A brief, weak, QLCS tornado occurred just southwest of Upland on this Sunday evening. During the early to mid-afternoon hours, thunderstorms over central Kansas combined into a multicell cluster. Between 4 and 5 PM CST, this cluster of storms moved into south central Nebraska to the south and west of Holdrege. From 5 to 7 PM CST, the storm organization increased with a small bow echo forming as the thunderstorm cluster moved east between Interstate 80 and the Kansas state line. Mesovortices developed and one briefly strengthened into a tornado in north-central Franklin county, just southwest of Upland. The tornado was on the ground for just a couple minutes, with the maximum damage intensity of EF-1. This small bow then moved more northeast toward Columbus, but weakened significantly after 8 PM CST. No additional severe weather was reported.
Two periods of heavy rain occurred over much of south central Nebraska. The first was associated with the MCS that produced the Upland tornado. The second was another MCS that originated in western Kansas and its northern fringe moved into south central Nebraska between midnight and 3 AM CST on the 27th. A swath of 2 to 4 inches of rain fell from Alma to Hastings to Aurora to Osceola. Some of the highest totals included 4.17 inches near Osceola, 4.05 at Stamford, 3.06 near Roseland, 3.91 near Juniata, and 3.85 near Clay Center. Flash flooding occurred in parts of Harlan county, where 18 inches of water was flowing down Brown Avenue in Alma, and a 6 ft culvert was washed out just north of Republican City, with the gravel road completely gone. This heavy rain would set the stage for widespread flooding of low-lying areas, creeks, and rivers as more periods of heavy rain were to come in the following days, especially on the 27th. Flooding continued through May 31st in some areas.
Low pressure was over Quebec and its cold front extended through the lower Great Lakes and had become stationary through the Midwest, across Kansas to Colorado. Through the day, part of this front moved north into south central and southeast Nebraska. In the upper-levels, a deep longwave trough was along the West Coast, with a subtropical high over northern Florida and a flat ridge over the eastern U.S. A shortwave trough was approaching the Central Plains from the Desert Southwest. Prior to the thunderstorms moving in, temperatures were in the middle 70s to near 80, with dewpoints in the lower 60s. Steep mid-level lapse rates between 7.5 and 8.0 C/km resulted in MLCAPE between 1500 and 2200 J/kg. Deep layer shear was between 40 and 50 kt. 0-3 km SRH was between 200 and 275 m2/s2.