345
FXUS62 KKEY 051840
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
240 PM EDT MON OCT 5 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- MINOR SALTWATER FLOODING OF LOW ELEVATION STREETS WILL CONTINUE
THROUGH THIS EVENING DUE TO HIGHER HIGH TIDES. SOME STORM
DRAINS WILL OVERFLOW. BOATERS CAN EXPECT LESS CLEARANCE UNDER
FIXED BRIDGES.
- BELOW NORMAL RAIN AND THUNDER CHANCES WILL CONTINUE THROUGH AT
LEAST TUESDAY. THERE IS LOW CONFIDENCE IN RAINFALL CHANCES FOR
THE LATTER PART OF THE WORK WEEK AND THE WEEKEND.
DISCUSSION
ISSUED AT 240 PM EDT MON OCT 5 2026
LOW LEVEL RIDGING HAS REMAINED THE DOMINANT FEATURE ACROSS THE
FLORIDA KEYS, REFLECTED IN THE GENTLE SOUTHEASTERLY FLOW NOTED ON
SURFACE OBSERVATIONS. TEMPERATURES HAVE CLIMBED INTO THE UPPER 80S
WITH HEAT INDEX VALUES NEAR 100F, BUT THESE LIGHT BREEZES HAVE
KEPT THE AIR FROM FEELING TOO STUFFY OR STAGNANT. EVEN THOUGH OUR
SENSIBLE WEATHER HERE AT HOME IS GENERALLY UNREMARKABLE, THERE ARE
A FEW KEY PIECES IN THE SYNOPTIC PATTERN REGARDING THE LONG TERM
FORECAST. SATELLITE IMAGERY SHOWS AN AREA OF DISORGANIZED SHOWERS
AND THUNDERSTORMS OVER THE SOUTHWESTERN GULF WATERS. A LENGTHY
COLD FRONT IS DRAPED ACROSS THE SOUTHEASTERN U.S., NOTED BY THE
WIDESPREAD CLOUD COVER OVER PORTIONS OF CENTRAL AND NORTHERN
FLORIDA. CIMSS VORTICITY ANALYSIS STILL SHOWS A SLOPPY AREA OF
CYCLONIC VORTICITY OVER EASTERN CUBA AND THE GREAT ANTILLES AREA,
AND IT IS CURRENTLY AIDING IN A MIX OF SHOWERS AND THUNDERSTORMS.
FIRST, WE NEED TO GET THROUGH TONIGHT AND TOMORROW. EVEN THOUGH
THE ATMOSPHERE DOES SUPPORT SOME SHALLOW SHOWERS, WE STILL LACK
ANY MEANINGFUL LIFT TO TRIGGER THIS ACTIVITY. IF ANY OUTFLOW
BOUNDARIES FROM AFTERNOON CONVECTION OUTSIDE OF OUR AREA CAN PASS
ACROSS OUR WATERS, WE MAY BE ABLE TO TRIGGER SOME ACTIVITY LATER
TONIGHT. WE'LL CONTINUE TO ADVERTISE A SLIGHT CHANCE (20%) OF
SHOWERS AND THUNDERSTORMS THROUGH TOMORROW NIGHT WITH OVERNIGHT
LOWS DIALING BACK TO THE LOWER 80S FOLLOWED BY AFTERNOON HIGHS IN
THE UPPER 80S.
OVER THE COURSE AND WEDNESDAY AND THURSDAY, THE COLD FRONT WILL
CONTINUE TO PRESS DOWN THE PENINSULA, AND IS PROGGED TO STALL
SOMEWHERE OVER CENTRAL OR SOUTHERN FLORIDA. THIS WOULD ERODE THE
RIDGING THAT HAS REMAINED ACROSS OUR AREA, AND COULD OPEN THE DOOR
FOR SOME BETTER RAIN CHANCES. THIS SET UP WOULD ALSO PLACE US IN
A TIGHTER MOISTURE GRADIENT, WHICH WOULD BE CONDUCIVE TO BETTER
RAINFALL CHANCES, BUT THE SOUTHERLY FLOW IN THE LOWER LEVELS
COULD RESULT IN A CUBAN SHADOW ACROSS OUR AREA. THIS WOULD KEEP
THE KEYS ON THE DRIER SIDE, AND CONFINE THE WETTER ACTIVITY TO OUR
NORTHERN WATERS. BOTH DETERMINISTIC AND ENSEMBLE GUIDANCES ARE
HAVING DIFFICULTY HONING IN ON WHERE THE BOUNDARY WILL SET UP, AND
THIS COULD MAKE OR BREAK THE FORECAST. ENSEMBLE MEMBERS DO HAVE
SOME AGREEMENT THAT SHOWERS WILL BRING MEASURABLE RAINFALL TO THE
KEYS AT SOME POINT OVER THE SECOND HALF OF THE WEEK, BUT THE
QUESTION IS WHEN IS THE ONSET OF RAIN? IT DEPENDS WHICH ENSEMBLE
MEMBER YOU ASK. THE TAKEAWAY IS THAT THERE IS A LOT OF UNCERTAINTY
REGARDING THE SPECIFIC DETAILS OF OUR SENSIBLE WEATHER AFTER
WEDNESDAY, BUT THE GENERAL PATTERN WILL SHIFT IN A WAY WHERE THE
BEST RAINFALL CHANCES ACROSS THE AREA WILL OCCUR LATER THIS WEEK.
WE WILL HAVE TO CONTINUE TO MONITOR GUIDANCE TRENDS AS THE FRONT
GRADUALLY PROGRESSES DOWN THE SUNSHINE STATE BEFORE WE CAN NARROW
DOWN RAINFALL TIMING, AMOUNTS, AND ANY POTENTIAL HAZARDS.
MARINE
ISSUED AT 240 PM EDT MON OCT 5 2026
BOATERS SHOULD BE AWARE OF REDUCED CLEARANCE BENEATH FIXED BRIDGES
NEAR TIMES OF HIGH TIDE AS A COASTAL FLOOD STATEMENT REMAINS IN
EFFECT FOR THE FLORIDA KEYS DUE TO HIGHER HIGH TIDES. OTHERWISE,
THERE ARE NO WATCHES, WARNINGS, OR ADVISORIES IN EFFECT FOR THE
FLORIDA KEYS LOCAL WATERS. FROM SYNOPSIS, RIDGING ACROSS THE AREA
WILL CONTINUE TO ENCOURAGE LIGHT TO GENTLE SOUTHEASTERLY BREEZES
ACROSS THE LOCAL WATERS. OCCASIONAL, ISOLATED SHOWERS ARE
POSSIBLE, BUT MOST OF THE AREA WILL STAY DRY THROUGH TONIGHT AND
TOMORROW. A COLD FRONT IS STILL ON TRACK TO STALL ACROSS THE
FLORIDA PENINSULA AND NORTHERN GULF DURING THE MIDDLE OF THE WEEK
WITH THE HIGHEST RAIN CHANCES REMAINING NORTH OF THE FLORIDA KEYS.
THIS WILL PROMOTE A SHIFT TO LIGHT TO GENTLE SOUTH TO SOUTHWESTERLY
BREEZES BY MIDWEEK.
AVIATION
(18Z TAFS)
ISSUED AT 240 PM EDT MON OCT 5 2026
VFR CONDITIONS WITH A MIX OF FEW TO OCCASIONALLY SCT SKIES NEAR
FL025 WILL PREVAIL THROUGH THE TAF PERIOD AT BOTH ISLAND
TERMINALS. SURFACE WINDS OUT OF THE SOUTHEAST WILL BACK TO THE
EAST WHILE FLUCTUATING BETWEEN 5 AND 10 KNOTS. ISOLATED LIGHT
SHOWERS ARE POSSIBLE THROUGHOUT THE FORECAST PERIOD, BUT IT IS
NEARLY IMPOSSIBLE TO PREDICT WHEN ANY ONE STRAY SHOWER MAY CROSS
EITHER TERMINAL. OPTING TO KEEP THE TAF PACKAGE DRY.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 80 89 80 88 / 20 20 20 40
MARATHON 80 88 80 88 / 20 20 20 40
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...DP
AVIATION/NOWCASTS....DP
DATA ACQUISITION.....DP
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