Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
538 FXUS62 KKEY 120758 AFDKEY Area Forecast Discussion National Weather Service Key West FL 358 AM EDT Wed Aug 12 2026 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... - A Coastal Flood Statement remains in effect for the Lower Keys, with minor saltwater flooding possible around the time of high tide late morning to early afternoon. - Rain and thunder chances through Thursday will generally be limited to any island cloud line formation or storms pushing off the South Florida Mainland in the afternoon and evening hours. - Previously expected elevated rain chances for Friday night through Saturday night now appear a bit less likely, with Saharan dust inhibiting more widespread shower activity. && .DISCUSSION... Issued at 400 AM EDT Tue Aug 11 2026 The 00z evening sounding at KEY sampled a relatively moist boundary layer up to around 825 mb, capped by a weak 2C inversion, along with substantial dry air aloft. Satellite-derived dust products indicate the Florida Keys remain on the southern periphery of a plume of Saharan dust extending from the southern Gulf eastward all the way to western Africa. Synoptic low-level wind and pressure analysis places a weak area of high pressure centered in the central North Atlantic, with a series of climatologically-favored easterly waves traversing the Atlantic to the south. With the lack of shower activity across the entire CWA, land-based surface observations indicate temperatures generally in the mid 80s across the Island Chain at this early evening hour. For today through Thursday, the aforementioned high pressure system will weaken, supporting a slackening overall low- level surface wind pattern. This wind pattern, coupled with northeasterly steering flow, will support possible cloud line development in the afternoon hours. In addition, outflow from any developing shower and thunderstorm activity over the South Florida Mainland may propagate southwestward, supporting isolated showers and thunderstorms in the evening hours. Coinciding these scenarios being depicted, there will continue to be substantial dry air above the boundary layer. In what would normally be a dry short- term forecast, will advertise low- end slight rain and thunder chances to account for these scenarios. Beyond Thursday, global numerical weather prediction models suggest the surface high will somewhat strengthen and rebuild westward in the North Atlantic. With the axis of the associated ridge positioned just north of South Florida, this will support general freshening east to southeast breezes. Forecast vorticity fields indicate a weak tropical wave currently in the vicinity of Hispaniola will push through the Straits of Florida just to the south of the Keys Friday afternoon through Saturday. Combined with the somewhat speed convergent flow for this period, this would seem to suggest a bit elevated rain and thunder chances for that period. However, forecast soundings suggest a continued poor thermodynamic profile owed to the continued overlay of Saharan dust. We will monitor moisture profile trends, as any modest undulation in deeper tropospheric moisture will win out over the dust, especially with low-level cyclonic support for ascent. As the wave departs, high pressure is expected to dominate the forecast beyond through at least the middle of next week. NASA dust aerosol forecast products suggest an even drier, dusty tropospheric profile will be possible, suggesting possible rare near-nil rain chances for late in the weekend through early next week. In terms of the tropics, although the National Hurricane Center is monitoring three possible areas in the North Atlantic for tropical cyclone development in the next seven days, all three systems will remain weak, with no expected impacts to the Keys. && .MARINE... Issued at 400 AM EDT Tue Aug 11 2026 A Coastal Flood Statement remains in effect for the Lower Keys, with minor saltwater flooding possible around the time of high tide late this morning through early afternoon. Boaters can expect less clearance under fixed bridges, especially around the time of the high tide. From synopsis, a high pressure system centered in the central North Atlantic will shift eastward and weaken through Thursday. Gentle east to southeast breezes will slacken, becoming light and variable at times in the afternoon hours. As the high restrengthens and builds westward, breezes will somewhat freshen for late in the work week through the weekend. && .AVIATION... (06Z TAFS) Issued at 400 AM EDT Tue Aug 11 2026 VFR conditions will prevail at both EYW and MTH through 13/06z. Light to gentle E to SE breezes may become light out of the northeast to east or variable for the early afternoon hours. This will tend to support possible cloud line development, mainly in the vicinity of EYW. Northeasterly steering flow will also support any afternoon storms over the South Florida Mainland to push southwestward towards the terminals after 00z. Due to low- level dry air, will keep explicit inclusion out of the TAFs for now. && .PRELIMINARY POINT TEMPS/POPS... Key West 92 82 92 82 / 10 0 10 10 Marathon 91 83 90 82 / 10 0 10 10 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...BT Aviation/Nowcasts....BT Data Acquisition.....RG/DM Visit us on the web at weather.gov/key Follow us on Facebook and X at: www.facebook.com/nwskeywest www.x.com/nwskeywest