Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
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 Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest