Temperatures were slowly warming Thursday across the South, where freezing rain glazed roads with ice, but a sprawling winter storm system remained in place across the upper Plains states.

The National Weather Service issued winter storm warnings and advisories for more than a dozen states. The brunt of the system is poised to hit Kentucky, Virginia and West Virginia, but several inches of snow are forecast for portions of Indiana, Ohio, Tennessee and North Carolina, as well as Minnesota and the Dakotas. Winter weather advisories stretched into Wisconsin and Minnesota.