Lake-effect snow streaming eastward from the Great Lakes into parts of Michigan, Wisconsin, northern Indiana, northeastern Ohio, Pennsylvania, western New York and southern Ontario on December 10, 2016. Snow on the ground can be seen in parts of New England and southern Canada. Cloud cover ahead of Winter Storm Caly can be seen in Iowa, Illinois, and Indiana. (NASA/Terra/MODIS) At a Glance An arctic air mass overtook the Great Lakes region in early to mid December.The air is more than...

Brandon Grimes, from left, 9, Braeden Beasley, 8, and Austin Ricks, 4, have a snowball fight in Asbury, Iowa, on Sunday, Dec. 11, 2016. The Dubuque, Iowa, area received 4 inches of snow overnight, less than forecasters had expected. (Nicki Kohl/Telegraph Herald via AP) Winter Storm Caly, the third named storm of the 2016-17 season, dumped sizable amounts of snow across the Northwest, Midwest and Northeast on a multi-day trek across the country. The storm was responsible for at least...

This is a developing weather story. Please . The latest winter system will lay down an over 2600-mile swath of snow from the Pacific Northwest, including Seattle and Portland, Oregon, to the Rockies, Plains, Midwest and Northeast into early next week. Winter storm watches are in effect for much of the Northwest and northern Rockies, meaning there is potential for significant snow, sleet or ice accumulations that my impact travel. (MORE: ) With the coldest air of the season either...