More than two dozen reported tornadoes spun out of the system in Alabama and Mississippi, AccuWeather said, and more heavy weather was expected to blow through northern Georgia during the night.
Seven deaths were reported in Arkansas where a falling tree killed a woman and her 8-year-old son in Little Rock and a 6-year-old White County boy was killed when a tree blew over on to his house, KARK-TV and KATV-TV in Little Rock reported.
Brian Smith of the National Weather Service told The Arkansas Democrat experts began surveying the damaged areas to determine if any of the many funnel clouds reported had touched down.
"This has probably been one of the more significant events we've had in awhile," Smith said.
The mayor of Clinton, Miss., told CNN his community suffered "extensive damage" from a tornado that narrowly missed a daycare center and school with an estimated 650 children inside.
"We have a lot to be grateful for," Mayor Rosemary Aultman said. "It could have been a lot worse."
Oklahoma was still tallying the damage from an outbreak of twisters Thursday night. One of the storms hit the small town of Tushka, killing two people and possible a third, The Oklahoman said. Dozens of injuries were also reported by emergency officials.