According to the National Weather Service, new data indicate the storm is tracking northward, which could increase the probability of more snow.

Up to a foot of snow is expected across several states due to the winter storm, with ice accumulating farther south.

Winter Storm Fern is calling for 8 to 12 inches of snow across Greater Cincinnati this weekend. Here's how it could impact Xavier basketball.

A high-impact and potentially historic winter storm is underway, delivering heavy snow, crippling ice, and days of life-threatening travel conditions to more than 245 million people from Arizona

Winter storm watch: The National Weather Service issues a winter storm watch when there is the potential for heavy snow or ice accumulation. The watch is typically issued at least 24 to 36 hours in advance. Criteria for the watch varies by location.

President Donald Trump has surged emergency aid and resources to 10 states shortly before a winter storm is set to hit much of the Northeast and parts of the South. “I have just approved Emergency Declarations for Tennessee,

The impending storm is the result of a classic winter setup: a powerful Arctic high-pressure system diving south from Canada meeting an “atmospheric river” of moisture streaming from the Pacific and the Gulf. As these air masses collide, a broad frontal boundary will serve as the tracks for a series of low-pressure systems.

Large parts of the eastern and central United States are expected to see heavy snow. But south of the snow line, forecasters are warning that the storm could deliver dangerously icy conditions. Exactly where that snow vs. ice line will fall was still uncertain on Wednesday.

This index, from NOAA's National Weather Service, attempts to scale the impacts from winter weather, taking into account factors such as snowfall, accumulated snow on rooftops, ice accumulation, the potential for a flash freeze, and blowing snow. Not all factors are in play in a given winter storm.