textproduct: Key West

KEY MESSAGES

- Areas of fog will impact portions of the Lower and Middle Keys, as well as the adjacent near through offshore Gulf waters this morning. - A strong high pressure system will spread southeastward off of North America early this week, freshening northeast to easterly breezes across the Keys. Beginning Monday night, breezy conditions will be possible and marine Cautions and Advisories may be required.. - A moderate drought continues for the entire island chain. Burn bans are possible, trees and bushes begin browning, and water supply decreases. For the upcoming week, there will be a slight chance for showers.

DISCUSSION

Issued at 430 PM EST Sat Feb 28 2026

Winds across the Keys are poorly defined this morning due to the tail end of a trough stretching northeastward from southern Florida. Earlier influx of dew points in the lower 70s over Gulf water near or slightly below 70 set the stage for fog formation. Light northerly breezes through the past evening hours drove some of this fog into portions of the Lower and Middle Keys. Despite the light flow recently shifting east to southeast, some areas of fog continue to linger across portions of the Lower Keys. Last evenings sounding indicated ample CAPE. Precipitable was also slightly above normal at 1.22 inches and moisture. However, forcing near the Keys is lacking and, at least at the time of the sounding, a very low inhibition layer was evident. As a result, despite a few showers and thunderstorms present over the broader area, the forecast area has been precipitation free.

The last remnants of the surface trough will move off to the northeast and east today as modest high pressure over the southeastern United States spreads southeastward into Florida. This will result in winds becoming light to gentle northeasterlies. This flow should drop dew points a couple of degrees to slightly below 70. The strengthening breeze and falling dew points, along with day time heating, should steadily eliminate fog potential. A relatively amplified mid latitude trough across the eastern United States will gradually push out to sea over the next 24 hours. Until this clears, ample CAPE and weak moist confluence will continue across our area. While forcing will be weak, and very low inhibition will help to limit activity, convective development cannot be completely ruled out. If a shower forms, it could also amplify into a thunderstorm. For this reason have kept rain chances slight, but also include the possibility for thunderstorms.

The forecast becomes more monotonous early this week. An expansive high pressure system will expand southeastward off of the North American coast and take the remainder of the week to lumber off into the Atlantic. This high will further ramp up northeast to easterly breezes across the Keys. Expect breezy conditions heading into mid week, lasting through the remainder of the week. Breezes will start out east northeast to easterly, and slowly veer east to southeasterly as the core of the high advances further east. The fast flow and ample moisture will be supportive of spats of shower activity. However, this will be held in check by lower to mid level ridging remaining in firm control. Highs will remain near 80 with overnight lows in the lower 70s. Dew points are expected to meander in the upper 60s.

MARINE

Issued at 430 PM EST Sat Feb 28 2026

A surface trough is lifting out off the northeast Atlantic Coast. The weak tail end of this trough is pulling out across the Bahamas and resulting in a rather flat pressure field and light breezes. A modest surface high over the southeastern United States will migrate southeastward across Florida. This will bolster northeasterly breezes tonight. Another more powerful surface high will spread southeastward off of North America and push breezes up another notch. A mix of cautions and possibly advisories may be required for portions of Keys waters beginning Monday night, and lasting well through the week.

AVIATION

(00Z TAFS) Issued at 430 PM EST Sat Feb 28 2026

Foggy conditions will linger near both island terminals, particularly EYW, but reduced categories onsite are not expected. Occasional observations of FEW to SCT clouds near FL005 may be reported during the first few hours of the TAF period, but the nearby fog causing this should lift near 16Z. Surface winds will remain light out of the north to northeast.

CLIMATE

On this day in 1874, the daily record high temperature of 89F was recorded in Key West. This is also tied for the warmest temperature ever recorded in March. Temperature data for Key West dates back to 1872.

Of note, on this day in 1996, the Key West ASOS was commissioned at the Key West International Airport.

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...Dense Fog Advisory for GMZ032>035.