Memorial Day Pop-up Storms

Returning home to Cedar Rapids, Iowa from Des Moines on Memorial Day afternoon, May 28, 2018, we experienced pop-up thunderstorms--and of unusual variety. All of the small clusters of summer-like storm cells exhibited a northwesterly directional track. Above, an anvil cloud looms before us at 2:53 pm CDT as we enter the eastbound on-ramp for Interstate 235 from 56th Street in Des Moines.

3:06 pm. Skies are darkening to the east as we near the Altoona, Iowa exit on Interstate 80.

3:10 pm. Approaching a rest area on Interstate 80, about 3 miles east of Altoona. We can start to see features on the horizon such as trees and structures begin to dissolve into the approaching heavy rain shaft ahead. This rain shaft would carry pea-to-dime size hail, prompting a severe warning by the National Weather Service in Des Moines.

IEM radar image capture for 3:10 pm, showing the shaded area for Polk County and the accompanying severe warning polygon box.

3:17 pm. Heavy rain and hail slowed traffic to a crawl, and amazingly dropped air temperatures from around 96 degrees F to 66 degrees F--a difference of 30 degrees! Image was captured near Mitchellville, Iowa.

3:24 pm. Looking northeast at rain shaft while eastbound on Interstate 80 near Colfax, Iowa. Again, from the camera's point of view, these storms were moving right-to-left. Nikon D7200 DSLR camera.