The weekend's pleasant weather including the unseasonably warm temperatures might be leaving the region this week.

A cold front is set to arrive in Butler County Tuesday night, according to Lee Hendricks, a meteorologist with Pittsburgh's National Weather Service office.

That front looks likely to supplant existing systems, Hendricks said, sending thermometers in the area down to more usual levels for early January.

“It's going to change here come Wednesday,” Hendricks said. “We're going to be in a period of much cooler air than what we've had for the past six weeks. We'll just have to see how things work out.”

That sounds dramatic, but the actual forecast isn't much to fear. As of Sunday, Wednesday looks likely to bring scattered snow showers. Hendricks said Butler County “may get less than an inch.” Temperatures look to hover around 30 degrees that day and fall into the 20s that night.

Those temperatures in the 20s don't look like they'll leave quickly. Such chilliness is forecast for all of Thursday.

Hendricks pointed out how oddly little snowfall the Pittsburgh area has received this year.

“We're well behind the curve on snow,” Hendricks said. “Even last month we had a grand total of two inches of snow. We're usually at about 8.5 inches in December.”

Even the cold weather that is on its way doesn't look too long lasting. High pressure on the West Coast, Hendricks said, is pushing cold air from Canada down to Pennsylvania. But that system will likely break down fairly quickly, he added.

“We should be trending to remain slightly above normal temperature-wise,” Hendricks said.