textproduct: Key West

KEY MESSAGES

- Rain and thunder chances peak today and are primed to decrease to below average chances by the weekend.

- Gentle to moderate breezes persist through tonight, but are expected to slacken to light to gentle late in the week. - Moderate to major Heat Risk is expected to be the primary concern this weekend into next week.

DISCUSSION

Issued at 435 AM EDT Wed Jun 10 2026 The pattern across the Keys this morning is peculiar. The KBYX radar display is surprisingly empty before sunrise across the Florida Keys this morning. Only occasional showers are percolating in the early morning hours amidst the gentle to moderate southeasterly breezes. Nighttime microphysics observations from GOES East indicate additional cloud cover across the Keys waters, except those would be high altitude ice clouds. Zooming out from the Keys indicates why the weather appears so uneventful. A high pressure system is located over the North Atlantic. A tropical wave is located near Western Cuba, however, a monsoonal pattern called the Central American Gyre (CAG) located over southern Mexico and Central America is of more interest. The CAG shifted the overall flow of moisture further west while the Atlantic High has maintained gentle to moderate breezes across the Keys. What does this mean for today's weather? Water vapor imagery indicates the moisture plume is still slightly over the Keys. Showers can still form along weak waves within the wind flow. Model soundings show little inhibition across the region, so a chance of showers and thunderstorms still lingers. Keep an eye on the radar and watch for any nearby showers!

Looking ahead, the pressure gradient starts to collapse across the Florida Keys. Eastward movement of the Atlantic High and westward movement of the CAG indicates the Keys will be in the doldrums between the two pressure centers. The CAG also is primed to divert additional Caribbean moisture away from the Florida Keys later this week. The result would be a collapse in wind speeds, to light to gentle breezes, and low shower coverage over the weekend. The complicating factor would be local effects. Light to gentle breezes mean cloud line patterns may develop, sea and land breezes become more of a factor, and boundary collisions over the water can set off disorganized showers. However, the environmental pattern looks to be on the drier end. Statistical guidance indicates a below average chance of rain late in the period. Overall, enjoy the dry conditions while they last.

MARINE

Issued at 443 AM EDT Wed Jun 10 2026 From synopsis, a high pressure system over the North Atlantic will provide support for persistent gentle to easterly breezes across the waters surrounding the Florida Keys. Shower coverage is expected to peak this afternoon while an easterly wave moves across western Cuba. The high pressure system is primed to move further east into the Atlantic, which will allow breezes to slacken to light to gentle. At the same time, the easterly wave will pull the flow of moisture west and allow a drier pattern to set up across the Keys. Shower and thunderstorm chances this weekend are expected to be low as a result.

AVIATION

(06Z TAFS) Issued at 443 AM EDT Wed Jun 10 2026 VFR conditions will prevail at both island terminals. Passing showers and isolated thunderstorms are possible in the early morning with accompanied MVFR CIGs and VIS. Coverage in activity is expected to increase by sunrise and peak before sunset. VCSH is included instead of SHRA due to lack of confidence in timing onset of showers.

CLIMATE

On this day in 2019, the daily record warm low temperature of 86F was recorded at the Florida Keys Marathon International Airport. That observation also ties for the warmest low temperature ever recorded in June and the all time warmest low for the Marathon area. Temperature records at Marathon date back to 1950.

OF NOTE In 2005, Tropical Storm Arlene passed west of the Florida Keys. It produced sustained winds of 45 mph and wind gusts to 55 mph in the Dry Tortugas. In Key West, wind gusts were 47 mph. Storm surge 1.35 feet above mean sea level at Key West Harbor, causing minor flooding. Wind damage to four homes occurred on Lower Matecumbe Key. Rain accumulations across the island chain were between 2 and 3 inches.

PRELIMINARY POINT TEMPS/POPS

Key West 89 81 89 81 / 40 20 30 10 Marathon 88 81 89 81 / 30 20 20 10

KEY WATCHES/WARNINGS/ADVISORIES

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