What started out as a cluster of low level jet induced storms over central Nebraska, turned into a derecho that had severe winds and left a path of wind damage from Nebraska into Illinois and then down into parts of southeast Missouri and western Kentucky and Tennessee. The initial convection initiated shortly after 3 am CDT in north central Nebraska within a very unstable nocturnal environment. MUCAPE values were in excess of 5000 J/kg throughout much of central Nebraska, along with DCAPE in excess of 1200-1500 J/kg, effective shear around 30 to 40 kts, roughly perpendicularly oriented 0-3 km shear vectors to the storm orientation, and supporting composite parameters such as MCS Maintenance and Derecho Composite that pointed towards a potentially long-lived convective complex.
The environment (thermodynamic, moisture, and wind profiles) roughly remained the same as the complex moved eastward, before taking on a more southeast and eventually southern motion, following a strong CAPE gradient.  What transpired in Iowa was an eastward moving complex that took on a more linear orientation throughout the morning and quickly trekked across the southern third of the state through the morning and early afternoon. In its wake was dozens of reports of whole trees down, power lines and poles down, other damage reports, and measured wind gusts in excess of 65-70 mph.

Thunderstorm Wind in POLK, IOWA
From 28-JUN-18 11:33:00 to 28-JUN-18 11:33:00 (CST-6)
Location: FT DES MOINES
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported a small tree uprooted.

Thunderstorm Wind in MARION, IOWA
From 28-JUN-18 11:45:00 to 28-JUN-18 11:45:00 (CST-6)
Location: KNOXVILLE
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported several large trees down in Knoxville.

Thunderstorm Wind in WAPELLO, IOWA
From 28-JUN-18 12:25:00 to 28-JUN-18 12:25:00 (CST-6)
Location: RUTLEDGE
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator reported a tree down on a house. Time estimated from radar.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:20:00 to 28-JUN-18 10:20:00 (CST-6)
Location: ADAIR
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

An Iowa DOT RWIS near Adair measured a 62 mph wind gust.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:15:00 to 28-JUN-18 11:15:00 (CST-6)
Location: INDIANOLA
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator recorded a 68 mph wind gust.

Thunderstorm Wind in POLK, IOWA
From 28-JUN-18 11:32:00 to 28-JUN-18 11:32:00 (CST-6)
Location: FT DES MOINES
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Broadcast Media

KCCI relayed a report from a viewer of a large tree down on a house.

Thunderstorm Wind in WAPELLO, IOWA
From 28-JUN-18 12:32:00 to 28-JUN-18 12:32:00 (CST-6)
Location: OTTUMWA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Iowa DOT RWIS near Ottumwa recorded a 58 mph wind gust.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:14:00 to 28-JUN-18 11:14:00 (CST-6)
Location: INDIANOLA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported multiple tree branches down 3 inches in diameter or greater near the Warren County Fairground. Time estimated from radar.

Thunderstorm Wind in WAPELLO, IOWA
From 28-JUN-18 12:38:00 to 28-JUN-18 12:38:00 (CST-6)
Location: OTTUMWA
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported wind gusts to 65 mph.

Thunderstorm Wind in UNION, IOWA
From 28-JUN-18 10:39:00 to 28-JUN-18 10:39:00 (CST-6)
Location: CRESTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Personal weather station near the intersection of Cherry St and Rea Rd measured a wind gust of 60 mph.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:17:00 to 28-JUN-18 11:17:00 (CST-6)
Location: INDIANOLA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported multiple tree branches down 3 inches in diameter and greater along Highway 92 in Indianola. Time estimated from radar.

Thunderstorm Wind in UNION, IOWA
From 28-JUN-18 10:45:00 to 28-JUN-18 10:45:00 (CST-6)
Location: CRESTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator estimated at least 60 mph wind gusts and reported that electricity was out at the time of the report.

Thunderstorm Wind in MADISON, IOWA
From 28-JUN-18 10:56:00 to 28-JUN-18 10:56:00 (CST-6)
Location: WINTERSET
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported branches down at their location in Winterset.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:25:00 to 28-JUN-18 11:25:00 (CST-6)
Location: INDIANOLA
Magnitude: 56.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a large tree down on a house.

Thunderstorm Wind in POLK, IOWA
From 28-JUN-18 11:32:00 to 28-JUN-18 11:32:00 (CST-6)
Location: (DSM)DES MOINES INTL
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Des Moines International Airport ASOS measured a 58 mph wind gust.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:24:00 to 28-JUN-18 11:24:00 (CST-6)
Location: INDIANOLA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator reported wind gusts to 58 mph.

Thunderstorm Wind in CASS, IOWA
From 28-JUN-18 09:55:00 to 28-JUN-18 09:55:00 (CST-6)
Location: ATLANTIC ARPT
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Atlantic Municipal Airport AWOS recorded a 61 mph gust.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:32:00 to 28-JUN-18 10:32:00 (CST-6)
Location: GREENFIELD
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Local fire department in Greenfield estimated up to 70 mph winds, causing numerous tree branches down and blocking some streets.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:30:00 to 28-JUN-18 11:30:00 (CST-6)
Location: INDIANOLA
Magnitude: 76.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Weather station at Simpson College measured an 88 mph wind gust before power was lost during the storm.

Thunderstorm Wind in CASS, IOWA
From 28-JUN-18 10:20:00 to 28-JUN-18 10:20:00 (CST-6)
Location: MASSENA SWAIN ARPT
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A personal/home weather station measured a 67 mph wind gust.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:40:00 to 28-JUN-18 10:40:00 (CST-6)
Location: ARBOR HILL
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimated 65 mph winds along with nickel sized hail. There were branches of at least 3 inch diameter down. Visibility was near zero during the heavy rain.

Thunderstorm Wind in UNION, IOWA
From 28-JUN-18 10:50:00 to 28-JUN-18 10:50:00 (CST-6)
Location: AFTON
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Broadcast Media

KCCI reported that multiple tree branches were down around town and that the town was without power at the time of the report.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:35:00 to 28-JUN-18 11:35:00 (CST-6)
Location: NORWALK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator reported a few 3 to 4 inch diameter tree branches down along Union Street near the Warren County border.

Thunderstorm Wind in UNION, IOWA
From 28-JUN-18 10:44:00 to 28-JUN-18 10:44:00 (CST-6)
Location: CRESTON
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Amateur radio operator reported power lines down along Highway 34 in Creston.

Thunderstorm Wind in MADISON, IOWA
From 28-JUN-18 10:53:00 to 28-JUN-18 10:53:00 (CST-6)
Location: MIDDLE RIVER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported numerous branches down.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:33:00 to 28-JUN-18 11:33:00 (CST-6)
Location: NORWALK
Magnitude: 70.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported many large branches and trees down. During the rainfall, about 2.5 inches of rain came in about half an hour along with pea sized hail. Winds were estimated in the 76 to 85 mph range.

Thunderstorm Wind in CASS, IOWA
From 28-JUN-18 10:10:00 to 28-JUN-18 10:10:00 (CST-6)
Location: ATLANTIC
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported multiple tree branches 3 inches in diameter or larger down through the town. Time estimated by radar.

Thunderstorm Wind in CLARKE, IOWA
From 28-JUN-18 11:02:00 to 28-JUN-18 11:02:00 (CST-6)
Location: MURRAY
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported large trees and power lines down in Murray.

Thunderstorm Wind in CASS, IOWA
From 28-JUN-18 10:20:00 to 28-JUN-18 10:20:00 (CST-6)
Location: MASSENA
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 20.00K
Reported by: Trained Spotter

Trained spotter reported 3 inch diameter tree branches down along with a few farm sheds toppled. Wide swaths of corn were also reported bent down in the vicinity.

Thunderstorm Wind in MARION, IOWA
From 28-JUN-18 11:40:00 to 28-JUN-18 11:40:00 (CST-6)
Location: BEWBERN
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported 6 to 12 inch diameter trees and power lines down.

Thunderstorm Wind in MONROE, IOWA
From 28-JUN-18 12:00:00 to 28-JUN-18 12:00:00 (CST-6)
Location: ALBIA
Magnitude: 64.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported numerous trees down in Albia.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:25:00 to 28-JUN-18 10:35:00 (CST-6)
Location: GREENFIELD
Magnitude: 56.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported that within the towns of Greenfield and Fontanelle 8 to 10 inch diameter trees, branches, and fences down. A greenhouse was blown over at the Shopko in Greenfield. Time estimated from radar.

Thunderstorm Wind in MADISON, IOWA
From 28-JUN-18 11:04:00 to 28-JUN-18 11:04:00 (CST-6)
Location: ST CHARLES
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported numerous large trees down in St. Charles.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:07:00 to 28-JUN-18 11:07:00 (CST-6)
Location: WICK
Magnitude: 56.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Broadcast media reported a truck overturned on Interstate 35 near mile marker 55.

Thunderstorm Wind in MADISON, IOWA
From 28-JUN-18 11:05:00 to 28-JUN-18 11:05:00 (CST-6)
Location: BEVINGTON
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 8 inch diameter tree down covering the road, along with nickel sized hail. They estimated winds to be around 60 mph.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:44:00 to 28-JUN-18 10:44:00 (CST-6)
Location: GREENFIELD
Magnitude: 61.00 EG
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a machine shed destroyed, a grain bin severely damaged, and multiple trees down.

Hail in CLARKE, IOWA
From 28-JUN-18 11:09:00 to 28-JUN-18 11:09:00 (CST-6)
Location: MURRAY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported quarter sized hail.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:20:00 to 28-JUN-18 11:20:00 (CST-6)
Location: INDIANOLA
Magnitude: 61.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported large trees down, damage to vehicles, and power lines down near Boston Ave in Indianola.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:21:00 to 28-JUN-18 11:21:00 (CST-6)
Location: CUMMING
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported a tree branch split at 43rd and Dawson in Cumming. Time estimated from radar.

Thunderstorm Wind in ADAMS, IOWA
From 28-JUN-18 10:28:00 to 28-JUN-18 10:30:00 (CST-6)
Location: STRINGTOWN
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public relayed a video display severe winds, estimated around 65 mph.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:35:00 to 28-JUN-18 10:35:00 (CST-6)
Location: GREENFIELD
Magnitude: 61.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported significant wind damage in Adair County near Greenfield. Multiple trees reported down and home damage about 3 miles south of Greenfield, and a radio tower on the hospital down.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:08:00 to 28-JUN-18 11:18:00 (CST-6)
Location: MARTENSDALE
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement replayed several reports of trees down between Martensdale and Indianola.

Hail in WAPELLO, IOWA
From 28-JUN-18 12:38:00 to 28-JUN-18 12:38:00 (CST-6)
Location: OTTUMWA
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported quarter sized hail.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:19:00 to 28-JUN-18 11:19:00 (CST-6)
Location: CUMMING
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported large trees down of at least 1 foot in diameter.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:25:00 to 28-JUN-18 11:25:00 (CST-6)
Location: SUMMERSET
Magnitude: 61.00 EG
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Public

Public reported grain bins knocked over and widespread tree damage, including trees snapped at the trunk.

Thunderstorm Wind in WARREN, IOWA
From 28-JUN-18 11:30:00 to 28-JUN-18 11:30:00 (CST-6)
Location: NORWALK
Magnitude: 57.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Social Media

Public relayed picture of a large tree on the roof of a home. Time estimated from radar.

Thunderstorm Wind in UNION, IOWA
From 28-JUN-18 10:40:00 to 28-JUN-18 10:40:00 (CST-6)
Location: CRESTON
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Creston Municipal Airport measured a 69 mph wind gust.

Thunderstorm Wind in ADAIR, IOWA
From 28-JUN-18 10:30:00 to 28-JUN-18 10:30:00 (CST-6)
Location: ORIENT
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Social Media

Public relayed a picture of a tree trunk snapped.