A freezing rain advisory is in effect from 4 to 9 a.m. Friday for Bedford, Blair, Centre and Huntingdon counties, the National Weather Service in State College said.
A brief period of freezing rain is expected around sunrise Friday.
Temperatures will be very close to freezing so problems are expected to be minor, the weather service said. However, a wide area across central Pennsylvania will have a two- to three-hour window when rain will begin as freezing rain and could cause a glaze of ice on trees, sidewalks and other colder objects.
Road surfaces may stay mild enough to keep ice from forming on all but the bridges and overpasses, the weather service said.