It might be a white Christmas after all — that is, if you celebrate Christmas Day like millions of other people in the world do on the Julian calendar, instead of in December.

This weekend, the new year is off to a chilly start, with lower temperatures and on-again, off-again snow flurries, according to the National Weather Service.

Low air pressure from the south, combined with winds traveling from the northwest, contribute to the cold weather, said Bill Modzelewski, meteorologist with the Pittsburgh branch of the National Weather Service.

Modzelewski said it may start snowing Saturday morning, with some breaks during the day. Snow will resume Saturday night, he said. Sunday, he said, Butler residents can expect more snow.

Meteorologist Lee Hendricks said Friday morning that the weekend flurries are not likely to stick around.

“We’re not really looking for any snow accumulation for Butler this storm,” Hendricks said.

Looking ahead to next week, Modzelewski said temperatures will rise on Tuesday and should be back to 40-some degrees. By the middle of the week, he said high temperatures could again be in the 30s.

This weekend, Modzelewski said the area can expect more snow rather than ice. Nonetheless, representatives from the Pennsylvania Department of Transportation said they are actively monitoring the weekend weather, examining “precipitation types, rates, and times to determine the best treatments for roadways.”

“If there is no rain predicted, we may pre­treat with salt brine — essentially a mix of water and salt — before snow starts to fall,” PennDOT representatives said. “This helps us get a jump start on removing ice and snow.”

“Salt usage also depends on the road traffic volumes,” PennDOT said. “On higher-volume roadways, salt is the primary winter material used, especially during rush hours and on bridges, hills, curves and intersections. On lower-volume roadways the amount of salt will be reduced, and antiskid will be used more.”

Hendricks said Friday that black ice may be an issue for drivers Saturday night and into Sunday morning, as temperatures dip into the 20-degree range.

The weekend chill comes after some weeks of balmier weather in December.

“The cold air stayed up in North Canada,” Modzelewski said regarding the higher temperatures seen in Butler County around Christmas. “We never had any strong cold fronts or anything to push that cold to our region.”

Hendricks said the weather is likely to change again before Saturday rolls around.

“This is still kind of an evolving system, so nothing’s exactly nailed down,” he said.