By Jon Herskovitz
(Reuters) - Large parts of the U.S. South are expected to be pelted with hail and storms that could produce tornadoes on Thursday, the day after several twisters damaged buildings and injured at least seven people in Oklahoma.
The National Weather Service has issued a flash flood watch stretching from Arkansas to Georgia, and put parts of southern Alabama and western Florida under a tornado watch.
The severe weather is being caused by a moist and unstable air mass ahead of a cold front that has been moving through Arkansas and Louisiana, said Greg Garrett, a forecaster with the NWS in Jackson, Mississippi.
He said sunny skies in parts of the region in the morning could cause the air mass to destabilize even more in the afternoon.
"When we start to have thunderstorms developing this afternoon, there is a good chance they could be widespread and severe again, similar to last night," he said.
On Wednesday night, emergency crews near Little Rock, Arkansas, performed a high-water rescue for a woman whose car was caught in floods.
At least four tornadoes were reported in Tulsa and Rogers counties in Oklahoma, according to the Storm Prediction Center. Another was reported in southern Kansas.
On Thursday, four schools were closed in Tulsa because of storm damage and a loss of power, local officials said.
In southern Mississippi, Alabama and western Florida, the NWS said there was a significant threat of tornadoes, damaging wind gusts and large hail on Thursday from the storm system.
The weather service said large parts of region could get about 3 inches of rain on Thursday, bringing significant risks of flooding in low-lying areas.
(Reporting by Jon Herskovitz in Austin, Texas; Addiitonal reporting by Lenzy Krehbiel-Burton in Tulsa, Okla. and Steve Barnes in Little Rock, Ark; Editing by Peter Cooney)