July 21 Beautiful Storm Structure In Johnson County Iowa

A revised Storm Prediction Center Enhanced Risk was posted from central to eastern Iowa on Friday afternoon, July 21, 2017, followed soon thereafter by Severe Thunderstorm Watch 429 (above). Almost unnoticed by me, a small cell began to form southwest of Williamsburg, Iowa in Iowa County around 3:35 pm. I had been expecting storms to initiate further north, more inside the Enhanced Risk and Watch 429 boxes. 20 minutes later--to my surprise--the cell had grown considerably and went severe-warned. It was time to head out and catch it!

Shown above is my position at 4:10 pm at the Cedar Rapids Blairsferry Road Interstate 380 overpass, with the arrow pointing toward the severe-warned cell. Below is the camera's view of the storm at the same moment. Note the strong updraft of the cell, evident even at just under 30 miles distant.

Now southbound on I-380 in southern Cedar Rapids at 4:18 pm (above). The storm cell is exhibiting a strong cauliflower-like updraft appearance with a wall cloud on its western (right in image) flank.

4:20 pm and just north of the Eastern Iowa Airport exit (Exit 13). Drawing closer to it with each mile. The wall cloud has become much more obvious now under the updraft. The most intense part of this storm was located about 14 miles to the SW, near Middle Amana, Iowa.

Two minutes later and just north of my eventual spotting position--the rest area just north of the Swisher, Iowa exit. The wall cloud now dominates the scene. Nikon D7200 DSLR camera.