A strong cold front moved across the state during the afternoon and overnight hours of the 21st into the 22nd.  The front stalled by the late evening hours over the southeast part of the state as a strong short wave lifted northeast out of the central Rockies.  Instability was limited as the cold air had moved into the western two thirds of the state.  Thunderstorms developed rapidly on the mid level cold front as the short wave lifted out.  The event was an elevated thunderstorm event with the instability above 800 mb.  MUCAPE in that area was around 1000 J/kg.  The freezing level was fairly low, in the 10,000 to 12,000 foot range, allowing for the easy production of hail.  That was combined with the fact that surface temperatures had fallen into the upper 40s to mid 50s.  Thunderstorms fired up in a line over southwest Iowa around midnight.  Most of the storms produced hail and heavy rain.  Several of the stronger storms produced hail of three quarters of an inch to one inch in diameter.  The storms produced copious amounts of hail with the hail lasting anywhere from 5 to 15 minutes at any one location with several reports of the ground being nearly covered.  Hail accumulated on Interstate 235 on the west side of the Des Moines Metro area to the point that cars had to pull off the road.

Hail in POWESHIEK, IOWA
From 22-APR-08 05:21:00 to 22-APR-08 05:21:00 (CST-6)
Location: MONTEZUMA
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Broadcast Media

KCCI TV reported hail up to nickel size covering a deck.

Hail in BOONE, IOWA
From 22-APR-08 02:07:00 to 22-APR-08 02:07:00 (CST-6)
Location: MACKEY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in TAYLOR, IOWA
From 22-APR-08 02:26:00 to 22-APR-08 02:26:00 (CST-6)
Location: BEDFORD
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in WARREN, IOWA
From 22-APR-08 03:40:00 to 22-APR-08 03:40:00 (CST-6)
Location: PROLE
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Dime to nickel size hail fell from 0330 to 0345 CST.

Hail in CASS, IOWA
From 22-APR-08 00:45:00 to 22-APR-08 00:45:00 (CST-6)
Location: LORAH
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report received via CoCoRaHS observation.

Hail in POLK, IOWA
From 22-APR-08 02:25:00 to 22-APR-08 02:25:00 (CST-6)
Location: CLOVER HILLS
Magnitude: 0.88 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Nickel size hail falling at I-235 and Valley West Drive was causing people to pull off the road.  Report was relayed from KCCI TV.

Hail in CASS, IOWA
From 22-APR-08 00:26:00 to 22-APR-08 00:26:00 (CST-6)
Location: ATLANTIC
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Penny to quarter size hail was reported falling heavily and accumulating.  Report was relayed by KJAN radio in Atlantic.

Hail in AUDUBON, IOWA
From 22-APR-08 00:35:00 to 22-APR-08 00:35:00 (CST-6)
Location: BRAYTON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Dime to penny size hail was covering the ground.

Hail in GUTHRIE, IOWA
From 22-APR-08 01:15:00 to 22-APR-08 01:15:00 (CST-6)
Location: GUTHRIE CENTER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in CASS, IOWA
From 22-APR-08 00:20:00 to 22-APR-08 00:20:00 (CST-6)
Location: ATLANTIC
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The Cass County Emergency Manager reported quarter size hail.

Hail in CASS, IOWA
From 22-APR-08 00:25:00 to 22-APR-08 00:25:00 (CST-6)
Location: LORAH
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail fell for several minutes and nearly covered the ground.

Hail in CASS, IOWA
From 22-APR-08 00:10:00 to 22-APR-08 00:10:00 (CST-6)
Location: LEWIS
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter reported nickel to quarter size hail in Lewis.