South Dakota, Wyoming, Nebraska: [Starting 2PM MST]

A surface cold front, working alongside a shortwave trough, will provide lift and instability for numerous thunderstorms to develop across this region.

Mid-level lapse rates, or the change of temperature with height, will be steep, so deep convection and strong updrafts are likely.

As a result, rotating supercells may produce large hail, damaging winds, and a couple of tornadoes.