526
FXUS62 KKEY 261433
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
1033 AM EDT SAT SEP 26 2026
..NEW DISCUSSION, MARINE, AVIATION
KEY MESSAGES
- SALTWATER FLOODING OF LOW ELEVATION STREETS AND LOTS IS LIKELY
THROUGH NEXT WEEK DUE TO A POTENT KING TIDE. DON'T DRIVE THROUGH
FLOODED ROADWAYS. BOATERS CAN EXPECT LESS CLEARANCE UNDER FIXED
BRIDGES.
- A COASTAL FLOOD STATEMENT IS IN EFFECT FOR THE LOWER TO MIDDLE
KEYS, AND A COASTAL FLOOD ADVISORY IS IN EFFECT FOR THE UPPER
KEYS. COASTAL FLOOD ADVISORIES WILL LIKELY BE REQUIRED FOR ALL OF
THE KEYS BY MONDAY NIGHT.
- INCREASING NORTHEASTERLY SWELL FROM A NOR'EASTER OFF THE EAST
COAST WILL PRODUCE 4 TO 5 FOOT SEAS THROUGH THE WEEKEND IN THE
EASTERN STRAITS OF FLORIDA OFF THE UPPER KEYS.
DISCUSSION
ISSUED AT 1032 AM EDT SAT SEP 26 2026
A VERY DRY WEATHER PATTERN WILL USHER IN THE LAST SATURDAY OF
SEPTEMBER ACROSS THE FLORIDA KEYS. KBYX RADAR RETURNS SHOW
DISORGANIZED SHOWER COVERAGE OVER THE FLORIDA STRAITS AND AN
OCCASIONAL SHOWER OVER THE OUTER GULF WATERS. GOES EAST
OBSERVATIONS INDICATE THE CLOUD COVER IS VERY SPARSE ACROSS THE
KEYS WATERS. THE 12Z KKEY SOUNDING HELPS ILLUSTRATE WHY QUIET
WEATHER SET UP ACROSS THE AREA. A VERY DRY AIR MASS MOVED OVER THE
KEYS OVER THE PAST FEW DAYS, AND THE SAMPLED PWAT WAS NEAR THE
10TH PERCENTILE VALUE FOR THE DAY. NEAR THE SURFACE, BREEZES ARE
GENTLE TO MODERATE NORTH TO NORTHEASTERLIES. DEW POINTS ALONG THE
ISLAND CHAIN ARE STILL IN THE LOWER TO MID 70S. FOR THOSE IN THE
FLORIDA KEYS, EXPECT WEATHER TO STAY MUGGY THIS AFTERNOON.
THIS WEEKEND, THE MAIN CONCERN WILL BE COASTAL FLOODING AND
MARITIME SWELL. A STRONG NOR'EASTER IS GENERATING STRONG WAVES
ALONG THE EAST COAST WHICH IS ADDING TO THE ALREADY PRESENT KING
TIDES. WHILE THE SWELL WILL START TO EBB LATE TONIGHT, THE COASTAL
FLOODING WILL PERSIST THROUGHOUT THE WEEKEND. KEEP AN EYE ON AREAS
OF THE KEYS PRONE TO COASTAL FLOODING AND TAKE PRECAUTIONS WHERE
NECESSARY!
MARINE
ISSUED AT 1032 AM EDT SAT SEP 26 2026
SHALLOW ISOLATED SHOWERS WILL WAX AND WANE OVER THE WATERS OF THE
FLORIDA KEYS. MARINE OBSERVATIONS ARE MEASURING GENTLE TO
MODERATE NORTH TO NORTHEASTERLY BREEZES.
FROM SYNOPSIS: AN EARLY SEASON COLD FRONT WILL REMAIN DRAPED ACROSS THE DISTANT
STRAITS OF FLORIDA FOR MUCH OF THE WEEKEND, SUPPORTING LIGHT TO
GENTLE NORTHERLIES. A NOR'EASTER OFF THE EASTERN SEABOARD WILL
SUPPORT A NORTHEASTERLY SWELL WITH LARGE PERIODS IN THE EASTERN
MARINE ZONES THROUGH SUNDAY. THE FRONT WILL PUSH BACK NORTHWARD ON
MONDAY THROUGH THE MARINE ZONES. WINDS WILL THEN CLOCK BACK
AROUND TO THE SOUTHEAST TO SOUTH FOR EARLY NEXT WEEK, ALSO
ACCOMPANIED BY INCREASING RAIN AND THUNDER CHANCES.
AVIATION
(12Z TAFS)
ISSUED AT 1032 AM EDT SAT SEP 26 2026
VFR CONDITIONS WILL PREVAIL AT EYW AND MTH FOR THE UPCOMING TAF
PERIOD. WHILE OCCASIONAL CLOUD LAYERS WILL BE ABLE TO RESULT IN
SHORT LIVED MVFR CIGS, THE PULSES OF CLOUD COVER WILL BE SHORT
LIVED. EXPECT GENERAL NORTH TO NORTHEASTERLY SURFACE WINDS TO
PERSIST.
PREV DISCUSSION
ISSUED AT 502 AM EDT SAT SEP 26 2026
A SIGNIFICANTLY DRIER AIRMASS ALOFT CONTINUES TO EXPAND ACROSS
THE FLORIDA KEYS EARLY THIS AM. BASED ON WATER VAPOR IMAGERY, THE
COLD FRONT HAS PROGRESSED SLIGHTLY FARTHER SOUTH THAN EXPECTED,
EXTENDING SOUTH-SOUTHWEST FROM THE PARENT NOR'EASTER SPINNING OFF
THE MID- ATLANTIC/NEW ENGLAND COAST, THROUGH THE BAHAMAS AND
ACROSS TO EVEN SLIGHTLY SOUTH OF CUBA. GENTLE TO MODERATE
NORTHERLY BREEZES WILL CONTINUE ACROSS THE KEYS AND SURROUNDING
WATERS THIS MORNING, BUT WILL BECOME LIGHT TO GENTLE BY THIS
AFTERNOON. THE NOR'EASTER WILL REMAIN TRAPPED BETWEEN BROAD
ATLANTIC RIDGING AND PERSISTENT RIDGING OVER THE CENTRAL CONUS
BEFORE EVENTUALLY BREAKING DOWN AND EJECTING TOWARDS THE NORTHERN
ATLANTIC DURING THE MONDAY TO WEDNESDAY TIMEFRAME. IN THE
MEANTIME, DEEP WEST-NORTHWESTERLY FLOW WILL CONTINUE ACROSS THE
KEYS THIS WEEKEND AS EMBEDDED SHORTWAVES ROTATE AROUND THE COASTAL
LOW AND MAINTAIN SOME MEASURE OF CYCLONIC FLOW OVER THE EASTERN
GULF. WE'RE ALREADY SEEING THE EFFECTS OF THIS WITH ISOLATED
SHOWERS ONGOING NEAR THE LOWER KEYS AND IN THE STRAITS OF FLORIDA
DESPITE A DEEP LAYER OF DRY AIR MEASURED ON OUR 00Z RAOB ABOVE
900MB. MIMIC-TPW IMAGERY SHOWS EVEN DRIER AIR SURGING SOUTH IN THE
EASTERN GULF. ANY ISOLATED DEVELOPMENT WILL REMAIN RATHER BENIGN
TODAY AND TOMORROW, AND MOST OF THE DAY WILL FEATURE MOSTLY SUNNY
SKIES WITH HIGHS IN THE MID TO UPPER 80S. SOME LOCATIONS ALONG THE
ISLAND CHAIN WILL SEE DEWPOINTS IN THE UPPER 60S TO NEAR 70
DEGREES ON SUNDAY WHICH WILL DROP HUMIDITY VALUES DOWN INTO THE
50-60% RANGE.
OUR PRIMARY CONCERN OVER THE NEXT COUPLE OF DAYS AND POTENTIALLY
INTO NEXT WEEK WILL BE SALTWATER FLOODING OF LOW-LYING AREAS ALONG
THE KEYS CAUSED BY A PEAK IN ASTRONOMICAL TIDES COMPOUNDED BY A
BACKED UP GULF STREAM DUE TO THE STRONG NOR'EASTER AND ASSOCIATED
GALE FORCE WINDS ALONG THE EAST COAST. A COASTAL FLOOD ADVISORY
HAS BEEN ISSUED FOR THE UPPER KEYS WHILE A COASTAL FLOOD STATEMENT
REMAINS IN EFFECT FOR THE LOWER TO MIDDLE KEYS THROUGH AT LEAST
THIS AFTERNOON, BUT EXTENSIONS ARE LIKELY. EVENTUAL UPGRADES MAY
BE NEEDED FOR THE LOWER/MIDDLE KEYS EARLY NEXT WEEK.
SPEAKING OF NEXT WEEK, IT CERTAINLY LOOKS AS THOUGH OUR BELOW-NORMAL
RAIN CHANCES WILL BE SHORT-LIVED. ON MONDAY, THE LOWER-LEVELS OF THE
ATMOSPHERE WILL BECOME INFLUENCED BY ATLANTIC RIDGING WHICH WILL
EXTEND ACROSS THE KEYS AND PROMOTE A SWITCH BACK TO LOW-LEVEL
SOUTHERLY FLOW. MEANWHILE TO OUR NORTH, THE CONTINENTAL RIDGE IS
PROGGED TO RETROGRADE WESTWARD JUST ENOUGH TO ALLOW THE UPPER-LEVEL
TROUGH ALONG THE COAST TO DEEPEN ACROSS THE SOUTHEAST AND INTO THE
GULF. BY MONDAY NIGHT, WE'LL SEE A QUICK RESURGENCE IN MOISTURE
CONTENT WITH INCREASING RAIN AND THUNDER CHANCES. THE MID TO UPPER-
LEVEL TROUGH WILL CONTINUE TO PROVIDE FORCING ACROSS THE AREA
THROUGH AT LEAST WEDNESDAY, EVEN AS THE NOR'EASTER BEGINS TO LIFT
AWAY, LEAVING BEHIND RESIDUAL UPPER-LEVEL TROUGHING ACROSS THE
FLORIDA PENINSULA TO AS FAR SOUTH AS THE YUCATAN. GLOBAL MODELS
INDICATE THAT PIECE OF LEFT BEHIND UPPER-LEVEL ENERGY MAY BEGIN TO
DEEPEN NEAR THE YUCATAN BY THE MIDDLE TO END OF THE WEEK,
POTENTIALLY SUSTAINING AN ACTIVE PERIOD ACROSS THE FLORIDA KEYS
THROUGH THE END OF THE FORECAST PERIOD. UNFORTUNATELY, A WET
FORECAST ON TOP OF KING TIDES MAY EXACERBATE THE FLOODING ISSUES,
BUT THE DETAILS WILL BE IRONED OUT AS WE GET CLOSER.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 87 78 87 78 / 10 10 10 10
MARATHON 86 77 85 78 / 10 10 10 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...COASTAL FLOOD ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR FLZ076.
GM...NONE.
PUBLIC/MARINE/FIRE...AJP
AVIATION/NOWCASTS....AJP
DATA ACQUISITION.....AJP
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