As the cold front moved southward Tuesday, it prompted a cold weather advisory for the Gulf Coast and pushed temperatures below freezing in El Paso, Texas.

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

The polar vortex of ultra-cold air usually spins around the North Pole, but it sometimes ventures south into the U.S., Europe and Asia. Some experts say such cold air outbreaks are happening more frequently, paradoxically, because of a warming world.