textproduct: Key West

KEY MESSAGES

-A series of high pressure systems docking in the central North Atlantic will support light to gentle northeast to east breezes through the weekend and mainly dry conditions. -Seasonal King Tides may support bouts of minor coastal flooding around the times of high tide for the end of the week into the weekend.

-Confidence continues to increase that a significant cold front will blast through the Florida Keys on Monday, ushering much cooler and windy conditions for early next week.

DISCUSSION

Issued at 400 AM EST Thu Nov 6 2025 Surface analysis depicts a seasonal battle of air masses in the vicinity of the Florida Keys. A stationary front stretches from the central Caribbean Sea northeastward to the west-central North Atlantic. Meanwhile, a modified continental high pressure is docked in the vicinity of Bermuda, supporting light to gentle northeast to east breezes across the Florida Keys. The 00z evening sounding at KEY sampled a nearly saturated layer based at around 850 mb, capped by a strong temperature inversion just above. The sounding also highlighted a relatively thick cirrostratus deck, consistent with overrunning moisture on the eastern flank of an upper-level low centered in the western Gulf. KBYX radar is detecting some meteorological echo returns dotting the Florida Keys and the adjacent nearshore and offshore waters, although most activity is likely not making it to the ground. Temperatures are generally in the mid 70s at this early Thursday morning hour.

The forecast through the weekend is generally routine. A secondary high will replace the aforementioned high in the central North Atlantic, supporting a continuation of the light to gentle northeast to east breezes and generally low measurable rain chances. We will need to monitor the progression of the upper- level low in the Gulf. Most ensemble mean numerical weather prediction guidance supports the low opening up into a shortwave trough, then propagating eastwards towards the Keys for Friday and Friday night. While this will support synoptic large-scale ascent, forecast soundings suggest the surface to 850 mb layer will remain quite dry for this forecast period. Given these competing factors, did elect to nudge PoPs upward to low-end chance levels for these periods (30%), although we will monitor model- to-model and run-to- run trends.

The major weather story will be a powerful cold front progged to sweep through the East Coast, including the Florida Keys, on Monday. Sea surface temperatures remain in the upper 70s adjacent to the Keys, which will support efficient turbulent mixing of higher winds aloft. Windy conditions, coupled with cool temperatures and low dew points will provide locals with a taste of Florida winter for early next week. Temperatures will slowly moderate and breezes slacken thereafter, as the associated high building behind the front pushes into the western North Atlantic.

MARINE

Issued at 400 AM EST Thu Nov 6 2025 No watches, warnings, or advisories are currently in effect for the coastal waters of the Florida Keys. A series of high pressure systems sliding through the North Atlantic will support light to gentle northeast to east breezes through the end of the work week. As the systems slide further eastward in the central North Atlantic and the associated ridge weakens, breezes will slacken further. A potent cold front will push through the Florida Keys marine zones on Monday, with fresh to strong northerlies expected in its wake for early next week. A Small Craft Advisory will likely be required for all of the Florida Keys marine zones as early as Monday morning.

AVIATION

(06Z TAFS) Issued at 400 AM EST Thu Nov 6 2025 Despite bouts of BKN ceilings based at around 050, VFR conditions will prevail at both EYW and MTH island terminals through the TAF period, along with slight rain chances around 10%. Mainly northeast breezes will remained sustained at 5 to 10 knots.

CLIMATE

On this day in 2019, the daily record high temperature of 88F was last recorded in Key West. Temperature records for Key West date back to 1872.

PRELIMINARY POINT TEMPS/POPS

Key West 84 75 84 75 / 10 20 30 30 Marathon 82 75 83 75 / 10 20 30 30

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...None.