textproduct: Key West

KEY MESSAGES

- Shower and thunderstorm coverage is expected to increase overnight with peak chances Sunday night, gradually tapering off early next week. Confidence remains low regarding total rainfall amounts.

- Mainly light southerly breezes this morning will shift northwest to north through the day, possibly surging briefly to gentle to moderate this evening.

- Shower and thunderstorm potential will trend downwards Monday through midweek.

DISCUSSION

Issued at 214 AM EDT Sun May 3 2026

A phased mid latitude trough reaches down through the southeastern United States. This has resulted in cyclogenesis off the Atlantic Coast with a trailing weak trough stretching through South Florida. In addition, modest upper level diffluence has moved in across Florida and the Keys and contributed to areas of rain with scattered showers and a few embedded thunderstorms across the southern and western portions of the forecast area this morning. Thus far, primarily light to moderate rain has affected the western half of the island chain. Aside from convective influences, winds are gentle southerlies. The persistent southerlies have maintained temperatures well above normal this morning with nearly all observations reporting above 80 degrees and dew points in the mid 70s.

Shower and thunderstorm chances will remain well above normal today into tonight. While the first upper shortwave trough will begin rotating out of the synoptic trough, a new southern stream trough will drive eastwards across the Gulf, reaching Florida by this evening. It is very possible that the current morning activity will taper off today. However, the lull in activity likely will be short lived as the next shortwave begins exerting its influence and the local environment recovers with modest instability and a nearly saturated column. The weak surface boundary will likely press southwards near the Keys today into this evening, shifting breezes northwest to north. A brief modest freshening will be possible as this happens, although uncertainty is high. Temperatures and dew points will slip a few degrees back to where we were before the southeasterlies kicked in.

While the Gulf shortwave trough will lift out into the Atlantic early Monday morning, broad mid latitude troughing will remain across our area stretching southwards past Cuba. This along with continued saturated lower levels and weak surface troughing near the island chain will remain supportive of convective, although to a lesser extent. Will maintain low to mid shower chances and slight thunder chances Monday and Monday night. The wind forecast will remain highly uncertain through this period due to the proximity of the surface trough amplifying slightly off of Florida's southeast coast, and winds wanting to surge south of the ridge moving southwards into Florida. Winds will be generally light to moderate with possibly another surge Monday evening.

By mid week the previously mentioned surface ridge will be better established across Florida and the nearby surface trough will wash out. This will return the Keys to the more usual light to gentle east to southeasterly breezes. Meanwhile a mid to upper level ridge will march eastwards across the Gulf, helping to dry out the free atmosphere. Rain chances will drop to slight with limited to no chance for thunderstorms. The south of east streamlines will result in highs climbing slightly above normal with dew points returning to a muggy mid 70s.

MARINE

Issued at 214 AM EDT Sun May 3 2026

A weak surface trough will slide slowly southwards into the Florida Straits today as a weak frontal boundary pushes down into the Keys. This has set the stage for much wetter than normal weather. Some stronger showers and thunderstorms will generate locally strong winds, blinding downpours, and at times, frequent lightning strikes. Weather will calm down as the frontal boundary slides southward into the straits and ridging builds southward across Florida. Expect light breezes to shift northwest to north this afternoon, then light to gentle northeasterlies tonight. Thereafter the high will gain full control and return the Keys to gentle east to southeasterlies.

AVIATION

(06Z TAFS) Issued at 214 AM EDT Sun May 3 2026

A wet weather pattern will affect the terminals through today. As a result, expect considerable cloudiness and occasional MVFR ceilings. In addition, showers and thunderstorms will be possible, bringing with them MVFR to IFR ceilings, gusty shifting breezes, and poor visibility in heavy rain.

KEY WATCHES/WARNINGS/ADVISORIES

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