The storm is predicted to extend from the Great Lakes to the central Appalachians, dumping snow and rain coupled with high winds over a wide area with blizzard conditions possible, Accuweather.com said Friday.
Some areas could see snowfall lasting into the middle of next week, and poor travel conditions will prevail, but it was unclear where the rain-snow divide would come.
The snow is expected to begin over Iowa Saturday and then spread east and north, dumping 6 to 12 inches with higher amounts expected in lake-effect regions, possibly as much as 3 feet.
In the Detroit area, traffic was moving slowly Friday morning after 1 to 2 inches fell.
Michigan State Police reported wrecks and spinouts on freeways. One crash closed a stretch of Interstate 94 in Dearborn, the Detroit Free Press reported.
In Minnesota's Twin Cities, blizzard conditions -- sustained winds over 35 mph with up to a foot of snow with temperatures falling below zero -- are possible Saturday, the Minneapolis Star Tribune said.