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 1103 AM EDT Wed Sep 9 2026

It has been quite active this morning with scattered showers and embedded thunderstorms making their way from east to west across the region. Most of the activity has stayed offshore, but what precipitation has managed to find land, has been mostly up in the Upper Keys. This hour the stronger activity has set up across the Southeast Gulf waters. This activity will continue a westward motion and stay just north of the Dry Tortugas.

Additional waves of moisture will continue to push through maintaining a threat for scattered showers and isolated thunderstorms through the afternoon and evening. The axis of an easterly wave will move through tonight with heightened rain/thunder chances for the overnight into early Thursday.

MARINE

Issued at 1103 AM EDT Wed Sep 9 2026

Scattered showers and isolated thunderstorms will continue to trek east to west across the coastal waters surrounding the Florida Keys. The stronger of the activity will be capable of gusty erratic winds, blinding downpours, and bouts of frequent lightning. Additional moisture will move through maintaining above normal rain/thunder chances through this evening and overnight. Outside of convection, expect gentle to occasionally moderate easterly breezes.

AVIATION

(15Z TAFS) Issued at 1103 AM EDT Wed Sep 9 2026

VFR conditions can be expected outside of any convection along with gentle easterly breezes. Any passing shower or thunderstorm will pose a risk for brief IFR conditions and gusty erratic winds. Coverage of showers and thunderstorms will remain scattered this afternoon and potentially increase overnight. Will monitor for adjustments that may be needed.

PREV 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.

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.