2018-06-28 REPORTS: MT/SD/ND/MN/NE

Jesse Risley

Staff member
Apr 12, 2006
Macomb, IL
I chased with Eugene Thieszen. We left Breckenridge, CO early Thursday morning for the initial target of Broadus, MT. Storms were expected to go up along a pre-frontal trough ahead of the cold front, beneath a seasonably strong H5 flow. The only factor that I initially had concerns about was low-level storm relative helicity, though models indicated that it was going to increase closer to 0z. Seeing moisture flow that peaked into very high percentile ranges for late June had me concerned that this could be a significant event given the magnitude of the instability that far north being depicted by the models, and that was supported by actual 12z rawinsonde data with very favorable surface moisture pulling into NE and MT.

CAMs were depicting several different supercells developing across eastern Montana and remaining discreet, at least for the first few hours. Based on surface analysis reviewed at Douglas, Wyoming during a lunch stop, we felt southeast Montana would be the more optimal play. As we headed up towards Broadus, we watched the agitated Cu field begin to form northwest of Gillette by mid-afternoon. After a quick fuel stop, the storm that would go on to produce the tornado spectacle was born southwest of Broadus. We took Highway 212 southeast and began following the storm. It struggled initially, especially the first few hours, with weak and disorganized low-level rotation and occasional shear funnels. The storm began to take on a much more impressive structure north of Alazeda, when It produced its first tornado, which was fairly hard to see because of the contrast. As we followed it east, as it got closer to the state line, it began producing a series of tornadoes, and the supercell would go on to produce no less than 7 tornadoes as it tracked into South Dakota well after dark. I didn't even have very good contrast on all of them. SRH values began to spike, concomitant with the 850 mb jet speed increase, and low-level southeasterly flow ramped up across the area right around 7 p.m. local time (these storms formed well south of the warm front). I am still a little bit in shock that it put on the tornado show that it did, but this type of moisture return into these easterly upslope areas of the high plains tend to reward handily as long as storms move into "CAPE bomb environments" with uncapped air in an otherwise favorable warm sector with easterly / southeasterly low-level flow.

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Last edited:
Jan 10, 2014
Sheridan, WY
This was one of my favorite chases. The structure on this cyclic supercell was insane and it dropped 4 tornadoes that I could see. It's not often that dewpoints in the 70's, extreme instability (up to 7000 cape), and strong wind shear all come together in this part of the plains, and I had a feeling this day would be big. My target was Baker, Montana. I got there early and spent the afternoon waiting. I fully expected to head in to North Dakota. But it didn't feel right jumping on that first storm by Watford City. I knew it would primarily be a late show as the LLJ ramped up. But it's always hard waiting around, as I kept questioning my decisions. Storms to the NW were merging together near the cold front, while the cell in Broadus was remaining isolated. It soon became apparent that was the storm of the day, as it matured and began moving into a prime environment. At 5:30, I headed towards Ekalaka to get ahead of it. The structure was visible from a long ways off, with a curled base making it look like a tsunami in the sky. Ahead of the storm, I saw features I've never seen before including clouds that looked like mountains with Kelvin-Helmholtz waves, and even a big shear funnel.

Sky Tsunami
by Kevin Palmer, on Flickr

The landscape was beautiful, even though hills got in the way sometimes and the roads were tricky to navigate.

Montana Mothership
by Kevin Palmer, on Flickr

I made it to Buffalo but still couldn't see the tornado that was on the ground since precip was in the way. I drove a little further south and waited until it finally emerged out of the rain. This was the EF-3 as it crossed from Montana into South Dakota, but it roped out 3 minutes later.

Tornado Road
by Kevin Palmer, on Flickr

Another funnel formed, dancing around and touching the ground a few times.

Tornadic Buffalo Supercell
by Kevin Palmer, on Flickr

Cute Little Twister by Kevin Palmer, on Flickr

The wall cloud to the right was beginning to show very rapid movement. A wedge touched down while I re-positioned. This was the 3rd tornado I saw, and it stayed on the ground for about 20 minutes.

Buffalo Tornado
by Kevin Palmer, on Flickr

This tornado lifted at 8:59, but the storm wasn't done yet. It cycled again, producing another wall cloud and dropping tornado #4. Shooting conditions were getting very challenging in the dark. I lost sight of this twister after 7 minutes.

The Last Twister
by Kevin Palmer, on Flickr

I was never closer than about 9 miles to a tornado. While part of me wishes I had gotten closer, being far way allowed me to capture plenty of time lapses showing both the tornado and structure above.