Several storms produced severe hail on this Monday late in the afternoon and into the early evening. Between noon and 1 p.m. CST, scattered showers developed over Webster and Adams Counties. There were a few embedded rumbles of thunder. These showers expanded and lifted northeast into Hall, Hamilton, and Merrick Counties. A brief non-supercell tornado touched down near Juniata, in Adams County, around 1:40 p.m. CST. This tornado occurred in the absence of any lightning and rain, although there was a shower off to the east. By 4 p.m. CST, a couple of the showers strengthened into thunderstorms. Scattered thunderstorms actually started increasing in coverage after 6 p.m. CST as an approaching shortwave trough began influencing the region. Several storms produced at least quarter size hail over Clay, Hall, Hamilton, and Webster Counties. Larger hail did occur, with tennis ball size being the largest, reported near Giltner, in southwestern Hamilton County. Car windows were broken. Between 6:30 p.m. and 8:30 p.m. CST, storms formed into a southwest-northeast oriented line across Hall and Hamilton Counties, resulting in cell-training. This resulted in rainfall totals exceeding 2 inches over Grand Island, including 2.72 inches on the northeast side of the city. Some urban flash flooding occurred, with roads being closed due to flooded underpasses. Manhole covers were also removed in some locations. The thunderstorm activity had moved east and south of south central Nebraska by 11 p.m. CST.
A north-northeast to south-southwest oriented quasi-stationary front extended from the eastern Dakota's through western Kansas into New Mexico. A lee-side low was near Colorado Springs. In the upper levels broad southwest flow was over much of the United States, with a ridge over the Great Lakes, and an elongated trough from Hudson Bay to central California. A weak shortwave trough was passing over the Central Plains. When the first storms initiated, late in the afternoon, temperatures were in the middle 70s, with dewpoints in the lower 60s. MLCAPE was between 1500 and 2000 J/kg. Effective deep layer shear was 40 to 45 knots. This environment was more than supportive of organized, persistent storms.