textproduct: Key West

KEY MESSAGES

- A swath of Saharan dust will remain across the Keys through mid week, resulting in virtually no rain chances.

- Warm and muggy conditions will continue throughout the work week, with light and often variable breezes.

DISCUSSION

Issued at 1030 PM EDT Tue Aug 18 2026

A weak split surface ridge across our area has resulted in generally weak west to northwesterlies across the Keys this evening. However, the formation of a heat low over South Florida has resulted in a moderate surge out of the southwest in the Upper Keys. Exceptionally stable conditions are in place across the Keys due to lower to mid level ridging spanning our area and the continued influx of Saharan air. This evenings sounding continued the stretch of record low precipitable water at .97 inches. The previous record for the 00Z sounding on the 19th was 1.46 inches. Skies have been clear through the evening hours with absolutely no precipitation echoes within the forecast area.

The weak split ridge will remain across the Keys through the overnight. As a result, surface winds will become a more uniform light west to northwesterly. Very stable conditions will persist overnight and rain chances will be zero. Virtually clear skies may allow for some radiational cooling in interior and protected locations. However, unlike last night, the light but persistent west to northwesterly flow will try to fight this off. Expect overnight lows to range broadly in the lower 80s. Dew points will remain in the mid 70s.

MARINE

Issued at 1030 PM EDT Tue Aug 18 2026

Split ridging straddling the Keys is producing primarily light breezes with a lot of variability due to a nearby col. The development of a South Florida heat low has resulted in an evening wind surge on waters immediately south and southeast of the mainland. Carysfort Reef is still sustained at 14 knots out of the south southwest, while Sand Key is less than 5 knots out of the northwest. This surge should abate in the next few hours.

AVIATION

(00Z TAFS) Issued at 1030 PM EDT Tue Aug 18 2026

VFR conditions will prevail at the island terminals overnight. Surface winds will be light and variable, tending northwesterly.

KEY WATCHES/WARNINGS/ADVISORIES

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