Thunderstorms erupted just before sunset Friday evening over southern Iowa. The storm environment was characterized by high instability and low shear, so the storms did not move very fast and their isolated nature allowed for an incredible viewing of a lightning show. The featured map presents lightning stroke density counts courtesy of Vaisala. The highest totals can be seen just southeast of Des Moines. Even with the marginal shear, they were likely able to produce brief tornadoes. A repeat situation is expected this evening over parts of southern Iowa.