Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
070 FXUS62 KKEY 110828 AFDKEY Area Forecast Discussion National Weather Service Key West FL 428 AM EDT Sat Oct 11 2025 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... -One more day of well above normal rain chances (80%) with numerous showers and scattered thunderstorms expected. -A Coastal Flood Advisory remains in effect for all Florida Keys. The combination of the current King Tide cycle and persistent bouts of rainfall will support additional flooding over roadways and low lying lots. Coastal flooding will likely continue through the holiday weekend. -A weak cold front is anticipated to press through the Keys later today ushering in drier air as it does. This will promote rapidly decreasing rain chances well as bring first taste of Fall to the Keys into next week. && .DISCUSSION... Issued at 428 AM EDT Sat Oct 11 2025 SPC Mesoanalysis shows an elongated area of non-tropical low pressure stretching from just east of Florida southwestward through the Keys. This has been keeping the Keys quite unsettled, especially yesterday. However, the overnight has not been nearly as busy. KBYX radar detected some showers across the northern Deep Gulf waters earlier in the night which have since dissipated. The main area of interest has been across the eastern Straits where an area of showers and thunderstorms has been ongoing for much of the night. In addition, a few isolated showers developed south of the Lower Keys which were moving steadily northward. Also, more showers have recently begun to develop across the offshore Gulf waters near the Dry Tortugas which were moving slowly northward. With the unsettled weather occurring, temperatures overnight have actually been quite comfortable. Most locations along the Island Chain are reporting temperatures in the mid to upper 70s with Big Pine Key the cool spot, reporting 72 degrees this last hour. Dew points are in the lower to mid 70s making it feel not quite as tropical out. Marine platforms surrounding the Island Chain are reporting variable breezes between 5 to 10 knots. .FORECAST... The aforementioned elongated area of low pressure will continue to slowly move north northeastward today. As it does, the low will continue organizing and strengthening. A cold front attached to this low pressure system will be sent southeastward along the Florida Peninsula and eventually through the Florida Keys by tonight. The 00z sounding last evening continued to show quite high PWAT values with 1.95 inches being measured. This is slightly above the 75th percentile for the date. Instability has actually come down quite a bit from yesterday with only around 700 J/kg being measured. Nonetheless, this is still enough to support thunderstorms. Therefore, a favorable upper level pattern and coinciding low pressure developing at the surface, ample moisture, and instability, we expect one more active day. PoPs have been raised to categorical (80%) for today to account for this, especially this morning. Drier air starts to move in this afternoon with a slight chance for showers and thunderstorms. The cool front is expected to pass through the Keys during the afternoon and evening hours which will shift winds from south southwest to west northwest. Winds will generally remain light to gentle. In addition, this will usher in a drier air mass leading to rapidly decreasing rain chances. Latest model guidance supports this when looking at the PWAT normalized anomaly. Drier air will infiltrate the Keys from the northwest later today and remain across the region through at least Monday night. Therefore, slight chance PoPs remain in the forecast through this time frame. Instability also looks quite meager resulting in no thunder included in the forecast. Latest guidance is indicating a somewhat complicated forecast regarding moisture for next week. The previous front that moved through over the weekend may try to creep back northward as a warm front and potentially become stationary across the Keys. However, the solutions remain at odds with each other. It appears likely that there will be a fairly tight gradient in place across the Keys with drier air to the north and moister air to the south. Latest indications are for the higher chances of rain and potential return of thunderstorms to the forecast to remain over the Straits. Any shift north will lead to a wetter forecast and return to higher humidity whereas any shift south will lead to a drier forecast and potentially lower humidity. Overall, the PoP forecast for next week is subject to change in subsequent updates. Stay tuned! && .MARINE... Issued at 428 AM EDT Sat Oct 11 2025 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, an elongated area of low pressure across the Keys will continue slowly drifting northeastward today. This will support one more day of well above normal rain chances along with south to southwesterly light to gentle breezes gradually backing to the northwest to north tonight and Sunday. This low will continue organizing and strengthening as it heads northeastward adjacent to the Mid- Atlantic coast. As it does this, it will drive an early season cold front towards the Keys, further shifting winds to the north to northeast. Northerly swells will be possible in our western marine zones today and tonight due to the influence of the low pressure system. In the wake of the front, high pressure builds across the eastern United States leading to freshening northeasterly breezes heading towards mid- week. && .AVIATION... (06Z TAFS) Issued at 428 AM EDT Sat Oct 11 2025 VFR conditions are expected to mostly prevail at the terminals through the TAF period. Periods of showers and an occasional thunderstorm are likely before 18z, with steadily decreasing chances expected after that. This is addressed via inclusion of VCSH until 18z. During any passing shower, before or after 18z, it is likely that CIGs and visibility may be temporarily reduced to MVFR or IFR levels. Later categorical changes will be addressed via amendment and routine TAF issuances as needed. South winds 5 to 10 knots will veer to the northwest by this afternoon. && .CLIMATE... On this day in 1909, the daily record rainfall of 8.94" was recorded as a category 3 Hurricane moved rapidly northeast from the western tip of Cuba along and just south of the entire length of the Keys. It caused nearly a million dollars in damage in Key West, drowned 12 railroad workers, and destroyed about 400 buildings. Sand Key recorded a minimum pressure of 28.37" with winds estimated at 100 mph before being swept out to sea. In Key West, the minimum pressure was 28.50". && .PRELIMINARY POINT TEMPS/POPS... Key West 83 77 86 77 / 60 20 20 10 Marathon 83 76 86 76 / 70 20 10 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...Coastal Flood Advisory until 6 AM EDT Sunday for FLZ076>078. GM...None. && $$ Public/Marine/Fire...MJV Aviation/Nowcasts....MC Data Acquisition.....MC Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest