textproduct: Key West

KEY MESSAGES

- Measurable rain chances will remain low through next weekend, at generally 10% or less.

- Conditions will remain seasonably warm and muggy, but we may see heat index values above 105F, particularly along the Upper Keys, through Tuesday.

- A pocket of Saharan Air currently centered over the Straits of Florida will slowly move west across our area starting late tonight, likely lingering through Wednesday.

DISCUSSION

Issued at 1021 PM EDT Mon Jun 22 2026 Another muggy night is unfolding across the Florida Keys. Dew points along the island chain from Key West to northern Key Largo are in the upper 70s tonight. Light to gentle easterly breezes are present along the reef, so the air is not as stagnant as the past couple of days. GOES East nighttime microphysics returns show indicate low level cloud cover is a bit more concentrated northwest of the Lower Keys. High altitude clouds are rather sparse, so stargazers may be in luck tonight. However, the lack of cloud cover and light to gentle breezes hints that radiational cooling could lower temperatures along the larger islands. Even though most of the radar is clear of meteorological echoes, sufficient moisture and instability exists in the atmosphere for showers to form.

The KBYX radar did, in fact, detect isolated showers north of the Lower Keys this evening. The 00Z KKEY sounding does offer some explanation for how showers were able to form. The balloon sampled an environment with more than sufficient instability, over 2000 J/kg of MLCAPE with a PWAT value above the 75th percentile for the day. SPC mesoanalysis suggests a weak convergence boundary is present where showers are flaring. There is low confidence these showers will be able to propagate back towards the island chain overnight.

While it was not sampled by the evening sounding, there is high confidence that a plume of the Saharan Air Layer will move over the Florida Keys waters during the overnight hours. There are pretty good odds that those in the Keys will wake up to milky skies tomorrow morning. Thus, opting to leave the inherited forecast package alone.

MARINE

Issued at 1021 PM EDT Mon Jun 22 2026 There are no watches, warnings, or advisories in effect for the Florida Keys coastal waters. From synopsis, a broad, weak high pressure system stretching from the Gulf Basin, across the Florida Peninsula, and into the central North Atlantic will fluctuate in strength over the next several days. As a result, expect both wind speeds and direction to be primarily mesoscale driven and at times chaotic. By Wednesday night, the high will begin to gradually build and allow for a slow freshening of east to southeast breezes.

AVIATION

(00Z TAFS) Issued at 1021 PM EDT Mon Jun 22 2026 VFR conditions will prevail at EYW and MTH for the upcoming TAF period. Winds are generally easterly and will oscillate in the 5 to 10 knot range. Expect cloud cover and shower coverage to decrease as a Saharan Air Layer moves over the island chain.

PRELIMINARY POINT TEMPS/POPS

Key West 84 90 84 90 / 10 10 10 10 Marathon 84 89 83 89 / 10 10 10 10

KEY WATCHES/WARNINGS/ADVISORIES

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