A blast of Arctic air taking over much of the U.S. is bringing powerful lake-effect snow to several states and shivering temperatures to parts of the South.

Forecasters warned that some areas would be “paralyzed” by the lake-effect snow. Portions of western New York had already recorded 17 inches of snow by Friday afternoon.

The National Weather Service warned that severe winter conditions—triggered by an Arctic blast—could persist over the weekend into Monday.

Areas of Michigan, northern New York, Ohio and Pennsylvania could receive several feet of snow over the weekend. The storm already brought deep snow to portions of Michigan’s Upper Peninsula.

Lake-effect snow generated by the Great Lakes is among the heaviest snowfall in the world. The ingredients are straightforward and come together a number of times each fall and winter. Cold air from Canada pours over the still unfrozen, relatively warm Great Lakes, the world's largest group of freshwater lakes.

We are tracking some heavy and persistent lake effect snow east of Lake Ontario and north of Syracuse through Sunday.

The NWS has issued lake effect snow warnings across upstate New York, predicting significant snowfall through the weekend. Here's the latest snowfall projections and timing for the storm.