Severe Weather Alert: Tornado & Flash Flood Threat—Live Updates

Residents across the Central Plains and Upper Midwest are bracing for a multi-day severe weather outbreak that is expected to peak late Sunday into Monday, May 17-18 2026. Forecasters warn that a volatile mix of warm Gulf moisture, potent upper-level energy and a strengthening low-pressure system will set the stage for tornadoes, destructive hail and hurricane-force straight-line winds. Tornado watch already in effect As of Sunday afternoon, the National Weather Service has issued a tornado watch for northeastern Nebraska, southeastern South Dakota, northwestern Iowa and southwestern Minnesota until 10 p.m. CDT. Meteorologists caution that “a few likely tornadoes, including the potential for intense long-track twisters, hail up to three inches and wind gusts to 85 mph” are possible within the watch area. Sunday: Two rounds of storms • Morning: A fast-moving cluster of thunderstorms will race across the upper Midwest, bringing 60-mph gusts and pockets of one-inch hail. • Afternoon-night: Discrete supercells are forecast to fire along a sharpening dryline from central Kansas to eastern Nebraska before merging into a powerful derecho-like squall line after dusk. Cities at highest risk include Grand Island, Sioux City and Sioux Falls. Monday: Outbreak expands south and east Monday is expected to deliver the most widespread danger, stretching from northern Texas through the Ozarks and northward to Michigan. The Storm Prediction Center highlights a corridor from Wichita and Kansas City to Omaha and Des Moines for “strong to intense tornadoes, destructive hail larger than softballs and widespread 70-90 mph wind damage”. Tuesday–Wednesday: Threat marches east The same frontal system will push severe storms into the Mississippi and Ohio Valleys on Tuesday, then into portions of the Southeast and mid-Atlantic by mid-week. While tornado probabilities should diminish, isolated spin-ups, flash flooding and damaging gusts remain concerns. Why May’s quiet start flipped so fast May typically leads the U.S. in tornado counts, but cooler-than-average temperatures east of the Rockies suppressed activity during the month’s first half. A pattern reversal is now funneling deep Gulf humidity northward beneath a strengthening jet stream, creating ideal conditions for explosive supercells. Safety checklist 1. Have multiple ways to receive warnings—including NOAA Weather Radio and smartphone alerts—since nighttime tornadoes will be possible. 2. Identify a sturdy shelter: a basement or small interior room on the lowest floor. Mobile-home residents should know the nearest storm shelter location. 3. Stock an emergency kit with flashlights, medications and a week of non-perishable food and water in case power outages linger. 4. Secure outdoor furniture and park vehicles in garages to reduce hail damage. Travel and event impacts Major interstates-80, 35 and 29 may experience closures due to overturned trucks and debris. Airlines are already issuing travel waivers for hubs in Minneapolis, Kansas City and Dallas-Fort Worth. Outdoor events from minor-league baseball games to college graduations could face delays, and organizers are urged to monitor forecasts hourly. Climate context While any single outbreak cannot be pinned solely on climate change, research shows a gradual eastward shift and lengthening of the U.S. severe weather season. Warmer sea-surface temperatures in the Gulf of Mexico add extra moisture and instability, increasing the odds of high-impact spring storm sequences. Bottom line An extended period of dangerous weather is underway. If you live from Texas to the Great Lakes, review your tornado plan now, stay alert for watches and warnings, and be prepared to act quickly when storms approach.