Cooling ahead of a Pacific trough moving into Montana today looks to support "substantive destabilization" as the SPC forecasts. CAPE values will be supported, with about 1000 j/kg once we can get enough daytime heating and break the cap. Strong forcing ahead of the trough will support thunderstorms. There's enough shear possible for some severe storms, including isolated thunderstorms!
There are kissing jets at 300mb, with good diffluence between the two paired with spreading winds and uplift in our target region of Montana. The vorticity advection will be rolling across the mountains to the west, with a good boundary in Montana, warm temperatures and some promising daytime heating. Dewpoints will be advecting to the northwest with the winds, heading right in our direction, near or just to south of Billings in our target region.
Like I mentioned before, afternoon models show about 1000 j/kg CAPE, which we would like to see at higher values but it's actually pretty good with the high elevations. Pair that with the upslope flow off the mountains and you'll have great uplift. Helicity models are close to 150 with some good looking shear, LCL heights about 1 km and PVA east of the mountains, so we're hoping to see something great!
One big concern is the widespread road network and the mountains blocking our travel north. It looks like we'll stick to southern and south-eastern Montana for the day and wait for the storms to come to us.