Generally speaking, a bit of everything occurred during an overnight/early morning severe mesoscale convective system that rolled across Iowa. The predominant weather revolved around damaging winds and heavy rainfall, though a few instances of severe hail and low end tornadoes were experienced as well. Among the reports, numerous trees were downed, buildings damaged or destroyed from straight line winds or one of the weak tornadoes, and numerous instances of 2 to 4 plus inches of heavy rainfall.
On the setup side of the coin, a lot of factors were in line for the event to potentially be a sustained nocturnal severe weather event. The previous day, the 19th, saw surface high pressure begin to exit the region eastward and allowing southerly return flow to work into eastern Nebraska and western Iowa. Tied in with mid to upper 70 dew points and steep mid-level lapse rates, a large area of 4000 plus J/kg CAPE values developed across eastern Nebraska and western Iowa and slowly built eastward. Additionally, effect bulk shear was consistently in the 40 to 50 kt range and low level shear roughly oriented to expected storm motion. As the evening progressed and the low level jet finally began to ramp up, boosting warm air advection and positive moisture flux, storms began to develop and eventually congeal. Organization, at least with regards to strong to severe criteria, was not immediate, waiting until around 5am local time to produce its first severe report. Severe reports then continued as the system moved southeast over the next 4 plus hours.

Heavy Rain in GUTHRIE, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: JAMAICA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

NWS employee recorded heavy rainfall of 2.29 inches over the last 24 hours.

Heavy Rain in HARDIN, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: IOWA FALLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 3.68 inches over the last 24 hours.

Heavy Rain in HUMBOLDT, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: DAKOTA CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 3.45 inches over the last 24 hours.

Hail in KOSSUTH, IOWA
From 20-AUG-19 08:10:00 to 20-AUG-19 08:10:00 (CST-6)
Location: ALGONA
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported ping pong ball sized hail.

Heavy Rain in POLK, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: (DSM)DES MOINES INTL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Des Moines International Airport ASOS recorded heavy rainfall of 2.35 inches over the last 24 hours.

Thunderstorm Wind in POWESHIEK, IOWA
From 20-AUG-19 05:30:00 to 20-AUG-19 05:30:00 (CST-6)
Location: GRINNELL ARPT
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported house, barn and outbuildings heavily damaged by winds. Multiple trees were also reported downed. Time estimated from radar.

Heavy Rain in POLK, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: WINDSOR HGTS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported heavy rainfall of 2.07 inches over the last 24 hours.

Thunderstorm Wind in WARREN, IOWA
From 20-AUG-19 04:59:00 to 20-AUG-19 04:59:00 (CST-6)
Location: LIBERTY CENTER
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported structure damage to outbuildings, hay bales blown across/on the road, and power lines down. Time estimated from radar.

Thunderstorm Wind in GUTHRIE, IOWA
From 20-AUG-19 04:20:00 to 20-AUG-19 04:20:00 (CST-6)
Location: ADAIR
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Automated mesonet site along Interstate 80 recorded a 60 mph wind gust.

Hail in DALLAS, IOWA
From 20-AUG-19 04:28:00 to 20-AUG-19 04:28:00 (CST-6)
Location: HADDEN HILL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported penny sized hail via the mPING app.

Heavy Rain in TAMA, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: CLUTIER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 3.45 inches over the last 24 hours.

Tornado in MARION, IOWA
From 20-AUG-19 05:21:00 to 20-AUG-19 05:23:00 (CST-6)
Location: TRACY
Tornado F-scale: EF1
Property damage: 15.00K
Crop damage: 0.20K
Reported by: NWS Storm Survey

The last of three tornadoes produced by a fast moving QLCS.  Tornado began west of Tracy in rural areas producing only crop and tree damage.  As the tornado moved through town, it produced mainly tree and minor structural damage to buildings in the town.  The tornado dissipated on the east side of Tracy.

Thunderstorm Wind in WARREN, IOWA
From 20-AUG-19 05:01:00 to 20-AUG-19 05:01:00 (CST-6)
Location: MILO
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Public reported, via mPING app, trees uprooted or snapped; roof blown off.

Heavy Rain in STORY, IOWA
From 20-AUG-19 01:15:00 to 20-AUG-19 05:00:00 (CST-6)
Location: IOWA CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported heavy rainfall of 3.1 inches. Beginning time estimated from radar.

Heavy Rain in TAMA, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: TRAER MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 2.32 inches over the last 24 hours.

Thunderstorm Wind in WARREN, IOWA
From 20-AUG-19 05:00:00 to 20-AUG-19 05:05:00 (CST-6)
Location: LACONA
Magnitude: 65.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported several structures damaged, including machine sheds, grain elevators, and power lines down. Time estimated from radar.

Thunderstorm Wind in LUCAS, IOWA
From 20-AUG-19 05:15:00 to 20-AUG-19 05:15:00 (CST-6)
Location: CHARITON MUNI ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Chariton Municipal Airport AWOS recorded wind gusts of 58 mph.

Heavy Rain in WARREN, IOWA
From 20-AUG-19 04:00:00 to 20-AUG-19 05:40:00 (CST-6)
Location: NEW VIRGINIA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported storm total heavy rainfall of 2 inches. Beginning and end times estimated from radar.

Thunderstorm Wind in LUCAS, IOWA
From 20-AUG-19 05:10:00 to 20-AUG-19 05:13:00 (CST-6)
Location: WILLIAMSON
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Department of Highways

Iowa DOT reported road closed due to downed power lines. Time of greatest winds estimated from radar.

Heavy Rain in DALLAS, IOWA
From 20-AUG-19 03:30:00 to 20-AUG-19 05:00:00 (CST-6)
Location: ADEL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported heavy rainfall of 2.55 inches. Beginning and end time estimated from radar.

Heavy Rain in HUMBOLDT, IOWA
From 20-AUG-19 01:50:00 to 20-AUG-19 04:30:00 (CST-6)
Location: LIVERMORE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported heavy rainfall of 2.25 inches. Beginning and end times estimated from radar.

Lightning in POLK, IOWA
From 20-AUG-19 05:19:00 to 20-AUG-19 05:19:00 (CST-6)
Location: GRIMES
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported a house fire started by lightning.

Heavy Rain in WRIGHT, IOWA
From 20-AUG-19 01:40:00 to 20-AUG-19 04:45:00 (CST-6)
Location: EAGLE GROVE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported heavy rainfall of 4.5 inches. Beginning and end times estimated from radar.

Heavy Rain in POLK, IOWA
From 20-AUG-19 03:45:00 to 20-AUG-19 06:15:00 (CST-6)
Location: CLIVE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported storm total heavy rainfall of 2.30 inches. Beginning and end time estimated from radar.

Thunderstorm Wind in GUTHRIE, IOWA
From 20-AUG-19 04:14:00 to 20-AUG-19 04:14:00 (CST-6)
Location: CASEY
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Northern half of roof on a house blown into the trees. Time estimated from radar.

Thunderstorm Wind in MARION, IOWA
From 20-AUG-19 05:18:00 to 20-AUG-19 05:18:00 (CST-6)
Location: RED ROCK
Magnitude: 56.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reported a semi blown over on mile long bridge north of Knoxville, including a reported serious injury. Time estimated from radar.

Heavy Rain in PALO ALTO, IOWA
From 20-AUG-19 01:00:00 to 20-AUG-19 03:30:00 (CST-6)
Location: DEPEW
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Local media relayed public report of heavy rainfall of 3.25 inches. Beginning and end times estimated from radar.

Tornado in MADISON, IOWA
From 20-AUG-19 04:21:00 to 20-AUG-19 04:23:00 (CST-6)
Location: WINTERSET ARPT
Tornado F-scale: EF1
Property damage: 5.00K
Crop damage: 0.50K
Reported by: NWS Storm Survey

The first of three tornadoes associated with a rapidly advancing QLCS.  The tornado produced EF1 damage to a rural residence along with damage to trees in the area.

Thunderstorm Wind in ADAIR, IOWA
From 20-AUG-19 04:15:00 to 20-AUG-19 04:15:00 (CST-6)
Location: ADAIR
Magnitude: 56.00 EG
Property damage: 60.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement and Iowa DOT reported 3 semis blown over near the westbound rest stop near MM 80 on Interstate 80. Three additional semis were blown over in the eastbound traffic lanes in the same area. Time estimated from radar.

Thunderstorm Wind in WARREN, IOWA
From 20-AUG-19 04:27:00 to 20-AUG-19 04:27:00 (CST-6)
Location: INDIANOLA ARPT
Magnitude: 65.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 3 foot wide, 40 to 50 foot tall maple trees down, partial roof missing on shed, windows blown out of outbuildings, and wood swing set flipped over about 1 mile south of Lake Ahquabi State Park. Time estimated from radar.

Thunderstorm Wind in WAPELLO, IOWA
From 20-AUG-19 05:53:00 to 20-AUG-19 05:53:00 (CST-6)
Location: OTTUMWA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Iowa DOT RWIS station along US Highway 63 recorded 58 mph wind gusts.

Thunderstorm Wind in GUTHRIE, IOWA
From 20-AUG-19 04:13:00 to 20-AUG-19 04:13:00 (CST-6)
Location: ADAIR
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency manager reported trees blown over on White Pole Road. A car ran into the downed trees.  The location is estimated, as well as the time from radar.

Tornado in WARREN, IOWA
From 20-AUG-19 04:55:00 to 20-AUG-19 05:00:00 (CST-6)
Location: INDIANOLA ARPT
Tornado F-scale: EF3
Property damage: 350.00K
Crop damage: 1.00K
Reported by: NWS Storm Survey

The second of three tornadoes associated with a fast moving QLCS.  The particularly strong tornado moved across rural Warren county producing mainly crop and tree damage.  However, the tornado encountered the several large steel buildings with I-beam construction.  Significant damage occurred to these buildings with some being totally destroyed producing the EF3 damage.  The tornado continued to the southeast beyond this area remaining in rural crop and woodland areas.

Heavy Rain in CARROLL, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: CARROLL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer, KCIM Radio, recorded heavy rainfall of 3.45 inches over the last 24 hours.

Thunderstorm Wind in DALLAS, IOWA
From 20-AUG-19 03:50:00 to 20-AUG-19 03:50:00 (CST-6)
Location: HADDEN HILL
Magnitude: 61.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported a 12 inch diameter tree down. Time estimated from radar.

Heavy Rain in DALLAS, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: ADEL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 2.15 inches over the last 24 hours.

Thunderstorm Wind in POLK, IOWA
From 20-AUG-19 04:29:00 to 20-AUG-19 04:29:00 (CST-6)
Location: URBANDALE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

NWS employee reported tree down over 61st street south of Merle Hay Mall. Time estimated from radar.

Heavy Rain in GRUNDY, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: DIKE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

KWWL recorded heavy rainfall of 2.25 inches over the last 24 hours.

Thunderstorm Wind in POLK, IOWA
From 20-AUG-19 04:30:00 to 20-AUG-19 04:30:00 (CST-6)
Location: CLOVER HILLS
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Public reported, via mPING, trees uprooted or snapped; roof blown off. Time estimated from radar.

Heavy Rain in GUTHRIE, IOWA
From 19-AUG-19 06:00:00 to 20-AUG-19 06:00:00 (CST-6)
Location: GUTHRIE CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Coop observer recorded heavy rainfall of 3.96 inches over the last 24 hours.

Thunderstorm Wind in POLK, IOWA
From 20-AUG-19 04:25:00 to 20-AUG-19 04:25:00 (CST-6)
Location: URBANDALE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Media reported several small and medium size tree branches down.