Although a few marginally-severe thunderstorms impacted the northwestern half of South Central Nebraska on this Sunday late afternoon/early evening, this event fell short of forecast expectations in terms of potential coverage/intensity of severe weather (more on this below). As for what actually happened, a handful of semi-discrete severe storms produced hail to half dollar size at Johnson Lake and nickel size near Sherman Reservoir, along with wind gusts around 60 MPH near Holdrege and Rockville. As for how the day played out, this seemed to be a case where factors such as the presence of early-day convection in/near the area, along with appreciable high level cloud cover much of the day, combined to hamper later-day airmass recovery and thus tempered the magnitude of the potential severe threat (SPC had upgraded most of South Central Nebraska to Enhanced Risk on morning Day 1 outlooks).
The first sign of potential complications showed its hand early in the day as a few clusters of elevated, non-severe storms flared up between sunrise and late morning, affecting several counties along/east of Highway 281. Meanwhile, an unrelated batch of higher clouds rolled in from the west, prompting a multi-hour period of mostly cloudy skies over South Central Nebraska lasting well into the afternoon. Then, as skies started clearing and airmass recovery began, an extensive batch of strong/severe convection erupted to the south over Kansas, likely disrupting northward moisture advection and further inhibiting late afternoon destabilization. Nonetheless, despite these factors working against a local severe threat, a broken line of semi-discrete severe storms finally initiated around 6 p.m. CDT in northwestern counties, along a northeast-southwest oriented front. However, these storms did not maintain intensity long, weakening within 60-90 minutes. In their wake, one more rogue severe storm flared up around 8:30 p.m. CDT over Phelps/Harlan counties, but also faded fast. Finally, shortly after sunset a briefly-severe storm just west of the local area made a run toward Dawson County, but weakened as it moved in, effectively slamming the door on any further severe threat. Not surprisingly given the forecast expectations, the general synoptic setup appeared rather solid for severe storms. In the mid-upper levels, broad west-northwest flow prevailed over the Central Plains as a series of embedded disturbances rotated around the south side of a large-scale trough/closed low over south central Canada. At the surface, steady southerly breezes prevailed, to the east of a quasi-stationary front draped through western/north central NE. However, surface dewpoints remained fairly modest by late-June severe weather standards, averaging upper 50s-mid 60s F. Even so, afternoon mixed-layer CAPE reached 2000-3000 J/kg thanks to steep mid-level lapse rates, in the presence of  30-40 knots of deep-layer wind shear.

Hail in SHERMAN, NEBRASKA
From 21-JUN-20 17:26:00 to 21-JUN-20 17:26:00 (CST-6)
Location: SHERMAN RES
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in SHERMAN, NEBRASKA
From 21-JUN-20 17:35:00 to 21-JUN-20 17:35:00 (CST-6)
Location: ROCKVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be near 60 MPH resulted in some small tree branches being downed.

Hail in GOSPER, NEBRASKA
From 21-JUN-20 17:40:00 to 21-JUN-20 17:42:00 (CST-6)
Location: JOHNSON RES
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PHELPS, NEBRASKA
From 21-JUN-20 19:30:00 to 21-JUN-20 19:30:00 (CST-6)
Location: ATLANTA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter