Very unstable conditions developed during the afternoon of August 20th over eastern Nebraska as a warm front set up from central into southeast Nebraska by early afternoon.  Temperatures were in the 90s with dew points in the 70s south of the boundary.  A strong upper level disturbance that moved across the state helped trigger thunderstorm development by mid afternoon as it brought a wind shift of drier air eastward to meet the unstable conditions.  Severe thunderstorms quickly developed and they congealed into several bow echo type configurations as they tracked across both the Lincoln and Omaha metro areas and then into southwest Iowa.  Moderate amounts of wind damage was reported with the activity along with scattered large hail reports.

Thunderstorm Wind in LANCASTER, NEBRASKA
From 20-AUG-07 17:35:00 to 20-AUG-07 17:35:00 (CST-6)
Location: DENTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm winds estimated at around 60 mph blew down an old grain elevator no longer in use in Denton.

Hail in BOONE, NEBRASKA
From 20-AUG-07 16:13:00 to 20-AUG-07 16:13:00 (CST-6)
Location: PRIMROSE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Reported near the jct of Highways 52 and 91.

Hail in SALINE, NEBRASKA
From 20-AUG-07 17:00:00 to 20-AUG-07 17:00:00 (CST-6)
Location: FRIEND
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BOONE, NEBRASKA
From 20-AUG-07 16:27:00 to 20-AUG-07 16:27:00 (CST-6)
Location: PRIMROSE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in COLFAX, NEBRASKA
From 20-AUG-07 17:30:00 to 20-AUG-07 17:30:00 (CST-6)
Location: SCHUYLER
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

A large section of a tree was blown onto the roof of a house in town causing moderate damage.

Hail in BOONE, NEBRASKA
From 20-AUG-07 15:55:00 to 20-AUG-07 15:55:00 (CST-6)
Location: PRIMROSE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in SEWARD, NEBRASKA
From 20-AUG-07 17:20:00 to 20-AUG-07 17:20:00 (CST-6)
Location: MILFORD
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm wind gusts were estimated at 70 mph according to the Milford Police Chief.  The winds broke large tree limbs in town and flipped two silage wagons.

Hail in SALINE, NEBRASKA
From 20-AUG-07 17:18:00 to 20-AUG-07 17:18:00 (CST-6)
Location: DORCHESTER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DODGE, NEBRASKA
From 20-AUG-07 18:21:00 to 20-AUG-07 18:21:00 (CST-6)
Location: AMES
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SAUNDERS, NEBRASKA
From 20-AUG-07 18:27:00 to 20-AUG-07 18:27:00 (CST-6)
Location: ASHLAND
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MADISON, NEBRASKA
From 20-AUG-07 19:00:00 to 20-AUG-07 19:00:00 (CST-6)
Location: NORFOLK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in SARPY, NEBRASKA
From 20-AUG-07 18:34:00 to 20-AUG-07 18:52:00 (CST-6)
Location: PAPILLION
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Strong winds spread from the Papillion area across Bellevue and Offutt AFB causing scattered tree damage and downed power lines.  A wind gust of 67 mph was measured at Offutt AFB at 752 pm CDT.

Thunderstorm Wind in SALINE, NEBRASKA
From 20-AUG-07 16:55:00 to 20-AUG-07 17:10:00 (CST-6)
Location: DORCHESTER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts estimated at 60 mph lasted for around 15 minutes southwest of Dorchester.  These strong winds downed numerous 4 to 6 inch tree limbs and caused some damage to a chimney.

Hail in SALINE, NEBRASKA
From 20-AUG-07 17:01:00 to 20-AUG-07 17:01:00 (CST-6)
Location: DORCHESTER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel size hail was accompanied by winds strong enough to break 2 inch tree limbs.

Hail in SALINE, NEBRASKA
From 20-AUG-07 17:08:00 to 20-AUG-07 17:08:00 (CST-6)
Location: FRIEND
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in BUTLER, NEBRASKA
From 20-AUG-07 17:25:00 to 20-AUG-07 17:25:00 (CST-6)
Location: BELLWOOD
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in SALINE, NEBRASKA
From 20-AUG-07 17:12:00 to 20-AUG-07 17:12:00 (CST-6)
Location: WESTERN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in SEWARD, NEBRASKA
From 20-AUG-07 17:16:00 to 20-AUG-07 17:16:00 (CST-6)
Location: MILFORD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CASS, NEBRASKA
From 20-AUG-07 18:30:00 to 20-AUG-07 18:30:00 (CST-6)
Location: LOUISVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm winds estimated at 60 mph downed eight inch tree limbs at the Louisville State Recreation Area.

Thunderstorm Wind in SALINE, NEBRASKA
From 20-AUG-07 16:58:00 to 20-AUG-07 16:58:00 (CST-6)
Location: TOBIAS
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter measured a thunderstorm wind gust of 68 mph which caused some tree damage in the area.

Thunderstorm Wind in SALINE, NEBRASKA
From 20-AUG-07 17:04:00 to 20-AUG-07 17:04:00 (CST-6)
Location: WESTERN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CASS, NEBRASKA
From 20-AUG-07 18:30:00 to 20-AUG-07 18:30:00 (CST-6)
Location: MANLEY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tornado in COLFAX, NEBRASKA
From 20-AUG-07 17:35:00 to 20-AUG-07 17:41:00 (CST-6)
Location: RICHLAND
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A tornado was first reported by emergency management and then verified by a NWS storm survey and later by video from a storm chaser.  The tornado caused sporadic tree and crop damage from 3 1/2 miles south of Richland, on the north bank of the Platte River where it first touched down, to around 4 miles east of Richland.

Thunderstorm Wind in SALINE, NEBRASKA
From 20-AUG-07 17:11:00 to 20-AUG-07 17:11:00 (CST-6)
Location: WILBER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A long door on rollers at a grainery were blown off by thunderstorm winds estimated at 60 mph.

Hail in LANCASTER, NEBRASKA
From 20-AUG-07 17:42:00 to 20-AUG-07 17:55:00 (CST-6)
Location: LINCOLN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail was reported across sections of the Lincoln area, including the downtown area, mid town and the intersection of Highway 77 and Interstate 80.  Some of the hail was up to golf ball size which was reported near 56th and Van Dorn Streets.

Thunderstorm Wind in LANCASTER, NEBRASKA
From 20-AUG-07 17:39:00 to 20-AUG-07 18:14:00 (CST-6)
Location: EMERALD
Magnitude: 71.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A damaging wind producing MCS tracked across the Lincoln area bringing wind gusts as high as 82 mph which were measured by the Lincoln ASOS at 650 pm CDT.  Other wind gusts of similar magnitude were reported just west of Lincoln near Emerald, in downtown Lincoln and at 70th and Cornhusker.  The strong winds knocked down numerous large branches and many trees across the area downing power lines and causing some building and vehicle damage. Scattered power outages were reported across town.  The winds also swamped several boats in the Capitol Beach area and blew over several semi trailers.  Scattered reports of hail accompanied the winds, with the largest being golf ball size near 56th and Van Dorn Streets.

Thunderstorm Wind in DOUGLAS, NEBRASKA
From 20-AUG-07 18:25:00 to 20-AUG-07 18:55:00 (CST-6)
Location: ELKHORN
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A bow echo raced across the Omaha metropolitan area bringing strong winds which downed numerous large tree limbs and uprooted a few trees.  This caused scattered damage across town, especially in the central and eastern parts of the city where felled trees caused damage to houses and vehicles and downed power lines.  An estimated 20,000 customers lost power.  A wind gust of 68 mph was measured by ASOS at Omaha Eppley at 746 pm CDT and a 60 mph gust was measured at 755 pm. Winds of 60 mph or greater were observed over most of the city.