For most of South Central Nebraska, the 24-hour period from the evening of Monday the 17th into the evening of Tuesday the 18th was simply dreary, damp and seasonably-cool, with no severe storm threat and daytime high temperatures only in the mid-60s to low-70s F. The majority of the area measured no more than 0.50-1.50 of rain, most of which accumulated over the course of several hours, thus causing few-if-any flooding issues. However, there were a few very localized exceptions. Most notably, a narrow corridor of heavy showers pivoted across the heart of Harlan County during the early afternoon, dropping as much as 2-3 in a short time and promoting flash flooding, particularly in and near Alma. Per law enforcement and emergency management reports, roughly one foot of water flowed across a short stretch of Highway 136, in addition to issues on several rural roads. A bit later in the afternoon and 85 miles farther east, a more subtle and brief localized flooding situation set up over western Thayer County, where emergency management reported several inches of water over Highway 5. Based on radar estimation and limited gauge reports, this area likely received no more than 1.50 of rain. In the mid-upper levels, this soggy period was driven by a fairly compact shortwave trough/mesoscale convective vortex (MCV), which slowly tracked along the Nebraska-Kansas border. While widespread rain and clouds kept instability very minimal, the combo of decent forcing and a moist airmass promoted pockets of high rainfall rates, driven by warm rain processes through the lower cloud layers.