ATLANTA — Some schools in the South are closing Wednesday as residents in several states brace for the possibility of intense tornadoes that travel for miles and hail the size of baseballs.

The Wednesday storms could produce intense tornadoes, The Storm Prediction Center said in a briefing.

Cullman County school campuses are closed today and city schools are operating remotely due to the weather threat.

At highest risk is a region that includes parts of Arkansas, Louisiana, Mississippi, Alabama and Tennessee. The area in the bullseye for possible tornadoes is home to more than 8 million people and includes Memphis, Tennessee; Birmingham, Alabama; Little Rock, Arkansas; and Jackson, Mississippi.

Parts of Texas, Oklahoma and Missouri will also be at risk of severe storms.

In parts of Louisiana, Mississippi and Alabama, any storm cell that develops Wednesday afternoon “could quickly become a supercell capable of producing strong tornadoes,” the Storm Prediction Center warned.

More than a dozen Alabama school systems canceled classes, planned online sessions or announced early dismissals because of the threat. More could be added to the list.

Communities across the South were also urging residents to know where their closest tornado shelters are. Cullman County residents can find the list of shelters here. There is one pet-friendly storm shelter at the city shelter on Sportsman Lake Road; pets are required to be in carriers.