The National Weather Service said that Sandy "has the potential to be an historic storm, with widespread wind damage and power outages." It said that the "prolonged wind will create the potential for long-lasting power outages and serious flooding."
Nutter said that he had spoken with President Obama, who offered federal help if needed, and that extra police and fire personnel would be on duty. He urged drivers to keep the streets clear for them.
The following are closures and service changes resulting from the storm:
* All Philadelphia public schools are closed Monday. Also closed are all early childhood and after-school programs. Go to philasd.org, or call the district's information hot line at 215-400- INFO (4636), for updates. Archdiocesan high schools and parish elementary schools are closed both Monday and Tuesday.
* SEPTA is suspending all service. CCT Paratransit service is available for reserved dialysis patients only as long as safe operations are possible. Amtrak and NJ Transit are both shut down.
* All city offices are closed except for public-safety operations, fire, police and rescue. There is no city trash or recycling service.
* Community College of Philadelphia, University of Pennsylvania, Drexel University, Temple University, Saint Joseph's University, University of the Arts, Philadelphia University and Villanova University are all closed.
* Philadelphia Parking Authority street parking is free.
Some tips to prepare for the storm:
* To see if you're in a flood-prone area in the city, go to ph.ly/PhillyFlood. If so, determine ahead of time where you would go and how you'll get there if your home floods.
* Clear clogged rain gutters and make sure trees and shrubs around your home are trimmed. Secure all outdoor furniture, decorations and trash cans.
* Fill the bathtub and other large containers with water to have a supply for drinking and for flushing the toilet.
- Daily News wire services contributed to this report