To all of our friends and family in the Northeast, be careful. This one promises to be a doozey!
Check out your local news or CNN to track the storm and get needed updates. You can also track the amount of snowfall in your area via social media reporting, here.
(CNN) Go home. Stay there. Seriously.
That's the message government officials across the Northeast offered residents Monday ahead of what could be a blizzard of historic proportions bearing down on the region.
"What you're going to see in the (next) few hours is something that hits very hard and very fast and people cannot be caught off guard," New York Mayor Bill de Blasio said, warning that mass transit options will begin to dwindle as the night wears on.
Private cars will be banned from using city streets as of 11 p.m, he said.
The National Weather Service, which isn't prone to exaggeration, is using terms like "life-threatening" and "historic" to describe the weather system taking aim at the Northeast -- with the worst expected to hit Monday night into Tuesday.
"This is going to be a lot of snow, no matter how you add it up, so we are going to be challenged," New Jersey Gov. Chris Christie said.
In New York, Gov. Andrew Cuomo declared a state of emergency, called out the National Guard and said he may order everyone to stay put later tonight, as governors in Connecticut and Massachusetts had already done.
In Philadelphia, Mayor Michael Nutter declared a snow emergency starting at 6 p.m. ET Monday. Cars left parked on snow emergency routes will be towed and owners ticketed, he said.
The first big storm of the year may drop up to 3 feet of snow on Boston and New York before it ends Tuesday, with freezing rain and strong wind gusts possibly reaching 55 to 65 mph. Blizzard and winter storm warnings have been issued from Maryland through Maine and into Canada. Up to 58 million people could be put into the deep freeze.
"I want everyone to understand that we are facing -- most likely -- one of the largest snowstorms in the history of this city," de Blasio said.
De Blasio: Don't underestimate this storm 01:09
That's saying something. The city's biggest snowstorm was in 2006, when 26.9 inches of snow fell. That's second to the 25.8-inch snowfall in December 1947.
Spinning your wheels
While the worst of the weather isn't expected to hit until late Monday into Tuesday, according to CNN forecasters, thousands of flights already have been canceled for Monday and Tuesday, Flightaware.comsaid.
Between 50% and 70% of flights have already been canceled Monday at New York area airports, with even more likely tomorrow, said Pat Foye, executive director of the Port Authority of New York and New Jersey.
American Airlines said it would suspend operations in Philadelphia, Boston and New York late Monday afternoon.
"We plan to resume operations as soon as it is safe to do so," airline spokeswoman Andrea Huguely said.
United Airlines has already canceled all Tuesday flights at Newark, LaGuardia and JFK, as well as Boston and Philadelphia, company spokeswoman Mary Ryan said.
The major U.S. airlines are offering fee-free rebooking of flights to and from the Northeast on Monday and Tuesday.
Amtrak plans to operate a normal Monday schedule but may re-evaluate later in the day.
Hunker down for the long haul
The storm will come in waves, with the New York, Boston and Philadelphia areas seeing light snow Monday morning and heavier snow in the afternoon, CNN meteorologists say.
The really heavy snow will begin Monday night and continue through Tuesday. Some areas will still be getting snow Wednesday.
Northeast braces for 'historic' storm 8 photos
New York Police Commissioner William Bratton said his force was well-prepared with a fleet of vehicles equipped with tire chains and more large SUVs capable of traversing snowy streets.
"We're prepared, and we will have extra resources if necessary," he said.
As elsewhere, New York officials urged residents to stock up for the storm ahead of time.
Many heeded the warnings and descended on stores like the King Kullen grocery in Valley Stream, Long Island,according to CNN affiliate WCBS. Some shoppers wondered if they were really prepared.
"I just got a call from my children's school that it was going to be canceled for Tuesday as well, so now I'm thinking it's bigger than I thought it was going to be," Patti Peretti said.
Some New York groups are already looking out for the most vulnerable residents.
"I think I'll use some of this, especially the soup," said Norma Amigo, 93, of the Upper West Side. "I will not go out if I think it's slippery out, because I fell two weeks ago."
New York state has at least 1,806 plows and more than 126,000 tons of salt to spray onto roads across the region.
The National Guard also was positioning six dozen personnel and 20 vehicles throughout the state Monday morning.
In Boston New England Patriots fans saw their beloved football team off to the Superbowl at a Monday morning celebration that wrapped up before the storm worsened.
Walsh said there was no doubt the city would be slammed, so a major effort now is making sure that people are safe. That includes checking on elderly residents and working to get homeless people off the streets and into shelters, he told CNN's "New Day."
"We have all the things we need to clean the city. It's really just being prepared heading into the storm," Walsh said.
"Our city has been through blizzards before and I am confident we are prepared," Walsh said earlier in a statement on the city website. The city has 700 pieces of snow-moving equipment and 35,000 tons of salt ready, he said.
Christine Carew, a sales associate at Charles Street Supply in Boston, said customers have been coming into the hardware store since it opened Sunday to grab sleds, shovels, ice melt and snow brushes.
"This is kind of typical," she told CNN about Boston getting a lot of snow. "We're more prepared for it. We know it's going to happen."
Tips to prepare for the storm
Government officials warned residents to fill up vehicle gas tanks, stock up on food, make sure they have enough heating fuel and to take other steps to prepare for the possibility of being stranded, possibly without power, for days.
Here are more tips from the Federal Emergency Management Agency:
• Make a family communications plan in case you are separated from your loved ones during the height of the storm.
• Make sure to keep ventilation to the outdoors clear when using kerosene heaters.
• Put off travel. But if you have to go out, keep a disaster supplies kit in your car. It should include a shovel, windshield scraper, small broom, flashlight, battery-powered radio, extra batteries, food and water, matches, a change of clothes, a pocketknife, a first aid kit and blankets.
• Check antifreeze levels, battery condition, exhaust and other vehicle systems before venturing out.
• Stay inside as much as possible, stay dry when you do have to go outside, and watch for signs of frostbite and hypothermia, including loss of feeling, uncontrollable shivering and disorientation.
Riding out the storm
On Plum Island, Massachusetts, Bob Connors said he'll try to ride out the storm but will move to higher ground if things get dicey, according to CNN affiliate WHDH. A 2013 storm destroyed homes on the island.
"When you're living on the edge of paradise like we are now, you give Mother Nature a lot of respect when we need to," said Connors.
Philadelphia could get 5 to 9 inches of snow Monday and an additional 6 to 10 inches Tuesday, the National Weather Service says. The School District of Philadelphia has already announced that schools will be dismissed at noon Monday.
On Sunday, the National Weather Service upgraded its blizzard watch to a blizzard warning for the area from northern New Jersey through southern Connecticut, including New York City. Twenty to 30 inches of snow is possible, with winds gusting 55 to 65 mph.
Visibility will be a major problem, said CNN meteorologist Judson Jones.
"This is not one of those storms you want to go out in while it's happening," Jones said. "You want to wait for the winds to die down ... before you go to the store."
Tuesday is shaping up to be a day when the reality of the weather sets in.
One of the inevitable aftereffects of snow -- flooding -- will quickly become a problem.
There could be coastal flooding in Massachusetts starting early Tuesday, with pockets of major flooding on east-facing coastlines, the state emergency agency said.
"Plan to work from home is the best advice for Tuesday," Jones said.
CNN's Sara Ganim, Joe Sutton and Dana Ford contributed to this report.