textproduct: Key West

KEY MESSAGES

- A Coastal Flood Advisory is in effect for all of the Florida Keys.

- Minor to moderate saltwater flooding of low elevation streets and lots is likely to continue over the next few day or so due to King Tide. Don't drive through flooded roadways. Boaters can expect less clearance under fixed bridges.

- A wet pattern and thundery pattern will continue through Friday. Rain and thunder chances will decrease over the weekend through early next week.

AVIATION

(18Z TAFS) Issued at 149 PM EDT Wed Sep 30 2026 While VFR conditions will prevail at both EYW and MTH through 18z Thursday afternoon, batches of scattered showers and thunderstorms will occasionally approach the vicinity of the terminals. Confidence is quite low in terms of timing and could really occur at any time throughout the TAF period, with sub-VFR ceilings and visibilities as well as crosswind gusts possible with any stronger storm. Have included a general mention of VCSH at EYW and a prevailing period of SHRA for now at MTH, along with a PROB30 group for when the focuses of convection could occur this evening.

MARINE

Issued at 1050 AM EDT Wed Sep 30 2026 There are no watches, warnings, or advisories in effect across the Florida Keys coastal waters at this time. Squally showers and thunderstorms had passed through the Lower and Middle Keys coast waters earlier this morning, leaving winds temporarily light and confused. Seas measured at Satan Shoal were running 3 feet with a 4 second period. From synopsis: A high pressure system along the Eastern Seaboard will shift further offshore and merge with an existing high pressure across the subtropical Atlantic and subsequently build through the remainder of the week. This will promote freshening breezes with an increasing likelihood of moderate to fresh breezes beginning Wednesday, continuing through late week. There is a good chance that marine Cautions may be required for portions of Keys waters at that time, and Advisories cannot be ruled out. In addition, a very wet pattern will remain across the Keys over the next few days, resulting in periods of scattered to numerous showers and thunderstorms.

PREV DISCUSSION

Issued at 417 AM EDT Wed Sep 30 2026 The Florida Keys are in a momentary lull with the KBYX radar surprisingly quiet all across our CWA. Nearest area of convection is moving off the north coast of Cuba and beginning to enter open waters. Time will tell if this activity lingers into our waters. Otherwise, we are in the thick of it so to speak. An upper level trough lies to our west across the central Gulf Basin, extending well into the Yucatan Peninsula. This has placed the Keys under a deep southerly flow that continues to transport tropical moisture from the western Caribbean. In fact, we're monitoring the nearly west to east line of convection that has been steadily moving north and is currently reaching Cuba. This line is on pace to reach the Keys between 0900-1200 today. Given this trajectory plus the deep tropical moisture influx and the presence of the nearby upper level trough, likely PoPs can be expected today. In addition, we continue to be under the influence of King Tides, therefore, should heavy rain coincide with times of high tide, we could see brief periods of enhanced flooding.

Meanwhile, to our north, a surface high pressure sits along the Eastern Seaboard. This feature will slowly meander offshore throughout the day and merge with an existing Atlantic Ridge and subsequently build. This will lead to freshening east to southeast breezes across the region. It is becoming increasingly likely that we will see a period of breezy conditions with marine Caution headlines likely across the surrounding coastal waters. There is a chance that given the early nature of this building high that models may be slightly underplaying the strength of the winds. Nonetheless, we can expect a period of moderate to fresh breezes at least through Friday. Thereafter, the ridge will gradually ease and allow for breezes to slowly slacken back to gentle to occasionally moderate over the weekend. As the high eases, we should see rain chances return closer to normal for what will be the first weekend of October.

PRELIMINARY POINT TEMPS/POPS

Key West 88 78 89 79 / 70 80 80 60 Marathon 87 79 88 80 / 70 80 70 50

KEY WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 5 AM EDT Thursday for FLZ076>078.

GM...Small Craft Advisory until 11 AM EDT Thursday for GMZ052>055- 072>075.