A warm, moist, and unstable airmass was in place over Iowa on the afternoon of the 21st.  A Warm front lifted north into the state with temperatures rising into the upper 80s to low 90s south of it with dew point temperatures in the upper 60s to low 70s.  This combination produced most unstable CAPE values in the 3000 to 4000 J/kg range and lifted indices in the -9 C. range.  The environment was not strongly sheared with 25 to 35 kts of effective shear.  The freezing level was quite high at 14,700 feet.  In spite of this, there was plenty of cape in the -10 to -30 C. layer of the atmosphere, with 500 J/kg available.  The LFC in the 1200 to 2000 meter range.  The MCS developed rapidly and move east-southeast across Iowa.  Many of the storms produced significant hail, with hail size ranging from nickel to over tennis ball size.  Two and one half inch diameter hail fell north of Renwick in Humboldt County.  Golf ball size hail fell in Hancock County in the Corwith area.  The largest hail occurred during the first couple hours of the systems development.  Most of the hail was in the three quarter to one inch diameter range later on.  Four tornadoes were reported with the system.  All of the were brief touchdowns however and caused little damage.  One touched down in Wright County near Eagle Grove.  Two others touched down in Butler County one west of Shell Rock, the other north of Steamboat Rock.  The fourth tornado touched down northwest of Kelly in Story County.  The final tornado touched down on the south side of Waterloo in Black Hawk County.  Many of the storms produced strong winds of at least 45 to 50 MPH.  There were several reports of winds in excess of 60 MPH however.  Numerous trees were blown down and a few power poles snapped.  Winds caused damage in the Poweshiek County with winds estemated at near 80 MPH.

Tornado in BUTLER, IOWA
From 21-JUN-07 15:24:00 to 21-JUN-07 15:24:00 (CST-6)
Location: SHELL ROCK
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 2.00K
Reported by: Law Enforcement

Brief touchdown with no significant damage.

Hail in DALLAS, IOWA
From 21-JUN-07 16:07:00 to 21-JUN-07 16:07:00 (CST-6)
Location: BOONEVILLE
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 21-JUN-07 14:10:00 to 21-JUN-07 14:10:00 (CST-6)
Location: CORWITH
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in HUMBOLDT, IOWA
From 21-JUN-07 14:20:00 to 21-JUN-07 14:20:00 (CST-6)
Location: RENWICK
Magnitude: 2.50 
Property damage: 40.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in CASS, IOWA
From 21-JUN-07 15:20:00 to 21-JUN-07 15:20:00 (CST-6)
Location: ATLANTIC
Magnitude: 57.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in BLACK HAWK, IOWA
From 21-JUN-07 14:47:00 to 21-JUN-07 14:47:00 (CST-6)
Location: CEDAR FALLS
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in DALLAS, IOWA
From 21-JUN-07 15:53:00 to 21-JUN-07 15:53:00 (CST-6)
Location: GRANGER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Amateur Radio

Hail in WRIGHT, IOWA
From 21-JUN-07 14:15:00 to 21-JUN-07 14:15:00 (CST-6)
Location: FLORENCE
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in JASPER, IOWA
From 21-JUN-07 16:32:00 to 21-JUN-07 16:32:00 (CST-6)
Location: NEWTON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Tornado in BLACK HAWK, IOWA
From 21-JUN-07 16:22:00 to 21-JUN-07 16:22:00 (CST-6)
Location: CASTLE HILL
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 2.00K
Reported by: County Official

Brief touchdown with no significant damage.

Hail in BUTLER, IOWA
From 21-JUN-07 14:30:00 to 21-JUN-07 14:30:00 (CST-6)
Location: APLINGTON
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Thunderstorm Wind in POLK, IOWA
From 21-JUN-07 15:51:00 to 21-JUN-07 15:51:00 (CST-6)
Location: POLK CITY
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in HUMBOLDT, IOWA
From 21-JUN-07 14:15:00 to 21-JUN-07 14:15:00 (CST-6)
Location: RENWICK
Magnitude: 2.00 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in DALLAS, IOWA
From 21-JUN-07 16:01:00 to 21-JUN-07 16:01:00 (CST-6)
Location: BOONEVILLE
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 21-JUN-07 14:20:00 to 21-JUN-07 14:20:00 (CST-6)
Location: CORWITH
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in HUMBOLDT, IOWA
From 21-JUN-07 14:11:00 to 21-JUN-07 14:11:00 (CST-6)
Location: RENWICK
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in HARDIN, IOWA
From 21-JUN-07 14:55:00 to 21-JUN-07 14:55:00 (CST-6)
Location: PT PLEASANT
Magnitude: 61.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in DALLAS, IOWA
From 21-JUN-07 15:49:00 to 21-JUN-07 15:49:00 (CST-6)
Location: PANTHER
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in WRIGHT, IOWA
From 21-JUN-07 14:15:00 to 21-JUN-07 14:15:00 (CST-6)
Location: FLORENCE
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in BLACK HAWK, IOWA
From 21-JUN-07 14:35:00 to 21-JUN-07 14:35:00 (CST-6)
Location: WASHBURN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in BLACK HAWK, IOWA
From 21-JUN-07 16:28:00 to 21-JUN-07 16:28:00 (CST-6)
Location: WATERLOO RANCH ARPT
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CASS, IOWA
From 21-JUN-07 15:18:00 to 21-JUN-07 15:18:00 (CST-6)
Location: MASSENA
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HAMILTON, IOWA
From 21-JUN-07 15:41:00 to 21-JUN-07 15:41:00 (CST-6)
Location: STANHOPE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Funnel Cloud in BLACK HAWK, IOWA
From 21-JUN-07 15:44:00 to 21-JUN-07 15:44:00 (CST-6)
Location: WATERLOO
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in PALO ALTO, IOWA
From 21-JUN-07 13:31:00 to 21-JUN-07 13:31:00 (CST-6)
Location: EMMETSBURG
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Broadcast Media

Hail in WARREN, IOWA
From 21-JUN-07 17:00:00 to 21-JUN-07 17:00:00 (CST-6)
Location: COOL
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Fire Department/Rescue

Hail in DAVIS, IOWA
From 21-JUN-07 18:39:00 to 21-JUN-07 18:39:00 (CST-6)
Location: WEST GROVE
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HUMBOLDT, IOWA
From 21-JUN-07 14:11:00 to 21-JUN-07 14:11:00 (CST-6)
Location: RENWICK
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in BUTLER, IOWA
From 21-JUN-07 15:11:00 to 21-JUN-07 15:11:00 (CST-6)
Location: GREENE
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in GUTHRIE, IOWA
From 21-JUN-07 15:15:00 to 21-JUN-07 15:15:00 (CST-6)
Location: ADAIR
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in WARREN, IOWA
From 21-JUN-07 16:37:00 to 21-JUN-07 16:37:00 (CST-6)
Location: NEW VIRGINIA
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in HANCOCK, IOWA
From 21-JUN-07 13:52:00 to 21-JUN-07 13:52:00 (CST-6)
Location: CORWITH
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Post Office

Thunderstorm Wind in ADAIR, IOWA
From 21-JUN-07 15:21:00 to 21-JUN-07 15:21:00 (CST-6)
Location: ADAIR
Magnitude: 50.00 MG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Mesonet

Funnel Cloud in BUTLER, IOWA
From 21-JUN-07 14:52:00 to 21-JUN-07 14:52:00 (CST-6)
Location: BUTLER CENTER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in WARREN, IOWA
From 21-JUN-07 16:40:00 to 21-JUN-07 16:40:00 (CST-6)
Location: ST MARYS
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in WARREN, IOWA
From 21-JUN-07 16:55:00 to 21-JUN-07 16:55:00 (CST-6)
Location: MEDORA
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in ADAIR, IOWA
From 21-JUN-07 15:36:00 to 21-JUN-07 15:36:00 (CST-6)
Location: HOWE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Emergency Manager

Hail in GREENE, IOWA
From 21-JUN-07 15:00:00 to 21-JUN-07 15:00:00 (CST-6)
Location: SCRANTON
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in POLK, IOWA
From 21-JUN-07 15:57:00 to 21-JUN-07 15:57:00 (CST-6)
Location: ANKENY
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in POLK, IOWA
From 21-JUN-07 16:14:00 to 21-JUN-07 16:14:00 (CST-6)
Location: DES MOINES
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in DECATUR, IOWA
From 21-JUN-07 17:30:00 to 21-JUN-07 17:30:00 (CST-6)
Location: LE ROY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in GREENE, IOWA
From 21-JUN-07 15:45:00 to 21-JUN-07 15:45:00 (CST-6)
Location: SCRANTON
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in DALLAS, IOWA
From 21-JUN-07 16:37:00 to 21-JUN-07 16:37:00 (CST-6)
Location: BOONEVILLE
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in POWESHIEK, IOWA
From 21-JUN-07 17:18:00 to 21-JUN-07 17:18:00 (CST-6)
Location: BROOKLYN
Magnitude: 70.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Public

Tornado in WRIGHT, IOWA
From 21-JUN-07 14:55:00 to 21-JUN-07 14:55:00 (CST-6)
Location: HOLMES
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 2.00K
Reported by: Law Enforcement

Report of a brief tornado touchdown.  No significant damage.

Thunderstorm Wind in DALLAS, IOWA
From 21-JUN-07 15:55:00 to 21-JUN-07 15:55:00 (CST-6)
Location: DE SOTO
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in KOSSUTH, IOWA
From 21-JUN-07 13:42:00 to 21-JUN-07 13:42:00 (CST-6)
Location: BANCROFT
Magnitude: 1.25 
Property damage: 10.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in CRAWFORD, IOWA
From 21-JUN-07 14:09:00 to 21-JUN-07 14:09:00 (CST-6)
Location: VAIL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 21-JUN-07 14:04:00 to 21-JUN-07 14:04:00 (CST-6)
Location: CORWITH
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in HAMILTON, IOWA
From 21-JUN-07 15:31:00 to 21-JUN-07 15:31:00 (CST-6)
Location: STANHOPE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in ADAIR, IOWA
From 21-JUN-07 15:45:00 to 21-JUN-07 15:45:00 (CST-6)
Location: FISK
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in MAHASKA, IOWA
From 21-JUN-07 17:07:00 to 21-JUN-07 17:07:00 (CST-6)
Location: LEIGHTON
Magnitude: 0.50 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Public

Hail in DAVIS, IOWA
From 21-JUN-07 18:52:00 to 21-JUN-07 18:52:00 (CST-6)
Location: BLOOMFIELD
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in CRAWFORD, IOWA
From 21-JUN-07 13:42:00 to 21-JUN-07 13:42:00 (CST-6)
Location: VAIL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Thunderstorm Wind in JASPER, IOWA
From 21-JUN-07 16:38:00 to 21-JUN-07 16:38:00 (CST-6)
Location: BAXTER
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in HANCOCK, IOWA
From 21-JUN-07 14:00:00 to 21-JUN-07 14:00:00 (CST-6)
Location: CORWITH
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Post Office

Hail in HANCOCK, IOWA
From 21-JUN-07 14:00:00 to 21-JUN-07 14:00:00 (CST-6)
Location: CORWITH
Magnitude: 2.00 
Property damage: 15.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in WRIGHT, IOWA
From 21-JUN-07 14:30:00 to 21-JUN-07 14:30:00 (CST-6)
Location: FLORENCE
Magnitude: 2.00 
Property damage: 25.00K
Crop damage: 5.00K
Reported by: Other Federal Agency

Hail in GREENE, IOWA
From 21-JUN-07 15:00:00 to 21-JUN-07 15:00:00 (CST-6)
Location: JEFFERSON
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail in MADISON, IOWA
From 21-JUN-07 16:35:00 to 21-JUN-07 16:35:00 (CST-6)
Location: ST CHARLES
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Amateur Radio

Thunderstorm Wind in BLACK HAWK, IOWA
From 21-JUN-07 16:30:00 to 21-JUN-07 16:30:00 (CST-6)
Location: WATERLOO
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in ADAIR, IOWA
From 21-JUN-07 15:32:00 to 21-JUN-07 15:32:00 (CST-6)
Location: FONTANELLE
Magnitude: 58.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in CASS, IOWA
From 21-JUN-07 15:00:00 to 21-JUN-07 15:00:00 (CST-6)
Location: ATLANTIC
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in WARREN, IOWA
From 21-JUN-07 16:32:00 to 21-JUN-07 16:32:00 (CST-6)
Location: ST MARYS
Magnitude: 0.88 
Property damage: 2.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Tornado in BUTLER, IOWA
From 21-JUN-07 14:51:00 to 21-JUN-07 14:51:00 (CST-6)
Location: KESLEY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 1.00K
Reported by: Trained Spotter

Brief touchdown in a field.

Tornado in STORY, IOWA
From 21-JUN-07 15:58:00 to 21-JUN-07 15:58:00 (CST-6)
Location: KELLEY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 2.00K
Reported by: Fire Department/Rescue

Brief touchdown with no significant damage.