textproduct: Key West

KEY MESSAGES

- There will be low chances for isolated showers and thunderstorms on Friday as a cold front pushes through the Florida Keys.

- Drier and cooler weather will filter in for the weekend, but winds will be breezy at times.

- After a brief lull, high pressure will build over the eastern US early next week which will enhance the pressure gradient and promote an extended period of windy conditions across the Florida Keys.

SHORT TERM DISCUSSION

Issued at 849 PM EST Thu Nov 12 2026 A mostly quiet evening has developed across the Florida Keys. Earlier showers near the island chain have dissipated and the focus for development has clearly shifted to the distant Straits of Florida and areas east into the Great Bahama Bank where numerous showers and embedded thunderstorms are ongoing in a region of much higher atmospheric moisture on the western periphery of a strong anticyclone centered east of the Lesser Antilles. Satellite imagery in combination with current surface observations depict a strong region of low pressure centered just off the New England coast with an expansive region of northwesterly winds over much of the eastern CONUS north of a cold front which currently extends northeast to southwest across the Florida Panhandle into the Gulf. This front will advance towards the Keys tonight which will serve as the precursor to the coolest airmass so far this season. Our surface winds have already begun to shift to the north-northwest along the island chain with mostly light breezes. I did lower PoPs for the northern portions of the forecast area including the island chain for tonight, focusing higher PoPs in the distant Straits near the ongoing activity. However, the front will arrive during the day tomorrow, and although coverage is expected to be minimal along the front, I suspect there will be enough moisture pooled along the boundary to at least support a slight chance of a shower or storm along the island chain, mainly during the afternoon. Most locations will remain dry. Northeasterly breezes will also begin to freshen during the afternoon as the pressure gradient strengthens in the wake of the cold front. Latest CAMs suggest the front will push south of the Keys tomorrow evening followed by a rapid decrease in tropospheric moisture.

PREV DISCUSSION

Issued at 200 PM EST Thu Nov 12 2026 Activity has been waxing and waning on our KBYX radar this afternoon. Previous showers that had lingered from this morning across the distant Florida Straits have mostly tapered off, but a broken line of showers across the southeastern Gulf is marching toward the island chain. Recent radar trends suggest that the pockets of showers that we can see right now are starting to collapse as an outflow boundary is becoming apparent on radar, but this outflow could trigger new activity as it closes in on Key West. Satellite derived PWAT values have been hit and miss in terms of collecting data due to the higher cloud cover, but dewpoints currently in the lower to mid 70s indicate there is still some moisture nearby to encourage additional shower activity. Since these showers are occurring far from any automated observation sites, we look to MRMS for rainfall estimates. Individual showers may have produced up to 0.50" to 0.75" of rainfall over the waters, so if these showers do make it to the island chain, flooding isn't a major concern. These showers are also moving at 10 to 15 knots, so residence time over the Keys shouldn't aid in significant rainfall amounts.

A cold front on our back doorstep will encourage these showers to continue through tonight and early tomorrow morning, but drier and cooler air behind it should start to filter in quickly. Stations that are located behind this front are currently reporting dewpoints in the upper 50s to mid 60s, but that is along the Gulf Coast of the peninsula. This first front isn't necessarily a wet front, but the cooler air behind will bring overnight lows tomorrow night into the upper 60s for most of us (except for the Upper Keys where the mid 60s will be possible).

A very brief lull will move in over the first half of the weekend while we wait for the next cold front, currently expected to make its presence known sometime Sunday afternoon/evening. While the air won't be particularly "cold" with it, statistical guidance suggests that gradient will be strong enough to invite an extended period of windy conditions across the area with a few bouts of showery weather. NBM 50th percentile values (a 50% chance of occurring) show sustained winds near 20 knots, or near 23 mph, during the middle of next week. Extended statistical guidance indicates that these stronger winds may start to slacken by next weekend.

MARINE

Issued at 849 PM EST Thu Nov 12 2026 There are no watches, warnings, or advisories in effect for the Florida Keys waters. A cold front will arrive during the day tomorrow. Light breezes have shifted to the northwest this evening in advance of the approaching front. Scattered showers may develop along the front tomorrow afternoon as it moves through the area, but will not have much impact on marine conditions. However, breezes will begin to freshen in the wake of the front, and Small Craft Should Exercise Caution headlines may be required as early as Friday evening. Winds may slacken a touch over the weekend, but a strong and expansive region of high pressure will build over the eastern US which will enhance the pressure gradient and promote an extended period of moderate to fresh, occasionally strong northerly breezes early next week.

AVIATION

(00Z TAFS) Issued at 849 PM EST Thu Nov 12 2026 VFR conditions will persist at both terminals through the TAF period. Surface winds will remain from the northwest near 7 knots. An incoming front will meander towards the Keys by the end of Friday. With this front, coverage of precip will be minimal and confidence for timing is low, therefore SHRA was not mentioned in this TAF issuance. A BKN upper-level cloud deck persists ahead of the front, though flight criteria will remain unaffected.

PRELIMINARY POINT TEMPS/POPS

Key West 75 82 69 77 / 10 20 0 0 Marathon 74 82 67 76 / 10 20 10 0

KEY WATCHES/WARNINGS/ADVISORIES

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