7.5.00 Broadus, MT

Strong east-southeast winds at the surface, dewpoints in the 60s and moderate mid and upper level flow prompted a target area of northwestern South Dakota this day. The surface moisture appeared deeper today than the previous few days and the easterly surface winds were much stronger with winds to 25 mph north of Belle Fourche. At 1 pm, I left Rapid City, SD for Belle Fourche, SD and anticipated that I would continue north to Buffalo, SD. A storm was developing over the northern Black Hills as I arrived in Belle Fourche. To the north it was clear so I stayed and watched the storm over Spearfish. Even though it had a severe thunderstorm warning (314 pm) on it, the storm seemed to be struggling to fully tap into the surface moisture. I watched this storm from around St. Onge until 454 pm when the updraft began to quickly dry up. The storm was on its last breath.

To the northwest, I could see a sharp anvil. I headed northwest on Highway 212 in hopes of catching this storm. At 515 pm, I talked to the NWS via ham radio since the weather net was operating and found out that the storm was about 15 miles west of Broadus, MT and it had a tornado warning.

I could see the updraft base by 603 pm while continuing to drive northwest on Highway 212. There was a definite wall cloud, but I was still too far away to determine yet if there was significant rotation. It had a classic supercell appearance, and inflow into the storm was 20-25 mph from the east-southeast. By 618 pm, I arrived at a vantage point 3 miles east of Broadus and could see visual signs of rotation. There were multiple brief lowerings from the wall cloud, but they all appeared to be fast moving, non-rotating scud and none lasted more than a minute. I moved west of Broadus at 630 pm and watched as the storm seemed to weaken. By 730 pm, the storm moved north of Broadus into some very poor road options, so I backtracked southeast on Highway 212. By 826 pm, I was in Hammond and could see the base to the north. There were no lowerings but I could still make out the vault region. In addition, it was still generating overshooting tops. After sunset, the storm produced one more impressive overshooting top.

	613 pm Although this looks like it could be tornado, I suspect it was not. It lasted for only a minute, and I was too far away to confirm its rotation.
	619 pm Wall cloud as viewed looking west from 3 miles east of Broadus on Highway 212.
	634 pm Wall cloud with some layered striations as viewed looking west from 1 mile west of Broadus on Highway 212. There was some rotation in the wall cloud, but it was weakening.
	634 pm View looking at the northern part of the wall cloud from just west of Broadus.
	644 pm View looking northwest from 3 miles west of Broadus on Highway 212. Even though the base was still lowered, it was shrinking and rotation was diminishing.
	759 pm View looking south-southeast towards a storm around the Hot Springs/Custer, SD area from Broadus. This pronounced overshooting top developed incredibly fast and completely collapsed within 3 minutes of this picture being taken.
	826 pm Now traveling southeast on Highway 212. Here is a view of the Broadus storm looking north from Hammond, MT. You can barely make out the vault region just west/left of the road.
	842 pm Splashing cirrus from a collapsing overshoot top. View is looking north from Highway 212.
	847 pm Overshooting top again developing just after sunset. View is looking northwest from Highway 212.