Thunderstorms formed over northwest Iowa near an old outflow boundary left behind from the morning convection.  Farther south, the airmass was capped with 700 mb temperatures warming to +15 C on the Omaha, NE sounding at 0000 UTC.  The atmosphere was slow to recover after the morning convection, but did destabilize to where there was 1000 to 2000 J/kg of CAPE and the lifted indices falling to -4 to -7 C.  Downdraft CAPE was not all that impressive, in the 500 to 800 J/kg range.  The effective shear in the area was 30 to 45 kts with CAPE in the -10 to -30 C. layer of the atmosphere around 300 J/kg.  Thunderstorms formed over southeast South Dakota and moved into northwest Iowa during the evening.  The storms were quite strong and produced very large hail to the west of the DMX CWA.  They weakened as they moved into a less favorable environment in the DMX CWA.  The freezing level was quite high at nearly 15,000 feet, making it difficult for large hail production from the weakening storms.  Several locations in Emmet County reported dime to nickel size hail with the storms.  In Kossuth County, the storms intensified some and produced quarter size hail.  Intense rainfall occurred with some of the storms.  In Estherville for example, about 2.5 inches of rain fell in about one and one half hours.  Deep moisture was in place in the atmosphere with 1.7 inches of precipitable water available.  Thunderstorms continued to develop across northern Iowa into the early morning hours.  The hail event transitioned into more of a wind event after midnight.  Winds of 60 MPH plus hit the Waterloo area resulting in considerable tree limb damage.  A semi-tractor trailer was overturned just northwest of Waterloo by the high winds.  Power outages were widespread across Black Hawk County.  Shortly after the event it was reported that nearly 20% of Black Hawk County was without power due to the wind damage.  Power poles were on fire in Waterloo.  Significant damage occurred in the Cedar Falls area as well.  At least 350 trees were damaged in the city of Cedar Falls.  One hundred of those were on the University of Northern Iowa campus.  High winds near 100 MPH toppled a radio station tower.  Damage around the city was extensive with numerous trees toppled, falling onto houses and cars.  High winds damaged a garage in Cedar Falls.  In addition, high winds caused considerable damage around town with 9000 homes without power at one point in the Waterloo/Cedar Falls area.  Media reports indicated that the damage totals in the Waterloo/Ceder Falls areas exceeded $5 million.  Fortunately there were no injuries reported.  In addition to the property damage, wind speeds were high enough to cause extensive crop damage at several locations.  By mid August, a Federal Disaster Declaration was made for Black Hawk County due to the extensive wind damage in the county.

Thunderstorm Wind in BUTLER, IOWA
From 10-JUL-09 02:30:00 to 10-JUL-09 02:30:00 (CST-6)
Location: NEW HARTFORD
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees and large limbs were down.

Thunderstorm Wind in BREMER, IOWA
From 10-JUL-09 02:00:00 to 10-JUL-09 02:00:00 (CST-6)
Location: SUMNER
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 25.00K
Reported by: NWS Employee

Corn was flattened and tree limbs were down a mile west of Sumner by estimated 60 MPH wind.

Thunderstorm Wind in BREMER, IOWA
From 10-JUL-09 02:00:00 to 10-JUL-09 02:00:00 (CST-6)
Location: SUMNER
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

A roof was blown off a shed.

Thunderstorm Wind in WORTH, IOWA
From 10-JUL-09 00:20:00 to 10-JUL-09 00:20:00 (CST-6)
Location: MANLY
Magnitude: 57.00 EG
Property damage: 25.00K
Crop damage: 50.00K
Reported by: Emergency Manager

Worth County EM reports widespread damage around Manly with trees and branches down and corn flattened to the ground.

Heavy Rain in WORTH, IOWA
From 10-JUL-09 00:40:00 to 10-JUL-09 01:00:00 (CST-6)
Location: MANLY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Worth County EM relayed 3.5 inches of rain overnight with 2.5 of it falling in 20 minutes.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:45:00 to 10-JUL-09 02:45:00 (CST-6)
Location: CEDAR CITY
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Trees were reported down on houses and cars with power lines down.  Report received from KWWL TV.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:45:00 to 10-JUL-09 02:45:00 (CST-6)
Location: CEDAR FALLS
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Trees were blown down, the power was out, and fences were blown down.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:44:00 to 10-JUL-09 02:44:00 (CST-6)
Location: CEDAR CITY
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Semi blown off road on highway 218 at the lone tree exit.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:44:00 to 10-JUL-09 02:44:00 (CST-6)
Location: CEDAR FALLS
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A tree and large branches blown down along Franklin St in Cedar Falls.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:45:00 to 10-JUL-09 02:45:00 (CST-6)
Location: (ALO)WATERLOO MUNI A
Magnitude: 77.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Public

Air traffic controller reports trees, estimated 3-4 feet in diameter, uprooted at the airport.  Limbs, estimated 8-10 inches in diameter were blown down.  Some hangar doors were bent in and a helicopter was blown into a fence.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:45:00 to 10-JUL-09 02:45:00 (CST-6)
Location: (ALO)WATERLOO MUNI A
Magnitude: 58.00 MG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:40:00 to 10-JUL-09 02:40:00 (CST-6)
Location: (ALO)WATERLOO MUNI A
Magnitude: 57.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Newspaper

A strong thunderstorms bowed out and damaged a garage in Cedar Falls.  Other damage around the city was extensive.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:42:00 to 10-JUL-09 02:42:00 (CST-6)
Location: (ALO)WATERLOO MUNI A
Magnitude: 70.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Newspaper

Widespread damage from Cedar Falls to the Waterloo Airport.

Hail in EMMET, IOWA
From 09-JUL-09 20:02:00 to 09-JUL-09 20:02:00 (CST-6)
Location: WALLINGFORD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in EMMET, IOWA
From 09-JUL-09 20:48:00 to 09-JUL-09 20:48:00 (CST-6)
Location: WALLINGFORD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in EMMET, IOWA
From 09-JUL-09 20:53:00 to 09-JUL-09 20:53:00 (CST-6)
Location: WELLINGFORD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Winds also reported as gusting to 40 MPH with heavy rain.

Hail in EMMET, IOWA
From 09-JUL-09 20:53:00 to 09-JUL-09 20:53:00 (CST-6)
Location: ESTHERVILLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Emergency Manager

Hail in KOSSUTH, IOWA
From 09-JUL-09 22:04:00 to 09-JUL-09 22:04:00 (CST-6)
Location: SWEA CITY
Magnitude: 1.00 
Property damage: 5.00K
Crop damage: 20.00K
Reported by: Law Enforcement

Hail in KOSSUTH, IOWA
From 09-JUL-09 22:12:00 to 09-JUL-09 22:12:00 (CST-6)
Location: SWEA CITY
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:46:00 to 10-JUL-09 02:46:00 (CST-6)
Location: NORTH CEDAR
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Blinding rain, along with small hail was reported.  Three inch tree branches were blown down.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:55:00 to 10-JUL-09 02:55:00 (CST-6)
Location: WATERLOO RANCH ARPT
Magnitude: 52.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The power was out as well.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:50:00 to 10-JUL-09 02:50:00 (CST-6)
Location: (ALO)WATERLOO MUNI A
Magnitude: 52.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A semi-tractor trailer was blown over at the intersection of Washington and Broadway.  Power was out in numerous places in Waterloo.

Heavy Rain in BUTLER, IOWA
From 10-JUL-09 02:00:00 to 10-JUL-09 05:08:00 (CST-6)
Location: ALLISON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Rainfall of 3.02 inches.  Twenty four hour total, but nearly all in past 3 hours.

Thunderstorm Wind in BLACK HAWK, IOWA
From 10-JUL-09 02:43:00 to 10-JUL-09 02:43:00 (CST-6)
Location: CEDAR FALLS
Magnitude: 91.00 EG
Property damage: 750.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Six inch diameter tree branches were down and a radio station tower collapsed.

Thunderstorm Wind in BREMER, IOWA
From 10-JUL-09 01:55:00 to 10-JUL-09 02:00:00 (CST-6)
Location: WAVERLY
Magnitude: 65.00 EG
Property damage: 50.00K
Crop damage: 200.00K
Reported by: Newspaper

Extensive crop damage was reported northwest of Waverly.

Heavy Rain in BREMER, IOWA
From 10-JUL-09 03:00:00 to 10-JUL-09 12:42:00 (CST-6)
Location: DENVER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 4.80 inches from late last night into the morning.

Heavy Rain in POWESHIEK, IOWA
From 10-JUL-09 04:00:00 to 10-JUL-09 10:05:00 (CST-6)
Location: MONTEZUMA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 2.30 inches from late last night into the morning.