I must admit, this day caught me by surprise. We started in eastern South Dakota. After morning analysis and looking at model data, it appeared to be a respectable chance for large supercells in eastern Kansas with extreme instability and decent shear. As we arrived in Jefferson county, Kansas a supercell exploded from a small cumulus tower. Within 20 minutes the top was at 60,000 feet. Within another 30 minutes a tornado formed. This tornado narrowly missed the town of Oskaloosa.