The storm front of a monster snowstorm arrived on Friday afternoon in Washington, D.C., threatening to dump as many as 30 inches (76 cm) of snow on parts of the Middle Atlantic region and bring record accumulations to the U.S. capital.

After days of planning by emergency officials and a scramble by residents to stock up on supplies, the blizzard got underway in the nation's capital at about 1 p.m. The storm, expected to end late on Saturday afternoon, could leave 2 to 2.5 feet (61 to 76 cm) on the ground and bring winds of 30 to 50 mph (48 to 80 kph), according to the National Weather Service.

The western suburbs of the capital were expecting up to 3 feet of snow. In Virginia, the National Guard planned to bring in up to 300 troops to deal with emergencies.

"I want to be very clear with everybody. This is a major storm," Washington Mayor Muriel Bowser said as the nation's capital braced for what could turn out to be one of the worst storms in its history.

"This has life-and-death implications and all the residents of the District of Columbia should treat it that way."

The Weather Channel said more than 85 million people in at least 20 states were covered by either a blizzard warning, winter storm watch, winter storm warning, winter weather advisory, or freezing rain advisory.

Airlines canceled nearly 6,300 flights for Friday and Saturday, most of them at airports in the New York and Philadelphia areas, according to FlightAware.com. Philadelphia's airport said it would cancel all flights scheduled for Saturday.

But the Port Authority of New York and New Jersey said it had no plans to shut its airports.

AccuWeather senior meteorologist Alex Sosnowski said Washington's snowfall could eclipse the "Snowmageddon" storm of 2010 that dropped 17.8 inches (45.2 cm). If forecasts prove accurate, the storm could rival the 1922 Knickerbocker storm, which dumped a record 28 inches (71 cm) on the city.

"I think it's going to be a nightmare, the rates of snow we're talking about," said Marisa Kritikson, 27, a nursing student at George Washington University in Washington.

New York Mayor Bill de Blasio, who declared a winter weather emergency for the largest U.S. city, asked people to limit travel to "absolute emergencies."

"There will be white out conditions, meaning the driver cannot see what's happening before them," de Blasio said.

After the storm arrives late Friday in New York City, snow accumulation could reach up to 18 inches (30 cm), with winds gusting to 50 miles per hour (80 kph), creating blizzard conditions. Southeastern Pennsylvania, including Philadelphia, was expecting 10 to 18 inches (25 to 45 cm) of snow.

The approaching storm led New Jersey Gov. Chris Christie to announce he was returning to his home state from New Hampshire, where he is vying for the Republican presidential nomination.

Earlier he insisted he would stay on the campaign trial but on Friday afternoon he tweeted: "I want to make sure the people of my state feel safe and secure."

Residents along New Jersey's coastline were preparing for potential flooding during high tides on Saturday and Sunday. In the beach community of Ocean City, emergency management officials warned of forecasts calling for the highest flood levels since Superstorm Sandy brought heavy damage in 2012.

High winds and a full moon could combine to create a high tide of nearly 8 feet (2.4 meters) in Atlantic City, officials said, still shy of the 10 feet (3 meters) that Sandy caused in Ocean City.

In New York City, the NWS issued coastal flood warning for the boroughs of Staten Island, Brooklyn and Queens as the city officials prepared for possible evacuations from low-lying areas.

SCRAMBLE FOR SUPPLIES

The storm arrived in Washington after pushing across Arkansas, Tennessee and Kentucky. It dropped 5 inches (13 cm) of snow in Arkansas and a wintry mess of snow, sleet and freezing rain in parts of Tennessee and Kentucky.

In addition to several inches of snow, the Charlotte, North Carolina, area could get up to a half inch of ice, causing concerns about power outages and dangerous driving conditions, officials said. Other parts of the state could get a foot of snow.

In the Washington area, home to about 6 million people, residents scrambled to prepare, picking stores clean of bottled water, food and other supplies.

"I have nine cases of wine, half and half and coffee, firewood and all my devices are charged. All I need now is a wing and a prayer," said Liz Scherer, 54, who works out of her home in the Washington suburb of Silver Spring, Maryland.

Federal employees in the Washington area were told their offices would close at noon on Friday to allow them to get home before the snow began piling up. City officials said everyone except emergency workers should stay off the streets.

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