The first widespread snowstorm of the season is weakening as it moves from the Midwest to the East.
It dumped more than 1 1/2 feet of snow in Michigan and made travel difficult in the Great Lakes region.
The storm, part of a system that began in the Rockies, is blamed for deaths in at least five states.
Snow is now falling across western Pennsylvania, but the total accumulation may be smaller than previous estimates.
The National Weather Service issued a winter storm warning for parts of western Pennsylvania, while an advisory is in effect for Pittsburgh. Forecasters say Pittsburgh could get one to two inches overnight.
The system is developing a second front with a mix of snow and rain in the New York City area and New Jersey.
High winds have knocked out power to more than 20,000 utility customers in upstate New York, while several inches of snow has fallen in some areas.
The storm is expected to spin its way northward through New England and into Canada into the weekend.