textproduct: Key West

KEY MESSAGES

- A reverse cloud line is possible today due to southwesterly flow. This flow will tend to favor waterspout development. Boaters are encouraged to keep an eye on the sky if venturing out.

- Small Craft Should Exercise Caution offshore of the Upper Keys due to a brief freshening of winds again this afternoon. Breezes will gradually slacken overnight.

- Heat indices may approach 105 to 110 degrees each afternoon for some Florida Keys island communities, especially in the Upper Keys.

FORECAST

The forecast for the next week or more is expected to remain fairly benign. High pressure will occasionally nudge into the region influencing the breezes across the area. Otherwise, a col region is expected to be the dominant feature, especially for late week into the weekend. A col region is usually an area of quiescent weather conditions in between the larger scale synoptic weather systems. Therefore, while southwest to west breezes are expected today, briefly becoming moderate to fresh this afternoon in the Upper Keys, a period of light and variable breezes is possible late week and into the weekend. Much drier air has infiltrated the Keys when compared to 24 hours ago. A reverse cloud line is possible today and again on Thursday as southwesterly flow remains across the Keys. It remains to be seen just how much moisture is present to determine how vigorous any cloud line becomes. If a mature cloud line can develop, waterspouts will be possible. However, there is the chance that it ends up being too dry today and tomorrow for the cloud line to really get going. We will see what happens. A slight chance of showers and thunderstorms is in place for today and Thursday as a result. Outside of any rain chances, the main story will be the heat. Daytime highs are expected to be near 90 degrees with some lower 90 degree readings with dew points in the mid to upper 70s. This will push the heat index values to 105 to 110 degrees at times, especially for some Upper Keys communities. Overnight lows also won't provide much relief in the lower to perhaps mid 80s.

MARINE

Issued at 431 AM EDT Wed Jul 29 2026 Small Craft Should Exercise Caution for briefly increasing winds once again across the nearshore waters adjacent to the Upper Keys as well as the eastern Straits of Florida. Otherwise, there are no watches, warnings, or advisories in effect across the Florida Keys coastal waters. From synopsis, troughing combined with the western periphery of an Atlantic surface ridge will maintain southwest to west breezes across the Keys today. Light to gentle breezes will freshen to moderate to fresh breezes this afternoon, especially across the adjacent nearshore and offshore waters to the Upper Keys. Also, a reverse cloud line is possible today which may result in waterspout formation. Breezes gradually slacken overnight through Thursday night as weak nebulous flow takes over. A col region sets up for late week into the weekend resulting in a potential period of variable breezes.

AVIATION

(06Z TAFS) Issued at 431 AM EDT Wed Jul 29 2026 VFR conditions are expected to persist at both EYW and MTH terminals through the TAF period. Near surface winds will remain mostly southwest to west through the period. Much drier air has moved over the Keys compared to 18-24 hours ago. However, just enough moisture may be present to influence a cloud line today. This will be a reverse cloud line since the flow is southwesterly. Due to this a slight chance of shower or a thunderstorm is possible. However, given the uncertainty in timing and placement and if this even develops, VCSH was not included in the TAF.

CLIMATE

On this day in 2009, the daily record warm low temperature of 86F was recorded in Key West. Temperature records for Key West date back to 1872.

On this day in 2023, the daily record warm low temperature of 84F was recorded in Marathon. Temperature records for Marathon date back to 1951.

PRELIMINARY POINT TEMPS/POPS

Key West 90 83 91 83 / 10 0 10 0 Marathon 90 83 91 83 / 10 0 10 0

KEY WATCHES/WARNINGS/ADVISORIES

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