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.

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.

A polar vortex is slated to sweep most of the continental US bringing winter storm warnings and a hazardous freeze to millions.

A winter storm will affect New York and the surrounding area starting Sunday. From 1 p.m. Sunday to 4 a.m. Monday, the tri-state area is expected to be hit with snow, according to the National Weather Service.

Snowfall forecasts have increased for a winter storm expected to blanket New Jersey with widespread areas of 4 to 8 inches of snow. Winter storm warning areas were expanded early Sunday and a state of emergency is in effect. National Weather Service and AccuWeather

A winter storm warning has been issued for New York, New Jersey and Connecticut as the entire region could get blanketed in snow.

Sunday’s system was expected to bring nothing more than a coating of snow, however, that quickly changed. As of Saturday afternoon, the National Weather Service believes Staten Island and the city will receive around four inches of snow;