At Souix City, I revise target further north to Sheldon. A large cell is moving into Lac Quiparle county, acquiring supercell characteristics, but I stick with the chosen target area, expecting storms to bust through cap in a southward propagation.
Cells continue to push up, flatten out, rain out.
I continue east on I90 at an easy pace, disgusted yet hoping. Hard to tell in the fading light of twilight. It's after 9 when I cross the river at La Crosse, lightning is visible in the tower, and suddenly, it blasts through the cap into a beautiful cell with knuckled anvil and an overshooting top, visible enough in a ghostly white hue. Tornado warning is issued Allamakee County in Iowa. Head south, through Chaseburg, appropriately enough, but the core beats me across the river.