Thunderstorms developed across portions of south central Nebraska during the evening of Tuesday, June 30th, along and just behind a cold front. Some of these thunderstorms became severe, bringing scattered instances of large hail, along with isolated severe wind. The first thunderstorm formed over Dawson County, just behind the cold front, around 8pm, and produced quarter size hail just north of Sumner. This storm continued to produce severe hail as it moved northeast into Custer County between 8pm and 9pm. A more extensive line of thunderstorms developed farther east around 8:30pm, from eastern Buffalo County northeast to Greeley County. This line moved east southeast. Southern portions of the line were the most intense and produced a swath of large hail reports ranging from quarter size up to half dollar size from Cairo into Grand Island. A severe wind gust of 62 mph was also measured at Central Nebraska Regional Airport (KGRI). The line of thunderstorms continued east southeast, affecting areas east of Highway 281 and north of Highway 6 between 9:45pm and midnight. However, no additional severe reports were received within these areas during this time.
The thunderstorms were supported by strong instability (mixed layer CAPE values of 4500-5500 J/kg) and modest effective shear (25-35kt). Steep mid level lapse rates near 8 C/km and a glancing influence from a progressive shortwave moving from Colorado into Nebraska Panhandle also aided in severe thunderstorm formation, though the position of this upper disturbance  kept the greatest deep layer shear displaced northwest from the cold front and strongest instability. The low level jet remained rather weak, thus the line of thunderstorms decreased in intensity after sunset with the onset of nocturnal cooling.

Hail in HALL, NEBRASKA
From 30-JUN-20 19:56:00 to 30-JUN-20 20:04:00 (CST-6)
Location: CAIRO
Magnitude: 1.50 
Property damage: 100.00K
Crop damage: 1.00M
Reported by: Public

Hail ranging in size from quarters to ping pong balls was reported along the path.

Hail in DAWSON, NEBRASKA
From 30-JUN-20 19:00:00 to 30-JUN-20 19:00:00 (CST-6)
Location: SUMNER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in HALL, NEBRASKA
From 30-JUN-20 20:10:00 to 30-JUN-20 20:10:00 (CST-6)
Location: CAIRO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in HALL, NEBRASKA
From 30-JUN-20 20:14:00 to 30-JUN-20 20:14:00 (CST-6)
Location: ALDA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in HALL, NEBRASKA
From 30-JUN-20 20:27:00 to 30-JUN-20 20:27:00 (CST-6)
Location: (GRI)GRAND IS RGNL A
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in HAMILTON, NEBRASKA
From 30-JUN-20 21:18:00 to 30-JUN-20 21:18:00 (CST-6)
Location: GILTNER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in HALL, NEBRASKA
From 30-JUN-20 20:26:00 to 30-JUN-20 20:26:00 (CST-6)
Location: (GRI)GRAND IS RGNL A
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Hail in HOWARD, NEBRASKA
From 30-JUN-20 20:35:00 to 30-JUN-20 20:35:00 (CST-6)
Location: ST LIBORY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter