Marine Weather and Tide Forecast for Longboat Key, FL

DISCUSSION
Issued at 1231 AM EST Thu Nov 6 2025 Quasi-zonal U/L pattern across the CONUS today and Friday will begin to amplify over the weekend with a deep trough developing over the eastern half of the U.S. Sunday and Monday. Main trough axis will rotate off the east coast of the U.S. Monday night and Tuesday with a resulting broad mean trough over the eastern U.S. and a broad ridge out west.

An U/L disturbance over the central Gulf will advect high cloudiness over the forecast area today and tonight. At the surface, high pressure over the mid Atlantic will extend over the Florida peninsula today and will move over the western Atlantic on Friday.
This will allow boundary layer winds to veer to the east and southeast, which will advect L/L moisture back across the area with dew points climbing into the mid to upper 60s...and temperatures to run several degrees above climatic normals. This will also increase the risk for fog to develop both Saturday night and Sunday night.

As the U/L pattern amplifies over the weekend, a strong area of Canadian high pressure will dive south out of Canada through the plains states. The associated cold front will push across west central and southwest Florida late Sunday and Sunday night. Deep layer moisture will be limited so only a slight chance of a shower or thunderstorm expected ahead of the frontal passage.

Much colder drier air will advect across the forecast area Sunday night and Monday in the wake of the front...with temperatures on Monday likely holding steady or falling slowly through the day with gusty northwest winds. High temperatures will be in the lower 60s north
mid to upper 60s central
and around 70 to the lower 70s south. As the cold air rides over the warm waters of the Gulf, a large area of strato-cu will likely develop and may advect locally onshore near the coast. Can't rule out an isolated sprinkle or light shower, primarily over the coastal waters.

Monday night will be clear and cold with overnight lows in the lower to mid 30s north
upper 30s to lower 40s central
and mid 40s south. North winds will persist which will make it feel even colder.
Potential that temps across northern areas could be a category colder if the center of the surface high sinks a bit further south allowing winds to collapse which would enhance radiational cooling.

The surface high will hold over the region on Tuesday with highs ranging from around 60 north to 70 south under sunny skies.
Another cold night on tap Tuesday night with lows in the mid to upper 30s north
lower to mid 40s central
and the upper 40s to around 50 south.

AVIATION
(18Z TAFS)
Issued at 1237 PM EST Thu Nov 6 2025

VFR conditions prevail through the period.

MARINE
Issued at 1231 AM EST Thu Nov 6 2025 Gradient will remain rather weak with east to northeast winds below cautionary levels today and Friday...becoming south to southeast Saturday and Sunday. A strong cold front will push across the waters Sunday night and Monday with winds shifting to the northwest and likely increasing to SCA levels across all of the waters.

TBW WATCHES/WARNINGS/ADVISORIES
FL...None.
Gulf waters...None.