A rather strong upper level low pressure moved southeast across Iowa during the day on the 14th.  A cold pool aloft was associated with the upper low, creating an unstable environment.  Moisture was limited, but there was enough moisture for thunderstorms to develop.  The primary form of severe weather was in the form of hail as the freezing level was between 8500 and 9500 feet during peak heating.  Most of the hail was in the penny to one inch diameter range.  A few locations reported hail up to the size of golf balls.  Most of the thunderstorms produced gusty winds, however in most cases the wind was not severe.  Winds of 60 to 75 MPH were reported with one of the stronger storms in Wapello County.  The winds caused damage to a barn north of the Ottumwa area.  Numerous reports of cold air funnel clouds were received.  None touched the ground however.

Thunderstorm Wind in WAPELLO, IOWA
From 14-MAY-03 15:42:00 to 14-MAY-03 15:42:00 (CST)
Location: OTTUMWA
Magnitude: 59 EG
Property damage: 15K
Reported by: UNKNOWN

Hail in WINNEBAGO, IOWA
From 14-MAY-03 13:27:00 to 14-MAY-03 13:27:00 (CST)
Location: LAKE MILLS
Magnitude: 0.75 
Reported by: UNKNOWN

Hail in BUTLER, IOWA
From 14-MAY-03 15:13:00 to 14-MAY-03 15:13:00 (CST)
Location: NEW HARTFORD
Magnitude: 1.75 
Property damage: 10K
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:17:00 to 14-MAY-03 13:17:00 (CST)
Location: CLEAR LAKE
Magnitude: 0.75 
Reported by: UNKNOWN

Hail in BREMER, IOWA
From 14-MAY-03 16:14:00 to 14-MAY-03 16:14:00 (CST)
Location: READLYN
Magnitude: 0.88 
Property damage: 2K
Reported by: UNKNOWN

Hail in GRUNDY, IOWA
From 14-MAY-03 14:20:00 to 14-MAY-03 14:20:00 (CST)
Location: GRUNDY CENTER
Magnitude: 0.88 
Property damage: 2K
Reported by: TRAINED SPOTTER

Hail in MARSHALL, IOWA
From 14-MAY-03 13:44:00 to 14-MAY-03 13:44:00 (CST)
Location: MARSHALLTOWN
Magnitude: 1.00 
Property damage: 5K
Reported by: TRAINED SPOTTER

Hail in FRANKLIN, IOWA
From 14-MAY-03 13:48:00 to 14-MAY-03 13:48:00 (CST)
Location: HAMPTON
Magnitude: 1.00 
Property damage: 5K
Reported by: TRAINED SPOTTER

Hail in WINNEBAGO, IOWA
From 14-MAY-03 13:05:00 to 14-MAY-03 13:05:00 (CST)
Location: THOMPSON
Magnitude: 0.88 
Property damage: 2K
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:15:00 to 14-MAY-03 13:15:00 (CST)
Location: CLEAR LAKE
Magnitude: 0.88 
Property damage: 2K
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:07:00 to 14-MAY-03 13:07:00 (CST)
Location: MASON CITY
Magnitude: 0.88 
Property damage: 2K
Reported by: UNKNOWN

Hail in JASPER, IOWA
From 14-MAY-03 13:43:00 to 14-MAY-03 13:43:00 (CST)
Location: KELLOGG
Magnitude: 0.88 
Property damage: 3K
Reported by: UNKNOWN

Hail in WINNEBAGO, IOWA
From 14-MAY-03 12:36:00 to 14-MAY-03 12:36:00 (CST)
Location: THOMPSON
Magnitude: 1.00 
Property damage: 3K
Reported by: UNKNOWN

Hail in WINNEBAGO, IOWA
From 14-MAY-03 12:52:00 to 14-MAY-03 12:52:00 (CST)
Location: FOREST CITY
Magnitude: 1.75 
Property damage: 10K
Reported by: UNKNOWN

Hail in JASPER, IOWA
From 14-MAY-03 13:20:00 to 14-MAY-03 13:20:00 (CST)
Location: MINGO
Magnitude: 1.75 
Property damage: 20K
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:42:00 to 14-MAY-03 13:42:00 (CST)
Location: CLEAR LAKE
Magnitude: 1.75 
Property damage: 10K
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:17:00 to 14-MAY-03 13:17:00 (CST)
Location: CLEAR LAKE
Magnitude: 0.75 
Reported by: UNKNOWN

Hail in CERRO GORDO, IOWA
From 14-MAY-03 13:18:00 to 14-MAY-03 13:18:00 (CST)
Location: CLEAR LAKE
Magnitude: 0.88 
Property damage: 2K
Reported by: LAW ENFORCEMENT