Update at 12:20 p.m. ET

Nearly 30 million people in the Northeast are bracing for what the National Weather Service is calling a potentially historic blizzard that could bring more than 2 feet of snow today and Tuesday to parts of the region.

Blizzard warnings have been issued all the way from the New Jersey shore to coastal New England from this afternoon through late Tuesday.

The National Weather Service said New York could get as much as 2 feet of snow; Boston and Providence, R.I., could get up to 2.5 feet. Wind gusts of up to 50 mph are expected inland, and some gusts could reach 75 mph on the Northeastern coast.

In New York, Gov. Andrew Cuomo declared a state of emergency for Bronx, Dutchess, Kings, Nassau, New York, Orange, Putnam, Queens, Richmond, Rockland, Suffolk, Ulster and Westchester counties.

Nonessential state workers in those counties are being asked to leave at 3 p.m. New York City's subway service will operate on a limited schedule after 7 p.m., he said.

"This is going to be a serious blizzard that should not be taken lightly," Cuomo said.

In Connecticut, Gov. Dannel Malloy, besides declaring a state of emergency, announced a travel ban for all roads starting at 9 p.m. tonight.

"People need to take this storm seriously," he said. "If current predictions are accurate, we will need people to stay off the roads so that emergency personnel and utility crews can get to the places they need to get to, and to make sure that our plows can keep critical roadways clear."

New Jersey Gov. Chris Christie declared a state of emergency for the state and authorized a staggered dismissal at 1 p.m. for state officers and nonessential workers. He said state offices will also be closed Tuesday.

In Boston, Logan Airport officials said no flights will leave the airport after 7:30 p.m. There will be no air traffic at the airport on Tuesday.

"This could be a storm the likes of which we have never seen before," New York City Mayor Bill de Blasio said Sunday.

De Blasio said today that all nonemergency traffic will need to be off the road after 11 p.m.

Weather Underground puts it this way: "By the time its last flake falls on Wednesday, the Blizzard of 2015 will likely pile up some epic snowfall amounts which may rank in the top ten in recorded history for all three of these cities."

The nor'easter could cripple travel. Already, thousands of flights have been canceledor delayed. Daniel Baker, CEO of the aviation tracking site FlightAware.com says this could be a good chance for stranded airline customers.

"The good news is that every airline is offering fee-free changes, and in some cases cancellations and rescheduling opportunities," he says.

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