textproduct: Key West

KEY MESSAGES

- A Coastal Flood Statement remains in effect. Low lying areas will see minor saltwater ponding around the times of high tide.

- A weak front will stall near or just south of the Florida Keys Tuesday morning. This will lead to low to medium chances for showers and thunderstorms over the next few days.

UPDATE

Issued at 925 PM EDT Mon Oct 12 2026 The frontal boundary that we've been tracking in recent days is finally knocking on the doorstep of the Florida Keys this evening and can be analyzed using the blended TPW product, which shows a narrow corridor of enhanced PWATs up to 1.9 inches across the far southern peninsula. Within this narrow region of moisture pooling associated with the weak boundary and to the south across the Keys, dewpoints in the mid/upper 70s are common at this time but there are plenty of sites reporting dewpoints in the 60s across much of the remainder of the peninsula, especially north of Lake Okeechobee. Meanwhile, latest KBYX radar imagery is detecting just mostly showers with an embedded storm or two moving to the SW around the Gulfside waters adjacent to the Middle and Upper Keys and also over the Atlantic waters across the Straits. Additional isolated to scattered activity may attempt to develop overnight as the aforementioned weak frontal boundary continues its gradual crawl southward, eventually stalling in the Straits into Tuesday. This will set the stage for higher rain chances on Tuesday in the Straits with Chance/Likely PoPs tomorrow there with mostly just Slight Pops for much of the island chain and especially the the Gulf waters to the north. Thus, this will not be a clean frontal passage in terms of scouring out deep-layer moisture in the entire column, which is why the Florida Keys will miss out on those sub-70 dewpoints that nearly the rest of the Sunshine State will experience. However, our humidity levels will still be a touch more comfortable Tuesday with dewpoints mostly in the mid 70s and overnight lows tonight in the mid/upper 70s.

DISCUSSION

Issued at 146 PM EDT Mon Oct 12 2026 So far today there has been minimal precipitation across our waters despite a frontal boundary evident on vis satellite and surface analysis extending from northeast to southwest across South Florida. CIMSS steering products indicate that ridging remains centered over the northern Gulf while Atlantic ridging extends across the Bahamas. Mid-upper level troughing extends south along the Florida Peninsula, promoting modest height falls (as noted on the 12Z RAOB) despite the overwhelming anti-cyclonic presence nearby. Nonetheless, it appears that subsidence from the surrounding regions of high pressure is winning the battle today as upper-level troughing and weak surface convergence have not been enough to produce much activity. In fact, minimal development is noted along the front beyond our waters. Also, MIMIC-TPW imagery shows the column of moisture ahead of the trough/surface front is becoming pinched in between a broad region of dry air advecting west across the Bahamas and the region of post- frontal dry air advecting south, so favorable moisture content is decreasing. Given the close proximity of the stalling front and associated thin moisture axis near or just north of the Florida Keys, it's difficult to not mention at least a chance of showers/storms through tonight. Additionally, the latest hi-res guidance continues to show some potential for mainland convection to track towards the Keys this evening. As far as tides and coastal flooding is concerned, tidal anomalies are very slowly decreasing, but overnight high tides continue to peak near Coastal Flood Statement criteria, so the Statement will remain in effect for the Florida Keys through at least tonight.

The diffuse frontal boundary will stall near or south of the island chain tomorrow morning with a sharp gradient of drier air expected to situate north of the Keys. This will continue to promote gentle to moderate northeasterly breezes across our coastal waters while 30- 40% PoPs become focused across the Straits of Florida. By midweek, the region of high-pressure over the Southeast will begin to shift towards the Western Atlantic. This will promote deep-southeasterly flow across the Florida Keys and should allow deeper moisture to return. Persistent gentle to moderate northeast to easterly breezes will continue during this time. By the end of the week, global models suggest the mid/upper-level ridge will be fully centered south of Bermuda while longwave troughing deepens across the Central to Eastern CONUS. Recent model runs have begun to resolve a stronger subtropical ridge which means the prospects of a strong frontal passage across the Keys this weekend has decreased. This evolution still bears watching over the coming days, but current solutions stall a cold front across the northern Gulf, focusing the higher winds north of our waters. Another feature to watch is an easterly wave currently in the Caribbean Sea. This feature may meander towards the Yucatan this week, potentially becoming more influential to our perceivable weather by the weekend.

MARINE

Issued at 146 PM EDT Mon Oct 12 2026 There are currently no watches, warnings, or advisories in effect across the Florida Keys coastal waters. Despite a cold front to our north, precipitation has been minimal so far today.

From synopsis, a couple of nearby features will define the weather across the Florida Keys for the first half of the week. The Atlantic Ridge is gradually weakening and retreating east towards the central Atlantic. Another region of high pressure is located over the Southeast and northern Gulf. Between the two high pressure centers lies a weak frontal boundary that is extending across south Florida. The front is forecast to slowly pass across the Keys waters by tomorrow. This will promote gentle to moderate northeast to east breezes. There will be slight chances for showers and a few thunderstorms over the next few days as the diffuse and weakening front stalls near the Straits of Florida. Late in the week, a strong cold front could develop and move towards the Florida Keys. Currently, there are low chances that the front will make it to the Florida Keys waters. We will continue monitoring this potential system.

AVIATION

(00Z TAFS) Issued at 925 PM EDT Mon Oct 12 2026 A weak frontal boundary will slide across the Florida Keys overnight with some isolated SHRA/TSRA development possible ahead of this boundary. However, only VCSH has been added to the most recent TAF issuance as overall coverage of any precip activity should be rather low with minimal restrictions at most. Thus, VFR conditions should generally prevail throughout the period with NE winds around 5-7 kts tonight and increasing to near 10 kts on Tuesday following the frontal passage.

KEY WATCHES/WARNINGS/ADVISORIES

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