textproduct: Key West

KEY MESSAGES

- Light to gentle easterly breezes are expected through Tuesday to Tuesday night. Passing showers are possible, but significant rainfall is not likely through tonight.

- There is high confidence for a chance of showers and thunderstorms mid week, but confidence in the wind forecast is low.

- Breezy conditions may be able to return late in the week.

DISCUSSION

Issued at 430 AM EDT Mon Apr 6 2026 Showers were percolating with more energy than the past few days across the Florida Keys coastal waters. KBYX radar scans show shallow, disorganized showers across the eastern waters, and some locations in the Middle and Upper Keys likely observed at least a trace of rainfall. Nighttime microphysics returns from GOES East are able to highlight some of the nighttime showers, but drier air aloft is putting a cap on this early morning rainfall. Last night's 00Z sounding sampled a very dry mid atmosphere, so for the moment thunderstorm chances are very low. While the upper atmosphere is dry, moisture levels near the surface are slowly rising. Dew points across the island chain are near 70 degrees, and GOES East sampled a derived PWAT near 1.45 inches just upwind of the Keys. Today, we have high confidence that the weather will be humid with light to gentle breezes, and just a little bit warmer than normal.

Later this week, the environment becomes much more complicated. A high pressure system descending out of central Canada into the Northern Plains will be sufficient to force a frontal boundary towards South Florida by tomorrow morning. The uncertainties revolve around where, exactly, the front stalls. Recent statistical models suggests the front will stall further north. This scenario places a general warm sector environment directly over the Florida Keys for most of the week. These conditions could start as soon as early Tuesday morning when moisture replaces the drier air aloft.

In contrast to the precipitation forecast, there is low confidence in the wind forecast later in the week. The strength of easterly breezes across the Keys depends on where and when the frontal boundary stalls. The difference between the 10th and 90th percentile wind speeds over the island chain on Wednesday is almost 13 mph. The current consensus favors light to gentle breezes as the frontal boundary approaches the Keys, gentle to moderate breezes after the boundary stalls, and then freshening to moderate to fresh breezes late in the week after the Atlantic High rebuilds enough to force the boundary south of the Keys. The pattern is complex, and it will not be a shock if the wind forecast changes by tomorrow morning. However, the prolonged period of moisture will be much appreciated.

MARINE

Issued at 430 AM EDT Mon Apr 6 2026 No watches, warnings, or advisories are in effect for the Florida Keys coastal waters. From synopsis, breezes slackened to light to gentle breezes across the Florida Keys nearshore waters over the weekend. There is high confidence these lighter near surface winds will persist through Tuesday to Tuesday night. A high pressure system building over the Northern Plains early this week will be sufficient to force a frontal boundary south towards the Florida Keys. There is high confidence that the environment will favor widespread showers and a chance of thunderstorms midweek. However, whether gentle or fresh to strong breezes are observed over the Keys waters before the weekend depends on where the frontal boundary moves. The current forecast places more confidence on the front stalling north of the Outer Gulf waters.

AVIATION

(06Z TAFS) Issued at 430 AM EDT Mon Apr 6 2026 VFR conditions will prevail at both EYW and MTH for the upcoming TAF period. Short lived showers will be able to form near the island terminals, but there is not enough confidence in where and when to try to time VCSH in the TAFs. MVFR CIGs will be able to form near showers, not at sufficient frequency to require a TEMPO. Near surface winds will remain below 10 knots. Shower coverage is expected to decrease after sunrise.

PRELIMINARY POINT TEMPS/POPS

Key West 83 72 81 69 / 20 30 40 40 Marathon 82 72 80 70 / 20 40 50 50

KEY WATCHES/WARNINGS/ADVISORIES

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