textproduct: Key West

KEY MESSAGES

-A potent cold front will race southeastward through the Florida Keys late today or this evening. In wake of the front, winds will clock northwest to north and freshen considerably. Near gale breezes will be possible. A Small Craft Advisory conditions expected for all Keys waters by this evening.

-The cold air mass behind the front along with one, possibly two, reinforcing front(s), have a good potential of keeping temperatures well below normal for the duration of the week.

-The reinforcing fronts will contribute to additional periodic and significant wind surges through the week.

AVIATION

(18Z TAFS) Issued at 1252 PM EST Mon Jan 26 2026 VFR conditions will prevail at both EYW and MTH through around 21z. A cold front is moving through our waters bringing in a line of showers and behind that, cloudy and windy conditions. MVFR to IFR CIGs will be possible and TEMPOs will be included if need be later this evening (around 21-00z). Near surface winds will quickly become west to northwest at near 15 knots and frequent gusts of near 25 knots around sunset. Tonight, around 00z, winds will turn to the northwest to north while staying elevated, potentially posing crosswind concerns.

PREVIOUS DISCUSSION

Issued at 400 AM EST Mon Jan 26 2026

Big changes are coming for Keys weather this week. To start things off, a potent cold front will drive southeastward across the Gulf and through the Keys today into tonight as a strong mid latitude trough moves through the eastern United States. Ahead of the front, a prefrontal trough will swing through South Florida and the Keys. Surface winds will firm up modestly out of the west. Highs today will be similar to yesterday at near 80 with dew points holding in the lower to mid 60s.

Low level convective support will be quite limited as the prefrontal trough barely scrapes across our area and the lower level flow becomes diffluent as the front reaches the Keys. Meanwhile upper level jet support will remain well to our north. As a result, despite high surface dew points, rain chances will remain slim at best. Behind this front, winds will surge out of the northwest to north, becoming windy. This front will inject much cooler and drier across the Keys. Expect highs and lows to slip 5 to 10 degrees below normal. The coolest lows will likely be found in the lee of South Florida due to radiational cooling and a South Florida land breeze. Dew points will plummet to near 50 Monday night and likely the 40s on Tuesday.

This will mark the beginning of a prolonged stretch of much cooler than normal weather, lasting through the remainder of the week. Highs will struggle to reach the upper 60s with lows falling broadly in the 50s. These persistent cold temperatures will be a consequence of the broad long wave trough remaining across the CONUS as a series of shortwaves swing through the eastern United States. In response, a couple of strong reinforcing surface highs driving southward through the eastern United States will reinforce the cool and dry air in place with additional northerly surges. There is a possibility that medium and long range temperatures may be cooler than forecast. This is due, in part, to the strength and duration of the cold air advection episodes, and the high likelihood that the shallow nearshore water temperatures will fall well into the 50s. For now, will hold forecast temperatures near the ensemble mean.

MARINE

Issued at 1131 AM EST Mon Jan 26 2026 Small Craft Advisory conditions are expected as early as this evening in the coastal waters as a cold front races in through from the northwest. From synopsis, a strong cold front will push through Keys coastal waters this afternoon through tonight. Winds will start out light to gentle out of the southwest, strengthening slightly through the day, as the tail end of a prefrontal trough advances eastward across South Florida and the Keys. Expect winds to freshen substantially as the front blasts through the Keys marine zones, clocking around to the northwest to north and becoming strong, gusting up to near 30 knots. Winds will relax substantially on Tuesday, as high pressure builds southeastward through the Southeast and across the Florida Peninsula. Additional wind surges are becoming increasingly likely Tuesday night into Wednesday night, as a reinforcing cold front rolls southward across the area.

KEY WATCHES/WARNINGS/ADVISORIES

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