A cold front moved southeast across Iowa during the afternoon of the 27th.  The initial surface wind shift line had passed, however the cold front aloft lagged the wind shift by at least 150 miles. The airmass became unstable by afternoon with CAPE values in the 2000 to 3000 J/kg range, and lifted indices between -4 and -7 C.  The atmosphere became more sheared as the afternoon progressed, with 30 to 45 kts of effective shear by late afternoon.  Available downdraft CAPE was 700 to 900 J/kg, with cape available in the -10 to -30 C. layer of the atmosphere between 300 and 400 J/kg.  Initially, a scattered line of thunderstorms formed over eastern parts of Nebraska and South Dakota.  The line became more solidified as it moved into Iowa.  A few rogue cells developed ahead of the line, and became severe.  One of them produced baseball size hail southwest of Earlham in Madison County.  For the most part, the storms produced hail in the three quarter to one inch diameter size.  The storms produced gusty winds in most areas.  There were several reports of winds around 60 MPH or so with the stronger storms.  Most of the wind damage was limited to trees and power lines.  A beta bow element moved through Cass County, destroying a machine shed there as high winds tore it apart.

Hail in WARREN, IOWA
From 27-JUN-08 17:39:00 to 27-JUN-08 17:39:00 (CST-6)
Location: SCOTCH RIDGE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in STORY, IOWA
From 27-JUN-08 17:50:00 to 27-JUN-08 17:50:00 (CST-6)
Location: MIDVALE
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds of 60 MPH were breaking 6 inch diameter tree limbs.  Heavy rain was reducing visibility to one quarter of a mile or less.

Thunderstorm Wind in STORY, IOWA
From 27-JUN-08 17:35:00 to 27-JUN-08 17:35:00 (CST-6)
Location: SLATER
Magnitude: 58.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in STORY, IOWA
From 27-JUN-08 17:38:00 to 27-JUN-08 17:38:00 (CST-6)
Location: SLATER
Magnitude: 58.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Measured wind gust reported by amateur radio operator.

Hail in DECATUR, IOWA
From 27-JUN-08 18:25:00 to 27-JUN-08 18:25:00 (CST-6)
Location: LAMONI
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

A small amount of penny size hail fell along with 40 MPH winds.

Hail in DECATUR, IOWA
From 27-JUN-08 18:30:00 to 27-JUN-08 18:30:00 (CST-6)
Location: LEON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Thunderstorm Wind in UNION, IOWA
From 27-JUN-08 18:05:00 to 27-JUN-08 18:05:00 (CST-6)
Location: AFTON
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Wind reported by the Afton News.

Hail in MADISON, IOWA
From 27-JUN-08 16:57:00 to 27-JUN-08 16:57:00 (CST-6)
Location: EARLHAM
Magnitude: 2.75 
Property damage: 20.00K
Crop damage: 25.00K
Reported by: Law Enforcement

Golf ball to baseball size hail was reported, along with 30 to 40 MPH winds.

Thunderstorm Wind in ADAMS, IOWA
From 27-JUN-08 17:10:00 to 27-JUN-08 17:10:00 (CST-6)
Location: CARBON
Magnitude: 65.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

High winds destroyed a machine shed.

Thunderstorm Wind in STORY, IOWA
From 27-JUN-08 17:45:00 to 27-JUN-08 17:45:00 (CST-6)
Location: MIDVALE
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated winds of 60 MPH, along with 4 to 6 inch tree limbs down.

Hail in ADAIR, IOWA
From 27-JUN-08 16:47:00 to 27-JUN-08 16:47:00 (CST-6)
Location: HOWE
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Broadcast Media

Report received from KCCI television.

Hail in MADISON, IOWA
From 27-JUN-08 16:55:00 to 27-JUN-08 16:55:00 (CST-6)
Location: EARLHAM
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Quarter size hail reported at 130th and Pitzer.

Thunderstorm Wind in STORY, IOWA
From 27-JUN-08 17:56:00 to 27-JUN-08 17:56:00 (CST-6)
Location: SLATER
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong winds were breaking tree limbs 3 inches in diameter.  There was also street flooding at Highway 210 and 510th St.  The intersection with the city drainage system was backing up with water over the road.

Hail in MADISON, IOWA
From 27-JUN-08 16:55:00 to 27-JUN-08 16:55:00 (CST-6)
Location: EARLHAM
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Public