Dark clouds loomed over northern Missouri amid “severe” thunderstorms on Tuesday, August 20. The National Weather Service (NWS) said the storms could bring winds up to 60 mph and produce “large” hail. The NWS also said an isolated tornado was possible. This video, filmed by Craig Lazenby, shows dark clouds hovering above Hannibal Regional Hospital in Hannibal, Missouri. The NWS predicted the storms in Missouri would continue for the next six days. Dramatic storm clouds were also spotted on Tuesday in Illinois and Minnesota. Credit: Craig Lazenby via Storyful.