A strong spring storm system moved through the Mississippi valley during the late afternoon and evening hours producing widespread severe weather.  In an unprecedented move, WFO Quad Cities held a press conference the day before to warn of a high probability of significant tornadoes in the afternoon and evening hours of Saturday May 10th, with the area most at risk south of a Keosauqua, Iowa to Princeton, Illinois line.  Supercell thunderstorms developed and continued into the evening hours spawning several long track tornadoes and produced copious amounts of large hail.  Luckily, most of the tornado tracks were in open country and therefore damage was minimized.

Thunderstorm Wind in HENRY, IOWA
From 10-MAY-03 18:56:00 to 10-MAY-03 18:56:00 (CST)
Location: WINFIELD
Magnitude: 56 EG
Property damage: 500K
Reported by: TRAINED SPOTTER

Power lines down;home damaged

Thunderstorm Wind in HENRY, IOWA
From 10-MAY-03 19:00:00 to 10-MAY-03 19:00:00 (CST)
Location: MT UNION
Magnitude: 56 EG
Property damage: 100K
Reported by: AMATEUR RADIO

4 to 8 inch tree limbs down

Hail in BENTON, IOWA
From 10-MAY-03 16:50:00 to 10-MAY-03 16:50:00 (CST)
Location: URBANA
Magnitude: 1.75 
Property damage: 1M
Reported by: EMERGENCY MANAGER

Hail in IOWA, IOWA
From 10-MAY-03 16:53:00 to 10-MAY-03 16:53:00 (CST)
Location: WILLIAMSBURG
Magnitude: 2.75 
Property damage: 1M
Reported by: LAW ENFORCEMENT

Hail in BUCHANAN, IOWA
From 10-MAY-03 16:55:00 to 10-MAY-03 16:55:00 (CST)
Location: HAZLETON
Magnitude: 1.75 
Property damage: 1M
Reported by: EMERGENCY MANAGER

Trained spotter reported at same time

Hail in LEE, IOWA
From 10-MAY-03 17:20:00 to 10-MAY-03 17:20:00 (CST)
Location: ARGYLE
Magnitude: 2.00 
Property damage: 500K
Reported by: NEWSPAPER

Hail in LINN, IOWA
From 10-MAY-03 17:21:00 to 10-MAY-03 17:21:00 (CST)
Location: CEDAR RAPIDS
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Southeast side of city

Hail in JOHNSON, IOWA
From 10-MAY-03 17:11:00 to 10-MAY-03 17:11:00 (CST)
Location: SWISHER
Magnitude: 0.75 
Reported by: OFFICIAL NWS OBS.

Hail in JEFFERSON, IOWA
From 10-MAY-03 17:26:00 to 10-MAY-03 17:26:00 (CST)
Location: PACKWOOD
Magnitude: 1.75 
Property damage: 500K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in WASHINGTON, IOWA
From 10-MAY-03 17:30:00 to 10-MAY-03 17:30:00 (CST)
Location: BRIGHTON
Magnitude: 56 EG
Property damage: 100K
Reported by: OFFICIAL NWS OBS.

Hail in IOWA, IOWA
From 10-MAY-03 17:08:00 to 10-MAY-03 17:08:00 (CST)
Location: LADORA
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Hail in BUCHANAN, IOWA
From 10-MAY-03 16:33:00 to 10-MAY-03 16:33:00 (CST)
Location: BRANDON
Magnitude: 1.75 
Property damage: 1M
Reported by: EMERGENCY MANAGER

Hail in KEOKUK, IOWA
From 10-MAY-03 16:41:00 to 10-MAY-03 16:41:00 (CST)
Location: SOUTH ENGLISH
Magnitude: 1.00 
Property damage: 500K
Reported by: TRAINED SPOTTER

Hail in LINN, IOWA
From 10-MAY-03 17:21:00 to 10-MAY-03 17:21:00 (CST)
Location: CEDAR RAPIDS
Magnitude: 1.75 
Property damage: 2M
Reported by: TRAINED SPOTTER

Far west side of city

Heavy Rain in MUSCATINE, IOWA
From 10-MAY-03 19:17:00 to 10-MAY-03 19:35:00 (CST)
Location: MUSCATINE
Magnitude: 1 
Property damage: 50K
Reported by: AMATEUR RADIO

Water 2 inches deep on streets

Funnel Cloud in LOUISA, IOWA
From 10-MAY-03 19:25:00 to 10-MAY-03 19:29:00 (CST)
Location: TOOLESBORO
Reported by: TRAINED SPOTTER

Reached 2/3rds of the way down with no debris cloud observed

Hail in BENTON, IOWA
From 10-MAY-03 16:07:00 to 10-MAY-03 16:07:00 (CST)
Location: KEYSTONE
Magnitude: 1.75 
Property damage: 500K
Reported by: EMERGENCY MANAGER

Hail in BENTON, IOWA
From 10-MAY-03 16:20:00 to 10-MAY-03 16:20:00 (CST)
Location: GARRISON
Magnitude: 1.75 
Property damage: 500K
Reported by: EMERGENCY MANAGER

Hail in LINN, IOWA
From 10-MAY-03 17:12:00 to 10-MAY-03 17:12:00 (CST)
Location: FAIRFAX
Magnitude: 1.75 
Property damage: 3M
Reported by: EMERGENCY MANAGER

Heavy Rain in SCOTT, IOWA
From 10-MAY-03 19:50:00 to 10-MAY-03 20:16:00 (CST)
Location: DAVENPORT
Magnitude: 1 
Property damage: 50K
Reported by: AMATEUR RADIO

Street flooding

Heavy Rain in SCOTT, IOWA
From 10-MAY-03 19:50:00 to 10-MAY-03 20:16:00 (CST)
Location: BETTENDORF
Magnitude: 1 
Property damage: 50K
Reported by: AMATEUR RADIO

Street flooding

Hail in KEOKUK, IOWA
From 10-MAY-03 16:43:00 to 10-MAY-03 16:43:00 (CST)
Location: NORTH ENGLISH
Magnitude: 1.00 
Property damage: 500K
Reported by: OFFICIAL NWS OBS.

Hail in BUCHANAN, IOWA
From 10-MAY-03 16:45:00 to 10-MAY-03 16:45:00 (CST)
Location: INDEPENDENCE
Magnitude: 0.88 
Reported by: OFFICIAL NWS OBS.

Hail in BUCHANAN, IOWA
From 10-MAY-03 16:48:00 to 10-MAY-03 16:48:00 (CST)
Location: OTTERVILLE
Magnitude: 1.75 
Property damage: 1M
Reported by: EMERGENCY MANAGER

Funnel Cloud in BUCHANAN, IOWA
From 10-MAY-03 16:48:00 to 10-MAY-03 16:48:00 (CST)
Location: ROWLEY
Reported by: EMERGENCY MANAGER

Hail in BUCHANAN, IOWA
From 10-MAY-03 16:30:00 to 10-MAY-03 16:30:00 (CST)
Location: HAZLETON
Magnitude: 1.00 
Property damage: 100K
Reported by: TRAINED SPOTTER

Hail in IOWA, IOWA
From 10-MAY-03 16:43:00 to 10-MAY-03 16:43:00 (CST)
Location: NORTH ENGLISH
Magnitude: 1.00 
Property damage: 500K
Reported by: OFFICIAL NWS OBS.

Hail in DELAWARE, IOWA
From 10-MAY-03 17:26:00 to 10-MAY-03 17:26:00 (CST)
Location: MANCHESTER
Magnitude: 0.88 
Reported by: LAW ENFORCEMENT

Funnel Cloud in BENTON, IOWA
From 10-MAY-03 16:25:00 to 10-MAY-03 16:25:00 (CST)
Location: KEYSTONE
Reported by: EMERGENCY MANAGER