(State College) -- Snow is likely headed to central Pennsylvania this evening. The National Weather Service says the region is under a winter storm watch from 7 p.m. Wednesday until 7 a.m. Thursday Snowfall could reach up to six inches in some areas of Schuylkill County. Meteorologist Bill Gartner says the Harrisburg area could see two to four inches, while Lancaster, Chambersburg and York could get less. He says rising creeks and streams are also a worry. "It's really going to be a race to see what happens first. Is it the rain ends or the cold air comes in? And right now we're looking at a combination of the two," Gartner says. He adds the snow will be the result of a rain storm system moving north colliding with cold air moving in from the Great Lakes. He says most of the system should be cleared out by tomorrow morning.