8 P.M. EST
The snow lets up, with none falling in Philadelphia and only light flurries in Providence, Rhode Island, in Boston and in New York City. But New York Mayor Bill de Blasio warns residents not to grow relaxed because of the lull: "This is literally the calm before the storm," he says.
Amtrak says it will suspend rail service in the New England region and modify service between New York and Washington on Tuesday because of snowy conditions. It says the Acela Express and Northeast Regional service between New York and Boston will be suspended.
7 P.M. EST
Snowfall totals: In New York City, close of 5 inches in Queens and more than 4 inches in Central Park, the National Weather Service says. In parts of Pennsylvania, as much as 3 inches.
Rhode Island Gov. Gina Raimondo tells residents to prepare for 2 to 3 feet of snow and expect to potentially be without power for days. "Stay in your house until you hear otherwise," Raimondo warns.
6 P.M. EST
Connecticut Gov. Dannel P. Malloy activates 400 members of the National Guard to assist with any emergency that may arise and orders all nonessential state workers to stay home Tuesday.
The New York State Thruway Authority is restricting all tractor-trailers on Interstate 87 between Newburgh and the New York City Line.
Snow predictions have risen in Maine to 2 feet, and dozens of school districts and businesses say they'll be closed Tuesday, including public schools in Bangor, Biddeford, Falmouth and Saco.
2,000 pieces: The size of the puzzle lifelong Augusta, Maine, resident Heather Gluck has on hand to bide her time if power goes out. "If I have to do it by candlelight tonight, I will," she said.
Flights canceled: About 7,500 through Wednesday.
5 P.M. EST
Broadway theaters are shuttering as the snowstorm begins to blast Times Square. All performances will be closed on Monday, a traditionally quiet night with few shows available, and no decision about Tuesday has been made.
Massachusetts: 500 National Guard troops are on stand-by to be quickly deployed if needed, says Gov. Charlie Baker.
Commuter trains: A Connecticut travel ban begins at 9 p.m., and Metro North is running more trains than normal to get commuters home well before heavy snow arrives tonight. In New York, Port Authority Trans-Hudson rail service will operate on weekend schedules after 9 p.m.
Weather unfit for man or beast: New York City's four zoos and aquarium will be closed Tuesday. The Wildlife Conservation Society says they closed at 3 p.m. Monday.
4 P.M. EST
Massachusetts Gov. Charlie Baker says hundreds of thousands of people could lose electricity and it could take several days for it all to be restored. Connecticut can expect at least 100,000 power outages, utility companies say.
A full jury was seated Monday in the Aaron Hernandez murder trial in Fall River, Massachusetts, but a judge pushed opening statements to at least Thursday because of the storm.
New Jersey: Road crews are salting major highways, and speed is restricted to 45 mph on the entire Garden State Parkway and New Jersey Turnpike.
Philadelphia: Snow emergency starts at 6 p.m. ahead of an expected 10 to 14 inches of snow. That means cars left on major arteries will be towed.
Flights canceled through Wednesday: About 7,000.
3 P.M. EST
Rhode Island Gov. Gina Raimondo to residents: Be off the roads by 8 p.m. before the full force of this "multiday event" arrives. And Massachusetts Gov. Charlie Baker issues an indefinite ban on all nonessential motor vehicle travel starting at midnight, punishable by a fine of up to $500. What they fear is that the impending winds of 60 to 70 mph and swirling snow will make travel extra-treacherous.
New York City's major stock exchanges say they plan to hold normal trading hours Tuesday despite the crippling load of snow expected in the city. Why? Most trades are now handled electronically.
Airlines: Most major carriers say they'll waive the change fee, typically $200, for passengers who reschedule their travel to or from the Northeast through Tuesday.
Amtrak: Trains will continue to run in the Northeast corridor, but passengers should expect reduced service in the 440-mile stretch between Boston and Washington.
2 P.M. EST
A spokesman at Manchester-Boston Regional Airport in New Hampshire says all flights likely will be canceled Tuesday - the first time the airport would close in 25 years. The southern part of the state expects about 2 feet of snow.
New York City Mayor Bill de Blasio says streets will be closed to all but emergency vehicles starting at 11 p.m. ahead of the 18 to 24 inches of snow expected. A blizzard warning is now on for the city through midnight Tuesday.
New York: Fire Department plans to have an extra 500 staffers on duty.
New Jersey: NJ Transit shuts down starting at 8 p.m. Monday and commuter trains won't be restored until at least Thursday morning.
Flights canceled: More than 6,000.
1 P.M. EST
New Jersey Gov. Chris Christie declares a state of emergency, and New York Gov. Andrew Cuomo considers a travel ban for the New York City area ahead of storm that is expected to start in earnest Monday evening.
Snow already is falling in Philadelphia and New York, but the worst is expected tonight and into Tuesday, with 1 to 3 feet across much of the region, affecting 35 million people.
A coastal flood warning has been issued from New Jersey to Massachusetts amid predictions of heavy winds, up to 75 mph in some areas.
Flights canceled: Nearly 6,000, scheduled for Monday and Tuesday.
Philadelphia: Schools close at noon, nonessential city workers to leave two hours later.
The Northeast shuts down against a snowstorm that could be one for the history books, with some 35 million people in its path in the Philadelphia-to-Boston corridor.
Snow is coming down in Philadelphia and New York, and Boston is up next in the afternoon. The worst of it is expected to hit tonight and into Tuesday, with 1 to 3 feet across much of the region.
Flights canceled: More than 5,000 and counting.