Well here we go folks, the Storm Prediction Center has issued a Severe Thunderstorm Warning. You can see in the graphic to the left which counties are affected by this watch until 10pm this evening. A complex of severe thunderstorms is currently moving through northeastern portions of Nebraska. Additional storms are expected to develop closer to sunset in Iowa along a surface boundary currently draped over northwest parts of the state.
The biggest change in overall risk is a new primary threat for northwest Iowa, large hail. You can see the hatched our risk are for hail in blue in the graphic to the right. Storms that develop earlier in the evening have a greater potential to produce hail stones larger than 1.00” in diameter, or about the size of a quarter. As the overnight hours begin, strong winds are expected to become the primary threat if storms can hold together over northern portions of Iowa. This seems likely as long as the cap currently preventing thunderstorm development in Iowa erodes after sunset.
All of this bears serious watching over the next few hours and we’ll be sure to launch our usual live coverage when and if the conditions warrant later tonight.