textproduct: Key West

KEY MESSAGES

- Well above normal rain chances (around 60-70%) will persist across the Florida Keys through the weekend and possibly into early next week.

- Heavy rainfall is becoming increasingly likely. Most locations in the Keys can generally expect an additional 2 to 4 inches of rainfall through Sunday, with locally higher amounts possible.

- Gentle to moderate (10 to 15 mph) breezes will relax by Friday. While breezes will then be light to gentle (5 to 10 mph) through the weekend, gusty winds will be possible with any thunderstorm.

DISCUSSION

Issued at 1041 PM EDT Thu Sep 17 2026

The weather was quite active earlier in the day but as we got into the afternoon, the activity quickly diminished. Some stuff lingered across the Southeast Gulf waters during the evening while convection tried to move in from between South Florida and the Bahamas. For a while it seemed as if convection would not re- trigger but in the last couple of hours the Straits of Florida have slowly started coming to life. Meanwhile, winds are slowly slackening and are already down closer to 10 knots as opposed to the 15 knots we had earlier this afternoon.

Moisture remains plentiful across the region. In fact, the PWat on tonight's sounding was 2.26 inches which is above the 90th percentile. Meanwhile, as we go further into the overnight an inverted trough moving across the Florida Peninsula looks to sharpen. This would allow for better convergence on top of the abundant moisture locked in place. That said, models have differing ideas of what will ultimately transpire overnight. The hi-res models show a more pessimistic outlook with all the activity staying out across the Straits of Florida and possibly inching close to the island chain towards dawn. Given the high uncertainty have decided against messing with PoPs for the overnight for the time being.

MARINE

Issued at 1041 PM EDT Thu Sep 17 2026

High pressure across the North Atlantic will maintain gentle to moderate northeast to east breezes through tonight. Winds will then slacken for Friday through the start of the weekend, becoming light to gentle out of the east and southeast, as the high north of the Keys marine zones weakens. An increasingly wet pattern will develop across the Florida Keys coastal waters through at least Sunday, as an upper- level low retrogrades westward towards South Florida and then eventually the Gulf. Confidence is low in the marine forecast for early next week, largely determined by where the upper-level low resides for that time frame.

AVIATION

(00Z TAFS) Issued at 1041 PM EDT Thu Sep 17 2026

VFR conditions expected outside of any passing showers or thunderstorms. High uncertainty on exact placement of additional activity overnight and future amendments will likely be needed. Otherwise, surface winds will hold at 10 knots or less.

KEY WATCHES/WARNINGS/ADVISORIES

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