The major low-pressure system that is set to impact the northeast United States and eastern Canada over the weekend will first impact the Midwest of the United States. Above is the possible timing of the precipitation as the low develops on the lee of the Rocky Mountains.
The picture below show the active winter storm warnings (in pink) and winter storm watches (purple) issued by the National Weather Service:
...WINTER STORM WARNING IN EFFECT FROM NOON FRIDAY TO 6 AM CST SATURDAY... * WHAT...Heavy snow expected. Total snow accumulations of 5 to 8 inches expected. * WHERE...Central to southern Iowa. * WHEN...From noon Friday to 6 AM CST Saturday. * ADDITIONAL DETAILS...Travel could be very difficult. Patchy blowing snow could significantly reduce visibility. The hazardous conditions could seriously impact the afternoon/evening commute.
Part of the northern Plains will also see the snow, but the big story will remain the cold Arctic air that has been sitting on the N Plains and Prairie Provinces, prompting wind chill advisories in the US and extreme cold warnings for Canada. Even colder air will make its way as this system drags cold air from the Arctic on its backside.