The National Weather Service has issued a dense fog advisory for Long Island Tuesday night into Wednesday morning.

Visibility could be a quarter of a mile or less, said the advisory, which started at 6 p.m. Tuesday and lasts until Wednesday at 6 a.m.

If driving, the service cautioned, "Slow down, use your low beam headlights and leave plenty of distance ahead of you in case a sudden stop is needed."

WeatherLatest forecast

In addition, rain is forecast to spread over the area after 8 p.m., with a total of a quarter to half an inch expected through Wednesday morning, said John Murray, of the weather service, based in Upton. The morning commute should not be affected, forecasters said.

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The fog results from warmer air sitting over the much colder water and snowpack, fed with plenty of moisture from the rain, said Faye Barthold, another weather service meteorologist.

Temperatures overnight are expected to be in the low 40s.

For Wednesday, highs near 52 and cloudy skies are expected, giving way to afternoon sun.