539
FXUS62 KKEY 090031
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
831 PM EDT THU OCT 8 2026
..NEW UPDATE, AVIATION
KEY MESSAGES
- A COASTAL FLOOD STATEMENT IS IN EFFECT, AND PARTICULARLY LOW
LYING AREAS WILL SEE SOME SALTWATER PONDING AROUND THE TIMES OF
HIGH TIDE.
- DRIER WEATHER THORUGH TONIGHT WILL GIVE WAY TO INCREASING RAIN
CHANCES FROM FRIDAY TO THE FIRST HALF OF THE WEEKEND.
- HURRICANE ISAIAS IN THE GULF DOES NOT POSE A DIRECT THREAT TO
THE FLORIDA KEYS, BUT IT WILL BRING INCREASING WESTERLY SWELL
INTO THE REGION.
UPDATE
ISSUED AT 821 PM EDT THU OCT 8 2026
A POCKET OF RELATIVELY DRIER AIR IS IN PLACE ACROSS THE FLORIDA
KEYS THIS EVENING AS DEEP TROPICAL MOISTURE REMAINS MORE CONCENTRATED
ACROSS THE CENTRAL PENINSULA, WHICH IS ASSOCIATED WITH A STATIONARY
FRONTAL BOUNDARY THAT IS EXTENDING EASTWARD TO THE NORTH OF
HURRICANE ISAIAS IN THE CENTRAL GULF. THIS DRIER AIR HAS GREATLY
LIMITED RAIN CHANCES ACROSS THE KEYS WITH RECENT KBYX RADAR
IMAGERY ONLY DETECTING A FEW STORMS ACROSS NORTHERN CUBA AND
NOTHING ACROSS THE KEY MARINE ZONES OTHER THAN SOME DEBRIS CLOUDS
PUSHING NORTHWARD FROM THE ACTIVITY OVER CUBA. THIS GENERAL DRIER
TREND SHOULD CONTINUE THROUGH THE REMAINDER OF THE EVENING AND
MOST OF THE OVERNIGHT PERIOD BUT A SURGE OF TROPICAL MOISTURE IS
EXPECTED TO APPROACH THE AREA ON FRIDAY AS A WEAK INVERTED TROUGH
EMBEDDED IN THE DEEP SOUTHERLY FLOW MOVES THROUGH AS ISAIAS
TRACKS TOWARDS THE NORTHERN GULF COAST. GIVEN THE SOUTHERLY
STEERING FLOW, ACTIVITY IS EXPECTED TO PRIMARILY DEVELOP INITIALLY
ACROSS THE EASTERN STRAITS AND NEAR AROUND ANDROS ISLAND AND THEN
DRIFT NORTHWARD INTO FRIDAY MORNING. ADDITIONAL ACTIVITY THEN IS
EXPECTED TO DEVELOP BY FRIDAY AFTERNOON ACROSS WEST CENTRAL CUBA
AND LIFT NORTHWARD ACROSS THE STRAITS THROUGHOUT THE DAY. OTHER
THAN A MINOR DECREASE IN POPS TONIGHT TO MOSTLY CAP VALUES AT 30%,
THE REMAINDER OF THE FORECAST IS ON TRACK AT THIS TIME WITH
OVERNIGHT LOWS IN THE LOW 80S.
DISCUSSION
ISSUED AT 1544 PM EDT THU OCT 8 2026
A COMPLICATED WEATHER PATTERN SET UP FROM THE SOUTHEASTERN UNITED
STATES TO THE LESSER ANTILLES OVER THE PAST FEW DAYS. HURRICANE
ISAIAS, UNDERSTANDABLY, DREW THE MOST ATTENTION FROM FORECASTERS
AND THE MEDIA. HOWEVER, THIS TROPICAL CYCLONE IS NOT THE ONLY
FEATURE MODIFYING WEATHER ACROSS THE FLORIDA KEYS. WATER VAPOR
SATELLITE OBSERVATIONS HIGHLIGHT A STALLED FRONTAL SYSTEM ACROSS
CENTRAL FLORIDA. UPPER LEVEL SATELLITE IMAGERY ALSO IDENTIFIES
ACTIVE SHOWERS SOUTHWEST OF HISPANIOLA AS PART OF A TROPICAL UPPER
TROPOSPHERIC TROUGH. MEANWHILE, SHOWER ACTIVITY IS SPARSE ACROSS
THE KEYS WATERS. WHAT HAPPENED, AND WHY ARE SHOWERS SO INACTIVE?
CURRENTLY, THESE THREE FEATURES ARE INDUCING SINKING MOTION ACROSS
SOUTHERN FLORIDA. OUTFLOW FROM HURRICANE ISAIAS IS RUNNING INTO
AIR DIRECTED NORTH BY THE PREVIOUSLY MENTIONED TUTT AND SINKING
OVER THE KEYS. MEANWHILE, PERSISTENT SOUTHERLIES MEAN THE KEYS ARE
IN THE LEE OF THE CUBAN LANDMASS. IN A SURPRISING TURN, A CUBAN
SHADOW WAS NOT OBSERVED BY THE 18Z SOUNDING. CUMULUS CLOUDS WERE
FINALLY ABLE TO BUBBLE UP NORTH OF THE ISLAND CHAIN IN THE
AFTERNOON HOURS. IN SPITE OF THESE NEARBY SHOWERS, WIDESPREAD
CONVECTION IS STILL UNLIKELY BECAUSE OF THE DRIER AIR ALOFT. TONIGHT,
EXPECT ANOTHER RELATIVELY UNEVENTFUL EVENING ACROSS THE ISLAND
CHAIN.
DRY CONDITIONS ARE NOT EXPECTED TO LAST THROUGH THE WEEKEND.
WHILE HURRICANE ISAIAS MOVES TOWARDS THE NORTHERN GULF COAST, THE
TUTT WILL CONTINUE MOVING WEST. THE REGION OF SINKING AIR WILL BE
REPLACED BY A REGION THAT MORE FAVORABLE FOR SHOWERS. AT THE SAME
TIME, A WEAK LOW LEVEL WAVE WILL MOVE NORTH TOWARDS THE KEYS THIS
WEEKEND. STATISTICAL MODELS HAVE SHOWN CONSISTENT HINTS THAT
SHOWER CHANCES WILL INCREASE DURING THE FIRST HALF OF THE UPCOMING
WEEKEND. A DRIER PATTERN IS EXPECTED TO SET UP ACROSS THE KEYS
AFTER THIS PULSE OF SHOWER ACTIVITY. MID-WEEK, THE PATTERN GETS A
BIT MORE COMPLICATED. SOME STATISTICAL MODELS SUGGEST A WEAK
FRONTAL SYSTEM COULD MOVE TOWARDS THE FLORIDA KEYS. FORECAST
UNCERTAINTY IS STILL HIGH DURING THIS PERIOD OF TIME, SO CHECK
BACK BEFORE MAKING ANY PLANS.
MARINE
ISSUED AT 344 PM EDT THU OCT 8 2026
A COASTAL FLOOD STATEMENT IS IN EFFECT FOR THE FLORIDA KEYS.
BOATERS SHOULD BE AWARE OF LESS CLEARANCE UNDER FIXED BRIDGING
AROUND TIMES OF HIGH TIDE. WHILE NO WATCHES, WARNINGS, OR
ADVISORIES ARE IN EFFECT FOR THE FLORIDA KEYS NEARSHORE AND
OFFSHORE WATERS AT THIS TIME, BREEZES ARE EXPECTED TO FRESHEN TO
MODERATE TO FRESH OVER THE WESTERN WATERS IN RESPONSE TO HURRICANE
ISAIAS. SMALL CRAFT SHOULD EXERCISE CAUTION HEADLINES MAY BE
REQUIRED FOR THE WESTERN ZONES OF THE FLORIDA STRAITS AND THE
OUTER GULF WATERS.
FROM SYNOPSIS: HURRICANE ISAIAS, CURRENTLY OVER THE SOUTHWESTERN
GULF WATERS, IS EXPECTED TO MOVE TOWARDS THE NORTH GULF COAST OVER
THE NEXT FEW DAYS, STRENGTHENING AS IT DOES SO. ENHANCED SWELL
GENERATED BY THE HURRICANE WILL INCREASE WAVE HEIGHTS IN THE
WESTERN FLORIDA STRAITS AND GULFSIDE WATERS TONIGHT THROUGH THE
FIRST HALF OF THE WEEKEND. A STATIONARY FRONT REMAINS DRAPED
ACROSS NORTH-CENTRAL FLORIDA WHICH WILL SLOWLY DRIFT SOUTHWARD
INFRINGING ON THE SURFACE RIDGE TO ITS SOUTH. BREEZES ARE EXPECTED
TO FRESHEN BEFORE THE WEEKEND IN RESPONSE WITH MODERATE TO FRESH
BREEZES POSSIBLE IN THE WESTERN WATERS. A PLUME OF MOISTURE WILL
ALSO MOVE INTO THE FLORIDA KEYS AT THE SAME TIME AND INCREASE
SHOWER AND THUNDERSTORM CHANCES.
AVIATION
(00Z TAFS)
ISSUED AT 808 PM EDT THU OCT 8 2026
VFR CONDITIONS WILL MOSTLY PREVAIL THROUGHOUT THE FORECAST
PERIOD, THOUGH BRIEF VSBY RESTRICTIONS MAY OCCUR AT TIMES DUE TO
POSSIBLE SHRA/TSRA ACTIVITY. CONDITIONS SHOULD BE MOSTLY DRY
OVERNIGHT WITH RAIN CHANCES INCREASING ON FRIDAY, THOUGH COVERAGE
SHOULD BE LOW ENOUGH SO THIS WAS NOT MENTIONED IN MOST RECENT TAF
ISSUANCE. IN ADDITION, WINDS WILL BE OUT OF THE SE THROUGHOUT THE
PERIOD NEAR 10 KNOTS BUT OCCASIONAL HIGHER GUSTS MAY ALSO OCCUR.
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...RG
AVIATION/NOWCASTS....RG
DATA ACQUISITION.....LIW
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