Weak high pressure was located over Iowa during the afternoon of the 22nd.  Moisture was drawn into Iowa on the back side of the high and the atmosphere became unstable by mid to late afternoon.  Lifted indices fell to -1 to -3 C and CAPE increased to 1000 to 2000 J/kg.  The freezing level was relatively low at 12,000 feet and this set the stage for steep low level lapse rates above 8 C in the lowest 3 km.  CAPE in the -10 to -30 C layer of the atmosphere increased to 100 to 300 J/kg, while the downdraft CAPE increased to 700 to 900 J/kg. There was a fair amount of shear available with 30 to 45 kts present.  A scattered line of thunderstorms developed from north central into west central Iowa.  They became severe with hail the primary mode of severe weather, along with spotty high wind reports.  Hail was around an inch with the stronger storms, along with winds in excess of 60 MPH causing tree damage.  Hail covered the ground to a depth of several inches in Pocahontas County, causing considerable damage to trees and crops in the area.  The damage was from one cell as it moved south-southeast through Pocahontas, Humboldt, and Webster Counties.  The largest hail was about one and one quarter of an inch in diameter that occurred in Humboldt and Webster Counties.

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:35:00 to 22-JUL-09 17:35:00 (CST-6)
Location: ROLFE
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Law Enforcement

Hail was reported by public three quarter to one inch in diameter.

Thunderstorm Wind in POCAHONTAS, IOWA
From 22-JUL-09 17:15:00 to 22-JUL-09 17:15:00 (CST-6)
Location: ROLFE
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Numerous tree branches blown down and blocking the road.

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:06:00 to 22-JUL-09 17:06:00 (CST-6)
Location: ROLFE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Law Enforcement

Hail was reported between Plover and Rolfe.

Hail in WEBSTER, IOWA
From 22-JUL-09 17:50:00 to 22-JUL-09 17:50:00 (CST-6)
Location: CLARE
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: SHAVE Project

Hail in WEBSTER, IOWA
From 22-JUL-09 17:45:00 to 22-JUL-09 17:45:00 (CST-6)
Location: CLARE
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Hail in HUMBOLDT, IOWA
From 22-JUL-09 17:30:00 to 22-JUL-09 17:30:00 (CST-6)
Location: GILMORE
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:10:00 to 22-JUL-09 17:10:00 (CST-6)
Location: ROLFE
Magnitude: 1.00 
Property damage: 10.00K
Crop damage: 150.00K
Reported by: Trained Spotter

Nickel to quarter size hail covered the ground to a depth of a few inches.  Trees were shredded and soybean fields were stripped down.  Tree limbs up to 7 inches in diameter were blown down.

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:45:00 to 22-JUL-09 17:45:00 (CST-6)
Location: PALMER
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:25:00 to 22-JUL-09 17:25:00 (CST-6)
Location: ROLFE
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 22-JUL-09 17:05:00 to 22-JUL-09 17:05:00 (CST-6)
Location: ROLFE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter