509
FXUS62 KKEY 260528
AFDKEY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
128 AM EDT SAT SEP 26 2026
..NEW 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 FLORIDA KEYS.
COASTAL FLOOD ADVISORIES MAY BE REQUIRED AS EARLY AS SUNDAY
NIGHT, AND WILL LIKELY BE REQUIRED FOR MUCH OF THE KEYS BY
MONDAY NIGHT.
- INCREASING NORTHEASTERLY SWELL FROM A NOR'EASTER OFF THE EAST
COAST WILL ALLOW SEAS TO BUILD TO 4 TO 5 FEET THROUGH THE
WEEKEND IN THE EASTERN STRAITS OF FLORIDA OFF THE UPPER KEYS.
DISCUSSION
ISSUED AT 1029 PM EDT FRI SEP 25 2026
A COMPLEX PATTERN IS CURRENTLY PLACE ACROSS THE LOWER 48. FIRST, A
DEEP AND HIGHLY AMPLIFIED UPPER LEVEL TROUGH IS IN PLACE JUST OFF
THE EASTERN SEABOARD WHICH IS CURRENTLY RESPONSIBLE FOR THE
ONGOING NOR'EASTER AT THE SURFACE JUST OFF THE MID-ATLANTIC
STATES. ON EITHER SIDE OF THIS TROUGH ARE TWO RIDGES WITH ONE OVER
THE CENTRAL NORTH ATLANTIC AND ANOTHER COMPLEX RIDGE ACROSS THE
SOUTHERN AND CENTRAL PLAINS. THE RIDGE ACROSS THE PLAINS ACTUALLY
HAS TWO DISTINCT CENTERS AS SEEN ON CIMSS PRODUCTS WITH ONE OVER
SE TEXAS AND THE OTHER OVER WISCONSIN. THE RIDGE OVER THE
ATLANTIC AND THE RIDGES ACROSS THE MIDDLE OF THE COUNTRY ARE
BASICALLY SQUEEZE PLAYING AND LOCKING THE TROUGH IN PLACE OFF THE
EASTERN SEABOARD FOR NOW WITH NO WHERE FOR THE ONGOING NOR'EASTER
TO GO. HOW DOES THIS AFFECT OUR WEATHER? AT THE SURFACE, A COLD
FRONT PRESSED THROUGH EARLIER THIS MORNING IN ASSOCIATION WITH
THE LOW PRESSURE OFF THE MID-ATLANTIC STATES. MARINE PLATFORMS
SURROUNDING THE ISLAND CHAIN ARE RECORDING NORTHWEST TO NORTH
BREEZES OF 5 TO 10 KNOTS SOUTH OF THE ISLAND CHAIN AND 10 TO 15
KNOTS NORTH OF THE CHAIN. KBYX RADAR IS DETECTING SOME SCATTERED
SHOWERS ACROSS THE NEARSHORE AND OFFSHORE WATERS ADJACENT TO THE
UPPER KEYS, INCLUDING THE UPPER KEYS. MRMS DATA SHOWS ESTIMATED
RAINFALL AMOUNTS FROM THESE SHOWERS RANGING ANYWHERE FROM A TRACE
TO IN EXCESS OF A HALF INCH OF RAINFALL. TEMPERATURES ALONG THE
ISLAND CHAIN ARE IN THE LOWER 80S AND DEW POINTS ARE IN THE MID
70S.
SHORT TERM FORECAST
THE 00Z EVENING SOUNDING SHOWS A FAIRLY DRY PROFILE. THE
EXCEPTION BEING JUST ABOVE THE SURFACE BETWEEN 950-925 MB WHERE A
SHALLOW MOIST LAYER REMAINS. THE PWAT VALUE MEASURED WAS 1.32
INCHES WHICH IS JUST BELOW THE 10TH PERCENTILE FOR THE DATE. THE
WIND PROFILE SHOWS NORTHWEST WINDS AROUND 1000 FT, NORTH-NORTHEAST
AROUND 2000 FT AND THEN NORTHWEST TO NORTH AROUND 3000 FT WHICH
WOULD SUGGEST MORE OF A NEUTRAL ADVECTION INSTEAD OF ANY COLD AIR
OR WARM AIR ADVECTION. IF THE WINDS WERE BACKING THROUGH THE WHOLE
PROFILE, THEN THIS WOULD BE MORE INDICATIVE OF COLD AIR
ADVECTION, ALBEIT, EXTREMELY WEAK. BASED ON THIS, NO CHANGES ARE
EXPECTED TO THE ONGOING FORECAST AND SINCE WE STILL HAVE SOME
MOISTURE IN THE LOWEST LEVELS, A FEW RESIDUAL SHOWERS OVERNIGHT
CANNOT BE COMPLETELY RULED OUT.
MARINE
ISSUED AT 1029 PM EDT FRI SEP 25 2026
THERE ARE CURRENTLY NO WATCHES, WARNINGS, OR ADVISORIES IN EFFECT
ACROSS THE FLORIDA KEYS COASTAL WATERS. 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
(06Z TAFS)
ISSUED AT 122 AM EDT SAT SEP 26 2026
VCSH WILL CONTINUE NEAR KEYW FOR ANOTHER FEW HOURS WITH OCCASIONAL
BOUTS OF MVFR CEILINGS POSSIBLE AT BOTH TERMINALS. IN ALL, VFR
CONDITIONS WILL PREVAIL FOR MUCH OF THIS TAF CYCLE DUE TO A LARGE
AMOUNT OF DRY AIR PRESENT ACROSS THE AREA IN THE WAKE OF A FRONT.
A SECONDARY TROUGH AXIS ROTATING SOUTH ACROSS THE EASTERN GULF
WILL OCCASIONALLY PRODUCE SPOTTY SHOWERS, BUT COVERAGE WILL BE
LIMITED. EXPECT PERSISTENT NORTHERLY SFC WINDS AROUND 5 TO 10
KNOTS.
PRELIMINARY POINT TEMPS/POPS
KEY WEST 88 77 87 77 / 10 10 10 10
MARATHON 86 77 86 77 / 10 20 10 10
KEY WATCHES/WARNINGS/ADVISORIES
FL...COASTAL FLOOD ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR FLZ076.
GM...NONE.
PUBLIC/MARINE/FIRE...MJV
AVIATION/NOWCASTS....DM
DATA ACQUISITION.....AP
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