The seasons first organized severe weather event took place during the late afternoon and evening hours of the 24th.  Very warm and relatively moist air moved into the state on a gusty south wind.  Afternoon temperatures reached the mid 80s to around 90 with surface dew points in the upper 50s to mid 60s.  Precipitable water values were ample in the one to one and one half inch range.  The atmosphere became quite unstable with lifted indices falling to the -5 to -7 C. range and CAPE values around 2000 J/kg.  The freezing level was between 11,500 and 12,000 feet during the event with 25 to 35 kts of effective shear.  A cold front moved into Iowa during the morning of the 24th, and moved slowly southeast during the day.  There was a sharp contrast across the front, with temperatures in the 50s in its wake.  Thunderstorms erupted during the late afternoon along the front and developed southeast as the front moved in a scattered to broken line.  The line produced hail for the most part, with much of it between nickle size and one and one quarter inches in diameter.  One storm became stronger as it moved through Adair County and produced golf ball size hail southeast of Orient.  There was one severe wind gust with this event.  That occurred in Union County northeast of the Creston Airport, with a 60 MPH wind gust.  Additional thunderstorms formed during the late evening over northwest Iowa.  They were not severe, however they produced considerable lightning.  Lightning struck three houses in the town of Graettinger in Palo Alto County.  Minor damage was done to each of the homes as the lightning produced small fires.

Hail in FRANKLIN, IOWA
From 24-APR-09 17:19:00 to 24-APR-09 17:19:00 (CST-6)
Location: ALEXANDER
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GREENE, IOWA
From 24-APR-09 18:05:00 to 24-APR-09 18:05:00 (CST-6)
Location: GRAND JCT
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in FRANKLIN, IOWA
From 24-APR-09 18:11:00 to 24-APR-09 18:11:00 (CST-6)
Location: HANSELL
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in UNION, IOWA
From 24-APR-09 21:49:00 to 24-APR-09 21:49:00 (CST-6)
Location: CRESTON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Reported by a RWIS mesonet sensor.

Hail in FRANKLIN, IOWA
From 24-APR-09 18:00:00 to 24-APR-09 18:00:00 (CST-6)
Location: HANSELL
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Lightning in PALO ALTO, IOWA
From 24-APR-09 23:15:00 to 24-APR-09 23:15:00 (CST-6)
Location: GRAETTINGER
Property damage: 45.00K
Crop damage: 0.00K
Reported by: Newspaper

Hail in BUTLER, IOWA
From 24-APR-09 18:20:00 to 24-APR-09 18:20:00 (CST-6)
Location: AREDALE
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CERRO GORDO, IOWA
From 24-APR-09 17:03:00 to 24-APR-09 17:03:00 (CST-6)
Location: HANFORD
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail report near Rockwell and relayed by KIMT TV.

Hail in UNION, IOWA
From 24-APR-09 21:47:00 to 24-APR-09 21:47:00 (CST-6)
Location: AFTON
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in FRANKLIN, IOWA
From 24-APR-09 17:28:00 to 24-APR-09 17:28:00 (CST-6)
Location: ALEXANDER
Magnitude: 1.00 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Numerous reports of quarter size hail.

Hail in FRANKLIN, IOWA
From 24-APR-09 17:55:00 to 24-APR-09 17:55:00 (CST-6)
Location: HANSELL
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GUTHRIE, IOWA
From 24-APR-09 18:00:00 to 24-APR-09 18:00:00 (CST-6)
Location: NORTH BRANCH
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BUTLER, IOWA
From 24-APR-09 19:02:00 to 24-APR-09 19:02:00 (CST-6)
Location: CLARKSVILLE
Magnitude: 1.25 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Report received from a KIMT spotter.

Hail in WRIGHT, IOWA
From 24-APR-09 16:51:00 to 24-APR-09 16:51:00 (CST-6)
Location: OLAF
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel to quarter size hail reported.

Hail in GUTHRIE, IOWA
From 24-APR-09 17:40:00 to 24-APR-09 17:40:00 (CST-6)
Location: NORTH BRANCH
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ADAIR, IOWA
From 24-APR-09 20:03:00 to 24-APR-09 20:03:00 (CST-6)
Location: ORIENT
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BUTLER, IOWA
From 24-APR-09 18:23:00 to 24-APR-09 18:23:00 (CST-6)
Location: WILMAR
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nearly all precipitation was in the form of hail with little rainfall.

Hail in BUTLER, IOWA
From 24-APR-09 18:53:00 to 24-APR-09 18:53:00 (CST-6)
Location: ALLISON
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BUTLER, IOWA
From 24-APR-09 18:22:00 to 24-APR-09 18:22:00 (CST-6)
Location: AREDALE
Magnitude: 1.25 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail reportedly covered the ground completely.

Hail in ADAIR, IOWA
From 24-APR-09 19:39:00 to 24-APR-09 19:39:00 (CST-6)
Location: ORIENT
Magnitude: 1.00 
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ADAIR, IOWA
From 24-APR-09 20:06:00 to 24-APR-09 20:06:00 (CST-6)
Location: ORIENT
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ADAIR, IOWA
From 24-APR-09 19:20:00 to 24-APR-09 19:20:00 (CST-6)
Location: FONTANELLE
Magnitude: 1.25 
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail reported to be quarter to half dollar size.