During the pre-dawn hours on this Wednesday morning, a fast moving line of elevated thunderstorms raced east-northeast at 50-60 MPH across several counties in South Central Nebraska mainly along and north of Interstate 80. While the majority of this activity was sub-severe, producing only small hail, the southeast periphery of the line intensified between 530-630 am CDT, dropping quarter to golf ball size hail at various points in Merrick and Polk counties before exiting the local area.  The largest reported golf ball size hail occurred in Shelby at 620 am CDT. A few miles northeast of town, an NWS cooperative observer reported half dollar size hail still on the ground two hours after it fell, thanks to cool surface temperatures in the upper 30s F. This ended up being the final severe thunderstorm event of 2013 within South Central Nebraska.
The first thunderstorms of the morning flared up over Dawson County shortly after 4 am CDT. During the ensuing few hours, storms quickly expanded into a northwest-southeast oriented line as they tracked east-northeast. On the synoptic scale aloft, this event occurred in the presence of subtle shortwave disturbances ejecting northeastward into the Central Plains out ahead of an expansive, large scale trough centered over the Intermountain West. On the smaller scale, storm initiation and intensification was tied to increasing warm air/moisture advection evident in the 850-700 millibar layer, accompanied by steepening mid level lapse rates. Mesoscale severe weather parameters around the time of the large hail featured around 1000 J/kg most-unstable CAPE in the presence of strong mid level flow around 50 knots at 500 millibars. This elevated convection occurred well north-northwest of a quasi-stationary surface front looped from far northeast Kansas into the Oklahoma Panhandle.

Hail in POLK, NEBRASKA
From 30-OCT-13 05:25:00 to 30-OCT-13 05:25:00 (CST-6)
Location: SHELBY
Magnitude: 1.25 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: COOP Observer

Half dollar size hail was still on the ground over two hours after it fell.

Hail in POLK, NEBRASKA
From 30-OCT-13 05:15:00 to 30-OCT-13 05:15:00 (CST-6)
Location: OSCEOLA
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

The ground was about 50 percent covered by half dollar size hail. The time was estimated from radar.

Hail in POLK, NEBRASKA
From 30-OCT-13 05:20:00 to 30-OCT-13 05:20:00 (CST-6)
Location: SHELBY
Magnitude: 1.75 
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Public

Golf ball size hail fell in the community of Shelby.

Hail in MERRICK, NEBRASKA
From 30-OCT-13 04:54:00 to 30-OCT-13 04:54:00 (CST-6)
Location: CENTRAL CITY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Nickel size hail was ongoing at the time of the report.

Hail in MERRICK, NEBRASKA
From 30-OCT-13 04:50:00 to 30-OCT-13 04:50:00 (CST-6)
Location: CENTRAL CITY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

This report of nickel size hail was received via Facebook.

Hail in MERRICK, NEBRASKA
From 30-OCT-13 04:55:00 to 30-OCT-13 04:55:00 (CST-6)
Location: CENTRAL CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

This report of quarter size hail was received via an NERAIN (Nebraska Rainfall Assessment and Information Network) observer.