The National Weather Service Storm Prediction Center says a severe thunderstorm watch will likely be needed this afternoon and evening across parts of northeast Nebraska and southeast South Dakota.
Forecasters say developing storms could initially become supercells capable of producing 1.5- to 2.5-inch hail and wind gusts of 75 miles per hour or more.
Storms may merge into a line later this evening, increasing the threat for damaging winds, particularly near the Nebraska-South Dakota border.
The Storm Prediction Center gives an 80 percent probability that a severe thunderstorm watch will be issued.
A tornado threat is also possible, with the most probable peak intensity listed at up to 90 miles per hour.