This early Saturday morning featured a somewhat rare phenomenon across much of the 24-county area, as southerly wind gusts of at least 50-70 MPH developed on the backside of a departing quasi-linear mesoscale convective system (MCS) due to the formation of an intense wake low. In some places, these high winds lasted for around an hour or more. A few of the peak measured wind gusts from airport sensors included 66 MPH at Grand Island, 59 MPH at Holdrege and 55 MPH at Hastings, all occurring between 230-530 AM CDT. Damage was reported across parts of the area as well, including small outbuildings destroyed and irrigation pivots overturned near Arcadia, and a fireworks tent and trailer blown over in Holdrege. Interestingly, the squall line itself did not produce a single severe-criteria report as it passed through the majority of South Central Nebraska between State Highway 92 and the Kansas border, although Hastings airport measured a 51 MPH gust along its leading edge at 130 AM CDT. This squall line first entered western parts of the area around Dawson and Buffalo Counties between 11 PM and midnight CDT, and eventually exited the local area out of Thayer and Nuckolls Counties between 3-4 AM CDT. Following the departure of this squall line, a few additional clusters of primarily multicell storms flared up and tracked east through parts of the area, one focused generally near the Highway 6 corridor and the other north of Highway 92. One of these storms briefly intensified into an elevated supercell as it passed through Adams and Clay Counties between 630-730 AM CDT, dropping a quick barrage of penny to quarter size hail on Hastings. Finally by 930 AM CDT, all thunderstorm activity had departed the eastern fringes of the 24-county area. Storm total rainfall through the night only averaged between 0.25-inch and 1-inch.
On the synoptic scale aloft, this event occurred in a typical early-summer pattern with South Central Nebraska positioned beneath modest quasi-zonal mid-level flow between the northern fringe of an expansive subtropical high dominating the southern United States, and stronger flow over the Northern Plains. At the surface, broad southerly flow preceded the arrival of the squall line, which evolved from initial thunderstorm development in southwest Nebraska and northeast Colorado during the early evening of the 22nd. This squall line and its subsequent multicell clusters were sustained across southern Nebraska by a nocturnally increasing low level jet, and in the presence of most-unstable CAPE averaging at least 1000-2000 J/kg. Significant wake low events such as this one are thought to develop in response to adiabatic warming in the wake of mature squall lines at the back edge of the rain shield, where evaporative cooling is unable to offset warming due to atmospheric subsidence, or downward motion.

High Wind in VALLEY, NEBRASKA
From 23-JUN-12 00:05:00 to 23-JUN-12 00:05:00 (CST-6)
Magnitude: 61.00 EG
Property damage: 300.00K
Reported by: COOP Observer

In and around Arcadia, small outbuildings were destroyed or damaged, roof and window damage to homes, trees were down, and pivots were upset due to high wind. This happened as a result of a wake low that developed well behind a squall line.

High Wind in DAWSON, NEBRASKA
From 22-JUN-12 23:55:00 to 22-JUN-12 23:55:00 (CST-6)
Magnitude: 50.00 MG
Reported by: AWOS

A non-thunderstorm wind gust of 58 mph occurred at the Lexington Airport. This happened as a result of a wake low that developed well behind a squall line.

Hail in ADAMS, NEBRASKA
From 23-JUN-12 05:45:00 to 23-JUN-12 05:50:00 (CST-6)
Location: HASTINGS
Magnitude: 1.00 
Reported by: Trained Spotter

Nickel to quarter size hail lasted for about five minutes.

Hail in ADAMS, NEBRASKA
From 23-JUN-12 05:44:00 to 23-JUN-12 05:44:00 (CST-6)
Location: HASTINGS
Magnitude: 0.75 
Reported by: Trained Spotter

Hail in ADAMS, NEBRASKA
From 23-JUN-12 05:44:00 to 23-JUN-12 05:44:00 (CST-6)
Location: HASTINGS
Magnitude: 0.88 
Reported by: NWS Employee

Hail in PHELPS, NEBRASKA
From 23-JUN-12 04:08:00 to 23-JUN-12 04:08:00 (CST-6)
Location: HOLDREGE
Magnitude: 0.88 
Reported by: Emergency Manager

Nickel size hail fell on the north side of Holdrege.

High Wind in PHELPS, NEBRASKA
From 23-JUN-12 02:55:00 to 23-JUN-12 02:55:00 (CST-6)
Magnitude: 51.00 MG
Reported by: AWOS

A non-thunderstorm wind gust of 59 mph occurred at the Holdrege Airport. This happened as a result of a wake low that developed behind a cold front.

High Wind in GOSPER, NEBRASKA
From 23-JUN-12 02:45:00 to 23-JUN-12 02:45:00 (CST-6)
Magnitude: 52.00 EG
Reported by: Emergency Manager

Multiple trampolines were blown about and tree branches were down in Elwood.  This was a non-thunderstorm wind gust that happened as a result of a wake low that developed well behind a squall line.

High Wind in PHELPS, NEBRASKA
From 23-JUN-12 02:44:00 to 23-JUN-12 02:44:00 (CST-6)
Magnitude: 52.00 EG
Property damage: 5.00K
Reported by: Emergency Manager

A fireworks tent and a trailer were blown over by high wind in Holdrege. This was a non-thunderstorm wind gust that happened as a result of a wake low that developed well behind a squall line.

High Wind in HALL, NEBRASKA
From 23-JUN-12 01:51:00 to 23-JUN-12 01:51:00 (CST-6)
Magnitude: 57.00 MG
Reported by: ASOS

A non-thunderstorm wind gust of 66 mph occurred at the Grand Island Central Nebraska Regional Airport. This happened as a result of a wake low that developed well behind a squall line.