Snow was falling in the Mid-Atlantic and New York City on Sunday. The coldest air in several years will descend across much of the country starting Monday, forecasters said.

Heavy snow is expected to blanket large portions of the Eastern U.S. while much of the country will endure dangerously cold temperatures in the coming days.

New York, New Jersey and Connecticut are under winter storm warnings today as the entire region braces for snow. Tri-State Area officials have been issuing warnings and discussing the states' preparations in the days leading up to the storm.

Most of the United States is being assailed with extreme winter weather this week as Arctic air blasts south from Canada, snow tracks up the Northeast coast and a potentially crippling winter storm takes aim at the South.

A winter storm expected to bring heavy snow to Philadelphia on Sunday is already impacting air travel.In Philadelphia and along the Interstate 95 corridor, expect 3-6 inches of snow to fall by the time the snowstorm wraps up Sunday night.

While it's not clear what impact a mix of rain, freezing rain, sleet and snow may have on the capital city, officials say now is the time to begin preparations.

The National Weather Service issued a winter storm watch at 1:27 p.m. on Sunday valid from Tuesday noon until Wednesday 6 a.m. for Coffee, Dale, Henry, Geneva and Houston counties.

With a winter storm moving through the tri-state Sunday afternoon, the New York City metro area’s three major airports were all seeing delays and cancellations. As of 2 p.m. Eastern, Newark Liberty International was seeing 254 cancellations into or out of the airport and another 82 delays Sunday,

The updated forecast on timing and track of the storm calls for the snow to end from southwest to northeast as midnight approaches. “The heaviest precipitation looks to occur between roughly 4 and 9 p.m. during which time snowfall rates could reach or exceed 1 inch per hour,” the National Weather Service said.

Dangerously cold temperatures are expected to settle in tonight over most of the state. A winter storm watch has been issued for south Alabama and lower central Alabama starting Tuesday. Precipitation—snow, sleet, freezing rain, or a wintry mix—will begin in southwest Alabama Tuesday morning and continue through the day, moving eastward.

TALLAHASSEE, Fla. (WCTV) - The National Weather Service (NWS) office in Tallahassee has issued a very rare Winter Storm Watch for all of the Big Bend and South Georgia. The watch goes into effect Tuesday afternoon and will run through Wednesday morning. But the watch could be upgraded to a warning as we get closer to Tuesday.