Capitol Hill police and snow plows work in Constitution Avenue during a winter storm in Washington January 23, 2016. [Photo/Agencies]

The storm was forecast to move offshore in southern New England early next week. Philadelphia and New York were expected to get up to 18 inches of snow before the storm abated.

Low-lying areas of New York and New Jersey might see flooding during high tides on Saturday and Sunday, officials said.

More than 4,200 US flights were cancelled on Saturday, most of them at airports in New York, Philadelphia and Washington, according to tracking website FlightAware.com.

Amtrak modified service on train routes along its busy Northeast Corridor and New Jersey Transit shut all bus, rail and light rail service early on Saturday and said it would restore service as "conditions permit."

The Washington Metropolitan Area Transit Authority, which includes the country's second-busiest subway system, took the rare step of suspending operations from late Friday through Sunday.