A cold front moved into Iowa during the afternoon from the northwest.  The airmass became very unstable ahead of the front.  Temperatures rose into the upper 80s to low 90s, with dewpoint readings in the upper 60s to lower 70s.  CAPE increased to 4000 J/kg by late afternoon with a lifted index between -10 and -18 C.  Downdraft CAPE was between 1200 and 1700 J/kg, with CAPE in the -10 to -30 C layer of the atmosphere in the 700 to 900 J/kg range.  The freezing level was very high, around 15,000 feet, with the LCL at 1250 meters.  Deep moisture was available for the system, with precipitable water values around 1.6 inches.  Little shear was available with only 20 kts of effective shear.  A line of thunderstorms formed along the cold front during the afternoon and tracked southeast into Iowa.  Several of the storms produced hail from the size of quarters to the size of golf balls.  Funnel clouds were also reported with a few of the storms.  As the thunderstorms continued into the later afternoon and evening, wind became a more dominant factor.  Numerous trees were downed by high winds in Wright and Franklin Counties.  The storms developed southwest with a line of significant thunderstorms extending from northeast into central Iowa by early to mid evening as new storms formed on the outflow boundary of the original development.  The storms continued to produce quarter to golf ball size hail and wind gusts of 60 to 70 MPH.  The winds caused spotty building damage, including a barn near Story City.  Six horses that were inside were killed.  The barn was east of Boone, where buildings and power lines were destroyed at the Central Iowa Expo grounds.  Two inch diameter hail was reported in parts of Wright and Boone Counties.  A heat burst produced 73 MPH winds in Marion County at the Knoxville Airport.  The temperature rose from 70 to 84 in 15 minutes, and the dewpoint dropped from 63 to 48 in 10 minutes.

Thunderstorm Wind in HARDIN, IOWA
From 22-JUL-13 17:35:00 to 22-JUL-13 17:35:00 (CST-6)
Location: ELDORA
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Large tree down in a yard several feet in diameter.

Thunderstorm Wind in HARDIN, IOWA
From 22-JUL-13 17:15:00 to 22-JUL-13 17:15:00 (CST-6)
Location: IOWA FALLS
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Dime size hail was reported as well.

Hail in BOONE, IOWA
From 22-JUL-13 19:15:00 to 22-JUL-13 19:15:00 (CST-6)
Location: BOONE
Magnitude: 2.00 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Amateur Radio

Hail in BOONE, IOWA
From 22-JUL-13 19:04:00 to 22-JUL-13 19:04:00 (CST-6)
Location: MACKEY
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in BOONE, IOWA
From 22-JUL-13 19:20:00 to 22-JUL-13 19:20:00 (CST-6)
Location: ERICSON
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Public

Hail in WORTH, IOWA
From 22-JUL-13 14:13:00 to 22-JUL-13 14:28:00 (CST-6)
Location: MANLY
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 50.00K
Reported by: Trained Spotter

Five minutes of ping pong hail was followed by 10 minutes of dime to quarter size hail.

Hail in DALLAS, IOWA
From 22-JUL-13 19:43:00 to 22-JUL-13 19:43:00 (CST-6)
Location: PERRY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Thunderstorm Wind in MARSHALL, IOWA
From 22-JUL-13 18:52:00 to 22-JUL-13 18:52:00 (CST-6)
Location: ALBION
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Many 12 inch diameter tree limbs downed.

Hail in GUTHRIE, IOWA
From 22-JUL-13 19:30:00 to 22-JUL-13 19:30:00 (CST-6)
Location: BAGLEY
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 20.00K
Reported by: Emergency Manager

Winds were estimated at 40 to 50 MPH.

Funnel Cloud in HANCOCK, IOWA
From 22-JUL-13 14:00:00 to 22-JUL-13 14:00:00 (CST-6)
Location: BRITT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Photo submitted to kimt television. The funnel occurred northwest of Britt.

Thunderstorm Wind in FRANKLIN, IOWA
From 22-JUL-13 17:10:00 to 22-JUL-13 17:10:00 (CST-6)
Location: COULTER
Magnitude: 61.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Approximately 20 large trees were downed in town.

Hail in WRIGHT, IOWA
From 22-JUL-13 16:25:00 to 22-JUL-13 16:25:00 (CST-6)
Location: CLARION
Magnitude: 2.00 
Property damage: 50.00K
Crop damage: 5.00K
Reported by: Public

Hail in HAMILTON, IOWA
From 22-JUL-13 17:48:00 to 22-JUL-13 17:48:00 (CST-6)
Location: WEBSTER CITY
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in MARSHALL, IOWA
From 22-JUL-13 18:30:00 to 22-JUL-13 18:30:00 (CST-6)
Location: STATE CENTER
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Three power lines downed.  Wind tied to outflow boundary ahead of the storm.

Hail in BOONE, IOWA
From 22-JUL-13 19:03:00 to 22-JUL-13 19:03:00 (CST-6)
Location: BOONE MUNI ARPT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in MARSHALL, IOWA
From 22-JUL-13 18:45:00 to 22-JUL-13 18:45:00 (CST-6)
Location: MARSHALLTOWN
Magnitude: 56.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Many trees down in town, some 3 to 4 feet in diameter.

High Wind in MARION, IOWA
From 22-JUL-13 21:55:00 to 22-JUL-13 21:55:00 (CST-6)
Magnitude: 63.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: AWOS

Heat burst with temps rising from 70 to 84 in fifteen minutes, dewpoint fell from 63 to 48 in ten minutes.

Thunderstorm Wind in GRUNDY, IOWA
From 22-JUL-13 17:22:00 to 22-JUL-13 17:22:00 (CST-6)
Location: DIKE
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 10.00K
Reported by: Public

Four to six 30 foot high trees, 12 inches in diameter, were downed.  Dime size hail also fell.

Hail in BOONE, IOWA
From 22-JUL-13 19:30:00 to 22-JUL-13 19:30:00 (CST-6)
Location: LUTHER
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 25.00K
Reported by: Trained Spotter

Winds of 40 MPH also reported with the hail.

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 19:03:00 to 22-JUL-13 19:03:00 (CST-6)
Location: AMES
Magnitude: 53.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in WORTH, IOWA
From 22-JUL-13 14:45:00 to 22-JUL-13 14:45:00 (CST-6)
Location: MANLY
Magnitude: 1.50 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Large hail along with 0.60 of rain.

Hail in HAMILTON, IOWA
From 22-JUL-13 18:15:00 to 22-JUL-13 18:15:00 (CST-6)
Location: KAMRAR
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in CERRO GORDO, IOWA
From 22-JUL-13 15:59:00 to 22-JUL-13 15:59:00 (CST-6)
Location: HURLEY
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Heavy Rain in FRANKLIN, IOWA
From 22-JUL-13 17:20:00 to 22-JUL-13 18:20:00 (CST-6)
Location: GENEVA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 3.2 inches in a little over an hour at Geneva.  No flooding.

Thunderstorm Wind in MADISON, IOWA
From 22-JUL-13 20:56:00 to 22-JUL-13 20:56:00 (CST-6)
Location: BEVINGTON
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six inch diameter tree branch down across the road.

Thunderstorm Wind in POLK, IOWA
From 22-JUL-13 19:50:00 to 22-JUL-13 19:50:00 (CST-6)
Location: ALLEMAN
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 250.00K
Reported by: Trained Spotter

Extensive crop damage was reported with stocks flattened.

Hail in WRIGHT, IOWA
From 22-JUL-13 16:30:00 to 22-JUL-13 16:30:00 (CST-6)
Location: CLARION
Magnitude: 1.50 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reports mostly dime to quarter size hail, with the largest measured at 1.5 inches.

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 19:00:00 to 22-JUL-13 19:00:00 (CST-6)
Location: NEVADA
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Report received via chat.

Hail in FRANKLIN, IOWA
From 22-JUL-13 16:43:00 to 22-JUL-13 16:43:00 (CST-6)
Location: GENEVA
Magnitude: 1.00 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds were estimated at 50 MPH as well.

Hail in STORY, IOWA
From 22-JUL-13 19:37:00 to 22-JUL-13 19:37:00 (CST-6)
Location: KELLEY
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 50.00K
Reported by: Amateur Radio

Winds estimated between 40 to 60 MPH.

Thunderstorm Wind in DALLAS, IOWA
From 22-JUL-13 19:38:00 to 22-JUL-13 19:38:00 (CST-6)
Location: WOODWARD
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimates the peak wind gust of 65 MPH.

Hail in BOONE, IOWA
From 22-JUL-13 19:13:00 to 22-JUL-13 19:13:00 (CST-6)
Location: BOONE
Magnitude: 1.50 
Property damage: 3.00K
Crop damage: 7.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 22-JUL-13 19:50:00 to 22-JUL-13 19:50:00 (CST-6)
Location: ALLEMAN
Magnitude: 1.00 
Property damage: 10.00K
Crop damage: 100.00K
Reported by: Trained Spotter

Trained spotter reports quarter size hail and 70 MPH winds.  Extensive crop damage with corn stocks bent to the ground.

Hail in BOONE, IOWA
From 22-JUL-13 19:25:00 to 22-JUL-13 19:25:00 (CST-6)
Location: BOONE MUNI ARPT
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 3.00K
Reported by: NWS Employee

Hail in WRIGHT, IOWA
From 22-JUL-13 16:52:00 to 22-JUL-13 16:52:00 (CST-6)
Location: BELMOND
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in DALLAS, IOWA
From 22-JUL-13 20:30:00 to 22-JUL-13 20:30:00 (CST-6)
Location: HADDEN HILL
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Pea size hail, report received through chat.

Hail in FRANKLIN, IOWA
From 22-JUL-13 17:00:00 to 22-JUL-13 17:00:00 (CST-6)
Location: CHAPIN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in GUTHRIE, IOWA
From 22-JUL-13 20:04:00 to 22-JUL-13 20:04:00 (CST-6)
Location: GUTHRIE CENTER
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 15.00K
Reported by: Trained Spotter

Hail in HAMILTON, IOWA
From 22-JUL-13 18:04:00 to 22-JUL-13 18:04:00 (CST-6)
Location: KAMRAR
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in WRIGHT, IOWA
From 22-JUL-13 16:30:00 to 22-JUL-13 16:30:00 (CST-6)
Location: CLARION
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in JASPER, IOWA
From 22-JUL-13 20:18:00 to 22-JUL-13 20:18:00 (CST-6)
Location: KELLOGG
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in HAMILTON, IOWA
From 22-JUL-13 17:49:00 to 22-JUL-13 17:49:00 (CST-6)
Location: STONEGA
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in WEBSTER, IOWA
From 22-JUL-13 18:28:00 to 22-JUL-13 18:28:00 (CST-6)
Location: DAYTON
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Public

Hail in HAMILTON, IOWA
From 22-JUL-13 17:32:00 to 22-JUL-13 17:32:00 (CST-6)
Location: BLAIRSBURG
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in HAMILTON, IOWA
From 22-JUL-13 17:15:00 to 22-JUL-13 17:15:00 (CST-6)
Location: WEBSTER CITY
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 20.00K
Reported by: Public

Hail in WEBSTER, IOWA
From 22-JUL-13 17:55:00 to 22-JUL-13 17:55:00 (CST-6)
Location: BORDER PLAINS
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 15.00K
Reported by: Social Media

Hail in HAMILTON, IOWA
From 22-JUL-13 17:25:00 to 22-JUL-13 17:35:00 (CST-6)
Location: STONEGA
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 20.00K
Reported by: Trained Spotter

Hail in HAMILTON, IOWA
From 22-JUL-13 17:50:00 to 22-JUL-13 17:50:00 (CST-6)
Location: WEBSTER CITY
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Social Media

Hail in HANCOCK, IOWA
From 22-JUL-13 14:50:00 to 22-JUL-13 14:50:00 (CST-6)
Location: GARNER
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Fire Department/Rescue

The golf ball size hail was reported on Henchen Street.

Hail in WRIGHT, IOWA
From 22-JUL-13 16:55:00 to 22-JUL-13 16:55:00 (CST-6)
Location: BELMOND
Magnitude: 1.50 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 19:21:00 to 22-JUL-13 19:21:00 (CST-6)
Location: AMES
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A 12 inch diameter tree blown down on a car.

Hail in HANCOCK, IOWA
From 22-JUL-13 14:01:00 to 22-JUL-13 14:01:00 (CST-6)
Location: MILLER
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Thunderstorm Wind in WRIGHT, IOWA
From 22-JUL-13 15:48:00 to 22-JUL-13 15:48:00 (CST-6)
Location: DOWS
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A large tree branch was downed. It took out a power line and blocked a road.

Hail in BOONE, IOWA
From 22-JUL-13 19:10:00 to 22-JUL-13 19:10:00 (CST-6)
Location: BOONE
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Mostly nickel size hail with a few golf ball size.

Hail in HAMILTON, IOWA
From 22-JUL-13 17:49:00 to 22-JUL-13 17:49:00 (CST-6)
Location: WEBSTER CITY
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in WRIGHT, IOWA
From 22-JUL-13 16:08:00 to 22-JUL-13 16:08:00 (CST-6)
Location: CORNELIA
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in BOONE, IOWA
From 22-JUL-13 19:15:00 to 22-JUL-13 19:15:00 (CST-6)
Location: MACKEY
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 18:54:00 to 22-JUL-13 18:54:00 (CST-6)
Location: STORY CITY
Magnitude: 58.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tree limbs of 6 to 12 inches and power lines down in parts of town. Also dime to penny sized hail.

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 18:52:00 to 22-JUL-13 18:52:00 (CST-6)
Location: ROLAND
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The emergency manager estimates winds of 70 MPH. Tree damage throughout Roland with many large tree branches 6 to 12 inches in diameter down and some trees down as well.

Thunderstorm Wind in BOONE, IOWA
From 22-JUL-13 19:19:00 to 22-JUL-13 19:19:00 (CST-6)
Location: JORDAN
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Roof blown of a farm expo building and power lines snapped at the base.

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 18:35:00 to 22-JUL-13 18:35:00 (CST-6)
Location: STORY CITY
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Report was received via the chat server.

Hail in BOONE, IOWA
From 22-JUL-13 19:27:00 to 22-JUL-13 19:27:00 (CST-6)
Location: LUTHER
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 15.00K
Reported by: Public

Funnel Cloud in WINNEBAGO, IOWA
From 22-JUL-13 14:10:00 to 22-JUL-13 14:10:00 (CST-6)
Location: FOREST CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter and member of the public both reported a funnel cloud just west to southwest of Forest City.

Thunderstorm Wind in STORY, IOWA
From 22-JUL-13 18:51:00 to 22-JUL-13 18:51:00 (CST-6)
Location: ROLAND
Magnitude: 58.00 EG
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Emergency Manager

The emergency manager reported a large grain bin damaged. It was dented in toward the top. A barn was damaged as well.

Hail in BOONE, IOWA
From 22-JUL-13 19:16:00 to 22-JUL-13 19:16:00 (CST-6)
Location: BOONE
Magnitude: 1.75 
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Funnel Cloud in HANCOCK, IOWA
From 22-JUL-13 14:10:00 to 22-JUL-13 14:10:00 (CST-6)
Location: HAYFIELD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter and member of the public both reported a funnel cloud just west to southwest of Forest City.

Hail in FRANKLIN, IOWA
From 22-JUL-13 15:25:00 to 22-JUL-13 15:25:00 (CST-6)
Location: ALEXANDER
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Public

Hail in MADISON, IOWA
From 22-JUL-13 21:01:00 to 22-JUL-13 21:01:00 (CST-6)
Location: BEVINGTON
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in BOONE, IOWA
From 22-JUL-13 19:45:00 to 22-JUL-13 19:45:00 (CST-6)
Location: MADRID
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Funnel Cloud in WINNEBAGO, IOWA
From 22-JUL-13 14:13:00 to 22-JUL-13 14:13:00 (CST-6)
Location: FOREST CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Photo submitted to abc 6 news in Austin, MN.