textproduct: Key West

KEY MESSAGES

- A strong pressure gradient associated with a cold front will support a prolonged period of windy conditions across the Florida Keys.

- A Small Craft Advisory is in effect for all coastal waters for hazardous winds and seas. These conditions will last through the next several periods.

- Shower and thunder chances will decrease during the early part of the week as a dry air mass approaches the Florida Keys.

DISCUSSION

Issued at 127 PM EDT Sun Oct 18 2026 A broad region of disturbed weather extends from the Bahamas west through the FL Straits towards northern Cuba along and ahead of a cold front which is draped nearly parallel over the Florida Keys. To our north and west, an expansive anticyclone is encompassing much of the eastern CONUS with water vapor imagery depicting deep layers of dry air advecting south into the Gulf and through the Florida Peninsula. Cloudy and windy conditions continue across the Keys and surrounding waters. Showers and thunderstorms are focused across the Florida Straits where deep tropical moisture is pooled ahead of the front. Surface and marine observations have been reporting continuous fresh to occasionally strong northeasterly breezes along the island chain and surrounding nearshore waters, supporting the ongoing Small Craft Advisory for all Florida Keys waters. High PoPs are forecast to remain focused across the Florida Straits where waves of showers and thunderstorms will occur through at least tomorrow. Chances decrease with northern extent, but passing showers and an occasional thunderstorm will be possible along the island chain through tonight. Activity near the Upper Keys has generally remained offshore, but we did see a slow moving thunderstorm affect the Key Largo area with radar estimated rainfall around 1.5". We'll need to keep an eye on redevelopment in that area which may lead to localized flooding.

A strong nor'easter is forecast to develop off the Carolina coast tonight while our cold front stalls in the Florida Straits. Persistent northerly mid to upper-level flow will eventually force the dry airmass south across the Keys during the day tomorrow and on Tuesday as the remnant front undergoes frontolysis and washes out. As such PoPs, will be on a gradual decline beginning tomorrow, and by Wednesday, our weather looks quite pleasant across the Keys. We may see several days with dewpoints in the 60s and highs in the lower to mid 80s. Despite decreasing PoPs, gradient winds will remain enhanced for the next few days, gradually slackening each day through the week with peaks at night and subtle lulls during the daytime. For now, expect the Small Craft Advisory to be needed for at least another day, perhaps two, due to fresh, occasionally strong northeasterly breezes leading to hazardous marine conditions.

MARINE

Issued at 127 PM EDT Sun Oct 18 2026 A Small Craft Advisory is in effect for all the Florida Keys waters. Widespread showers and embedded thunderstorms remain focused across the Straits of Florida this afternoon.

From synopsis, a cold front is situated nearly parallel to the Florida Keys waters with fresh to strong breezes occurring across the nearshore and offshore waters. Hazardous winds and seas are expected to continue through this afternoon, and a Small Craft Advisory is in effect for all the Florida Keys waters. The cold front is expected to stall across the Straits of Florida tonight. Expect fresh to strong northeasterly breezes to prevail through the first half of the week. Shower chances will gradually decrease by Monday as drier air begins to move in while the front is forced further south.

AVIATION

(18Z TAFS) Issued at 127 PM EDT Sun Oct 18 2026 VFR conditions will generally prevail through this TAF period. A cold front has stalled near the Keys this afternoon which may result in occasional drops in flight criteria, but most of the SHRA/TSRA is remaining south of the terminals. Will maintain VCSH through 00Z with a PROB30 for SHRA and MVFR ceilings from 00-03Z. A strong pressure gradient will support northeasterly sfc winds of 10-15 kts with gusts of 20 to 25 kts.

PRELIMINARY POINT TEMPS/POPS

Key West 77 86 75 86 / 50 40 20 10 Marathon 78 85 76 85 / 50 40 10 10

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...Small Craft Advisory until 11 PM EDT this evening for GMZ031>035- 042>044-052>055-072>075.