Downed trees, roofs ripped off houses after suspected tornado in Owasso on Wednesday, April 2, 2025. Video source: Whitney Eidschun/TMX via CNN U.S. government forecasters are using a relatively rare “high-risk” designation — the highest category they use — to warn that a major tornado outbreak appears likely Wednesday in an area that's home to about 2.5 million people. That area most at risk of catastrophic weather on Wednesday includes parts of west Tennessee including Memphis; northeast Arkansas; the southeast corner of Missouri; and parts of western Kentucky and southern Illinois. The Norman, Oklahoma-based Storm Prediction Center says that “multiple long-track EF3+ tornadoes, appear likely.” Tornadoes of that magnitude are among the strongest on the Enhanced Fujita scale, used to rate their intensity. Historically, the “high-risk” designation has been used sparingly, but it did appear just a couple of weeks ago to warn of a deadly tornado outbreak in mid-March. The Storm Prediction Center uses five categories to warn of expected severe weather, ranging from marginal to high. Its forecast maps are color-coded, with the lowest risk areas in green and the highest shown in magenta. The “high risk” designation is used when severe weather is expected to include “numerous intense and long-tracked tornadoes” or thunderstorms producing hurricane-force wind gusts and inflicting widespread damage, according to the agency. On many days when the “high risk” designation was used in recent years, the forecasts became reality. On May, 6, 2024, the Storm Prediction Center assigned the high-risk category to parts of Kansas and Oklahoma, warning of “multiple significant tornadoes along potentially long paths.” The forecast was prescient, as dozens of tornadoes gouged the landscape. One of the strongest twisters tore through the small town of Barnsdall, Oklahoma and then struck the larger community of Bartlesville. Aerial video showed many homes reduced to piles of rubble. About 25 people were rescued from homes where buildings had collapsed on or around them, the town’s mayor said at the time. On March 31, 2023, the Storm Prediction Center outlined two areas along the Mississippi River Valley at high risk for tornadoes. Hours after that forecast was issued, multiple twisters collapsed a theater roof during a heavy metal concert in Illinois and shredded homes and shopping centers in Arkansas. More local videos here: https://bit.ly/2Pa0d1l Subscribe to NEXT: http://bit.ly/2eP1GwI Stay connected: 9NEWS Website: http://www.9news.com/ Facebook: https://www.facebook.com/ilike9news X: https://x.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.