Sorry to jump in on this late, but I have a few things to toss in the mix based on earlier posts about the storm environment in IA on Saturday:
1. Winds were 50-80 kt through most of the storm depth, but a large portion of the vertical shear was concentrated in the lowest 1 km. The storm motions were 40-50 kt, resulting in storm-relative winds of 20-45 kt in the mid-upper parts of the storms. Even though the total CAPE was not more than about 1000 J/kg, the shear profiles were fairly typical of "classic" supercells, not super tilted mush piles.
2. Some folks expected a linear convective mode based on winds or shear parallel to the dryline. Well, I came up with a roughly 60 degree angle between the 0-6 km shear vector (oriented toward the NNE) and the dryline in IA (arcing back to the NNW). Also, storm motion was slightly faster than the dryline motion, so storms were able to move off the boundary. The net result will normally be discrete cells in that sort of environment.
Rich T.
