As of Thursday morning, 110 million Americans were under alerts for a large winter storm moving east. These included winter alerts, ice storm warnings and flood alerts stretching from the southern Plains to New England.
Through Thursday, a wintry mix of ice and sleet will continue for the southern Plains and the Mississippi Valley through the evening. On the cold side of the storm, snow will increase in coverage and intensity across the Midwest and the southern Great Lakes. Heavy rain with some isolated strong storms will roll across the Southeast. Slick travel is expected from Iowa to Maryland.
Late Thursday into early Friday, the wintry mix will move into the mid-Atlantic and the Northeast, while heavy snow spreads across New England.
The Friday morning commute from Philadelphia to Boston will be a messy one, with much of the Interstate 95 corridor seeing a mix of rain, freezing rain, sleet and snow. The Washington area could also experience some slick travel conditions through the midmorning.
New York City has one of the most complex forecasts of the major metro areas, with a combination of snow, sleet, freezing rain and rain expected during the period between late Thursday and Friday afternoon.
Boston, meanwhile, has a higher confidence forecast due to its dominant precipitation type expected to be snow. This will result in 6 to 12 inches of snow between Friday morning and evening.
The storm will finally move off the Atlantic coast by Friday evening.
Ice amounts could be 0.10 inches to 0.50 inches through Friday stretching from north Texas to the Northeast. As of Thursday morning, there were more than 30,000 customers without power in Arkansas, 16,000 in Tennessee and 2,000 in Texas.
Cities that could see icing include Dallas, Little Rock, Arkansas, St. Louis, Indianapolis, Philadelphia, New York and Hartford, Connecticut.
Snow amounts are expected to be in the order of a couple inches across the Midwest and the Great Lakes, with higher amounts of 6 to 12 inches or more possible across New England.
In addition to Boston, cities expecting accumulating snow include Chicago, 2 to 5 inches, Detroit, 1 to 3 inches, Cleveland, 1 to 3 inches, Buffalo, New York, 4 to 8 inches, Hartford, 4 to 8 inches, and Albany, New York, 8 to 12 inches.
About 1 to 2 inches of rain will fall from the Tennessee and the Ohio Valleys into parts of the Southeast and the mid-Atlantic. This could cause urban and river flooding due to already saturated soils and high water levels.
As the storm exits, arctic air will be left in its wake.
On Wednesday afternoon, New York, Boston, Hartford, Providence, Rhode Island, Portland, Maine, and Newark, New Jersey, all set record highs in the upper 60s and lower 70s. By Thursday morning, all of these locations were under winter alerts for the approaching winter storm.
Thursday will feature high temperatures 20 to 35 degrees colder compared to Wednesday’s record highs in the Northeast, as a colder air mass streams in, dropping temperatures below average. This chilly air will remain in place for the next couple of days before returning to near average over the weekend.
The colder than average temperatures won’t be confined to the Northeast. High temperatures Thursday were also forecast to be 15 to 30 degrees below average across the entire middle of the country and 5 to 10 degrees below average across California.
This cold air mass will also stay in place the next couple of days before moderating into the weekend.
Kathryn Prociv is a senior meteorologist and producer for NBC News.