textproduct: Key West

KEY MESSAGES

- Windy conditions will continue across the Keys through Wednesday morning. Breezes will gradually slacken thereafter through late Thursday evening.

- Breezes will once again freshen Friday through early next week, with another period of windy conditions for the Keys.

- Seasonal king tides combined with northeasterly winds will lead to coastal flooding through early next week, with the greatest impacts in the Upper Keys.

DISCUSSION

Issued at 120 PM EDT Tue Oct 20 2026 Surface analysis places a deepening low pressure system a few hundred miles east of the Outer Banks of North Carolina. Meanwhile in its wake, a 1032 mb high pressure system is parked in southeastern Canada. The interaction of these two synoptic features continues to produce breezy to windy conditions for the Florida Keys. The northeasterly breezes on the back side of the low pressure system is also acting to back up the Gulf Stream running along the Eastern Seaboard. Tides are elevated, particularly in the Upper Keys, where a Coastal Flood Advisory has now been issued. Local Doppler radar is only detecting a few isolated showers, mainly in the Upper Keys, with GOES-19 visible satellite imagery largely depicting mostly sunny skies across the Florida Keys and the adjacent nearshore and offshore marine zones. Cool advection around the continental high has caused temperatures to struggle a bit to recover today, with most island communities only hovering just above 80F at this early afternoon hour.

As the aforementioned low slowly progresses northeastward in the west-central North Atlantic and the high weakens, the pressure gradient gripping the Florida Keys will slowly weaken over the next 48 hours. With that said, the lull in breezes will be short- lived, as a second high dives from Canada southward towards the Mid- Atlantic. At the same time, there is growing global ensemble support for a plume of moisture associated with the front extending from the low in the North Atlantic then surging northward for late Friday through much of the weekend. There is also increasing support to suggest weak cyclogenesis occurring somewhere in the vicinity of the Bahamas late in the weekend. The ultimate evolution of this potential feature will have major implications on the rain and thunder chances for this period. Regardless, an extended period of windy conditions is nearly certain for Friday through early next week. Warm sea surface temperatures across the Keys will support efficient downward turbulent mixing of higher wind speeds aloft, with near- gales possible for a period late Saturday night through Monday.

If this wasn't complicated enough, persistent northeasterly strong breezes, combined with some of the highest seasonal predicted tides of the year, will support an extended period of coastal flooding concerns for the Keys, likely continuing into much of next week.

MARINE

Issued at 120 PM EDT Tue Oct 20 2026 A Small Craft Advisory remains in effect for all Florida Keys marine zones. Winds will begin to slacken and seas subside throughout the day on Wednesday, before breezes once again freshen for Friday through early next. Small Craft Advisories will once again likely be required for that time frame, with near-gale winds possible, especially Saturday night through Monday. Seasonal king tides combined with strong northeasterlies breezes will support an extended period of coastal flooding for late this week through early next week. Boaters can expect less clearance under fixed bridges, especially at around the times of high tide. A Coastal Flood Advisory is in effect for the Upper Keys, and a Coastal Flood Statement is in effect for the Middle Keys.

AVIATION

(18Z TAFS) Issued at 120 PM EDT Tue Oct 20 2026 Although a passing shower cannot be ruled out, especially in the favored overnight period, impacts to ceilings and visbilities from any activity should be minimal through 18z Thursday afternoon. Near- surface winds out of the northeast will frequently gust to near 20 knots, with gusts decreasing and becoming less frequent after 12z Thursday morning.

PRELIMINARY POINT TEMPS/POPS

Key West 86 75 85 75 / 10 20 10 10 Marathon 85 75 84 76 / 10 10 10 10

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...Small Craft Advisory until 6 AM EDT Wednesday for GMZ031>035- 042>044-052>055-072>075.