We found ourselves in Guernsey, WY to start the day, and we were in pretty good position for the day's severe weather prospects. Models were consistent with a long-lived supercell from SD to NE. After the weather briefing, we drove through Guernsey State Park on our way to Lusk, WY. It was a beautiful drive, and we stopped once to take pictures. When we arrived in Lusk, we ate at The Pizza Place, which has been around since 1996. The food was decent, and the longer lunch actually worked in our favor. Bill was wanting to drive up to Rapid City, SD, where models were wanting to initiate thunderstorms. Along the way, we stopped in Edgemont, SD for a pit/fuel stop, and we noticed a cell a few miles away. Bill liked the look of this storm, and it was isolated from the activity near Rapid City. We decided to hedge our bets with this cell, and we definitely were not disappointed! As we were driving south on US 18/85, we drove into the storm in order to see how large the hail was. At that time, the hail was about an inch in diameter, which was enough for the storm to become severe warned. Because of its slow, southward movement, we were able to stay in front of it very easily. As we got closer to Lusk, there was more development to the east, which was also moving slowly. We took US 20 east out of Lusk, as this road would be our best bet to watch the Edgemont cell and monitor the new activity. The Edgemont cell became a beast, and it ingested any storms in its path. As we continued to chase it, the cell showed signs that it would drop a tornado, but it kept getting undercut by its own outflow, which is rain-cooled air from the storm. As we got south of Harrison, NE, the storm showed awesome structure, and it kept going through different phases. At one point it would have a pseudo-shelf cloud, and then it would develop a nice, rotating wall cloud, and then back again. I guess you could say the storm had a bit of an identity crisis, because it did not know what it wanted to to. In either case, it kept ingesting storms in its way, and it gave us a good show all the way to Henry, NE, when it substantially weakened. We were on this storm for 5+ hours, and we were certainly not disappointed, especially since the previous two days were not that great. After driving 341 miles, we stayed overnight in Gering, NE.