381
FXUS62 KKEY 101415
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1015 AM EDT SAT OCT 10 2026
..NEW DISCUSSION, MARINE, 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.
- POST-TROPICAL CYCLONE ISAIAS HAS MOVED INLAND INTO SOUTHERN
ALABAMA AFTER MAKING LANDFALL LAST NIGHT NEAR DESTIN, FL.
RESIDUAL WESTERLY SWELL WILL CONTINUE THIS AFTERNOON AND EVENING
ACROSS THE WESTERN HALF OF THE COASTAL WATERS.
- ELEVATED RAIN CHANCES ARE EXPECTED BEGINNING THIS AFTERNOON,
PEAKING TONIGHT, BEFORE DECREASING OVER THE REMAINDER OF THE
HOLIDAY WEEKEND.
DISCUSSION
ISSUED AT 1015 AM EDT SAT OCT 10 2026
POST-TROPICAL CYCLONE ISAIAS HAS BEEN ABSORBED INTO THE MID-
LATITUDE WINDS. HOWEVER, THE EFFECTS OF ISAIAS WILL CONTINUE TO BE
FELT THROUGH THE FIRST HALF OF THE WEEKEND. DEEP LAYERS OF
MOISTURE ARE SURGING ACROSS SOUTH FLORIDA AND THE KEYS. THE
MORNING 12Z KKEY SOUNDING SAMPLED A DAILY RECORD MAXIMUM PWAT FOR
THE DAY. THE CHALLENGE FOR THIS AFTERNOON IS WHAT WILL HAPPEN WITH
ALL THIS MOISTURE. THE SOUNDING MEASURED LITTLE TO NO INSTABILITY
IN THE ENVIRONMENT, YET SHOWERS AS OBSERVED BY KBYX ARE
STRUGGLING TO FORM OVER THE EASTERN WATERS OF THE KEYS. VISIBLE
SATELLITE OBSERVATIONS DO NOT SEE WIDESPREAD CLOUD COVER OVER THE
KEYS. MEAN LAYER WINDS OBSERVED BY THE SOUNDING WERE NEAR 20
KNOTS, SO THE FLOW FIELD IS TOO STRONG TO OBSERVE A CUBAN SHADOW.
SHOWERS ARE ABLE TO FORM OVER THE OUTER GULF, BUT HAVE NOT BEEN
ABLE TO DEVELOP INTO THUNDERSTORMS. THE THOUGHT IS THAT AS WHAT
USED TO BE ISAIAS MOVES NORTH, THE PRESSURE GRADIENT WILL WEAKEN
AND CAUSE WINDS TO SLACKEN ACROSS THE KEYS. HOWEVER, THAT WOULD BE
THE LATE AFTERNOON TO EVENING HOURS. THIS AFTERNOON, EXPECT
GENTLE TO MODERATE BREEZES ACROSS THE UPPER AND MIDDLE KEYS WHILE
MODERATE TO FRESH BREEZES LINGER OVER THE LOWER KEYS. SHOWER
COVERAGE IS ON TRACK TO REMAIN SURPRISINGLY LOW, A SLIGHT CHANCE
TO A CHANCE, UNTIL THE LATE AFTERNOON. THE PROBLEM IS ALL THE
ATMOSPHERE NEEDS IS A BIT OF LIFT FOR SHOWERS TO DEVELOP. TONIGHT,
A BUILDING ATLANTIC HIGH IS EXPECTED TO FRESHEN WINDS OVER THE
EASTERN WATERS AND THUS PROVIDE THAT SOURCE OF LIFT. CHECK BACK
TONIGHT BECAUSE THE ENVIRONMENT IS PRIMED FOR RAINFALL. FINALLY, A
COASTAL FLOOD STATEMENT REMAINS IN EFFECT ACROSS THE ISLAND
CHAIN.
MARINE
ISSUED AT 1015 AM EDT SAT OCT 10 2026
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL WINDS DECREASE AND SEAS
SUBSIDE FOR THE WESTERNMOST WATERS OF THE FLORIDA KEYS. NO OTHER
WATCHES OR WARNINGS ARE IN EFFECT FOR THE NEARSHORE OR OFFSHORE
WATERS SURROUNDING THE FLORIDA KEYS.
FROM SYNOPSIS: POST-TROPICAL CYCLONE ISAIAS MADE LANDFALL LAST
NIGHT NEAR DESTIN, FL. HOWEVER, THE LINGERING EFFECTS OF THE
HURRICANE WILL BE FELT THIS AFTERNOON AND TONIGHT. MODERATE TO
FRESH SOUTHEAST TO SOUTH BREEZES ARE EXPECTED TO CONTINUE
THROUGHOUT THE FLORIDA KEYS COASTAL WATERS, ESPECIALLY THE SE
GULF, WESTERN STRAITS, AND THE NEARSHORE WATERS SURROUNDING THE
LOWER KEYS. ELEVATED SWELLS WILL PERSIST THROUGH THE WESTERN FL
STRAITS AND THE SE GULF WATERS THROUGH TONIGHT. BREEZES WILL ONLY
MODESTLY SLACKEN TO GENTLE TO MODERATE AS THE CYCLONE CONTINUES TO
MOVE AWAY AND RIDGING BUILDS IN BEHIND IT. THE ENVIRONMENT WILL
REMAIN PRIMED FOR SHOWERS THROUGH SUNDAY BEFORE DRYING OUT DURING
THE START OF THE WEEK. AFTERWARDS, A FRONTAL BOUNDARY ASSOCIATED
WITH POST- TROPICAL CYCLONE ISAIAS MAY PUSH THROUGH THE FLORIDA
KEYS BY MID- WEEK.
AVIATION
(12Z TAFS)
ISSUED AT 1015 AM EDT SAT OCT 10 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH FOR THE UPCOMING TAF
PERIOD. GUSTS ARE UP AND DOWN ACROSS THE KEYS WATERS WITH
INCREASED SHOWER COVERAGE OVER THE WATERS NORTH OF THE TERMINALS.
WINDS ARE EXPECTED TO SLACKEN AFTER SUNSET, AND SHOWER COVERAGE IS
ON TRACK TO INCREASE LATE IN THE PERIOD.
CLIMATE
ON THIS DAY ON 2009, THE DAILY RECORD WARM LOW TEMPERATURE OF 84F
WAS RECORDED IN KEY WEST. TEMPERATURE RECORDS FOR KEY WEST DATE
BACK TO 1872. ALSO, ON THIS DAY IN 1975, THE DAILY RECORD WARM LOW
TEMPERATURE OF 83F WAS RECORDED IN MARATHON. TEMPERATURE RECORDS
FOR MARATHON DATE BACK TO 1951.
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AJP
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