A cold front moved into northwest Iowa during the mid to late afternoon hours.  The airmass became unstable by the early afternoon with CAPE in the 2000 to 3000 J/kg range.  Downdraft CAPE was between 800 and 1200 J/kg.  The freezing level was around 13,000 feet.  Precipitable water was around 1.3 to 1.4 inches.  Shear was moderate with 30 to 40 kts of effective shear.  The LCL was quite high around 1750 meters due to dry air in the low levels of the atmosphere.  Thunderstorms developed along the cold front over north central Iowa initially.  The storms produced very heavy rainfall with several reports of penny to nickel size hail received.  One storm produced quarter to half dollar size hail in Hancock County.  Storms became more numerous by early evening.  Many produced small hail.  One storm in Pocahontas County produced hail up to quarter size.  Very heavy rainfall occurred over parts of north central Iowa.  The storms produced around 2 inches of rain in an hour.  More than 3 inches of rain fell in the Aplington area of Butler County.

Hail in POCAHONTAS, IOWA
From 25-JUL-13 16:45:00 to 25-JUL-13 16:55:00 (CST-6)
Location: WESTVIEW
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Hail in BLACK HAWK, IOWA
From 25-JUL-13 18:25:00 to 25-JUL-13 18:32:00 (CST-6)
Location: CEDAR FALLS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Pea to penny size hail lasted for a total of 5 to 10 minutes.

Hail in HANCOCK, IOWA
From 25-JUL-13 15:30:00 to 25-JUL-13 15:40:00 (CST-6)
Location: CRYSTAL LAKE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:00:00 to 25-JUL-13 17:00:00 (CST-6)
Location: POCAHONTAS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: NWS Employee

Hail in POCAHONTAS, IOWA
From 25-JUL-13 16:43:00 to 25-JUL-13 16:43:00 (CST-6)
Location: VARINA
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 10.00K
Reported by: Public

Heavy Rain in BUTLER, IOWA
From 25-JUL-13 23:00:00 to 25-JUL-13 23:00:00 (CST-6)
Location: APLINGTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall total of 3.1 inches in the past several hours.

Hail in POCAHONTAS, IOWA
From 25-JUL-13 16:45:00 to 25-JUL-13 16:55:00 (CST-6)
Location: WESTVIEW
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Heavy Rain in BUTLER, IOWA
From 25-JUL-13 18:20:00 to 25-JUL-13 20:20:00 (CST-6)
Location: PARKERSBURG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall total of 2.5 inches in the past several hours.

Hail in HANCOCK, IOWA
From 25-JUL-13 15:40:00 to 25-JUL-13 15:40:00 (CST-6)
Location: CRYSTAL LAKE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 25-JUL-13 15:50:00 to 25-JUL-13 15:50:00 (CST-6)
Location: HAYFIELD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 25-JUL-13 15:42:00 to 25-JUL-13 15:42:00 (CST-6)
Location: CRYSTAL LAKE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 10.00K
Reported by: Emergency Manager

Penny size hail covering the road.

Hail in HANCOCK, IOWA
From 25-JUL-13 16:23:00 to 25-JUL-13 16:23:00 (CST-6)
Location: GARNER MUNI ARPT
Magnitude: 1.00 
Property damage: 2.00K
Crop damage: 10.00K
Reported by: Trained Spotter

Hail in HANCOCK, IOWA
From 25-JUL-13 15:39:00 to 25-JUL-13 15:54:00 (CST-6)
Location: HAYFIELD
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 25.00K
Reported by: Public

Hail fell for 15 minutes in Hayfield.

Hail in HANCOCK, IOWA
From 25-JUL-13 16:25:00 to 25-JUL-13 16:25:00 (CST-6)
Location: GARNER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Public

Hail in POCAHONTAS, IOWA
From 25-JUL-13 16:42:00 to 25-JUL-13 16:42:00 (CST-6)
Location: VARINA
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:05:00 to 25-JUL-13 17:05:00 (CST-6)
Location: POCAHONTAS MUNI ARPT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: Trained Spotter

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:00:00 to 25-JUL-13 17:10:00 (CST-6)
Location: POCAHONTAS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:04:00 to 25-JUL-13 17:04:00 (CST-6)
Location: WESTVIEW
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 5.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:02:00 to 25-JUL-13 17:02:00 (CST-6)
Location: WESTVIEW
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 10.00K
Reported by: SHAVE Project

Hail in POCAHONTAS, IOWA
From 25-JUL-13 17:03:00 to 25-JUL-13 17:03:00 (CST-6)
Location: WARE
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 15.00K
Reported by: SHAVE Project