A surface low pressure system was centered over Kansas and Nebraska with attendant warm front draped across north central Iowa. This was bisected by an outflow boundary from morning convection across western Iowa. As morning activity exited the are the atmosphere quickly recovered steep low and mid level lapse rates exceeded 8 C/km with 0-6 km shear over 40 knots. Near the remnant outflow boundary 0-1 km SRH exceeded 150 m2/s2. Storms developed along this boundary and moved east along the warm front, spawning a number of tornadoes across the state. In fact, this is in the top 5 for tornadoes occurring in a single day for the state of Iowa since reliable records began in the 1980s. By evening convection congealed into an MCS, bringing heavy rain to portions of the state. A line of training storms set up north of the Des Moines metro, resulting in localized flash flooding.

Tornado in BREMER, IOWA
From 14-JUL-21 16:21:00 to 14-JUL-21 16:43:00 (CST-6)
Location: BABCOCK
Tornado F-scale: EF2
Property damage: 1.00M
Crop damage: 2.00K
Reported by: NWS Storm Survey

The tornado moved into Bremer county from Butler county.  The tornado impacted a couple of acreages just east of the county line producing EF0 and EF1 damage before weakening and becoming an intermittent funnel.  The tornado destroyed 2 barns just north of the 4th street SW exit off of Highway 218.  It then crossed the Cedar River just southwest Waverly doing damage to houses on both sides of the river, mostly EF0 and EF1 damage.  After crossing Hilton Avenue, it intensified and produced EF2 damage with extensive tree damage along with toppling a high voltage power line.  The tornado continued farther east and slowly weakened, staying mostly in open rural land.  The tornado eventually lifted to the northwest of Denver.

Tornado in CERRO GORDO, IOWA
From 14-JUL-21 16:52:00 to 14-JUL-21 17:05:00 (CST-6)
Location: ROCKWELL
Tornado F-scale: EF0
Property damage: 10.00K
Crop damage: 2.00K
Reported by: Trained Spotter

Tornado was reported by a trained spotter northeast of Rockwell.  Tornado path was determined using high resolution satellite imagery.  The tornado developed and moved to the east, mostly across open agricultural fields.  It did blow down a grain bin on a farmstead and with some minor tree damage as well.  The tornado then began to move southeast continuing to remain in open cropland.  One final farmstead was impacted with some tree damage before the tornado lifted.

Tornado in BREMER, IOWA
From 14-JUL-21 17:12:00 to 14-JUL-21 17:18:00 (CST-6)
Location: BUCK CREEK
Tornado F-scale: EF0
Property damage: 1.00K
Crop damage: 1.00K
Reported by: Emergency Manager

Emergency manager reported a tornado east of the Readlyn area.  Video and high resolution satellite imagery was used to determine the path of the tornado in eastern Bremer county.  The tornado remained mostly in rural agricultural land, but did produce some minor tree damage at a farmstead.

Heavy Rain in STORY, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: IOWA CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 5.50 inches.

Heavy Rain in WAPELLO, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: BLAKESBURG ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 4.71 inches.

Heavy Rain in STORY, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: IOWA CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 4.44 inches.

Heavy Rain in APPANOOSE, IOWA
From 14-JUL-21 09:23:00 to 15-JUL-21 09:23:00 (CST-6)
Location: ICONIUM
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A 24 hour rain total of 3.26 inches with rain still in progress.

Heavy Rain in MONROE, IOWA
From 14-JUL-21 21:00:00 to 15-JUL-21 10:51:00 (CST-6)
Location: ALBIA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A rain total of 3.08 inches overnight through the morning.

Thunderstorm Wind in STORY, IOWA
From 14-JUL-21 07:41:00 to 14-JUL-21 07:41:00 (CST-6)
Location: NEVADA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Trees down on power lines.

Tornado in HAMILTON, IOWA
From 14-JUL-21 15:05:00 to 14-JUL-21 15:23:00 (CST-6)
Location: STRATFORD
Tornado F-scale: EF0
Property damage: 2.00K
Crop damage: 3.00K
Reported by: NWS Storm Survey

Tornado developed just northeast of Stratford and moved east northeast for duration of the event.  Tornado remained almost entirely in agricultural fields.  It did encounter a farmstead near the end of the path and produced some tree damage.  As this tornado began to rope out, another tornado developed in close proximity and continued for some distance.  Track was enhanced using hi-resolution satellite imagery.

Flash Flood in STORY, IOWA
From 14-JUL-21 20:02:00 to 15-JUL-21 01:04:00 (CST-6)
Location: MAXWELL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reports water over the intersection of Woodlawn and 2nd Street at least 6 inches deep. Report via social media.

Heavy Rain in POLK, IOWA
From 14-JUL-21 17:00:00 to 14-JUL-21 20:07:00 (CST-6)
Location: ALLEMAN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 3.40 inches of rain.

Heavy Rain in STORY, IOWA
From 14-JUL-21 17:00:00 to 14-JUL-21 20:29:00 (CST-6)
Location: MAXWELL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public report of 5.20 inches of rain.

Tornado in WEBSTER, IOWA
From 14-JUL-21 15:46:00 to 14-JUL-21 15:47:00 (CST-6)
Location: FARNHAMVILLE
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.50K
Reported by: Storm Chaser

Brief tornado observed by storm chasers with path determined through use of high resolution satellite imagery.  Path was entirely in agricultural fields.

Heavy Rain in LUCAS, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: RUSSELL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 4.10 inches.

Hail in BUTLER, IOWA
From 14-JUL-21 15:48:00 to 14-JUL-21 15:48:00 (CST-6)
Location: ALLISON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Report via mping app.

Tornado in CALHOUN, IOWA
From 14-JUL-21 14:52:00 to 14-JUL-21 15:17:00 (CST-6)
Location: LAKE CITY
Tornado F-scale: EF3
Property damage: 2.50M
Crop damage: 5.00K
Reported by: NWS Storm Survey

This was the first and strongest tornado of the day.  It developed west southwest of Lake City and produced tree and power line damage.  The tornado moved into and across the southern portion of Lake City.  Imagery from UAV's and chasers show that the tornado was multi-vortex as it passed through the city.  Up to EF2 damage occurred as it passed through town.  As the tornado moved east of the town, it began to consolidate into a larger funnel and strengthen.  It passed through a farmstead producing considerable damage to the farmhouse and out buildings with EF3 damage noted on the house.  The tornado continued for a few more miles and impacted a confinement facility before lifting to the northwest of Lohrville.  Fortunately, no injuries or deaths occurred with this tornado.

Heavy Rain in LUCAS, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: DERBY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.90 inches.

Heavy Rain in BLACK HAWK, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: WATERLOO
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.84 inches.

Tornado in HAMILTON, IOWA
From 14-JUL-21 15:21:00 to 14-JUL-21 15:40:00 (CST-6)
Location: STANHOPE
Tornado F-scale: EF1
Property damage: 10.00K
Crop damage: 4.00K
Reported by: NWS Storm Survey

This tornado developed northeast of Stanhope and tracked across mostly open agricultural fields.  It did interact with two farmsteads early in it's track, producing EF1 damage to trees.  The tornado lifted before reaching Interstate 35 north of Ellsworth.

Hail in BUTLER, IOWA
From 14-JUL-21 16:14:00 to 14-JUL-21 16:14:00 (CST-6)
Location: CLARKSVILLE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Funnel Cloud in MARSHALL, IOWA
From 14-JUL-21 17:02:00 to 14-JUL-21 17:02:00 (CST-6)
Location: GREEN MTN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple reports of a funnel cloud near Green Mountain near 170th and Wallace Avenue.

Tornado in SAC, IOWA
From 14-JUL-21 16:11:00 to 14-JUL-21 16:13:00 (CST-6)
Location: NEMAHA
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.50K
Reported by: Storm Chaser

Tornado captured on video by a storm chaser.  This brief tornado remained in open agricultural fields and did not impact any damage indicators, hence the EFU rating.

Heavy Rain in WAYNE, IOWA
From 14-JUL-21 23:30:00 to 15-JUL-21 01:27:00 (CST-6)
Location: HUMESTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report of 2.22 inches of rain in 2 hours.

Heavy Rain in MONROE, IOWA
From 14-JUL-21 21:00:00 to 15-JUL-21 04:00:00 (CST-6)
Location: ALBIA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report of 2.51 inches of rain overnight.

Heavy Rain in MONROE, IOWA
From 14-JUL-21 21:00:00 to 15-JUL-21 05:51:00 (CST-6)
Location: ALBIA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm total rainfall of 2.75 inches.

Tornado in TAMA, IOWA
From 14-JUL-21 18:05:00 to 14-JUL-21 18:08:00 (CST-6)
Location: DYSART
Tornado F-scale: EF1
Property damage: 25.00K
Crop damage: 1.00K
Reported by: NWS Storm Survey

Tornado developed near the southwest corner of Dysart and moved east southeast.  The tornado had a very broad circulation with smaller vorticies embedded within the larger circulation.  The tornado produced mostly EF0 damage with some EF1 damage to houses on the far southwest side of town.  The remainder of the path was in agricultural fields to the south of town.  The tornado then moved from Tama county into Benton county.

Heavy Rain in JASPER, IOWA
From 14-JUL-21 07:00:00 to 15-JUL-21 07:00:00 (CST-6)
Location: NEWTON MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

A 24 hour rain total of 2.03 inches.

Heavy Rain in BUTLER, IOWA
From 14-JUL-21 07:00:00 to 15-JUL-21 07:00:00 (CST-6)
Location: ALLISON MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A 24 hour rain total of 2.05 inches.

Heavy Rain in POWESHIEK, IOWA
From 14-JUL-21 07:00:00 to 15-JUL-21 07:00:00 (CST-6)
Location: MONTEZUMA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A 24 hour rain total of 2.24 inches.

Heavy Rain in KOSSUTH, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: SWEA CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.83 inches.

Heavy Rain in APPANOOSE, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: UNIONVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.61 inches.

Heavy Rain in BLACK HAWK, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: GILBERTVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.42 inches.

Tornado in BUTLER, IOWA
From 14-JUL-21 16:16:00 to 14-JUL-21 16:21:00 (CST-6)
Location: SHELL ROCK
Tornado F-scale: EF1
Property damage: 300.00K
Crop damage: 1.00K
Reported by: NWS Storm Survey

Tornado developed southwest of Shell Rock and moved along 250th Street.  The tornado impacted several farmsteads along 250th producing EF1 damage to buildings and trees at many of the locations.  The tornado was also quite wide with the the max width extending over 600 yards.  The tornado continued into Bremer county.

Thunderstorm Wind in BLACK HAWK, IOWA
From 14-JUL-21 17:17:00 to 14-JUL-21 17:17:00 (CST-6)
Location: WATERLOO
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous trees down. Time estimated via radar.

Thunderstorm Wind in BLACK HAWK, IOWA
From 14-JUL-21 17:22:00 to 14-JUL-21 17:22:00 (CST-6)
Location: WATERLOO
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees down. Time estimated via radar.

Tornado in SAC, IOWA
From 14-JUL-21 16:35:00 to 14-JUL-21 16:38:00 (CST-6)
Location: LYTTON
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.50K
Reported by: Storm Chaser

Storm chaser captured the tornado with a UAV.  The footage was used to determine the path of the tornado which remained in rural agricultural fields, hence the EFU rating.

Funnel Cloud in MARSHALL, IOWA
From 14-JUL-21 19:15:00 to 14-JUL-21 19:15:00 (CST-6)
Location: MELBOURNE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reports a brief funnel cloud 2 miles ESE of Melbourne.

Tornado in BUTLER, IOWA
From 14-JUL-21 15:57:00 to 14-JUL-21 15:59:00 (CST-6)
Location: BUTLER CENTER
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.70K
Reported by: Storm Chaser

Storm Chaser report of a tornado southeast of Allison.  Track was determined through use of high resolution satellite imagery.  No damage indicators were impacted, therefore the EFU rating.

Heavy Rain in GRUNDY, IOWA
From 14-JUL-21 07:00:00 to 15-JUL-21 07:00:00 (CST-6)
Location: GRUNDY CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A 24 hour rain total of 2.26 inches.

Heavy Rain in STORY, IOWA
From 14-JUL-21 07:00:00 to 15-JUL-21 07:00:00 (CST-6)
Location: MIDVALE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A 24 hour rain total of 3.02 inches.

Heavy Rain in APPANOOSE, IOWA
From 14-JUL-21 07:03:00 to 15-JUL-21 07:03:00 (CST-6)
Location: FORBUSH
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A 24 hour rain total of 2.10 inches with ponding in low lying areas.

Heavy Rain in APPANOOSE, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: ICONIUM
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.35 inches.

Heavy Rain in BLACK HAWK, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: HUDSON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.30 inches.

Heavy Rain in DAVIS, IOWA
From 14-JUL-21 08:00:00 to 15-JUL-21 08:00:00 (CST-6)
Location: FLORIS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A 24 hour rain total of 2.13 inches.

Thunderstorm Wind in STORY, IOWA
From 14-JUL-21 19:23:00 to 14-JUL-21 19:23:00 (CST-6)
Location: COLO
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reports large tree branches down.

Flash Flood in STORY, IOWA
From 14-JUL-21 19:30:00 to 15-JUL-21 01:04:00 (CST-6)
Location: IOWA CENTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Report of water over the road at 305th and 630th with 3 to 4 inches of rainfall in the area.

Heavy Rain in STORY, IOWA
From 14-JUL-21 17:00:00 to 14-JUL-21 19:40:00 (CST-6)
Location: IOWA CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reports 5.60 inches of rain since 6 pm local time.