2021-05-23 EVENT: CO/KS/NE/WY/SD

Jesse Risley

Staff member
Apr 12, 2006
Macomb, IL
The setup for today has been looking better and better as we approach the event.

A potent upper-level disturbance and forcing for ascent coupled with a dryline near I-25 will set the stage for thunderstorm initiation early this afternoon.

The low-level thermal environment appears quite ambient, upper-50s to lower-60s Tds pushing towards the front range in CO. MLCAPE values AOA 1500 J/KG will be co-located with an environment characteristic of 150-250 m2/s2 SRH values with stalwart S/SE surface flow pushing westward towards the surface DL/boundary. Morning skew-T/Log-P profiles prog classic curvatures indicative of adequate streamwise vorticity for tornadogensis this afternoon; however, some meridional flow aloft may contribute to cells trending towards clustering several hours after initiation. Initiation southwest of Limon may have the greatest potential for initial tornadogenesis, before other discrete cells along a line from Wray-Simla and further SE towards the KS border, which also looks poised to arrive to dine on the relatively rich atmospheric feast. Forecast wind shear profiles aloft, combined with steep lapse rates and notable hydrolapses, also support the risk for large hail. I expect the threat to transition to damaging winds into parts of KS and NE this evening. Conditional tornadic risk also exists up near the warm front, surface cyclone as it pushes into the SW Black Hills region today, and, although this is a less than favorable terrain, it could also reward this afternoon if storms stay discrete.