A massive storm system was marching toward the Northeast on Wednesday, upending post-Christmas travel plans after dumping snow and sleet on the middle of the country on Christmas Day and producing tornadoes through the South.

The storm, which stretches from Michigan to Florida, has been blamed for six deaths so far.

As the storm moves from the Tennessee Valley to the Mid-Atlantic, heavy snowfall, tornadoes and significant icing are possible, the National Weather Service said. 

The storm could dump as much as 18 inches of snow from western New York to central Maine. In a region stretching from the upper Ohio Valley to the interior Northeast, residents and travelers may see 6 inches of snowfall.