textproduct: Key West

KEY MESSAGES

- An extended period of wet and windy conditions will develop across the Florida Keys tonight due to an approaching cold front. Drier conditions may gradually return by the early to middle part of next week, but winds are forecast to remain elevated.

- A Small Craft Advisory will likely be required by late this evening for the Gulf waters, spreading across the remaining waters late tonight or during the morning hours on Sunday.

DISCUSSION

Issued at 116 PM EDT Sat Oct 17 2026 Somewhat surprisingly, the lull in activity continues this afternoon across our waters with only a few areas of isolated showers in the distant Straits. A broken cloud line has developed north of the Lower Keys, but precip has been minimal along the line so far. Current surface analysis indicates the northeast to southwest oriented front is near the Tampa area where a broad region of showers in ongoing in the Gulf waters, but the front's forward motion is beginning to slow down as it moves closer to the Atlantic ridge which is still trying to hold on across the Bahamas and through Cuba. Moisture is already quite high across the area with measured PWATs above the 90th percentile on our morning RAOB. CIMSS steering products show that the southern extent of the mid to upper-level trough axis over the Eastern CONUS is nosing into the Gulf and slowly shifting eastward, so we will see increasing synoptic scale support for scattered to numerous showers and storms as we progress through the next 24 hours in addition to increasing surface convergence along and ahead of the approaching cold front. As we head into tonight, showers and scattered thunderstorms will become more widespread across the entire area. Winds will also begin to quickly ramp up from north to south this evening and through the overnight hours. We will likely begin to see Small Craft Advisory conditions across the southeastern Gulf as early as midnight, with fresh to strong northeasterly breezes expanding south across the remaining area through the morning hours on Sunday. Winds are likely to remain elevated through at least the middle part of next week.

The front will slowly push through the Florida Keys waters during the day tomorrow before stalling either near the Keys or slighty to the south across the Florida Straits. As usual, there will be a moisture gradient delineating low PoPs and dry conditions to the north of the front with high PoPs and wet conditions to the south. Highest PoPs are currently forecast across the Florida Straits from Sunday night through at least Tuesday, but there will be chances for isolated to scattered showers and perhaps a few thunderstorms along the Island Chain during this time. Meanwhile, a strong nor'easter is still forecast to develop east of the Outer Banks of the Carolinas tonight. This system will potentially loiter along the Eastern Seaboard for much of next week while broad mid to upper-level ridging becomes reestablished over Texas and the Central CONUS. This orientation will provide continued northerly flow across the Florida Keys along with the arrival of a much drier mid-level airmass by Tuesday night as the front is finally shoved further to our south. It's becoming more likely that this will help to promote a period of lower rain and thunder chances, lower humidity, and highs in the lower to mid 80s from Wednesday through at least the end of the work week.

MARINE

Issued at 116 PM EDT Sat Oct 17 2026 Small Craft Advisory conditions are expected to develop as early as tonight for portions of the Florida Keys coastal waters while a cold front moves south across the Gulf. The front is currently located near Tampa with a broad region of showers ongoing in the Gulf, but to the north of our waters.

From synopsis, a cold front is progressing southeastward across the central and eastern Gulf today. Breezes are on track to stay light to gentle northeasterlies this afternoon before the front reaches the northernmost Gulf waters tonight. Once the cold front begins its passage across the Keys waters, breezes are expected to freshen rapidly amidst squally conditions. A Small Craft Advisory will likely be required for part of or all the Florida Keys waters tonight into Sunday. Fresh, occasionally strong, northeasterly breezes are expected to persist through the first half of the week. Shower chances will peak tonight and Sunday.

AVIATION

(18Z TAFS) Issued at 116 PM EDT Sat Oct 17 2026 There are VFR conditions at both sites for now with a lull in activity, but an approaching cold front will bring gradually deteriorating flight conditions by this evening. Expect prevailing SHRA by 05Z with northeasterly sfc winds of 10-15 kt gusting to 20 to 25 kt. MVFR ceilings are also expected to develop. The highest coverage of precip should start to shift to the south of the terminals by 11-12Z, but will maintain VCSH.

PRELIMINARY POINT TEMPS/POPS

Key West 76 86 76 86 / 80 70 50 40 Marathon 77 85 77 85 / 80 70 50 40

KEY WATCHES/WARNINGS/ADVISORIES

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