A line of rain began passing through the Cedar Rapids area around 3:00 pm CDT on Friday, September 9, 2016. Behind it was clearing and a renewed instability. Behind and west of that was a cold front with severe-warned areas in Guthrie and Hamilton counties in Iowa. The line lost its severe warnings as it approached eastern Iowa, but stronger areas remained in the south. There was still a defined line approaching Cedar Rapids just before 6:00 pm, and that, with darkening skies to the west, prompted me to grab my gear and head out. Once in the open, a beautiful shelf cloud appeared, swallowing up conditions that included 72 degree F temps, 70 degree dew points and 89% humidity. This was a weather photographer's delight: little wind, little rain and no threatening lightning, but a beautiful "end-of-the-world" shelf cloud appearance. In the image above, I am northbound at 6:02 pm on Alburnett Road (W58), about .2-mile south of Tower Terrace, in Marion, Iowa. Image taken through open driver's window looks west.
One minute later and about .2-mile north of Tower Terrace on Alburnett Road.
Moments later. Image looks westward down the left flank of the shelf cloud.
6:04 pm. Shot through windshield. Northbound on Alburnett Road just south of W. Williams Drive in northern Marion. Shelf cloud is now covering half of the sky. Nikon D7200 DSLR camera.
The line of storms which would feature the beautiful shelf cloud was still west of the Des Moines area at 3:00 pm, and sported two severe-warned areas. Note the line of showers moving through the Cedar Rapids area at right, and the sun-renergized area of instability between them.
6:00 pm radar screen capture. My observation position is shown with the target icon and black arrows indicate storm movement. Note the stronger areas of the gust front in the south. Wind gusts never exceeded 39 mph in Cedar Rapids, well below severe levels.
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