A very warm and humid airmass was in place over Iowa on the 8th.  High temperatures were in the low to mid 90s, with dewpoint readings around 70.  A cold front moved into Iowa and pushed southeastward through the state during the late afternoon and evening hours.  The airmass was initially capped over Iowa with 700 mb temperatures of +10 to +13 C.  CAPE was in the 3000 to 4000 J/kg range, with about 900 J/kg available in the -10 to -30 C layer of the atmosphere.  The freezing level was over 14,500 feet.  The LCL height was quite high, 1500 to 2000 meters initially, however as moisture worked into the area, precipitable water values increased to 1.5 to 1.75 inches, and the LCL fell to under 1000 meters.  The atmosphere was moderately sheared, with 30 to 40 kts available.  Thunderstorms formed northeast of Iowa initially and gradually developed southwestward along the cold front, back into Iowa.  The storms continued build back into central Iowa.  The primary mode of severe weather came in the form of hail.  Numerous reports of 1 to 2 inch diameter hail were received.  Hail, nearly baseball in size, fell in Jasper County near Baxter.  Most of the severe weather was concentrated in northeast Polk, Story, Marshall, Jasper, and Tama Counties.  A gustnado was reported for a brief period south of Hudson in Black Hawk County.  There was little in the way of high wind reported with the storms in spite of the fact there was nearly 1500 J/kg of downdraft CAPE available.  Gusty winds occurred, but were below severe levels.

Hail in TAMA, IOWA
From 08-JUN-11 16:27:00 to 08-JUN-11 16:27:00 (CST-6)
Location: LINCOLN
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-JUN-11 16:40:00 to 08-JUN-11 16:40:00 (CST-6)
Location: ANKENY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in TAMA, IOWA
From 08-JUN-11 16:29:00 to 08-JUN-11 16:29:00 (CST-6)
Location: LINCOLN
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in GRUNDY, IOWA
From 08-JUN-11 16:15:00 to 08-JUN-11 16:15:00 (CST-6)
Location: REINBECK
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in TAMA, IOWA
From 08-JUN-11 16:34:00 to 08-JUN-11 16:34:00 (CST-6)
Location: LINCOLN
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Dime to quarter size hail reported.

Hail in TAMA, IOWA
From 08-JUN-11 16:40:00 to 08-JUN-11 16:40:00 (CST-6)
Location: BUCKINGHAM
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail in STORY, IOWA
From 08-JUN-11 17:25:00 to 08-JUN-11 17:25:00 (CST-6)
Location: COLLINS
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in MARSHALL, IOWA
From 08-JUN-11 17:45:00 to 08-JUN-11 17:45:00 (CST-6)
Location: MELBOURNE
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in POLK, IOWA
From 08-JUN-11 16:48:00 to 08-JUN-11 16:48:00 (CST-6)
Location: ANKENY
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in TAMA, IOWA
From 08-JUN-11 17:18:00 to 08-JUN-11 17:18:00 (CST-6)
Location: TRAER
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in STORY, IOWA
From 08-JUN-11 17:33:00 to 08-JUN-11 17:33:00 (CST-6)
Location: COLLINS
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Trained spotter reported quarter size hail at the intersection of 690th and 295th northwest of Collins.  Relayed by county EM.

Hail in JASPER, IOWA
From 08-JUN-11 18:28:00 to 08-JUN-11 18:28:00 (CST-6)
Location: BAXTER
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Amateur Radio

Hail in JASPER, IOWA
From 08-JUN-11 18:33:00 to 08-JUN-11 18:33:00 (CST-6)
Location: BAXTER
Magnitude: 2.25 
Property damage: 10.00K
Crop damage: 10.00K
Reported by: NWS Employee

Largest stone measured 2.25 inches in diameter.

Hail in POLK, IOWA
From 08-JUN-11 16:45:00 to 08-JUN-11 16:45:00 (CST-6)
Location: ANKENY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in TAMA, IOWA
From 08-JUN-11 17:06:00 to 08-JUN-11 17:06:00 (CST-6)
Location: GLADBROOK
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail was dime to quarter size.

Hail in TAMA, IOWA
From 08-JUN-11 17:45:00 to 08-JUN-11 17:45:00 (CST-6)
Location: BUCKINGHAM
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in JASPER, IOWA
From 08-JUN-11 18:30:00 to 08-JUN-11 18:30:00 (CST-6)
Location: BAXTER
Magnitude: 1.25 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: NWS Employee

Hail in MARSHALL, IOWA
From 08-JUN-11 17:19:00 to 08-JUN-11 17:19:00 (CST-6)
Location: STATE CENTER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in STORY, IOWA
From 08-JUN-11 17:23:00 to 08-JUN-11 17:23:00 (CST-6)
Location: COLLINS
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in MARSHALL, IOWA
From 08-JUN-11 18:50:00 to 08-JUN-11 18:50:00 (CST-6)
Location: LAUREL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 20.00K
Reported by: Amateur Radio

Amateur radio operator in Laurel reported hail falling heavily, mostly penny size, shredding leaves off of trees.

Hail in MARSHALL, IOWA
From 08-JUN-11 18:48:00 to 08-JUN-11 18:48:00 (CST-6)
Location: LAUREL
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 10.00K
Reported by: Public

Golf ball size hail reported.

Hail in POLK, IOWA
From 08-JUN-11 17:53:00 to 08-JUN-11 17:53:00 (CST-6)
Location: ANKENY
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: NWS Employee

Hail in JASPER, IOWA
From 08-JUN-11 18:35:00 to 08-JUN-11 18:35:00 (CST-6)
Location: BAXTER
Magnitude: 2.50 
Property damage: 15.00K
Crop damage: 10.00K
Reported by: Trained Spotter