This Monday evening got somewhat more active than anticipated, as a pair of supercell storms affected mainly the northeast quadrant of South Central Nebraska, resulting in several reports of large hail (up to 2 diameter), damaging winds (up to around 75 MPH), and even one EF-1 tornado. This tornado (spawned by the eastern supercell) touched down in northwestern York County around 7:45 p.m. CDT and tracked east-southeast for less than 2 miles, causing minor damage to a home while also damaging several grain bins and snapping a few large trees. The largest hail reports (2) originated from the Bradshaw and Alda areas. In addition, golf ball size hail occurred near Benedict and Waco, and much of the city of York saw a few minutes of hail to at least half dollar size. As for thunderstorm winds, the highest measured gust was 60 MPH at the York airport. However, especially the eastern supercell produced a concentrated swath of damaging winds, estimated to around 75 MPH in some places. Crop damage (from a combo of both hail/wind) was extensive along this storm's track from central Merrick County into northeastern Hamilton County and northwestern-through-east-central York County.
Taking a closer look at event evolution/timing, a smattering of weak, elevated storms got underway as early as early-mid afternoon across various parts of the 24-county area, producing little more than brief downpours and small hail. By late afternoon, another round of fairly weak storms flared up within counties mainly north of Interstate 80. However, between 6:30-8:30 p.m. CDT, the situation escalated as one of these initially-weak storms rapidly became severe over Howard County, becoming a legitimate supercell as it tracked east-southeast through parts of Merrick-northeastern Hamilton and York counties. This storm yielded the majority of local severe weather reports/damage (including the York County tornado), before exiting into eastern Nebraska shortly after 8:30 p.m. CDT. Meanwhile, back to the west, another supercell initiated over far northeastern Buffalo County around 8 p.m. CDT. Like its predecessor, it also tracked east-southeast for a few hours,  producing large hail in the Alda and Stockham areas before weakening over northern Fillmore County around 10 p.m. CDT. Thereafter, non-severe storms continued percolating well into the night within areas mainly south of Interstate 80 and east of Highway 281, with all of South Central Nebraska finally storm-free by 3 a.m. CDT on the 7th.
In hindsight, this was actually a decent setup for supercell storm development. However, right up until the early evening hours, locations as far north as Merrick/York counties seemed somewhat unfavorable for higher-end severe potential, especially given that the primary west-east oriented surface front resided well to the south over northern Kansas. However, even in the post-frontal airmass over South Central Nebraska, the combo of afternoon high temperatures into the 80s F and dewpoints in the upper 60s-low 70s F promoted mixed-layer CAPE around 2000 J/kg. This healthy instability, in tandem with seasonably-strong deep-layer wind shear of 40-50 knots and modest forcing provided by a shortwave trough invading from the northwest, proved plenty-sufficient to support a few supercells.

Thunderstorm Wind in MERRICK, NEBRASKA
From 06-AUG-18 18:02:00 to 06-AUG-18 18:02:00 (CST-6)
Location: ARCHER
Magnitude: 52.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Wind gusts estimated to be near 60 MPH knocked down a few large tree limbs.

Thunderstorm Wind in MERRICK, NEBRASKA
From 06-AUG-18 18:20:00 to 06-AUG-18 18:20:00 (CST-6)
Location: CENTRAL CITY
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Wind gusts estimated to be near 60 MPH knocked down a few tree limbs in town.

Thunderstorm Wind in HAMILTON, NEBRASKA
From 06-AUG-18 18:30:00 to 06-AUG-18 18:30:00 (CST-6)
Location: HORDVILLE
Magnitude: 65.00 EG
Property damage: 100.00K
Crop damage: 3.00M
Reported by: Newspaper

Wind gusts estimated to be near 75 MPH resulted in damaged and destroyed empty grain bins as well as some tree damage.

Thunderstorm Wind in YORK, NEBRASKA
From 06-AUG-18 19:15:00 to 06-AUG-18 19:15:00 (CST-6)
Location: YORK ARPT
Magnitude: 52.00 MG
Property damage: 100.00K
Crop damage: 1.00M
Reported by: AWOS

This wind gust actually occurred at the York Airport (the latitude/longitude is correct).

Hail in MERRICK, NEBRASKA
From 06-AUG-18 18:02:00 to 06-AUG-18 18:02:00 (CST-6)
Location: ARCHER
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 4.00M
Reported by: Fire Department/Rescue

Hail in HAMILTON, NEBRASKA
From 06-AUG-18 18:25:00 to 06-AUG-18 18:25:00 (CST-6)
Location: MARQUETTE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in MERRICK, NEBRASKA
From 06-AUG-18 18:29:00 to 06-AUG-18 18:29:00 (CST-6)
Location: CENTRAL CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in YORK, NEBRASKA
From 06-AUG-18 18:40:00 to 06-AUG-18 18:55:00 (CST-6)
Location: BRADSHAW
Magnitude: 2.00 
Property damage: 250.00K
Crop damage: 5.00M
Reported by: Fire Department/Rescue

Hail lasted for approximately 15 minutes, ranging in size from quarters to 2 inches in diameter.

Hail in YORK, NEBRASKA
From 06-AUG-18 18:57:00 to 06-AUG-18 18:57:00 (CST-6)
Location: BENEDICT
Magnitude: 1.75 
Property damage: 250.00K
Crop damage: 5.00M
Reported by: Storm Chaser

Hail in YORK, NEBRASKA
From 06-AUG-18 19:05:00 to 06-AUG-18 19:10:00 (CST-6)
Location: WACO
Magnitude: 1.75 
Property damage: 250.00K
Crop damage: 5.00M
Reported by: Trained Spotter

Hail in YORK, NEBRASKA
From 06-AUG-18 19:00:00 to 06-AUG-18 19:05:00 (CST-6)
Location: YORK ARPT
Magnitude: 1.25 
Property damage: 250.00K
Crop damage: 5.00M
Reported by: Public

Hail up to the size of half dollars was reported in and around York.

Hail in HALL, NEBRASKA
From 06-AUG-18 19:36:00 to 06-AUG-18 19:36:00 (CST-6)
Location: ALDA
Magnitude: 2.00 
Property damage: 100.00K
Crop damage: 1.00M
Reported by: Social Media

Hail up to 2 inches in diameter was reported.

Hail in HAMILTON, NEBRASKA
From 06-AUG-18 20:30:00 to 06-AUG-18 20:30:00 (CST-6)
Location: STOCKHAM
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CLAY, NEBRASKA
From 06-AUG-18 20:43:00 to 06-AUG-18 20:43:00 (CST-6)
Location: SUTTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tornado in YORK, NEBRASKA
From 06-AUG-18 18:43:00 to 06-AUG-18 18:47:00 (CST-6)
Location: ARBORVILLE
Tornado F-scale: EF1
Property damage: 25.00K
Crop damage: 1.00M
Reported by: NWS Storm Survey

This brief EF-1 tornado occurred in northwest York County, causing damage approximately 7 miles north of Bradshaw. A home was damaged, mainly to soffits and garage doors, and there was also some roof damage. Grain bins were damaged along with several trees. Some larger cedar trees were snapped 2-3 feet above ground. Two irrigation pivots were damaged along the path. Peak winds were estimated to be 90 MPH.
This tornado was associated with a supercell and a much larger scale wind and hail event in the region. There were numerous irrigation pivots overturned or damaged, and crop damage was widespread, especially around and just to the east of the tornado path. Some soybean fields were stripped and beat to the ground, and corn fields were cut down by the wind and hail to only three feet tall in spots.