textproduct: Key West

KEY MESSAGES

-A Small Craft Advisory remains up for the Keys Coastal waters due to fresh northerly breezes.

-Breezy conditions along the Island Chain will slacken Thursday, but the cool northerly component of our breezes will keep temperatures on the chilly side of normal.

-Probabilities are increasing for a damp and cold weekend across the Florida Keys. Portions of the Upper Keys may see wind chills in the 30s by Saturday night and Sunday morning.

MARINE

Issued at 217 PM EST Wed Jan 28 2026

Breezes have briefly slackened to moderate to fresh across the Florida Keys coastal waters this afternoon. Expecting breezes to wax and wane through the evening and overnight. A surge in winds will come down the west coast of Florida, followed by a brief lull, then another surge as a drainage wind comes off the mainland. As such, expecting Small Craft Advisories to remain in place through the overnight. Thereafter, breezes will slacken, most notably across the waters north of the island chain as a fast moving high pressure passes across the eastern half of the U.S. Winds across the Hawk and Straits of Florida will stay slightly elevated due to a mesoscale boundary that will sit along and just north of the Cuban coast. Otherwise, eyes turn to the next potential weather maker this weekend. Confidence continues to grow that this next cold front passage will be stronger and produce gale- force winds even for the Florida Keys! Once this system passes through, strong high pressure will build in keeping winds elevated through Monday.

AVIATION

(18Z TAFS) Issued at 217 PM EST Wed Jan 28 2026

Occasional MVFR conditions have been affecting the MTH terminal as a shield of light rain aloft is moving through. Once this passes through during the late afternoon and early evening, VFR conditions should return. Surface winds have backed to the northwest but will return from the north and northeast as a surge comes off the mainland overnight. Outside of a brief lull, gusty winds near 20 knots are expected through the forecast period.

PREV DISCUSSION

Issued at 520 AM EST Wed Jan 28 2026

Breezy north winds have persisted through the overnight shift, and frequent gusts near 20 mph coupled with temperatures in the mid to upper 50s have reminded us that, even though we live in Florida, it is still wintertime. The good news is that weather has remained dry along our island communities, and our KBYX radar is just detecting two areas of shower activity across the distant Florida Straits. The 00Z sounding from last night's balloon launch showed a substantial dry column of air, but there was also a thin layer of saturation near 850mb. Even though that sounding isn't necessarily the best representation of the current column, GOES-19 Nighttime Microphysics shows a blanket of cloud cover over much of the area, indicating that there is some moisture lingering aloft. The environment doesn't look particularly favorable for any noteworthy shower activity, but with some amount of moisture near the lower levels, carrying a slight chance (10%) of rainfall today seems reasonable.

Outside of the chillier temperatures, the next few days don't seem terrible. North to northeasterly breezes will gradually slacken as high pressure tracks eastward toward the North Atlantic, and high temperatures will try to approach the 70F during peak heating in the afternoon. Any cloud cover that can linger into the nighttime will act as insulation, and overnight lows should trend warmer with each passing night.

The weekend is where this forecast may either shine, or fall apart. Another winter storm in the southeastern U.S. will send a potent cold front down the Florida peninsula Friday night into early Saturday. Similar to our previous cold front, breezes will seem to change at the flick of a switch as the leading edge of the front arrives. Probabilistic guidance suggests there is a 60% to 70% chance for sustained winds to exceed 30 mph by Saturday night. These strong winds coupled with a reinforcing push of colder air could lead to a weekend that many of us have not seen in a long time. The NBM is giving the Upper Keys a notable chance, near 70%, for overnight lows less than 40F Saturday night. When we shift the threshold to 35F, that probability comes down to 25% to 30%. Regardless of the number, guidance is starting to find agreement that this weekend may see a push of winter weather that many of us haven't seen in a very long time. Breezes will have the opportunity to slacken on Sunday, but the colder air will still linger into the new week. Model trends over the next 24 to 48 hours are going to be crucial for increasing confidence in this forecast.

PRELIMINARY POINT TEMPS/POPS

Key West 56 71 62 72 / 0 10 30 40 Marathon 54 71 62 72 / 10 10 30 40

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.