After an afternoon high of 51 degrees Wednesday, the overnight hours on Long Island will bring areas of fog after 10 p.m. and lows of about 40 degrees, the National Weather Service said.

The average low for this time of year is in the mid-20s, said Joe Pollina, weather service meteorologist in Upton.

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Thursday will bring mostly cloudy skies, with temperatures rising to around 60 degrees in areas closer to New York City, into the upper 50s for most of the rest of the Island and in the lower 50s over the Twin Forks, he said.

The overnight hours should be featuring areas of fog, with some drizzle and rain possible after midnight. Overnight lows are forecast to be “incredibly warm,” Pollina said, reaching around the mid- to upper 40s. That would be even above what the average daily high temperatures are at this time of year, which is 42 degrees, he said.

That means a record for the day — that of warmest low temperature — could be broken Thursday. The record is 46 degrees, set in 1990