In Atlanta, where public schools were closed, forecasters expect freezing rain and up to three inches of snow starting Friday morning. With the northern half of Georgia under a winter storm warning, Gov. Brian P. Kemp declared a state of emergency on Thursday because of the forecast and said it would be in place through Tuesday.

An area stretching from Texas to Tennessee braced Wednesday for the possible arrival of freezing rain and snow even as some other parts of the U.S. hit by the plunging polar vortex this week began to shake off its icy effects.