What to expect from major nor’easter

A nor’easter is expected to march up the East Coast on Sunday into Monday, bringing significant snow for the I-95 corridor and placing New York City under a blizzard warning for the first time in nearly a decade.

More than 50 million Americans are bracing for winter storm conditions, including heavy snow and high winds, beginning on Sunday and continuing into Monday.

People in areas under the blizzard warning should expect heavy snow, on the order of 12-18 inches, and winds gusting as high as 40-60 mph.

Over 3,000 flights were cancelled as of Saturday evening, according to airline data. Airlines are moving planes out of the storm’s path so they are ready to go once airports reopen.

Cancellations and delays are expected through at least Wednesday.

Timing of the storm

This coastal storm will start taking shape over the coastal Carolinas early Sunday, bringing rain to the Mid-Atlantic and some scattered light to moderate snow from northern Virginia up into Pennsylvania and into parts of New Jersey and New York starting Sunday morning into the afternoon.

By late Sunday afternoon, the coastal storm will begin to quickly intensify off the Mid-Atlantic as it tracks to the northeast and parallels the East Coast, quickly changing everything from Virginia to New York to Massachusetts to all snow as colder air comes into play.

The storm is expected to intensify overnight Sunday into Monday.

By early Monday morning, the storm will be bringing heavy snow, strong wind gusts and coastal flooding across much of the coastal Northeast — from Dover, Delaware, to Philly and New York City and Boston. The Jersey Shore, Long Island, the southern coast of New England and Cape Cod could all see blizzard and whiteout conditions early Monday from the combination of heavy snow and very strong wind gusts.

By late Monday morning into the afternoon, the snow becomes more intermittent from New Jersey and New York to the west, while the snow over New England will remain consistent and potentially heavy. Wind gusts will continue to be strong over the region throughout Monday.

Northeast winter storm set to arrive Friday, just before possible weekend nor’easter

New York Gov. Kathy Hochul declared a state of emergency for 22 counties, including New York City, where she said snow totals could reach as high as 2 feet.

“We’re all New Yorkers, we think we can handle anything but you need to hear this from me … this is one to take seriously,” she said during a news conference Saturday.

The governor said the National Guard will be available to help during the blizzard.

New Jersey Gov. Mikie Sherrill declared a state of emergency for all 21 counties starting at noon Sunday.

“I’m urging you again, do what you got to do now. There’s a great hockey game on in the Olympics tomorrow. U.S. is going for the gold. Stay at home and watch that,” Sherrill said. “If you don’t have anything else, you could do a puzzle, eat some chili, but whatever you do, try to stay home tomorrow and off the road.”

New Jersey Transit President Kris Kolluri reiterated for people to stay home and said that NJ Transit will do its best to run regular service tomorrow but will continue to monitor the situation and make adjustments as needed.

The National Weather Service has upgraded southern Delaware, the Jersey Shore, all of New York City, Long Island and coastal Connecticut to a blizzard warning for increased confidence in snowfall of more than one foot and gusty winds that will likely cause blizzard conditions.

Coastal flood watches are also up from coastal Delaware to the Jersey Shore and Long Island to the coast of southern New England for minor to moderate coastal flooding during high tide.

1st blizzard warning in NYC since 2017

New York City Mayor Zohran Mamdani also asked New Yorkers to stay inside and stay off the roads for their safety, at a press conference Saturday.

Mamdani warned New Yorkers that Monday morning commute will be extremely hazardous with heavy snowfall and peak winds creating “slippery conditions and greatly reduced visibility,” even “dangerously icy sidewalks and streets,” he said.

Snowfall in New York City is expected to start Sunday morning starting at 6 a.m., growing heavier over the day. By 6 p.m., intense snowfall is expected to begin and dangerous winds will increase overnight into Monday morning and into the evening, Mamdani said.

New York City is currently expecting from 13 to 17 inches of snow, with a slight chance the city may get 20 inches of snow, according to Mamdani.

ABC News’ Sam Sweeney contributed to this report.