Weak low pressure lingers over the area, generating mostly calm Long Island waters, the National Weather Service said Thursday in its marine forecast.
A small craft advisory for waters from Moriches Inlet to Montauk Point and areas 20 nautical miles out expired at noon, the service's Upton office said.
Seas in that South Shore stretch were at 4 to 5 feet but were to subside starting at daybreak, the service said.
Winds from the north and northwest stay from 5 to 10 knots for most of the day, but starting Saturday they shift to the south and southeast and climb as high as 15 knots.
The Fourth of July weekend calls for conditions mostly staying at below small craft advisory levels.
Inland conditions for Nassau and Suffolk counties Thursday call for daily highs in the 80s and sunny skies, with clouds gradually moving in by nighttime.