June kicked off with a round of active weather on this Friday evening, as a squall line/linear mesoscale convective system (MCS) tracked across the majority of South Central Nebraska from north-to-south. Fortunately, severe weather reports were fairly limited in number and primarily concentrated within northern counties, with convection exhibiting a gradually-weakening trend as it sank south of the Interstate 80 corridor. Among the highlights of this event included a brief tornado just east of Ord, ping pong ball size hail near Loup City, and numerous broken tree branches up to 6 inches in diameter near Shelby. This storm complex was largely non-severe farther south, although a mesonet station in southwestern Clay County managed to clock an isolated 58 MPH gust.
As for timing, the initial severe storms of the afternoon/early-evening developed slightly north of the local area, and it wasn't until 830-930 p.m. CDT that quasi-linear convection entered Valley/Sherman/Greeley counties. Over the next few hours, this squall line expanded farther southwest, while also becoming more west-east oriented and gradually losing overall-intensity. Eventually, between 230-330 a.m. CDT on the 2nd, storms departed into Kansas from far southeastern local counties such as Nuckolls/Thayer. From a meteorological perspective, this was a fairly classic late-spring severe weather setup. In the mid-upper levels, a shortwave trough tracked from the northern/central Rockies toward the Dakotas between the 1st and the 2nd, with Nebraska along the southern periphery of strongest forcing. At the surface, Nebraska resided in between primary low pressure centers during the evening, with one mainly over ND and the other in western KS. Severe storms initially developed along a pre-frontal trough, with the actual north-south oriented cold front passing through South Central Nebraska during the overnight hours. Ahead of these boundaries, a very unstable airmass developed locally, with early evening temperatures around 90 F and dewpoints around 70 F yielding mixed-layer CAPE around 3000 J/kg. Combined with moderate deep-layer (0-6 km) shear of 30-40 knots and a strengthening nocturnal low level jet of 40+ knots, this was a somewhat volatile environment for severe weather. However, overall storm severity ended up underachieving somewhat locally. For one thing, the early-onset of a linear storm mode likely muted the large hail threat. Secondly, the more concentrated swath of severe-criteria winds ended up targeting eastern Nebraska more so than south central parts of the state.

Hail in VALLEY, NEBRASKA
From 01-JUN-18 20:16:00 to 01-JUN-18 20:16:00 (CST-6)
Location: ORD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in SHERMAN, NEBRASKA
From 01-JUN-18 21:13:00 to 01-JUN-18 21:13:00 (CST-6)
Location: HAZARD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in HAMILTON, NEBRASKA
From 01-JUN-18 22:57:00 to 01-JUN-18 22:57:00 (CST-6)
Location: HORDVILLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in FRANKLIN, NEBRASKA
From 01-JUN-18 23:39:00 to 01-JUN-18 23:49:00 (CST-6)
Location: HILDRETH
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, NEBRASKA
From 01-JUN-18 22:00:00 to 01-JUN-18 22:00:00 (CST-6)
Location: SHELBY
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Numerous broken tree branches occurred, with up to 6 inch diameter for the largest tree branches. This occurred from strong outflow ahead of a line of thunderstorms moving in.

Thunderstorm Wind in CLAY, NEBRASKA
From 01-JUN-18 23:46:00 to 01-JUN-18 23:46:00 (CST-6)
Location: GLENVILLE
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

This peak wind gust was recorded from a personal weather station located 4 miles east of Pauline.

Tornado in VALLEY, NEBRASKA
From 01-JUN-18 20:14:00 to 01-JUN-18 20:14:00 (CST-6)
Location: ORD
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A storm chaser captured video of a brief touchdown slightly east of Ord. Winds were estimated at 80 mph, and there was no reported damage.

Hail in SHERMAN, NEBRASKA
From 01-JUN-18 21:52:00 to 01-JUN-18 21:52:00 (CST-6)
Location: ROCKVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in SHERMAN, NEBRASKA
From 01-JUN-18 21:32:00 to 01-JUN-18 21:32:00 (CST-6)
Location: LOUP CITY
Magnitude: 1.50 
Property damage: 15.00K
Crop damage: 150.00K
Reported by: Emergency Manager