Between 9 p.m. and 1 a.m. CDT on this Saturday evening into very early Sunday morning, the northern section of a fairly compact, but localized-intense mesoscale convective system (MCS) centered along the Nebraska-Kansas border took aim on mainly far southern portions of South Central Nebraska. Although available mesonets within the majority of affected counties clocked wind speeds no higher than 57 MPH, there was clearly a narrow swath of notably-higher winds that caused minor to moderate damage, particularly along the apex of a bowing segment that peaked in intensity within southern Franklin and Webster counties between 10-11 p.m. CDT. The most noteworthy damage reports originated from Franklin itself, where multiple trees were downed and some minor structural damage occurred. In the aftermath of the storm, the front page headline of the Franklin County Chronicle declared Chain Saws Hum on Father's Day. Just downstream in north central Webster County, a roof was ripped off of a motor home. After peaking in intensity within those counties, winds gradually weakened as the bowing segment pushed farther east-northeast, with the final, marginally-severe report of the night consisting of estimated 50-60 MPH winds in east-central Clay County.
This MCS first organized and intensified to severe levels within northeast Colorado between 5-7 p.m. CDT, with its northern edge invading South Central Nebraska into Furnas/Harlan counties between 9-10 p.m. CDT and eventually departing the local area out of Fillmore/Thayer counties between 12-1 a.m. CDT. Turning to the meteorology behind this event, this was a fairly classic setup for High Plains MCS development. In the mid-upper levels, broad west-northwesterly flow prevailed over the region, with forcing aided by a low amplitude shortwave trough. At the surface, South Central Nebraska resided to the north of a west-east oriented quasi-stationary front draped through central Kansas. This placed the local area in an easterly wind regime and within the northern reaches of a low-level moisture/instability gradient. During the early evening, a rather unstable airmass occupied far southern local counties ahead of the approaching convective complex, with dewpoints well into the 60s (F) promoting mixed-layer CAPE of 2000-3000 J/kg. Although effective bulk shear was not overly-strong (only around 35 knots), the combination of a surging cold pool and the development of a 30-40 knot southerly low level jet aided MCS intensification.

Thunderstorm Wind in CLAY, NEBRASKA
From 19-JUN-21 22:40:00 to 19-JUN-21 22:40:00 (CST-6)
Location: CLAY CENTER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm wind gusts of 50 to 60 mph occurred near Road T and Road 311.

Thunderstorm Wind in FRANKLIN, NEBRASKA
From 19-JUN-21 21:25:00 to 19-JUN-21 21:25:00 (CST-6)
Location: FRANKLIN
Magnitude: 61.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple trees blown down in Franklin. Multiple power lines blown down across Franklin County and several transformers knocked out.

Thunderstorm Wind in WEBSTER, NEBRASKA
From 19-JUN-21 22:00:00 to 19-JUN-21 22:00:00 (CST-6)
Location: COWLES
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Public

Roof was ripped off of a motor home. Tree branches were blown down as well.