389
FXUS62 KKEY 091453
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1053 AM EDT FRI OCT 9 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.
- 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 FOR THE FIRST HALF OF THE WEEKEND.
- WINDS WILL BE ELEVATED OVER THE WATERS SURROUNDING THE LOWER
KEYS THIS AFTERNOON.
- INCREASING MOISTURE ACROSS THE KEYS THIS AFTERNOON THROUGH
SATURDAY NIGHT WILL LEAD TO HIGHER RAIN CHANCES. THE PEAK IN
ACTIVITY IS EXPECTED TONIGHT.
DISCUSSION
ISSUED AT 1053 AM EDT FRI OCT 9 2026
HURRICANE ISAIAS INTENSIFIED INTO A CATEGORY 3 SYSTEM THIS
MORNING. THE FIRST HURRICANE OF THE ATLANTIC SEASON IS ALSO THE
FIRST MAJOR HURRICANE. DESPITE THE STORM'S SIZE AND INTENSITY, THE
HURRICANE IS NOT EXPECTED TO BRING HAZARDOUS WEATHER TO THE
FLORIDA KEYS. BREEZES ALONG THE WESTERN STRAITS AND THE OUTER GULF
ARE ELEVATED DUE TO THE NEARBY HURRICANE. MARINERS IN THE WESTERN
WATERS OF THE FLORIDA STRAITS AND THE OUTER GULF WILL EXPERIENCE
ELEVATED WAVES AND SWELL GENERATED BY HURRICANE ISAIAS THROUGH THE
FIRST HALF OF THE WEEKEND.
WET CONDITIONS ARE SETTING UP ACROSS THE FLORIDA KEYS THIS
WEEKEND. SHOWERS THIS MORNING SET UP ACROSS THE EASTERN HALF OF
THE CWA. THESE SHOWERS WERE ABLE TO FORM ALONG THE NORTHERN EDGE
OF AN INVERTED TROUGH OVER THE EASTERN HALF OF CUBA. MEANWHILE,
THE MOISTURE BEING PULLED NORTH BY HURRICANE ISAIAS WILL KEEP
WASHING ACROSS THE FLORIDA KEYS. THE FORECAST CHALLENGE FOR THIS
AFTERNOON WILL BE WHAT HAPPENS WITH THIS MOISTURE. SATELLITE
OBSERVATIONS ACTUALLY SHOW A TONGUE OF DRY AIR OVER THE WESTERN
STRAITS. CLOUD COVER IS MORE SPARSE OVER THE LOWER KEYS COMPARED
TO THE MIDDLE AND UPPER KEYS. THE MORNING KKEY SOUNDING SAMPLED AN
ENVIRONMENTAL PWAT BETWEEN THE 50TH AND 75TH PERCENTILE, DESPITE
THE NEARBY HURRICANE. OUTFLOW FROM HURRICANE ISAIAS IS ACTUALLY
LIMITING SHOWER DEVELOPMENT OVER OUR WESTERN WATERS.
THIS AFTERNOON, EXPECT A DECREASE IN SHOWER ACTIVITY OVER THE
LOWER AND MIDDLE KEYS, WHILE THE UPPER KEYS HAVE A HIGHER CHANCE
TO OBSERVE RAINFALL. THE MAIN ISSUE WILL BE WINDS. GUSTS ALONG THE
REEF ARE ABLE TO EXCEED 20 KNOTS. WHILE THE STRONGER WINDS IN THE
LOWER ATMOSPHERE ARE NOT ABLE TO MIX DOWN TO THE SURFACE, SHOWERS
THAT DO MANAGE TO FORM WILL BE FAST MOVING. GUSTS OF 25 TO 30
KNOTS ARE POSSIBLE NEAR EVEN SHALLOW SHOWERS. THIS MEANS A COUPLE
OF CHANGES ARE NECESSARY FOR THE MORNING UPDATE. HURRICANE ISAIAS'
WIND FIELD IS LARGER THAN EXPECTED, SO THE AREA OF SMALL CRAFT
SHOULD EXERCISE CAUTION HEADLINES WAS EXPANDED. A SMALL CRAFT
ADVISORY ENDED UP BEING REQUIRED FOR THE WESTERNMOST WATERS.
MARINE
ISSUED AT 1053 AM EDT FRI OCT 9 2026
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE OUTER GULF WATERS AND
THE STRAITS OF FLORIDA WEST OF HALFMOON SHOAL. SMALL CRAFT SHOULD
EXERCISE CAUTION UNTIL WINDS DECREASE FOR THE BAYSIDE WATERS AND
THE WATERS SOUTH OF THE LOWER KEYS. BREEZES ARE EXPECTED TO
SLACKEN LATER TONIGHT AS THE HURRICANE MOVES NORTH.
HURRICANE ISAIAS INTENSIFIED TO A CATEGORY 3 HURRICANE. THE
HURRICANE IS FORECAST TO MAKE LANDFALL IN NORTHERN FLORIDA
TONIGHT. FRESH BREEZES WERE ABLE TO DEVELOP OVER THE NORTHWESTERN
WATERS ON THE PERIPHERY OF THE HURRICANE. ELEVATED SWELLS WILL
PERSIST THROUGH THE FLORIDA STRAITS AND THE OUTER GULF WATERS
THROUGH THE FIRST HALF OF THE WEEKEND. BREEZES ARE ON TRACK TO
DECREASE WHILE HURRICANE ISAIAS MOVES NORTH. MEANWHILE, A PLUME
OF MOISTURE WILL MOVE NORTH FROM EASTERN CUBA TONIGHT THROUGH THIS
WEEKEND. EXPECT AN INCREASE IN SHOWER AND THUNDERSTORM CHANCES.
BREEZES WILL BE ABLE TO SLACKEN DURING THE FIRST HALF OF THE
WEEKEND.
AVIATION
(12Z TAFS)
ISSUED AT 1053 AM EDT FRI OCT 9 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH FOR THE UPCOMING TAF
PERIOD. WHILE THUNDERSTORMS WERE ABLE TO DEVELOP NEAR MTH THIS
MORNING, VCTS CONDITIONS WANED NEAR THE TERMINAL. WHILE DRIER
CONDITIONS ARE EXPECTED NEAR THE TERMINALS THIS AFTERNOON, SHOWER
COVERAGE WILL INCREASE TONIGHT AS HURRICANE ISAIAS MOVES NORTH.
EXPECT VCSH TO RETURN TO THE TAFS WITH PERIODS OF VCTS POSSIBLE
OVERNIGHT. WINDS WILL REMAIN SOUTHEASTERLY, AND ARE EXPECTED TO
DECREASE AFTER SUNSET.
CLIMATE
ON THIS DAY IN 2009, THE DAILY RECORD WARM LOW TEMPERATURE OF 84F
WAS RECORDED IN KEY WEST. TEMPERATURE RECORDS FOR KEY WEST DATE
BACK TO 1872. ON THIS DAY IN 2009, THE DAILY RECORD WARM LOW
TEMPERATURE OF 83F WAS RECORDED IN MARATHON. TEMPERATURE RECORDS
FOR MARATHON DATE BACK TO 1951.
OF NOTE
AT PENNEKAMP STATE PARK: IN 2011, A RAINFALL OF 11.02" WAS RECORDED.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 88 82 88 82 / 30 60 40 60
MARATHON 88 81 89 82 / 50 50 30 40
KEY WATCHES/WARNINGS/ADVISORIES
FL...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR GMZ033-034-
055-075.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AJP
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