Low pressure moving along a cold front helped produce supercell thunderstorms with large hail, damaging winds, and tornadoes over much of Iowa the afternoon and evening of June 28th, 2017. This event produced two EF2 tornadoes between Cedar Rapids and Dubuque, Iowa, and a few other weak tornadoes in eastern Iowa.

Thunderstorm Wind in DUBUQUE, IOWA
From 28-JUN-17 19:23:00 to 28-JUN-17 19:23:00 (CST-6)
Location: (DBQ)DUBUQUE MUNI AR
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in DELAWARE, IOWA
From 28-JUN-17 18:15:00 to 28-JUN-17 18:15:00 (CST-6)
Location: HOPKINTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Large branches blown down.

Thunderstorm Wind in BUCHANAN, IOWA
From 29-JUN-17 21:23:00 to 29-JUN-17 21:23:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

No damage reported.

Thunderstorm Wind in DUBUQUE, IOWA
From 29-JUN-17 22:44:00 to 29-JUN-17 22:44:00 (CST-6)
Location: KEY WEST
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

No damage reported.

Thunderstorm Wind in DELAWARE, IOWA
From 28-JUN-17 18:17:00 to 28-JUN-17 18:17:00 (CST-6)
Location: SAND SPG
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Power lines were reported down due to wind.

Tornado in JONES, IOWA
From 28-JUN-17 17:58:00 to 28-JUN-17 18:01:00 (CST-6)
Location: LANGWORTHY
Tornado F-scale: EF2
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado touched down south of Central City in the county fairgrounds outfield area, and tracked about 12 miles northeast through Prairieburg before lifting in rural Jones County. The most intense damage occurred near and in Prairieburg. At a farmstead just southwest of town, a woman was injured when her garage collapsed on her. In Prairieburg, the grain elevator sustained severe damage, one mobile home was lofted and destroyed, and another mobile home severely damaged. On the east edge of town, a horse barn was destroyed. One horse was killed and two others sustained injuries. Northeast of town, a hog building was destroyed, killing several young hogs. This EF2 tornado moved in from Linn County.

Tornado in DELAWARE, IOWA
From 28-JUN-17 18:16:00 to 28-JUN-17 18:18:00 (CST-6)
Location: SAND SPG
Tornado F-scale: EF2
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A narrow EF2 tornado with winds estimated at 120 mph touched down in a field about miles 4 north of Monticello and tracked east northeast from Jones County into Delaware County. The tornado struck neighboring farmsteads at the junction of 148th Ave. and Jones-Delaware Co Road. Two grain bins and seven outbuildings were destroyed. Two garages had the doors blown in and five wooden power poles were snapped, including three larger transmission lines. The most unusual damage was an 18 foot missile that was formed from four sections of a grain bin roof that were folded into a narrow cone shape and propelled into the garage attic over 100 yards away. This EF2 tornado began in Jones County, and moved into Delaware County.

Tornado in JONES, IOWA
From 28-JUN-17 18:14:00 to 28-JUN-17 18:16:00 (CST-6)
Location: MONTICELLO
Tornado F-scale: EF2
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A narrow EF2 tornado with winds estimated at 120 mph touched down in a field about 4 miles north of Monticello and tracked east northeast from Jones County crossing into Delaware County. The tornado struck neighboring farmsteads at the junction of 148th Ave. and Jones-Delaware County Road. Two grain bins and seven outbuildings were destroyed. Two garages had the doors blown in and five wooden power poles were snapped, including three larger transmission lines. The most unusual damage was an 18 foot missile that was formed from four sections of a grain bin roof that were folded into a narrow cone shape and propelled into the garage attic over 100 yards away. This EF2 tornado began in Jones County, and moved into Delaware County.

Tornado in LINN, IOWA
From 28-JUN-17 17:38:00 to 28-JUN-17 17:58:00 (CST-6)
Location: CENTRAL CITY
Tornado F-scale: EF2
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado touched down south of Central City in the county fairgrounds outfield area, and tracked about 12 miles northeast through Prairieburg before lifting in rural Jones County. The most intense damage occurred near and in Prairieburg. At a farmstead just southwest of town, a woman was injured when her garage collapsed on her. In Prairieburg, the grain elevator sustained severe damage, one mobile home was lofted and destroyed, and another mobile home severely damaged. On the east edge of town, a horse barn was destroyed. One horse was killed and two others sustained injuries. Northeast of town, a hog building was destroyed, killing several young hogs. This EF2 tornado continued into Jones County, Iowa.

Tornado in BENTON, IOWA
From 28-JUN-17 18:26:00 to 28-JUN-17 18:26:00 (CST-6)
Location: VINTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A brief touchdown of an EF0 tornado that was seen on a citizen's video was confirmed by a location of isolated damage of two trees and an adjacent corner of a metal outbuilding's roof where a single panel was blown off.

Tornado in JONES, IOWA
From 28-JUN-17 18:56:00 to 28-JUN-17 19:00:00 (CST-6)
Location: OXFORD JCT
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The EF1 tornado began in a field and traveled mostly through farm land and wooded river valley southwest of Oxford Junction.  Just south of Oxford Junction, two non anchored mobile homes were destroyed, a machine shed was damaged, and a camper was blown over.

Hail in BENTON, IOWA
From 28-JUN-17 18:20:00 to 28-JUN-17 18:20:00 (CST-6)
Location: VINTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail was accompanied by 40 to 50 mph winds.

Thunderstorm Wind in BUCHANAN, IOWA
From 29-JUN-17 21:21:00 to 29-JUN-17 21:21:00 (CST-6)
Location: INDEPENDENCE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds sustained around 60 mph were estimated by the spotter, along with heavy rain. The spotter thought higher gusts occurred, but no damage was seen.