Storm Cell With No Competition

In an otherwise benign sky on Wednesday evening, June 26, 2013 I was surprised to see a blossoming thunderhead far off into the distance and sporting a overshooting top. I was on the road with my camera by 6:45 PM and headed north on Highway 13 north and east of Marion, Iowa. Appearing local, I would later discover the storm cell was actually about 85 miles from my eventual spotting position near the northern Linn County town of Coggon. Both of the upper images were shot around 7:19 PM and look north from Heatons Valley Road, just east of Highway 13 and about 2.25 miles south of Coggon. The overshooting top, a strong updraft feature resembling a small dome, can be seen at upper left on the structure. At this moment it was rising at an altitude of 50-55,000 feet. The bottom image is a radar screen capture corresponding to the photos. It shows the storm's location in extreme northeast Iowa (Allamakee County), near the Minnesota border.