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Visible loop for June 24, 2003 case. Identify the various air masses. Enhanced cumulus line moving east, storms later form on this. Points to notice: 1) cloud streets throughout most of eastern NE (parallel to low-level flow), 2) old MCS boundary from n-central NE to se-SD to southern MN with stable wave clouds to the north of the boundary (oriented perpendicular to flow at top of boundary layer, 3) stratoform clouds in western NE with warm frontal boundary just east of stratiform field (note: there is a low in ne-CO).

The MCS boundary moves north with time (fast/rock), possibly merging with warm front. Organized n-s line of enhanced Cu in eastern NE merges with warm front/MCS boundary and a storm forms in se-SD. Storm becomes tornadic almost immediately (first report at 21:30 UTC). Second storm forms on Cu line in eastern NE and splits at around 22:30 UTC. Several tornado reports near 23:00 UTC near Missouri River. Meanwhile, the original MCS boundary storm produced intense outflow boundary as it dissipates and a new storm form. A large tornado touches down in Sanborn county SD at 23:19 UTC with this storm. Note that a thunderstorm forms at around 20:30 UTC near OMA NE. That this storm is blocking the low-level flow can be seen with the dissipation of the clouds streets north of the storm beginning almost immediately. The effect is particularly noticable at 22:45 UTC. Also, notice that the storms in nc-IA that move into the clear area, dissipate.