THE SOUTHEAST TO
SOUTH FOR SUNDAY THROUGH EARLY NEXT WEEK. SHOWER COVERAGE ACROSS
THE FLORIDA KEYS COASTAL WATERS WILL REMAIN LOW WHILE A LAYER OF
DRY AIR LINGERS IN THE LOWER ATMOSPHERE.
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...BT
AVIATION/NOWCASTS....BT
DATA ACQUISITION.....BT
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