Severe thunderstorms swept across parts of Nebraska and Iowa on Wednesday, August 19, bringing large hail, damaging wind gusts and torrential rainfall as an organized storm system moved east across the central United States.
The Storm Prediction Center placed portions of the Mid and Lower Missouri Valley under a Slight Risk of severe thunderstorms, with damaging winds and hail identified as the main threats. Severe Thunderstorm Watch 599 covered parts of Nebraska and southwestern Iowa into Wednesday afternoon.
STORM STRUCTURE OF THE YEAR THANK YOU NEBRASKA #newx pic.twitter.com/yYjNHt3GcK
— Ryan Scholl |-/ (@WxScholl) August 18, 2026
Warnings issued as storms intensified across Nebraska included the potential for hail around golf-ball size and wind gusts near 60 mph (97 km/h). More broadly, forecasters warned that the strongest storms could produce gusts approaching 70 mph (113 km/h) and hail around ping-pong-ball size.
Storms Shift From Nebraska Into Iowa
The severe-weather corridor gradually shifted east during the day, with thunderstorms spreading from Nebraska toward Iowa.
By Wednesday afternoon, the National Weather Service in Des Moines expected thunderstorms across central and southern Iowa, particularly south of Interstate 80, with some storms capable of producing large hail and damaging winds.
The threat was expected to continue into the evening as storms encountered a warm and humid air mass farther east.
Colors, textures, storm structure and perfect light all coming together at once…This is a real supercell near Sidney, Nebraska. Nature at its most powerful and beautiful.Sometimes the sky reminds us just how small we are and how incredible this world can be.#Supercell #Nebraska pic.twitter.com/DAXSBcoHLQ
— GreenDiscovery (@discokfyo) August 18, 2026
What Is Fueling these Severe Thunderstorms?
A combination of strong atmospheric instability and wind shear is providing the ingredients necessary for organized thunderstorms.
Warm, moisture-rich air near the surface has increased the amount of energy available to developing storms. At the same time, a shortwave disturbance moving through the central Plains is providing additional lift needed to initiate and sustain convection.
Ryan Scholl is getting HAMMERED with large hail in Ord, Nebraska right now!
— Max Velocity (@MaxVelocityWX) August 18, 2026
📷️ Ryan Scholl pic.twitter.com/NDEjVyrV5B
Winds also change in speed and direction with height, creating deep-layer wind shear. This allows thunderstorms to become better organized and remain intense for longer than ordinary summertime storms.
Individual stronger cells can use that environment to produce large hail, while storms merging into clusters or line segments increase the potential for damaging straight-line winds.
The Storm Prediction Center expected the severe-weather threat to extend farther into the Mid-Mississippi Valley as the system progressed eastward.
Locally heavy rainfall is another concern. Recent rounds of thunderstorms have already left parts of the Midwest unusually wet, meaning intense downpours could produce localized flooding where storms repeatedly cross the same areas.
The severe-weather episode is expected to become increasingly focused east of Nebraska as the shortwave disturbance and associated thunderstorms continue across the Midwest.
