A wide swath of the United States faces the potential for severe weather on Thursday as powerful thunderstorms threaten to deliver damaging winds, large hail and heavy rain across at least 12 states. According to forecasts from the National Weather Service's Storm Prediction Center (SPC), the threat spans from the southern Plains through the Lower Mississippi Valley to the Ohio Valley and Lower Great Lakes.Why It MattersAny storms that develop could impact a populated and expansive area.The SPC designated a "Slight" risk zone for severe thunderstorms across parts of the Lower Mississippi Valley, Tennessee and Ohio Valleys, the Great Lakes area, and from the Texas and Oklahoma Panhandles into northern Texas.Large population centers in this risk area included Columbus, Ohio, Oklahoma City, Nashville, Cleveland, and Pittsburgh.The risk area spanned more than 320,000 square miles and encompassed a population of more than 35 million people.What To KnowAccording to the SPC, a "slight" risk means that scattered severe storms are possible, though they will likely be short-lived and/or not widespread. Isolated intense storms are possible within this risk zone.States in this risk zone included parts of Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Kentucky, West Virginia, Pennsylvania, Indiana, and Ohio.The NWS said in its forecast for Thursday that a storm system was developing along a stalled weather front in the southern Plains and would slowly get stronger as it moves northeast, passing through the Mid-Mississippi Valley and Midwest, and reaching the Great Lakes by Thursday night.As the system moves forward, the NWS said it would bring an end to the heavy rain and severe storms that have recently hit the south-central U.S. However, areas to the east—like the Mid-Mississippi, Ohio, and Tennessee Valleys—can expect more showers and some severe storms on Thursday. These storms could bring strong winds, hail, and possibly an isolated tornado.Meanwhile, rain and thunderstorms were expected to spread into the central and lower Great Lakes region later on Thursday as the storm gets closer.The National Weather Service forecast office in Tulsa, Oklahoma, said that heading into the early hours of Friday, large hail—up to the size of golf balls would be possible, as well as winds up to 80 miles per hour.What People Are SayingThe National Weather Service said on X on Wednesday: "Portions of the Southern Plains are expected to see another round of thunderstorms late Thursday into Friday that could result in additional flash flooding. Thunderstorms will also spread into the Ohio and Mississippi Valleys on Thursday. Some storms could be severe. Stay weather aware tomorrow!"The NWS Weather Prediction Center (WPC) said on X, Wednesday: "Storms late Thursday could bring more heavy rain & flash flooding to southern OK, northern TX & western AR—already hit hard this week. Storms likely continue into Friday with risks spreading farther south & east. Stay weather aware!"What Happens NextAccording to the WPC, the potential for strong to severe thunderstorms will return for the southern Plains on Friday.