Area Forecast Discussion
Issued by NWS Key West, FL
Issued by NWS Key West, FL
642 FXUS62 KKEY 060859 AFDKEY Area Forecast Discussion National Weather Service Key West FL 359 AM EST Sat Dec 6 2025 ...New DISCUSSION, MARINE, AVIATION... .KEY MESSAGES... -Mainly light to gentle southeast breezes expected through the weekend. -Weak cloudline could develop later this morning and afternoon. -Moisture increases Saturday night through Monday ahead of a possible frontal system early next week. -Humidity will also continue to rise with dew points reaching potentially the upper 70s for Sunday. && .DISCUSSION... Issued at 359 AM EST Sat Dec 6 2025 It has been a quiet but interesting overnight for the Florida Keys. The Keys lie on the western edge of a retreating high that`s out across the southwestern North Atlantic. This is leading to a col-region with light and variable winds across all waters. This col can also be seen on radar as very isolated showers are developing in a fan-like appearance across the Straits of Florida. Otherwise, skies are mostly clear with current temperatures hovering around the mid 70s with dew points in the lower 70s. Moisture in the low levels will be increasing as low level ridging slides east. This will place us in a southwest wind between 935 and 700 mb. In a typical summertime pattern with light winds at the surface and a moisture rich southwest flow just above the surface would spell cloud lines. However, last night`s sounding showed a sharp and pronounced inversion present at 850 mb. The question for today is can we mix out that inversion enough to see clouds build and produce an isolated shower. The hi-res CAMs seem to suggest the cloud line theory for this afternoon with slight chances for rain. Given that this is December, will opt for lower rain chances than current guidance. Nonetheless, moisture will gradually pool across south Florida and the Florida Keys as we remain in southwesterly flow in the low levels. This will lead to a gradual rise in rain chances for the weekend, peaking Sunday night into Monday. This is when we`re expecting the next front to slowly push through by Monday afternoon. Thereafter, models slightly diverge on how far south the front will actually push. The ECMWF has the front sliding into the Straits and south of the island chain, while the GFS has it parked over the island chain. Ultimately this will have implications on rain chances for next week. That being said, there does not appear to be a whole lot of support either in the lower or upper levels. While moisture will be plentiful, there won`t be much to act upon it other than a weak orphaned frontal boundary. Time will tell. && .MARINE... Issued at 359 AM EST Sat Dec 6 2025 Light to gentle east to southeast breezes expected today as the Keys lie in a weakened pressure gradient. Breezes will briefly freshen later this morning and then relax back by the afternoon and evening. Any noticeable freshening of breezes will not be until late Sunday as a cold front approaches from the north. Winds will steadily box around the compass, becoming southwest to west Sunday night, then west to northwest Monday. In the wake of the frontal passage, we can expect a brief surge in winds with moderate to fresh northerlies overnight Monday into Tuesday. Thereafter, breezes will slacken to gentle to moderate, generally from the north to northeast. We`re keeping an eye on another potential frontal passage by next weekend. && .AVIATION... (06Z TAFS) Issued at 359 AM EST Sat Dec 6 2025 Prevailing VFR conditions are expected for MTH and EYW for the 06Z TAF period. Light, occasionally variable, southeasterly winds will prevail. Stray to isolated showers may be possible near the terminals in the afternoon as low level winds become southwesterly. && .CLIMATE... On this day In 2016, the daily record high temperature of 88F was recorded at the Florida Keys Marathon International Airport. This measurement tied the record for the warmest temperature recorded in December. Temperature data for Marathon dates back to 1950. && .PRELIMINARY POINT TEMPS/POPS... Key West 83 74 83 73 / 10 20 30 40 Marathon 82 74 82 74 / 10 20 20 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...LIW Aviation/Nowcasts....AJP Data Acquisition.....AJP Visit us on the web at weather.gov/key Follow us on Facebook and Twitter at: www.facebook.com/nwskeywest www.twitter.com/nwskeywest