Severe thunderstorms are expected this afternoon and into tonight across central Nebraska, east into Iowa, and north into Sioux Falls, South Dakota.
These storms will be capable of producing damaging winds, hail and flooding downpours. An isolated tornado or two cannot be ruled out.
Storms will bubble up over northern Nebraska in the mid-afternoon, while storms in Iowa are likely to hold off until the evening hours. Storms will then progress east across Iowa during the overnight hours.
Residents of northern Illinois and southern Wisconsin will want to be on alert for the first round of strong storms during the morning hours of Sunday as this complex races east.
A moist atmosphere and above normal July rainfall will combine to create a heightened flood threat with tonight's storms across much of the Upper Midwest.
By Sunday afternoon the severe weather threat will translate east from Illinois into much of Michigan and Ontario.
Cities like Milwaukee and Chicago are going to receive two rounds of storms on Sunday. A second line of severe storms is expected to move through late in the day and will be capable of producing damaging winds, hail and flooding rainfall.
As severe thunderstorms blossom in the afternoon, residents and travelers through these areas should remain alert for torrential downpours, damaging winds and hail.
Lightning is always a threat with thunderstorms. Those with plans outdoors should seek shelter as soon as thunder is heard to avoid being struck by lightning.