A line of fierce thunderstorms moving across Texas was expected to raise the risk of tornadoes, hail and damaging winds across the Deep South on Tuesday.

The South Texas storms left thousands of people without power and windows broken after hail the size of golf balls damaged some buildings, but no one was injured after the bad weather Monday night, according to the Kinney County Sheriff's Office in that state.

Now, more than 6 million people in parts of five states — Louisiana, Mississippi, Alabama, Florida and Georgia — are in an area of moderate risk for a few strong tornadoes and other severe weather Tuesday, the Storm Prediction Center in Norman, Oklahoma, estimated.

"This whole system is evolving quite rapidly, and we expect things to start to pick up in the next few hours," Greg Carbin, a meteorologist at the Storm Prediction Center, said at midday. Carbin noted that a tornado warning had already been issued in Louisiana, though there were no reports of any twisters touching down.

In Arkansas, heavy rain, powerful winds and some snow were forecast for parts of the state Tuesday and Wednesday. The National Weather Service in Little Rock described the storm system as a "three-headed monster" on its Facebook page.

As the storms move into southeast Louisiana on Tuesday afternoon, forecasters said severe weather would occur from the Baton Rouge area eastward across Louisiana into areas north of Lake Pontchartrain north of the Gulf coast. Forecaters said southeastern Louisiana was under a tornado watch until 5 p.m. local time.

Schools across south Louisiana and Mississippi canceled classes ahead of the storm.

In Alabama and Georgia, forecasters issued flash flood watches ahead of the storm system, which was expected to drop 1 to 2 inches of rain, with higher amounts possible in some areas. The warnings, which covered large parts of both states, were expected to be in effect through Wednesday afternoon.

The National Weather Service said new rain on already saturated soil could cause roads to flood, as well as low-lying areas and small streams. The weather service projected that some of the heaviest rain would fall in metro Atlanta and in parts of the north Georgia mountains, where up to 3 inches was expected.

The stormy weather canceled school in parts of South Texas and apparently contributed to a school bus flipping on a rain-slick highway in Houston.

The bus driver suffered minor injuries in the accident Tuesday morning, Houston Independent School District spokeswoman Lila Hollin said. No students were on board during what's believed to be a weather-related crash, Hollin said. The school bus ended up on its side atop an embankment.