Gust Fronts & Straight Line Winds

At 2:20 pm CDT on Thursday, June 27, 2019 a 210-mile-long gust front (above), stretching from about Dysart, Iowa to about 30 miles west of Wausau, Wisconsin was advancing swiftly southeastward, bringing with it gusty straight-line winds, heavy rain and hail.

By 3:25 pm I was on the road and facing this interesting low hanging scud structure while northbound on Alburnett Road just north of Marion, Iowa and just south of County Home Road (E34).

3:28 pm. First spotting position on North Marion Road, one-tenth-mile north of County Home Road. The panoramic image above looks north. A possible microburst feature can be seen in the background at left center.

3:29 pm. If this was a funnel, it was very brief, high-based and anemic. Image looks north.

3:31 pm. At the very least a rain shaft and at the most a minor microburst feature. Looking northwest from North Marion Road, just north of County Home Road north of Marion. Shortly thereafter the storm began losing its visual appeal from this location, so I moved east on County Home Road, then south back into Marion.

A new severe warning went up near the Anamosa area east of Marion around 3:46 pm (above). The target icon shows my position.

3:48 pm. Brief spotting position number two. Camera looks east at severe-warned cell from 35th Avenue, about a quarter-mile east of 35th Street in Marion.

3:49 pm. A panorama of the same view. The heavy rain and hail core at left is evident.

3:58 pm. Now eastbound (actually northeastbound) on US Highway 151, 1.2 miles northeast of Highway 13 in Marion. Heavy rain and hail feature to my "one o'clock" position. I soon decided to break off pursuit of this storm as it was swiftly moving east and I was out of position. 70-plus mph straight-line winds were generated by this storm.

In just about 20 minutes another area to the northwest also became severe-warned. I had time to go home and collect some addition spotting equipment, then set out north on Highway 13 north of Marion. Above, I am about two miles south of Ryan, Iowa at 5:45 pm. The approaching gust front was adorned with a shelf cloud low on the horizon.

5:49 pm. Last spotting position of the day. Looking north at severe cell from 170th Avenue at 310th Street (D47), about 1.2 miles southeast of Ryan in Delaware County.

Radarscope image capture corresponding to the photograph above it, with my position shown by the target icon.

5:50 pm. Panoramic view of the same storm. Despite its impressive appearance at this time,  in less than 15 minutes the storm began to weaken and the severe warning was allowed to expire. The storm was tracking left-to-right in the picture. Nikon D7200 DSLR camera.

Last shot from the storm--literally a captured lightning bolt. The image is a GoPro Hero 4 Silver video frame grab from about 6:00 pm.