Chase Log: July 21st, 2019 Osage City, KS Supercells

A nice midsummer chase resulted in some supercellular structure in Osage and Coffey Counties.

Up until the morning of the 21st, this day looked pretty boring. A cold front sagged southwards into KS, and along with some decent mid-level flow for late July, severe weather looked possible. An outflow boundary set up south of the cold front, and a 5% tornado risk was issued for NE KS on the morning of the event. I decided to keep an eye out to see what developed. I thought that the Herington-Council Grove area would be the best spot, but I didn’t go there immediately. I went to Topeka around 3 pm, and around 4 pm cells were firing in northern Lyon County. I headed south on US 75 to take a look. By the time I arrived, a nice looking supercell had developed right on the boundary north of Reading and west of Osage City.IMG_0832 (2).jpg

5:10 pm, a couple miles NW of Lyndon, Kansas, looking southwest. The supercell looked great on radar and had a nice updraft base, and it was moving very slowly. Unfortunately, a cluster of cells had developed to the south and was moving towards the storm. IMG_0839 (2).jpg

5:15 pm, same location. A wall cloud is beginning to develop on the updraft base. Rotation was also evident at this time. As the cells from the south merged with this storm, the storm became outflow dominant. If the storms hadn’t merged when they did, it’s possible a tornado would have eventually formed considering the storm was right on the boundary. I repositioned south and east so I could stay ahead of the storms which were moving more quickly now.IMG_0841 (2).jpg

5:23 pm, a few miles south of Lyndon and just east of US 75, looking west. The wall cloud feature looks nice, but didn’t seem like it was going to produce anything. After a few minutes of watching this, the south end of the cluster of storms looked to be developing better close to I-35. I abandoned this area of storms and headed south quickly. I drove through Melvern, then crossed I-35 close to Waverly.IMG_0842 (2).jpg

5:45 pm, a couple miles NW of Waverly. A huge shelf/wall cloud hybrid was apparent to my west. The storm had a very strong mesocyclone aloft, and I thought I might see something, but there wasn’t a tornado. It was fairly outflow dominant at this time (and for most of its life). The storm turned right hard and moved fairly quickly southeast. I drove south and west to keep ahead of it. IMG_0845 (2).jpg

6:04 pm, six or seven miles south of Waverly, looking northwest. The storm would go through a couple cycles of inflow and outflow dominance. Here it began an inflow cycle. I drove east and north hoping to get a better look at the innards of the storm. About ten minutes after this photo, it looked like a sizable RFD cut and lowering formed, but it dissipated quickly. After that point, the storm became permanently outflow dominant, and I headed for home.

Although I didn’t see a tornado, it was a fairly successful chase, and helped wash some of the bad taste from a disappointing spring away. Can’t ask for too much in late July anyway.