textproduct: Key West

KEY MESSAGES

- Conditions are favorable today for cloud line development over, or adjacent to, the Florida Keys. Cloud line development will carry the risk of waterspouts.

- Slight chances of showers and thunderstorms will persist through the middle of the week.

- Light to gentle east to southeasterly breezes will occasionally become variable over the next couple of days.

DISCUSSION

Issued at 1041 AM EDT Tue Jun 30 2026

Overnight convection quickly simmered down shortly after sunrise and we are left with a few very isolated showers across the Straits of Florida. This lull, however, is a deceptive lull. This is primarily due to a frontal boundary that is slowly pushing south across the Southeast U.S. and into the Sunshine State. As it has moved southward, it has flattened and weakened the western periphery of a ridge that is centered out across the Atlantic. This in turn is resulting in winds actively becoming light and variable. Meanwhile, between 925-700 mb, a low-level ridge remains in place. This feature is providing a northeast to east wind just above the boundary layer. This is potentially setting up for a cloud line to develop across the Keys during the late morning and afternoon hours. The only caveat is that we're dry above the boundary layer. This means as convection tries to become more vertical it will have to contend with this drier layer.

If enough lower level moisture is able to be lifted up, we could see a well-developed cloud line today. The main risk will be the potential for waterspouts to develop. A waterspout would most likely appear beneath a dark, flat bottom of a building cumulus line, just at the hint of rain. If you see a waterspout, stay away, and call in the report to your Florida Keys National Weather Service, at 3 0 5 2 9 5 1 3 1 6 extension 3. If you see a spout, give us a shout! We'd greatly appreciate it!

Lastly, no changes were needed or made to this forecast cycle.

MARINE

Issued at 1041 AM EDT Tue Jun 30 2026

Breezes will be light and variable for the remainder of the day across a majority of the coastal waters. The exception will be across the extreme Southeast Gulf waters where a late afternoon surge will develop along the west coast of Florida and spill in our waters. Expect breezes to clock around from the northwest and freshen to gentle breezes across the SE Gulf in the late afternoon. Then towards and just after sunset, we expect a surge to come off the mainland. This secondary surge will effect the SE Gulf as well as the adjacent waters north of the island chain. Expect a quick freshening of gentle to briefly moderate north to northeast breezes during the evening and early portions of the overnight. By the late overnight and early pre-dawn hours, breezes will clock around back from the east to southeast and slacken appreciably once again.

AVIATION

(15Z TAFS) Issued at 1041 AM EDT Tue Jun 30 2026

VFR conditions will continue in the short-term. Keeping an eye out for a cloud line to develop within the next couple of hours and persist into the evening. Should a fully matured cloud line develop, we could see isolated showers and thunderstorms develop over the island terminals. Exact timing is highly uncertain at this time and will add mentions of VCSH/TS as needed if conditions evolve.

PRELIMINARY POINT TEMPS/POPS

Key West 92 83 92 83 / 20 20 20 20 Marathon 90 82 89 83 / 20 20 20 20

KEY WATCHES/WARNINGS/ADVISORIES

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