textproduct: Key West

KEY MESSAGES

-Gale Warning in effect through Sunday morning. Gale-force winds may develop as early as this afternoon, continuing through Sunday morning.

-Very cold and windy conditions are expected tonight behind a cold front blasting through the Florida Keys today. These conditions will continue through at least Monday morning. A Wind Advisory is in effect for the Island Chain, and a Cold Weather Advisory is in effect for the Upper Keys.

-The strong onshore winds may result in minor to moderate coastal flooding on our gulf and bay side waters late Saturday and Coastal Flood Statements/Advisories may be required.

DISCUSSION

Issued at 1109 AM EST Sat Jan 31 2026

The first rounds of showers is sweeping through this morning. Shower activity has been relatively light but the bigger concern are the winds accompanying these showers. Light to gentle breezes this morning have quickly ramped up to moderate to fresh with the first surge. Looking upstream there will be additional reinforcing surges, each one ticking up winds as they pivot through. Still expecting gale-force winds by the afternoon and becoming more widespread during the evening. The peak of the strongest winds looks to be before or just around midnight. Thereafter, breezes will undergo a very gradual slackening process.

No big changes made to the going forecast. A Gale Warning, Wind Advisory, and Cold Weather Advisory all remain in effect. Rain chances will remain likely (60-70 percent) with rainfall amounts on the order of one to two-tenths of an inch. For our coastal waters forecast, only changes made were to the initial conditions to reflect the rapidly deteriorating conditions.

MARINE

Issued at 1109 AM EST Sat Jan 31 2026

Gale Warning remains in effect. The first of several wind surges have begun moving across the coastal waters surrounding the Florida Keys. Light to gentle breezes earlier this morning have sharply freshened to fresh to strong with the first round of showers. Breezes will only further freshen from this point, reaching near- gale by the afternoon. Gale-force winds could arrive as early as this afternoon in the southeast Gulf waters and then quickly overspread the rest of our waters this evening and overnight.

AVIATION

(15Z TAFS) Issued at 1109 AM EST Sat Jan 31 2026

Rounds of showers will continue to sweep across both of the Florida Keys terminals through the afternoon and evening. These showers will continue to provide IFR conditions. MVFR CIGs are expected to return later this afternoon as the main front pushes through and helps to scour out some of the lower level moisture. Otherwise, expect gale-force gusts to move in towards sunset and continue through the overnight.

PREV DISCUSSION

Issued at 605 AM EST Sat Jan 31 2026 Calm and damp conditions lingered during the overnight shift as temperatures are sitting near 60F, and the accompanying dew points are only a couple of degrees behind. Some quick math gives us relative humidity values around 90% to 95%! Northwest to northerly breezes have been light with automated stations along the island chain reporting sustained winds near 5 mph. While our KBYX radar hasnt had much shower activity to track during this shift, a few light showers are currently crawling into our Gulf waters. Overlaying GOES-19 Cloud Top imagery, we can see an expansive band of cloud cover stretched across the Gulf, the peninsula, and into the North Atlantic. These showers and clouds are associated with an approaching cold front. Surface analysis suggests the leading edge of this cold front is closer to the backside of this band of clouds, so the initial push of showers this morning/early afternoon will be an appetizer for whats to come.

If leading showers continue to march across our waters at their current speed, we should see rainfall arrive to the island chain around 9 AM or 10 AM, give or take an hour or so. Flooding from rainfall isnt necessarily a concern as showers will move through quickly, and shouldnt have to option to linger over our island communities, but any localized areas that drain poorly may have some ponding water. Even though breezes will increase with these prefrontal showers, hi-res guidance indicates a very brief and narrow area of lulling breezes may sneak in behind the line of showers. If this comes to fruition, do not be fooled by it. Breezes will drastically sharpen by the late afternoon and early evening hours, and a Wind Advisory is in effect for tonight. Loose and unsecured outdoor objects may blow around, and driving high profile vehicles, especially over our bridges, may be difficult. Winds are expected to peak during the overnight hours tonight with sustained winds approximately near 30 mph. This will result in gusts as high as 45 mph. Cold air filling in rapidly as the front rolls through has resulted in wind chill concerns, especially because dangerous wind chills are not something we typically see anywhere in the Florida Keys. This has resulted in a Cold Weather Advisory for the Upper Keys. Probabilistic guidance points to high chances (near 80%) of wind chills dipping below 30F for a few hours during the night in the Upper Keys. Chances for these exceptional wind chills are much lower across the Middle Keys, around 20%, so we have opted to keep the Cold Weather Advisory isolated to the Upper Keys. Please do not assume that we are in the clear in the Middle, and even Lower, Keys. This is record breaking cold air. Climate reanalysis calculated that this air mass is around 5 to almost 6 standard deviations below normal, and the chances of seeing another winter like this are around 10%.

When the cold front exits tomorrow, the tightened gradient from the drastic temperature difference between air masses will lead to continued near gale breezes early Sunday morning. Breezes will gradually slacken over the first few days of the new week, and temperatures will be even slower to recover. The good news is that the air behind this front is exceptionally dry. GEFS and EC ensembles are pointing to PWAT values around 0.1 to 0.3 inches. Mostly sunny skies should help to take the edge off of the colder air for our long-time Floridians, and we should feel much more comfortable by the middle of the week. Guidance near the end of the week is a little bit all over the place right now, because the models are still tackling the current situation. For now, the progressive pattern suggests another cold front at the end of next week is not out of the question, but details related to the resulting sensible weather are still unclear.

PRELIMINARY POINT TEMPS/POPS

Key West 72 50 59 51 / 60 20 0 0 Marathon 68 45 55 46 / 50 10 0 0

KEY WATCHES/WARNINGS/ADVISORIES

FL...Wind Advisory from 7 PM this evening to 10 AM EST Sunday for FLZ076>078.

Cold Weather Advisory from 10 PM this evening to 10 AM EST Sunday for FLZ076.

GM...Gale Warning for GMZ031>035-042>044-052>055-072>075.