Now that the models seem to be settling on the fact that a decent trough will be coming through next weekend, it is at least reasonable to look at that period. (N.B.: The models also suggest another couple day period towards midweek (~23-24) and towards the weekend but there's no convergence of the solutions yet). So I've posted the GFS's surface pattern for Friday and Saturday afternoons (18th and 19th) with the surface dew point field on Saturday morning.
The pattern suggests northwestern South Dakota on Friday afternoon and southeastern South Dakota/ne Nebraska on Saturday afternoon. I haven't posted the mid and upper tropospheric charts. Those show southwesterly 500 mb flow of around 25-30 knots over the Friday preliminary target and 35-40 knots over the Saturday preliminary target.
With a rental car pickup around 11AM, it is very feasible that Thom and I could make it easily to northwestern South Dakota by 4-5PM or so. The distance is around 450 miles.
The other issue is the surface dew point and, thus, CAPE field. One can hand wave about whether the GFS is being optimistic, pessimistic or realistic. No matter what, the forecasts suggest a dry line/triple point somewhere close to the target regions mentioned above. This is six to seven days in advance...and I am only posting such detail simply because many runs of the two models suggest that next weekend will have decent chase opportunities in the northern Plains.
