textproduct: Key West

KEY MESSAGES

- Moisture will linger across the region through the end of the week, supporting rain and thunderstorm chances.

- The primary threat for any stronger thunderstorms will be dangerous lightning strikes. When thunder roars, go indoors. If on a boat, stay low, or go below.

- Heat index values will range from 100-108 degrees daily with little relief from the muggy conditions overnight. Know the signs of heat stress, take frequent breaks, and stay hydrated.

DISCUSSION

Issued at 400 AM EDT Wed Sep 9 2026

After many days without much of a prevailing wind, a light east easterly breeze is becoming more evident across the area. This is a result of surface ridging extending from the Gulf Coast States, through the Mid Atlantic and out into the Atlantic. The local environment remains seasonably moist and unstable. Surface conditions are seasonable with temperatures broadly in the lower to mid 80s with dew points in the upper 70s. Earlier nearby convective activity precluded an evening sounding in Key West. However, the sounding out of Miami indicated precipitable water was very high at 2.35 inches. Ample CAPE and limited low level inhibition was present and not far off the usual. Synoptically, deep layered ridging is stacked over the southeastern United States, while a mid to upper level trough is slowly spinning westward through the northwestern Caribbean Sea.

The surface ridge reaching across the Southeastern United States will become better established across the Florida Peninsula today into tonight. As a result, breezes should firm up out of the east to southeast, becoming gentle tonight. Deep layered moisture is projected to remain high, along with CAPE remaining high with little to no inhibition. As a result, rain chances will remain slightly above normal. No trend in temperatures are expected and highs will continue near 90 with lows in the lower to mid 80s. Sultry conditions will remain with dew points often pushing well into the upper 70s.

Through the remainder of the week, the surface ridge will push out into the Atlantic while the axis settles southwards into Florida. Overall, breezes will remain gentle, with peaks in the evening and lulls during the day. Guidance continues to indicates at least a couple of swathes of enhanced lower level moisture riding westward across our area and help to nudge PoPs slightly above normal.

MARINE

Issued at 400 AM EDT Wed Sep 9 2026

A surface ridge spanning from the Gulf Coast States to well east of the Mid Atlantic coast will gradually spread eastward over the next few days. As a result, light east to southeasterly breezes will gradually strengthen to a gentle to moderate breeze over the next couple of days. Winds may strengthen a bit to further to moderate later in the week and weekend as the ridge to our north settles slightly southward. Winds will tend stronger in the evening and night, while lulling during the day.

AVIATION

(00Z TAFS) Issued at 400 AM EDT Wed Sep 9 2026

Seasonably active weather remains in place. While VFR conditions will prevail, bouts of sub VFR conditions along with thunderstorms will be possible at the island terminals. Surface winds will be light out of the east to southeast, picking up to a light to gentle breeze.

PRELIMINARY POINT TEMPS/POPS

Key West 92 83 92 82 / 50 40 60 30 Marathon 90 83 90 82 / 40 50 40 30

KEY WATCHES/WARNINGS/ADVISORIES

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