Long Island will see an unseasonably warm start to the week, turning into colder days by Wednesday, according to the National Weather Service.

On Sunday, a dense fog advisory is in place for Long Island until 10 a.m., with visibility of less than a quarter-mile, said Mike Layer, meteorologist with the service's Upton bureau.

The fog is forecast to become patchy as the day continues, with overcast skies lingering throughout the day, Layer said.

High temperatures on Sunday are forecast to be in the upper 40s, with lows in the mid-40s.

A 30 percent to 40 percent chance of precipitation begins Sunday night, and continues into Monday morning, Layer said.

Clouds will continue into Monday, with highs at an unseasonable mid- to upper 50s, Layer said. Colder air moving in Monday night will push lows into the low to mid-30s, he said.

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Tuesday will be cooler, with highs in the low 40s and mostly cloudy skies. A slight chance of showers returns on Tuesday. Lows will be in the lower 30s.

Wednesday will see a 30 percent to 40 percent chance of precipitation, more likely in the eastern sections of the island, Layer said. Highs will be in the low 40s with mostly cloudy skies, and lows will be in the upper 20s to low 30s.

Dry conditions will prevail on Thursday, with partly to mostly sunny skies. Highs will be around 40, with lows in the low to mid-20s.

Friday will continue to be chilly, with highs in the mid- to upper 30s.