HARRISBURG, — A winter storm descending on Pennsylvania threatened to bring a foot or more of snow to parts of central and eastern parts of the commonwealth today, prompting governmental office and school closures and speed and vehicle restrictions on local interstates.

The National Weather Service predicts 10 to 14 inches of snow for the Lehigh Valley and Berks County in eastern Pennsylvania, 6 to 12 inches in parts of central Pennsylvania and 6 to 10 inches in the Philadelphia area.

State officials said the Capitol complex in Harrisburg would be closed with nonessential workers there and in Philadelphia, Reading and Scranton state office buildings given the day off. The Philadelphia School District and archdiocese of Philadelphia announced that all public and parochial schools are closed. City offices in Philadelphia were also closed with nonessential employees told not to report.

The Pennsylvania Department of Transportation said the speed limit will be 45 mph on many interstates in eastern and central Pennsylvania. In addition, empty straight trucks, large combination vehicles such as tandem trailers and doubles, trailers pulled by passenger vehicles, motorcycles and recreational vehicles were barred from interstates during the storm.

The Pennsylvania Turnpike also imposed a 45 mph speed limit from the Blue Mountain Tunnel to Delaware Bridge exit and on the entire northeast extension. Officials earlier banned empty and double tractor-trailers but later expanded the ban to noncommercial or recreational trailers pulled by passenger vehicles.

The storm threatened widespread problems for commuters and the possibility of more power outages on the heels of last week’s ice storm, especially given high winds that could topple trees and branches onto power lines.

“Snow has become a four-letter word in Delaware County, and all along the East Coast this winter,” said Tom McGarrigle, chairman of the Delaware County Council outside Philadelphia.

The state put 450 National Guardsmen on duty overnight and activated the emergency operations center in Harrisburg.

“I’m really concerned about the power grid in the southeast, given that it’s just been put back up,” said Pennsylvania Emergency Management Agency director Glenn Cannon.

Precise predictions about the scope and location of the largest accumulations were hard to come by, but some were saying it would be the Harrisburg area’s biggest storm so far this winter.

“These storms are always tricky, these coastal storms,” said meteorologist Craig Evanego with the National Weather Service in State College. “You get the narrow swath of the heaviest snow, and it’s hard to say where that will happen.”

Numerous municipalities in the projected path imposed special parking and travel restrictions ahead of the storm’s arrival, and schools began to announce closings late Wednesday.