Marine Weather and Tide Forecast for Key West, FL

DISCUSSION
Issued at 400 PM EDT Thu Oct 15 2026

Deep layered ridging stretches from the southeastern United States into the Adjacent Atlantic. This is maintaining gentle to moderate easterly breezes across the Keys and surrounding waters. Despite the ridging deep layered moisture remains rather high at above 2 inches of precipitable water. Instability was good and inhibition nearly non existent. Altogether, this has been supportive of isolated showers and a very rare thunderstorm across the area. A few island locations were briefly affected by a light to moderate shower. Warm and fairly humid conditions remain with highs close to 90 and dew points in the mid to upper 70s.

The upcoming forecast will be dominated by the evolution of the next mid latitude trough currently amplifying across the heart of North America. Over the next couple of days the trough will amplify as it swings into eastern North America and link up with an upper level low over the Gulf of America. This will shove the deep layered ridge eastward into the Atlantic. Consequently, surface winds will trend downwards, becoming light through this period, possibly becoming variable Friday night. The already high deep layered moisture will remain elevated and may climb slightly. This along with continued instability and lack of inhibition will keep at least mid chance for precipitation despite the decelerating flow. Temperatures will remain near to slightly above normal with dew points holding in the mid to upper 70s.

The mid latitude trough will swing out into the Atlantic late this week, followed by deep layered ridging pushing eastward into the eastern United States. This will thrust a strong cold front southward across the Gulf of America, Florida, and the Atlantic Coast. Breezes are expected to freshen considerably beginning late Saturday, however guidance has been hinting at the front slowing to a crawl, possibly stalling within our forecast area. The combination of the frontal baroclinic zone, copious associated deep layered moisture, and fresh breezes will have a very high likelihood of considerable shower coverage with a chance for thunderstorms with the best chances occurring from late Saturday into early next week.

Unfortunately, improving weather and any post frontal cooling, drying and relaxing breezes will be completely dependent on when the front is finally flushed out of our area. The latest guidance drives the front southward into the northwestern Caribbean Sea in the Tuesday time frame. However, consistency has been poor. Stay tuned.

MARINE
Issued at 400 PM EDT Thu Oct 15 2026

Over the next couple of days a mid latitude trough will push eastward through the eastern United States and displace a surface ridge eastward off of the southeast into the Atlantic. As a result, gentle to moderate breezes tonight will steadily give way to light breezes, possibly becoming variable tomorrow night.
Uncertainty ramps up considerably for this weekend and into next week as all guidance points to a strong cold front advancing southward across the Gulf and Florida late Friday and stalling across the Keys this weekend. This will bring with it freshening northeasterly breezes and considerable moisture and rain chances.
The extent, coverage, and duration of this wind surge and enhanced rain chances will be highly dependent on where this front decides to stall and it is way to early to know. Expect at least a few periods of Small Craft Advisories over some or all of our waters and categorical rain chances with a chance for thunderstorms. Stay tuned.

AVIATION
(15Z TAFS)
Issued at 400 PM EDT Thu Oct 15 2026

VFR conditions will prevail at the island terminals overnight.
Surface winds will be gentle out of the east.

PRELIMINARY POINT TEMPS/POPS
Key West 88 82 88 79 / 20 40 50 50 Marathon 89 82 89 79 / 20 40 40 50

KEY WATCHES/WARNINGS/ADVISORIES
FL...None.
GM...None.