A trough of low pressure lifted north into Iowa during the day on the 24th.  A weak short wave lifted northeast across the boundary.  Strong thunderstorms fired to the south of Iowa and became enhanced as they interacted with the boundary.  The atmosphere became moderately unstable with CAPE around 1000 to 1500 J/kg and lifted indices fell to around -6 C.  The CAPE in the hail producing level was not all that high, but the freezing level was only 11,000 feet.  Numerous reports of pea to slightly larger size hail were received.  Downdraft CAPE was in the 700 to 1000 J/kg range.  Shear was relatively weak with 20 to 30 kts of shear available.  As the line lifted through central Iowa, which was during peak heating, it intensified.  There were numerous reports of 50 MPH winds all along the line as it extended from west central, through central, into southeast Iowa.  One segment of the line became severe and produced 60 to 70 MPH winds at several locations in central Iowa.  A few funnel clouds were observed as well.  A grain bin and shed were damaged south of Jamaica in Guthrie County.  Scattered tree and outbuilding damage occurred across Dallas, Polk, and into Marshall Counties.  A exit sign was blown down by the high winds south of Woodward in Dallas County.  Lightning struck an accounting building near Charition, blowing out bricks from the building and damaging some electrical components.

Lightning in LUCAS, IOWA
From 24-MAY-11 14:10:00 to 24-MAY-11 14:10:00 (CST-6)
Location: CHARITON
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Newspaper

Thunderstorm Wind in GUTHRIE, IOWA
From 24-MAY-11 13:45:00 to 24-MAY-11 13:45:00 (CST-6)
Location: JAMAICA
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Grain bin and shed damaged by straight line winds with estimated gusts near 70 MPH along Wood Road.

Thunderstorm Wind in DALLAS, IOWA
From 24-MAY-11 13:55:00 to 24-MAY-11 13:55:00 (CST-6)
Location: PERRY MUNI ARPT
Magnitude: 50.00 MG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: AWOS

AWOS measurement at the Perry Airport.

Thunderstorm Wind in POLK, IOWA
From 24-MAY-11 13:50:00 to 24-MAY-11 13:50:00 (CST-6)
Location: RIDER
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reports 55 to 60 MPH winds at the WalMart in Grimes.  Four inch diameter trees snapped.

Thunderstorm Wind in POLK, IOWA
From 24-MAY-11 13:53:00 to 24-MAY-11 13:53:00 (CST-6)
Location: RIDER
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: NWS Employee

Damage to a large wooden railing on the front porch of a house.   Winds estimated up to 60 MPH.

Thunderstorm Wind in STORY, IOWA
From 24-MAY-11 14:24:00 to 24-MAY-11 14:24:00 (CST-6)
Location: SLATER
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency Manager reported wind gust of 60 MPH.

Thunderstorm Wind in DALLAS, IOWA
From 24-MAY-11 14:00:00 to 24-MAY-11 14:00:00 (CST-6)
Location: WOODWARD
Magnitude: 57.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: State Official

Power lines down due to high winds.

Thunderstorm Wind in POLK, IOWA
From 24-MAY-11 14:12:00 to 24-MAY-11 14:12:00 (CST-6)
Location: SAYLORVILLE
Magnitude: 52.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several three inch diameter tree limbs down at the DMACC campus in Ankeny.

Thunderstorm Wind in MARSHALL, IOWA
From 24-MAY-11 15:14:00 to 24-MAY-11 15:14:00 (CST-6)
Location: LA MOILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Law enforcement reports 60 MPH winds.

Thunderstorm Wind in DALLAS, IOWA
From 24-MAY-11 14:10:00 to 24-MAY-11 14:10:00 (CST-6)
Location: WOODWARD
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Six inch tree branch and 14 inch tree branch blown down.

Thunderstorm Wind in DALLAS, IOWA
From 24-MAY-11 13:58:00 to 24-MAY-11 13:58:00 (CST-6)
Location: MORAN
Magnitude: 61.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Highway exit sign was blown down at highway 210 and highway 141.