October got off to an active start, with the first event unfolding between the evening of Sunday the 1st and the pre-dawn hours of Monday the 2nd as thunderstorms rumbled across the vast majority of South Central Nebraska in generally west-to-east fashion. While the bulk of this activity was sub-severe, some of the initial storms yielded a smattering of large hail and damaging wind reports primarily within Dawson and Gosper counties. The most significant ground-truth reports featured estimated 75 MPH winds near Johnson Lake, which downed large tree branches and blew off a portion of a grain bin roof. Otherwise, there were several instances of penny to quarter size hail in that same general area, including in and near communities such as Lexington, Overton and Elm Creek. Well to the southeast of the primary zone of severe activity, a completely separate, isolated storm lifting northeast from Kansas dropped quarter size hail in far southern Webster County near Guide Rock.  Rainfall-wise, the majority of the 24-county area tallied between 0.50-1.50, with one of the isolated higher totals featuring 2.20 southwest of Ravenna.
Breaking down timing and evolution, the most intense storms of the evening impacted the local area between 7:30-10:00 p.m. CDT. Initially, a cluster of strong-to-severe cells spread into the Dawson/Gosper counties area from the west, yielding the majority of wind/hail reports. With time, this cluster expanded/merged into other activity to its northeast and southwest, forming a nearly solid line of gradually-weakening convection that marched across the majority of South Central Nebraska before departing eastward after midnight. Separate from the main action, an isolated supercell storm drifted across portions of Webster/Nuckolls counties mainly between 8:30-10:00 p.m. CDT before dissipating. However, this long-lived storm had waned in intensity even before reaching far southern Nebraska, after initiating hours earlier in northwest Kansas.
In the mid-upper levels, this was a rather favorable early-fall severe weather setup, as small-scale disturbances overspread the Central Plains in enhanced southwesterly flow, rotating around the periphery of a large scale trough anchored over the Northern Rockies. At the surface, afternoon and evening storms first developed west of the local area, focused along both a cold front stretched through western/northern Nebraska and also northeast of low pressure centered over eastern Colorado. Breezy southerly winds ushered in an increasingly moist and unstable airmass, with dewpoints climbing into the upper 50s-low 60s F. Shortly before severe storms moved in during the evening, mesoscale analysis featured around 1000 J/kg mixed-layer CAPE and effective deep-layer shear around 50 knots. Storm organization was aided by a southerly low level jet accelerating to 50-60 knots at 850 millibars.

Hail in BUFFALO, NEBRASKA
From 01-OCT-17 19:55:00 to 01-OCT-17 19:55:00 (CST-6)
Location: KEARNEY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in DAWSON, NEBRASKA
From 01-OCT-17 20:03:00 to 01-OCT-17 20:03:00 (CST-6)
Location: OVERTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DAWSON, NEBRASKA
From 01-OCT-17 20:05:00 to 01-OCT-17 20:05:00 (CST-6)
Location: LEXINGTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WEBSTER, NEBRASKA
From 01-OCT-17 20:15:00 to 01-OCT-17 20:15:00 (CST-6)
Location: GUIDE ROCK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DAWSON, NEBRASKA
From 01-OCT-17 20:20:00 to 01-OCT-17 20:20:00 (CST-6)
Location: OVERTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOSPER, NEBRASKA
From 01-OCT-17 20:25:00 to 01-OCT-17 20:25:00 (CST-6)
Location: SMITHFIELD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BUFFALO, NEBRASKA
From 01-OCT-17 20:28:00 to 01-OCT-17 20:29:00 (CST-6)
Location: ELM CREEK
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in GOSPER, NEBRASKA
From 01-OCT-17 19:50:00 to 01-OCT-17 19:50:00 (CST-6)
Location: JOHNSON RES
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be near 60 MPH resulted in some tree limbs of 2-3 inches in diameter being downed.

Thunderstorm Wind in DAWSON, NEBRASKA
From 01-OCT-17 19:50:00 to 01-OCT-17 19:50:00 (CST-6)
Location: LEXINGTON ARPT
Magnitude: 65.00 EG
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be near 75 MPH resulted in some scattered irrigation pipes and larger tree limbs downed in the area. A section of roof from a grain bin was also removed by the wind.