A dense fog advisory has been extended for Long Island waters until Friday afternoon, the National Weather Service said in its marine report.

The advisory covers waters from Montauk Point to Sandy Hook, New Jersey, and offshore 20 nautical miles, the service's Upton office said.

Also included in the advisory are Long Island Sound and all Long Island bays.

The service said fog is lifting over New York Harbor, which is excluded from the extension.

The service said fog is likely to be an issue Saturday morning, with visibility at times to less than one nautical mile.

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Otherwise, a week southerly wind flow is likely to keep waters mostly calm; that flow is expected to increase starting Monday, the service said.

Mostly, weather conditions inland for Long Island on Friday call for sunny skies and temperatures in the low to mid 70s.