Twenty states, from Texas to Delaware, were on alert Friday for snow and ice as the storm continued to move across the South.

At least 46 million people were under a winter storm warning as of Thursday as the storm spreads along the Gulf Coast Friday, according to the weather service. The storm should weaken by Saturday, bringing lighter snow between 1 and 3 inches to parts of the Northeast, the Mid-Atlantic and the Ohio Valley before exiting off the Carolinas.

Snow, freezing rain and rain are underway in the southern Plains as a potent winter storm strengthens Thursday.