Thunderstorms brought heavy rain and a landspout to portions of south central Nebraska the evening of Sunday, May 24 into the early morning hours of Memorial Day, Monday, May 25.
Just after 6 PM CDT Sunday evening, weak thundershowers began developing along a frontal boundary that was located from near Stockton, KS to Red Cloud, NE to Shelby, NE. One of these weak thundershowers managed to spawn a landspout tornado a few miles west of Davenport, NE, in extreme northeastern portions of Nuckolls County. This landspout, unlike most, did cause some damage as nearly a dozen empty coal railroad cars were overturned. The aforementioned line of thunderstorms strengthened slightly during the evening, per radar reflectivity, before weakening with loss of daytime heating around sunset. The landspout was the only known severe weather caused by this line of thunderstorms as the main focus for severe convection remained further south across Kansas near the Interstate 70 corridor.
Showers and thunderstorms blossomed over south central Nebraska and north central Kansas after 10 PM Sunday and continued through the entire overnight. This activity remained non-severe, but very slow storm motions and abundant deep layer moisture allowed for heavy rain rates and, subsequently, pockets of very heavy rainfall. The heaviest rainfall amounts of 4 to 8 inches (per radar and ground truth observations) appeared to focus across northwest Adams County and southwest Hall County. Numerous county roads became submerged in water and impassable late Sunday night into early Monday morning. The most severe impact, however, was to a residence northwest of Kenesaw as flood water filled the basement and even encroached on the main floor, prompting their rescue early Monday morning. The rescue had to be done via air boat because so many roads in the area were under water and impassable.
The heavy rain from Sunday night into Monday morning occurred over areas that were already saturated from recent heavy rains from May 21-23, and this likely contributed to the flooding impacts from this event. Very slow storm motions and seasonably high precipitable water values near 1.5 were also meteorological factors to this heavy rain event. The tornado occurred in conditions fairly typical of landspouts as it was along a surface front with abundant ambient vorticity that was stretched into the vertical axis by steep low level lapse rates and sufficient 0-3 km CAPE near 100 J/kg.