MINNEAPOLIS (AP) — Bitterly cold temperatures persisted from the Northern Plains to parts of the Great Lakes and northern New England. Schools in some Upper Midwest communities canceled classes for a second day Friday or delayed start times as the coldest air of the season lingered.

The National Weather Service issued a wind chill advisory for parts of North Dakota, Minnesota, Wisconsin, Iowa, Illinois and Missouri on Friday and several New England states.

Wind chill readings in northern Minnesota dropped to about 30 degrees below zero early Friday. The National Weather Service expected the dangerously cold airmass to give way to more moderate temperatures this weekend.