textproduct: Key West

KEY MESSAGES

- Moderate to major saltwater flooding of low elevation streets and lots is likely to continue over the next few day or so due to King Tide. Don't drive through flooded roadways. Boaters can expect less clearance under fixed bridges.

- A Coastal Flood Warning is in effect for the Upper Keys, particularly along the sounds, bay side of Key Largo. A Coastal Flood Advisory is in effect for the Middle and Lower Keys.

- A wet pattern is expected for the next several days across the Keys. This will maintain above normal rain and thunder chances through at least Thursday.

DISCUSSION

Issued at 928 PM EDT Tue Sep 29 2026

A very wet pattern remains entrenched across our area this evening. A few features are contributing to this soggy weather. A very amplified upper level trough stretching down the Atlantic Coast states and through the Gulf into the Yucatan, has placed Florida and the eastern Gulf under a broad area of upper level diffluence. While the best lift, as seen in satellite imagery, appears to be to our west and northwest, there was more than enough support across our area. In addition, a spoke of a lower level Atlantic ridge stretches westward across the Florida Straits. This is resulting in a veered steering flow that continues to pump deep tropical moisture northward across the Keys. This evenings sounding indicated considerable moisture at 2.24 inches of precipitable water, ample CAPE, and weak low level inhibition. As a result of all the above, multiple bands of showers and thunderstorms, some of which were strong, were able to crisscross the Keys and its waters through the evening. The organized veering flow was able to generate a few short lived mesocyclones. Currently, a broad swath of showers and a few thunderstorms remains aligned across the Lower Keys and the adjacent near through offshore waters. Convective influences has already periodically driven temperatures down into the mid 70s at most island locations, while dew points have slipped to near 70.

The upper level trough will shift southeastward into the eastern Gulf overnight, while the southern periphery begins balling up over the Yucatan. This will keep the Keys on its diffluent eastern periphery. In addition, a southeasterly steering flow around the Atlantic ridge will continue to stream deep tropical moisture across our area. Furthermore, the surface ridge axis will consolidate across the southeastern United States and will likely result in light to gentle east to southeasterly breezes picking up to gentle to moderate. As a result of the above, the wet pattern is not expected to go anywhere through short term. However, due to the considerable coverage of convection that has repeatedly flourished across our area through the afternoon and evening, it is proable that a quieter stretch will eventually set in once the most recent round of activity finally exhausts itself. At this time, there is no reason to adjust the currently advertised likely PoPs. Expect overnight lows to be largely be determined by rain cooling and will generally range broadly in the 70s. Dew points may slowly climb towards the mid 70s as the boundary layer begins to recover.

MARINE

Issued at 928 PM EDT Tue Sep 29 2026

A broad surface ridge spanning the eastern United States and the adjacent Atlantic will maintain gentle to moderate east to southeasterly breezes across Keys waters overnight. With that said, winds in the immediate future will be dominated by outflow boundaries, both new and old, due to the copious convective activity that worked its way across our waters from just about all directions. A very wet pattern will remain, however a break will probably set in over the next few hours due to the atmosphere having been worked over multiple times.

AVIATION

(00Z TAFS) Issued at 928 PM EDT Tue Sep 29 2026

A wet pattern will remain in place across the Keys through the overnight period. With that said, the environment is becoming worked over after an active first half. As a result, there is a good chance that a sizable break is in store for much of the overnight period. Aside from convective influences, surface winds will be light to gentle out of the east to southeast.

KEY WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Warning until 7 AM EDT Wednesday for FLZ076. Coastal Flood Advisory until 7 AM EDT Wednesday for FLZ077-078. GM...None.