A warm and humid airmass was in place across Iowa on the 25th.  The flow was quite weak with only 5 to 10 kts of shear.  Afternoon temperatures warmed into the 80s with dew points in the mid 60s to around 70.  There was a fair amount of instability with available CAPE around 3500 J/kg by early to mid afternoon.  A weak cold frontal boundary extended from north central into southwest Iowa by mid afternoon.  Thunderstorms developed in the unstable air ahead of this boundary.  Spotty reports of high winds and hail were received.  Hail up to an inch in diameter covered the ground in Union County near Cromwell.  High winds of 70 to 85 MPH occurred with some of the storms.  Power poles were broken by high winds in Forest City in Winnebago County.  A garage was destroyed in Guthrie County when the wind blew into the open doors and tore the garage from its foundation and slamming it into grain bins.  With the weak flow, the storms were very slow moving.  Heavy rainfall occurred with some of the storms, which resulted in local flash flooding.  Heavy rainfall resulted in 2 feet of running water over the road west of Greenfield on Highway 92.  In Union County, reports of 3.5 to over 4 inches of rain were received.  Three and one half inches of rain fell in 30 minutes southwest of Cromwell in Adams County.

Hail in CARROLL, IOWA
From 25-MAY-10 14:01:00 to 25-MAY-10 14:01:00 (CST-6)
Location: COON RAPIDS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Unknown

Hail in STORY, IOWA
From 25-MAY-10 18:09:00 to 25-MAY-10 18:09:00 (CST-6)
Location: IOWA CENTER
Magnitude: 0.88 
Property damage: 3.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail falling in clusters with winds estimated at 45 MPH.

Heavy Rain in ADAMS, IOWA
From 25-MAY-10 16:44:00 to 25-MAY-10 17:14:00 (CST-6)
Location: STRINGTOWN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Relay of a public report of 3.5 inches of rain in a 30 minute period southwest of Cromwell.

Thunderstorm Wind in WINNEBAGO, IOWA
From 25-MAY-10 16:55:00 to 25-MAY-10 16:55:00 (CST-6)
Location: FOREST CITY
Magnitude: 75.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Power poles were downed near Forest City.

Hail in UNION, IOWA
From 25-MAY-10 16:17:00 to 25-MAY-10 16:17:00 (CST-6)
Location: CROMWELL
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: Trained Spotter

Quarter size hail covering the ground.

Heavy Rain in UNION, IOWA
From 25-MAY-10 15:00:00 to 25-MAY-10 16:43:00 (CST-6)
Location: SPAULDING
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall since 1500 CST was 4.2 inches.

Hail in GUTHRIE, IOWA
From 25-MAY-10 15:23:00 to 25-MAY-10 15:23:00 (CST-6)
Location: HERNDON
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Emergency Manager

Hail in ADAIR, IOWA
From 25-MAY-10 15:00:00 to 25-MAY-10 15:00:00 (CST-6)
Location: FONTANELLE
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 5.00K
Reported by: Emergency Manager

Flash Flood in UNION, IOWA
From 25-MAY-10 17:06:00 to 25-MAY-10 20:45:00 (CST-6)
Location: SPAULDING
Flood cause: Heavy Rain
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Water was reported over 110th St near Three Mile Creek.  Travel was not recommended along 120th and 120th St. in northwest Union County.

Flash Flood in UNION, IOWA
From 25-MAY-10 16:35:00 to 25-MAY-10 20:45:00 (CST-6)
Location: SPAULDING
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The Union County Sheriff reported water over Highway 25 from 110th Street N northward to the Adair County line.

Thunderstorm Wind in GUTHRIE, IOWA
From 25-MAY-10 15:19:00 to 25-MAY-10 15:19:00 (CST-6)
Location: HERNDON
Magnitude: 60.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A garage was destroyed.  Garage doors were open and the wind lifted the garage off the foundation and rolled it east into grain bins, damaging the bins as well.  Two power poles were snapped along Highway 4 just south of the garage.

Flash Flood in ADAIR, IOWA
From 25-MAY-10 14:30:00 to 25-MAY-10 18:45:00 (CST-6)
Location: FONTANELLE
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Two feet of water was reported over Highway 92 near Indian Ave.