Marine Weather and Tide Forecast for Key Colony Beach, FL

DISCUSSION
Issued at 1045 AM EDT Sun Oct 11 2026 This October Sunday opens with an extremely humid atmosphere across the Florida Keys. Dew points at the Key West International Airport this morning were able to increase to 80 F, and that observation was corroborated by the ASOS located at the Florida Keys Marathon Airport and sensors across the Florida Keys. GOES East derived Total Precipitable Water estimated PWATs in the 2.2 to 2.3 inch range across the Lower and Middle Keys. The morning KKEY 12Z sounding sampled an environmental PWAT near 2.5", easily exceeding the record value for the day. Despite the more than plentiful moisture, showers have struggled to form across the Florida Keys over the past 24 hours. While showers were able to form over the eastern Straits last night and clouds are bubbling north of the island chain this morning, one would not guess we observed a record amount of moisture. Instead, a mixture of low level divergence, broad ridging in the lower levels of the atmosphere, and backing winds near the surface are limiting shower coverage this morning.

What happens during the rest of the day? A slowly building ridge is located near the Keys, and satellite observations show a dry air mass, estimated PWATs of 1.4 to 1.6", moving into the Florida Keys eastern waters. Observations from Miami verify this air mass.
The morning 12Z KMFL sounding measured a PWAT over 2.2", but a pronounced dry layer was present above 20 kft. Two hours later, ACARS soundings from the Miami airport indicate the PWAT dropped by around three quarters of an inch. This dry layer will easily be able to limit convection over the eastern Keys. Later this afternoon, showers will be limited by this dry air mass.
Unfortunately, this will not be able to translate to the surface.
Dew points are on track to remain high through the day. A brief pulse in thunderstorms is possible just as the drier air moves in.
Winds are on track to remain generally southeasterly and light to gentle. Keep an eye on the radar this afternoon, but otherwise enjoy the mostly sunny skies!

MARINE
Issued at 1045 AM EDT Sun Oct 11 2026 There are no watches, warnings, or advisories currently in effect for the nearshore or offshore waters of the Florida Keys. Boaters should be aware of less clearance under fixed bridges around times of high tide as a Coastal Flood Statement is in effect for the Florida Keys.

From synopsis: weak high pressure along the North Gulf Coast combined with the Atlantic ridge will continue to promote peaking and lulling breezes through at least Monday. In addition, breezes will back to the northeast as the high along the North Gulf Coast strengthens. As the high builds, a front associated with Post- Tropical Cyclone Isaias will push through the Keys sometime Monday night or Tuesday. In the wake of the front, high pressure will remain across the Southeast U.S. promoting gentle to moderate northeast to east breezes through much of the week. Drier air moving into the Keys this afternoon will also lead to decreased rain chances through at least mid week.

AVIATION
(12Z TAFS)
Issued at 1045 AM EDT Sun Oct 11 2026 VFR conditions will prevail at both island terminals through the TAF period with only FEW to occasionally SCT skies near FL015 and 020. Very isolated instances of light showers may occur around 15Z to 18Z, but any activity onsite will be short lived with little to no impact. Surface winds out of the southeast near 10 knots will gradually back to the east.

CLIMATE
On this day in 1909, the daily record rainfall of 8.94" was recorded in Key West as a Category 3 Hurricane moved rapidly northeast from the western tip of Cuba along and just south of the entire length of the Keys. It caused nearly a million dollars in damage in Key West, drowned 12 railroad workers, and destroyed about 400 buildings. Sand Key recorded a minimum pressure of 28.37" with winds estimated at 100 mph before being swept out to sea. Rainfall records for Key West date back to 1871.

PRELIMINARY POINT TEMPS/POPS
Key West 90 83 90 80 / 20 10 20 30 Marathon 90 83 90 80 / 20 10 20 30

KEY WATCHES/WARNINGS/ADVISORIES
FL...None.
GM...None.