June 7, 2005 Badlands Supercell

***2005 Master Class Tour***

June 7, 2005 Badlands Supercell

This was the first full chase day of the 2005 Master Class Tour and we got an early start. We rallied the troops and departed our Kansas City hotel at 6:30 am, heading north and west all the way to the Badlands of western South Dakota where we encountered a beautiful supercell.

Tour Leaders: David Gold and Bill Gargan

Tornadoes seen: 1

Number of supercells responsible for tornadoes: 1

Meteorological Synopsis and Summary


Fig. 1: The 12Z June 07 300 mb analysis. Note the strong trough and associated jet streak over the western U.S.	Fig. 2: The 19Z June 07 surface chart, with isodrosotherms (deg F), warm front and dry line positions displayed.	Fig. 3: The VAD time series from UNR (Rapid City) around 17Z. The overall quality of the vertical wind profile is not quite "there" yet. However, substantial vertical shear is already evident in these profiles by 17Z!	Fig. 4: Modified 12Z UNR sounding, assuming surface temperature/dewpoint combination of 84/65. The result (over 5000 J/KG of SBCAPE) is probably a bit exaggerated due to the fact that this air mass was only realized over the slightly lower elevations east and southeast of Rapid City.

It was fairly clear that the threat area was going to be over the northern high plains and, consequently, we knew that we had to make a hard push northwestward on Day 1. Thanks to a solid Verizon wireless internet connection from Council Bluffs, Iowa to west of Chamberlain, South Dakota (SD), we were able to download more than enough data to keep tabs on the day's evolving weather situation. A beautiful early June upper-tropospheric pattern was in place, featuring a deep western trough and attendant southwesterly flow over the northern high plains (Fig. 1). Beneath the stout upper-level southwesterly flow, southeasterly surface winds were strengthening over southwestern South Dakota (Fig. 2), yielding a tremendous vertical wind profile over the region (Fig. 3). Moreover, a moist axis was becoming established into south-central SD by early afternoon, emanating from the moist pool over the mid-Missouri River Valley. Relatively clear skies (not shown) allowed rapid surface-based heating and temperatures in the lower to mid 80's F, combined with dewpoints that rose into the mid to upper 60's F, allowed very high SBCAPE to materialize over western SD by late afternoon (see the anticipated sounding - Fig. 4). High CAPE+strong shear=supercells so we became quite confident that this would be the predominant convective mode over the region. We pressed westward on I-90 and by the time we approached Belvidere, SD we could see an amazing little LP updraft to our distant SW, an updraft that was associated with an expansive anvil and looooong streaming inflow tail. However, we were still a bit conflicted: there was a violent looking supercell approaching Enning, SD (as seen on the Baron ThreatNet radar system that we had onboard) and - as such - was a mighty enticing prospect. We sat for a minute or two on the north side of the interstate looking southwest at the ever-improving LP supercell and also at the menacing beast near Enning on our radar display. Realizing that the storm to our southwest was moving slowly northeast into a very warm and moist air feed, we decided to give up any lingering aspirations to target the Enning storm and we effectively committed ourselves to sticking with what I shall hereafter call the Wanblee storm. We needed a vantage point that would allow us to see under the updraft base and we found one by going south of I-90 and then finding an overlook that afforded us the view that we sought. Although we were quite some distance from the storm, we were content to view the well-structured updraft from this scenic vista. Somewhat to our surprise, tornadogenesis soon commenced and we rushed to slap zoom lenses on our camera gear. Roger and Tour 5, having spent the night in the area and committed to this storm from the get-go, were much closer to this storm and the ensuing tornado that it produced. Nonetheless, we were content to view the development from a distance. After the tornado dissipated, we moved south to get in front of this increasingly well-structured updraft and closer to any subsequent tornadoes. It turns out that no additional tornadoes occurred, but the storm did come mighty close along Hwy 73 northeast of Wanblee where it sported a rapidly rotating wall cloud. Outflanked due to a lack of roads, we maneuvered and managed to get out in front of the storm again northwest of Cedar Butte. We had to let the storm cross ahead of us on our unpaved road and then gained ground eastbound on I-90 once again. The storm attained a beautiful shelf cloud before really gusting out and producing one hell of a haboob which chased us all the way to our hotel in Mitchell.