A small craft advisory was extended Thursday for South Shore waters, the National Weather Service said in its marine forecast.

The service's Upton office said seas in the 3- to 5-feet range and some wind gusts of up to 25 knots are likely through the afternoon, prompting the advisory to be extended.

The advisory runs through the afternoon hours and covers Moriches Inlet to Montauk Point; Fire Island Inlet to Moriches Inlet; and Sandy Hook, New Jersey, to Fire Island Inlet.

Also, some morning fog could appear over Long Island Sound and in New York Harbor.

The service said seas could remain close to the 5-feet threshold Thursday night but conditions are expected to be too marginal to extend the advisory further.

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Slightly weakening wind conditions should bring all areas below small craft advisory levels Friday, the service said.

Inland conditions Thursday across Nassau and Suffolk counties are expected to be partly sunny, with daily highs in the mid to upper 70s and a 30 percent chance of rain.