Severe weather on Wednesday has prompted tornado watches for parts of four southern states, including some areas still cleaning up damage from a swarm of twisters that hit last week.

Portions of Arkansas, northern Louisiana, east Texas and southeast Oklahoma were under a tornado watch issued by the National Weather Service, which is also forecasting wind gusts in excess of 75 mph and inch-size hail. The tornado warnings are expected to stay in effect through Wednesday night.

A wildfire burning in northeast Oklahoma has prompted evacuations.

A major storm system is pushing east out of the Rocky Mountains and is expected to bring severe weather outbreaks to the South.

Severe weather is forecasted for cities such as Dallas, Jackson, Memphis and Mobile.

A possible tornado touched down in Springdale, Arkansas early Wednesday, causing heavy damage to an elementary school and injuring seven people, two critically, according to ABC affiliate station KATV in Little Rock.

The Springdale School District said on its Facebook page that George Elementary School was damaged by a potential tornado. The district posted photos showing the elementary school’s destroyed gymnasium and reported that the school’s kitchen and cafeteria were severely damaged.

A tornado watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. People in those areas are advised to be on the lookout for threatening weather conditions and stay tuned for announcements from local authorities.

The National Weather Service issued a tornado warning Tuesday night as storms moved into Oklahoma’s Seminole County, producing 60 mph wind gusts and inch-size hail.

The weather service also confirmed a tornado in eastern St. Joseph, Missouri, Tuesday night. No injuries were immediately reported and a damage assessment is taking place Wednesday.

Oklahoma emergency management officials were not only dealing with tornado warnings Wednesday but also fire warnings as well. Evacuations have been issued in Roger Mills County, Oklahoma, due to a wildfire. Roger Mills Emergency Management officials on Tuesday asked that residents to evacuate their homes in the Durham and Dead Warrior Lake areas in northwestern Roger Mills County, where severe weather is expected to move in on Wednesday.

Some areas where tornado watches have been issued were struck last week by more than 60 tornadoes that ripped through the southeast. Most of the tornadoes were reported in Texas, where a 73-year-old woman was killed and 10 people were injured in Grayson County.

Two tornadoes touched down on March 22 in New Orleans, causing widespread damage in St. Bernard’s Parish, including the Ninth Ward, Chalmette and Arabi. One person was killed in Arabi, officials said.

Severe weather this week has also stretched into the northeast, where a snow squall on Monday led to a multiple-car pileup on Interstate 81 in Pennsylvania. The Pennsylvania State Police said on Wednesday that six people were killed in the pileup in Schuylkill County that included 39 commercial vehicles and 41 passenger vehicles.

Interstate 81 reopened just after midnight Wednesday following an investigation and cleanup.

ABC News’ Max Golembo and Whitney Lloyd contributed to this report.