A trans-continental storm system that wreaked havoc on Thanksgiving travel is making a mess Monday for the millions returning to work in the Northeast, snarling air travel and closing schools and government offices across the region.

The National Weather Service said that the large storm system is transitioning into a nor'easter off the New Jersey coast, bringing significant snow across interior portions of New York and New England, especially in the mountains, as freezing rain and sleet are forecast to impact areas close to the Interstate 95 corridor.

More than 350 flights into or out of the U.S. were canceled Monday morning, with more than 1,500 delays reported, according to flight-tracking website FlightAware. Airports in the New York and Boston areas accounted for many of the delays.

"The problem is, that this is coming off the busiest travel season in terms of Thanksgiving travel," Fox News Senior Meteorologist Janice Dean said on "Fox & Friends."

A nor'easter will bring heavy snow to inland portions of the Northeast through Tuesday morning.

She added: "This is going to be kind of an ongoing situation over the next couple of days, the worst of it coming this afternoon into the overnight for the Northeast. This is on top of snow that we already received over the weekend."

DEADLY WINTER STORM TAKES AIM AT NORTHEAST, HUNDREDS OF FLIGHTS CANCELED

The NWS's Weather Prediction Center said winter storm warnings stretch from northeast Pennsylvania to southern Maine, with storm total snowfall of 10 to 20 inches expected for some of these locations by Tuesday morning.

Snow accumulations from the storm through Tuesday morning.

"This will likely lead to major travel disruptions across these areas," forecasters said.

The nor'easter will impact travel particularly along the East Coast on Monday. (Fox News)

Many buses from New York City to Pennsylvania and upstate destinations such as Ithaca and Binghamton were canceled, and tractor-trailers were banned or lower speed limits put in place on stretches of interstate highways in New Jersey and Pennsylvania.

The storm system has impacted travel since Sunday across much of the region as the system moved out of the Midwest.

State police had responded to more than 550 storm-related crashes across New York by 7 p.m. on Sunday. Icy roads caused crashes on Interstate 84 in Pennsylvania, and ice closed part of Interstate 81 near Binghamton, New York, for a time.

In Maryland, nearly 60 cars were involved in a pileup that snarled holiday traffic in the western part of the state.

Maryland State Police said there were 58 vehicles involved in 29 separate collisions Sunday on westbound Interstate 68. A total of 10 people were taken to a local hospital with injuries, none of them life-threatening.

Authorities say it's unclear what caused the initial collision but heavy fog in the area is believed to be a factor in the pileup.

WINTER STORM CREATES THANKSGIVING HOLIDAY TRAVEL 'HAVOC' WITH BLIZZARD CONDITIONS, SNOW TO HIT NORTHEAST

Schools closed preemptively or canceled activities in several states as rain was expected to turn into snow in the region’s first significant storm of the season, a nor’easter so named because the winds typically come from the northeast.

Stephen Willard pushes his wheelchair through the snow as he heads to his apartment in Keene, N.H., Sunday, Dec. 1, 2019. (Kristopher Radder/The Brattleboro Reformer via AP)

“We've got our shovels ready. We've got the snowblower ready. We're prepared,” Paul Newman, of Wethersfield, Connecticut, told the Associated Press.

New York told state workers in some government offices to stay home Monday, and New Jersey planned to close offices for nonessential employees at noon.

CLICK HERE FOR THE FOX NEWS APP

The same storm has pummeled the U.S. for days as it moved cross country, dumping heavy snow from California to the Midwest and inundating other areas with rain.

Neighbors work together in an effort to clear out as much snow as possible from E. 8th Street, Sunday, Dec. 1, 2019, in Duluth, Minn. (Alex Kormann/Star Tribune via AP)

At least eight deaths have been associated with the storm system, including one on Interstate 84 in Pennsylvania on Sunday, WNEP reported.

A U-Haul truck sits snowed in by plows on First Street in downtown Duluth, Minn., on Sunday, Dec. 1, 2019. (Alex Kormann/Star Tribune via AP)

Duluth, Minnesota, is cleaning up more than 21 inches of snow. Major highways reopened in Wyoming and Colorado after blizzard conditions and drifting snow blocked them.

The Associated Press contributed to this report.