The overnight hours of Tuesday the 20th into the early morning of Wednesday the 21st were quite stormy, especially within the northeast half of South Central Nebraska. However, the vast majority of strong to severe activity (along with heavy rainfall) concentrated within a 10-20 mile wide, northwest-southeast oriented stripe centered from roughly Hazard-Grand Island-Lushton. Despite several radar-indicated signatures of large hail within this zone, various factors (such as the time of day) resulted in hardly any ground-truth verification. The main exception was at a well-known, 45-acre melon and pumpkin patch seven miles east of Ravenna, where 45 minutes of hail (some up to golf ball size) ruined the majority of the season's produce. As for heavy rain, most locations within the main swath tallied between 1.50-3.00 overnight. However, there were very localized higher exceptions, including 3.84 at the aforementioned melon patch east of Ravenna and 3.66 at Dannebrog. There was also an unofficial report of 5.50 in far northeastern Buffalo County, but this was certainly a high-end outlier. There were no ground-truth reports of flash flooding during the night. However, heavy rain over southern Hamilton County pushed the West Fork Big Blue River out of its banks during the day, with minor flooding reported near Stockham (side note: due to repeated rounds of rain, minor flooding ended up persisting along local portions of the West Fork Big Blue River for the next 10 days).
Timing-wise, rapid storm development got underway within the primary northwest-southeast corridor shortly before midnight CDT, with convection peaking in intensity 12-3 a.m. CDT before weakening but expanding in coverage. The initial concentration of storms within such a narrow swath was a classic signature of increasing nocturnal warm air advection/convergence in the 850-700 millibar layer. In the mid-upper levels, broad quasi-zonal flow prevailed over the Central Plains, containing subtle, low-amplitude disturbances. The mesoscale environment was primed for robust-but-slow-moving storms, featuring 2000-3000 J/kg mixed-layer CAPE but only 20-30 knots of deep-layer wind shear. At the surface, South Central Nebraska resided slightly north of a quasi-stationary front draped west-east through northern Kansas, and within a very moist/humid airmass marked by dewpoints well into the 70s F.

Hail in BUFFALO, NEBRASKA
From 20-AUG-19 23:40:00 to 21-AUG-19 00:25:00 (CST-6)
Location: RAVENNA
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 500.00K
Reported by: Broadcast Media

Hail ranging in size from peas to golf balls fell for approximately 45 minutes, ravaging a 45-acre melon and pumpkin patch east of Ravenna. About a month later, it was reported that the business lost 80-90 percent of its produce from this storm.

Heavy Rain in BUFFALO, NEBRASKA
From 20-AUG-19 23:00:00 to 21-AUG-19 02:00:00 (CST-6)
Location: RAVENNA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

A rainfall total of 5.50 inches was reported six miles south-southwest of Boelus, most of which fell between 12-3 a.m. CDT. This was an unofficial public report and likely a higher-end outlier, as another report from nearly the same area was only 3.84 inches.