textproduct: Key West

KEY MESSAGES

- Small Craft Advisory conditions expected for all Keys waters by Friday evening, persisting through at least early next week. Near- gale breezes will be possible at times Sunday evening through Monday evening.

- Gusty winds in frequent fast-moving showers will push through the Keys Friday night through Monday. Isolated thunderstorms are also possible and will have the potential for local wind gusts 45 to 50 mph.

- Moderate coastal flooding in the Upper Keys will expand to the Lower and Middle Keys Sunday evening through early next week, with major coastal flooding possible in the Upper Keys.

DISCUSSION

Issued at 935 AM EDT Thu Oct 22 2026 The 12z sounding at KEY sampled modestly falling geopotential heights throughout the depth of the troposphere along with slight moistening from the surface up to around 800 mb. The observed freezing level also dropped over 1 kft since last evening, highlighting the increasing influence of an upper-level trough, with its positively tilted axis nearly over the Florida Keys. Despite this, the sounding also sampled meager low- level lapse rate, as well as a series of residual temperature inversions through 750 mb, suggesting low- level ridging remains in place across the Keys. This low-level ridging will disintegrate over the next twenty-four hours, as a perturbation emerges over the eastern Caribbean and slides northward.

For today, chances of measurable will remain near-nil. The exception to this may be the Upper Keys, as showers near the South Florida Mainland may try to brush these islands, mainly this afternoon and evening. Besides these isolated showers there, mostly sunny skies, continued low humidities, and comfortable temperatures topping out in the lower 80s remains on track. No changes proposed to the inherited short-term forecast.

MARINE

Issued at 935 AM EDT Thu Oct 22 2026 As breezes freshen overnight, Small Craft Exercise Caution headlines may be required for portions of the Keys marine zones. Small Craft Advisories will likely be required for all Keys coastal waters by Friday evening. Tides will remain elevated for the next several days, peaking Sunday night through Tuesday. Boaters can expect less clearance under fixed bridges.

From synopsis, high pressure centered near the Great Lakes region will continue to slide eastward and strengthen over the next several days. The high will interact with a developing disturbance in the eastern Caribbean, supporting freshening northeasterly breezes over the next several days. Breezes will peak Sunday night through Monday night, when strong to near gale breezes will be possible. The freshening breezes and a surge of moisture will also support elevated rain and isolated strong thunderstorm chances Friday night through Monday.

AVIATION

(12Z TAFS) Issued at 935 AM EDT Thu Oct 22 2026 VFR conditions will prevail at both island terminals through 12z Friday morning, along with near-nil rain chances. Near-surface winds out of the northeast will lull this afternoon, before peaking again late in the TAF period, when 18 to 20 knot gusts will be possible.

PRELIMINARY POINT TEMPS/POPS

Key West 83 75 82 74 / 0 20 20 50 Marathon 83 74 82 74 / 10 20 40 50

KEY WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 5 AM EDT Friday for FLZ076.

GM...None.