EF1 tornado in Richardson County, Nebraska

At approximately 3:46 PM CST, a tornado developed 4 miles east of Bern, KS, and tracked northeast before crossing into Richardson county, Nebraska (see Storm Data for Kansas for more information on the beginning portion of this tornado in Kansas). The tornado continued west of 639 Boulevard, damaging some trees. It continued northeast, crossing 639 Boulevard and producing significant damage to the roof of a large metal outbuilding. The tornado then crossed US Highway 75 just northwest of the intersection with 641 Avenue, causing further tree damage and impacting a second metal outbuilding in the area. Additional tree damage occurred near Rock Creek and 642 Avenue. Maximum estimated wind speeds peaked at 100 mph.

On the afternoon of May 18, severe thunderstorms produced tornadoes, damaging winds gusts, hail and flash flooding across southeast Nebraska. a strong shortwave trough ejected eastward across the region, providing robust forcing for large-scale ascent. Despite lingering morning cloud cover, very steep mid-level lapse rates combined with the daytime heating of a moist low-level airmass to generate strong instability south of an advancing cold front. Mesoanalysis revealed strong theta-e advection extending from central Kansas through southeast Nebraska and southwest Iowa, highlighting the rapid return of a highly volatile environment. Thunderstorms initially initiated on the warm side of the boundary over northwest Kansas before additional development began over far southeast Nebraska by 2:00 PM CST. This convection initially exhibited discrete supercell characteristics before eventually transitioning into a broader multicell cluster. Additional cells developed north of the cold front across eastern Nebraska, bringing primarily an isolated hail threat.

The system dropped large hail up to golf ball size (1.75 inches) and generated destructive straight-line winds, including a measured peak gust of 90 mph. The initial supercell storm mode was particularly prolific for tornadogenesis, resulting in 8 tornado across southeast Nebraska. While several of these tornadoes were brief, others caused concentrated damage to trees, farm outbuildings, and irrigation pivots'most notably in Johnson, Nemaha, and Richardson counties. In several instances, these tornadoes were embedded within even broader swaths of intense 80 to 95 mph downburst winds. As the storms transitioned into a messy multicell cluster, torrential downpours also triggered isolated reports of flash flooding.