Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
716 FXUS62 KKEY 121809 AFDKEY Area Forecast Discussion National Weather Service Key West FL 209 PM EDT Sat Sep 12 2026 ...New AVIATION... .KEY MESSAGES... - Moisture will linger across the region through the weekend, supporting slightly above normal rain and thunderstorm chances. - The primary threat for any stronger thunderstorms will be lightning strikes. When thunder roars, go indoors. If on a boat, stay low, or go below. - Heat index values will range from 100-108 degrees daily with little relief from the muggy conditions overnight. Know the signs of heat stress, take frequent breaks, and stay hydrated. && .AVIATION... (18Z TAFS) Issued at 158 PM EDT Sat Sep 12 2026 VFR conditions will prevail at both island terminals through the TAF period, but there will be a window of opportunity for nearby showers and thunderstorms around 22Z. Individual showers and thunderstorms may be strong at times, but confidence is low regarding when and where they will occur. Opting to keep a general VCSH and VCTS for both sites. Generally south winds near 5 knots will keep crosswind concerns very low, and wind direction will back to the east to southeast later this evening. && .PREV DISCUSSION... Issued at 400 AM EDT Sat Sep 12 2026 Over the next few days, the surface through lower level ridge will retreat into the Atlantic as a mid latitude trough takes shape and pushes off the Atlantic Coast. The remaining ridge to our north will weaken and mainland day time heating will effectively batter the surface ridge. As a result, east to southeasterly breezes should trend downwards with bouts of variability. A moisture rich swath across the Central Bahamas and eastern Cuba is expected to spread westward across our area through the weekend and should help to keep rain chances above normal through at least today. The weakening steering flow with no support aloft may counter this some. For now will maintain the already advertised 50% PoPs for today, which is below global models and above the NBM. No trend in temperatures or moisture is expected. Highs will remain near 90, lows in the lower 80s and dew points in the upper 70s. Through the first half of the weak, sharp deep layered ridging will build over the eastern United States as the mid latitude trough moves out to sea. This will setup robust surface ridging stretching along the Atlantic through Gulf coast states while an unusually amplified surface through lower level trough off the Atlantic Coast. A band of stronger northeasterly breezes will develop off the Southeast Atlantic Coast, Florida, and the Gulf. While there is uncertainty with how this unfolds, there is the added uncertainty as to how far south this band will reach. For now guidance shows breezes firming up slightly out of the northeast to the east for the Keys. Surface dew points may actually slip into the mid 70s for a change. Rain chances may be near to slightly However, for now, rain chances are expected to be near normal early in the week due to some drying and stabilization coming with the northern fringes of a Saharan layer. However, chances should return to slightly above normal heading into mid week as as band of lower level moisture pushes southwestward into our area. && .MARINE... Issued at 1011 AM EDT Sat Sep 12 2026 Ridging across the southeastern United States and Florida will maintain light to gentle east to southeasterly breezes over the next few days, becoming variable at times. Low level moisture will remain abundant and keep convective potential slightly above normal today, but fall back to near normal early in the week as drier lower levels filter in. The ridge will be reinforced late in the forecast and may drive freshening northeast to easterly breezes. && .PRELIMINARY POINT TEMPS/POPS... Key West 82 92 81 92 / 30 40 30 40 Marathon 82 90 82 90 / 30 40 30 30 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...DP Aviation/Nowcasts....DP Data Acquisition.....DP/PV Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest