Philadelphia public and parochial schools will be closed Friday as the snowstorm is expected to intensify overnight.

In Pennsylvania, the Turnpike Commission says a 45-mph speed limit is now in effect the length of I-476 from the Mid-County Interchange to Clarks Summit (north of Scranton) and has been extended on I-76/I-276 from Morgantown to the Delaware River Bridge. All abandoned vehicles will also be removed from the roadway, and heavy wreckers are staged at several areas of the turnpike to be used if needed, the commission said Thursday night.

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In New Jersey, Gov. Chris Christie declared a state of emergency for the Garden State on Thursday afternoon and ordered all non-essential state employees to stay home from work on Friday.

The state of emergency means New Jersey's director of Emergency Management will coordinate preparation for the incoming snowstorm with county and local officials.

"The impending weather conditions over the next several days will produce a variety of dangerous travel conditions throughout the state," said Gov. Christie. "I've authorized state officials to take all necessary action in advance of the storm, and my Administration will continue monitoring conditions throughout the remainder of the storm. I encourage all New Jerseyans to stay off the roads if possible so that our first responders and public safety officials can safely respond to any emergency situations."

PennDOT had warned motorists earlier that many roads will be dangerous to drive on for the next couple days. Motorists were asked only to travel during the snowstorm if they absolutely must so that PennDOT maintenance crews have an easier time clearing highways.

"PennDOT follows weather forecasts just like our customers do, but the bottom line is that weather is unpredictable and we need to be prepared for quick changes in weather and road conditions," PennDOT Secretary Barry J. Schoch said. "If significant precipitation is forecast, people shouldn't travel unless they must. This ensures that everyone stays safe and crews can focus on treating the roads."

No state of emergency in Pennsylvania has been declared as of 6 p.m. Thursday.

SEPTA suggests checking its System Status page to find out what buses, trains and subways are running on Friday morning.

Real-time flight information from the Philadelphia International Airport can be accessed here.