Change of Plans, Change of Location

Many times intercepting the right storm or going in the right direction for storm initiation is a challenge for mobile spotters. Such was my situation on Saturday, July 20, 2019. A healthy storm cell less than 50 miles northwest of Des Moines, Iowa, and moving ESE, went severe warned at 4:15 pm. My dilemma was now this: head south and west for an intercept that would be about four hours away and hope the storm maintains its current strength, or do the opposite and go northeast where the Storm Prediction Center had posted an Enhanced Risk (above) earlier at 11:15 am. The risk included the possibility of tornadoes. A thin line of storms began advancing east northwest of Cedar Rapids before 5:00 pm, so I made the decision with my spotting partner to head north on Highway 13.

We arrived at our spotting location at the intersection of 255th Street (D34) and Highway 13, about 3.25 miles south of Manchester, Iowa in Delaware County. By this time the previous line of storms had almost died out. It soon became apparent nothing was going to happen in this area. In the image above, cumulus towers form far to our southeast at 5:53 pm CDT. And guess what? The aforementioned storm cell in central Iowa to our southwest was still rolling along and holding its severe warning. Time to bail and head back the way we came.

The fastest route to intercept the storm was to take County Home Road (E34) west to connect with Interstate 380 south. Above, the leading edge of the storm cell is beginning to blot out the setting sun at 6:32 pm as seen from County Home Road, about .8-mile west of Highway 13.

6:35 pm. A brief pause at the four way stop on County Home Road and Alburnett Road north of Marion, Iowa produces this image of the storm cell, whose most intense area is about 62 miles to the southwest, near Lynnville, Iowa in Jasper County.

6:35 pm. Continuing west again on County Home Road. Leading edge of the storm has now covered the sun.

6:47 pm. Now southbound on Interstate 380 near Cedar Lake in Cedar Rapids. The immensity of the storm's anvil is evident.

6:48 pm. Vertical image includes the Cedar River Tower and Quaker Oats in downtown Cedar Rapids.

6:52 pm. Southbound on Interstate 380, about .1-mile south of US Highway 30. Southern sky is dominated by the storm's anvil.

7:19 pm. Continuing south on US Highway 218 near the Kalona/Highway 22 exit (Exit 80) in northern Washington County. Mammatus formations now appear under the severe-warned cell's anvil.

7:34 pm. Looking west at the mammatus-laden anvil, while southbound on US Highway 218 near Haskins, Iowa.

7:36 pm. Similar shot, while located just north of Ainsworth, Iowa in Washington County.

7:58 pm. Now at our stationary spotting location (Pilot Flying J gas station/truck stop on North Grand Avenue in Mount Pleasant Iowa, Henry County). At left, fellow spotter Billy Gant readies his camera as the storm approaches our position.

8:01 pm. Looking northeast at more mammatus formations. I checked into the Washington County Skywarn amateur radio net (W?ARC repeater, 147.045), and provided periodic reports throughout my spotting stay here.

8:05 pm. Approaching shelf cloud panorama looking west. Copious amounts of lightning were occurring predominately from the right half of this image.

Radarscope frame capture corresponding to 8:06 pm, showing our position (target icon), the severe-warned polygon and the area of high reflectivity bearing down on us.

8:07 pm. Billy Gant (foreground) photographs the incoming shelf cloud and gust front in this image looking southwest.

8:11 pm. Another panoramic capture.

8:13 pm. Dramatic capture of mammatus skies, looking southeast.

8:15 pm. Looking due west. This feature caused us alarm. It's dark rising motion met the rear underside of the shelf cloud from ground up. It completely dissipated however, in just a few minutes.

8:17 pm. Another shot of the ominous feature.

Radar image corresponding to 8:15 pm. Our location is indicated by the target icon, with the white arrow pointing to the area where the feature from the two above images was captured. Black arrows indicate storm movement.

8:28 pm. Scud-like fingers protrude from the leading edge of the gust front. The blurred image was caused by shooting it hand-held, with the shutter staying open longer from darkening conditions. At 9:10 pm the severe warning was lifted, the storm weakened, and we were on our way back home. Nikon D7200 DSLR camera.