Once again a very unstable airmass was in place over Iowa with a weak frontal boundary extending northeast to southwest across the state an old outflow boundary extending east to west along the southern Iowa border.  The atmosphere was weakly capped during the early evening with lifted indices around -10 C and CAPE values around 4000 J/kg.  During the evening the low level jet increased to around 40 kts and thunderstorms erupted in northwest Iowa.  They were enhanced by a fast moving jet streak moving across southern Minnesota.  The thunderstorms formed into a line rather quickly and dropped very heavy rainfall of up to 2 inches per hour and hail during the early stages of the MCS development.  There were numerous reports of hail of penny size up to golf ball size in western into north central Iowa.  After midnight, the line transitioned into a wind producer and began to move southeast.  High winds of 60 to 65 MPH were common as the storms move into central and north central Iowa.  Numerous reports were received of trees and power lines downed by the storms, however damage was not widespread.

Hail in SAC, IOWA
From 04-JUL-03 21:50:00 to 04-JUL-03 21:50:00 (CST)
Location: SAC CITY
Magnitude: 1.75 
Property damage: 5K
Crop damage: 10K
Reported by: UNKNOWN

Hail in CRAWFORD, IOWA
From 04-JUL-03 23:23:00 to 04-JUL-03 23:23:00 (CST)
Location: SCHLESWIG
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Hail in CRAWFORD, IOWA
From 04-JUL-03 23:30:00 to 04-JUL-03 23:30:00 (CST)
Location: KIRON
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: EMERGENCY MANAGER

Thunderstorm Wind in GRUNDY, IOWA
From 04-JUL-03 23:53:00 to 04-JUL-03 23:53:00 (CST)
Location: GRUNDY CENTER
Magnitude: 56 EG
Property damage: 5K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in STORY, IOWA
From 04-JUL-03 23:51:00 to 04-JUL-03 23:51:00 (CST)
Location: AMES
Magnitude: 52 EG
Property damage: 5K
Reported by: UNKNOWN

Thunderstorm Wind in BLACK HAWK, IOWA
From 05-JUL-03 00:10:00 to 05-JUL-03 00:10:00 (CST)
Location: WATERLOO
Magnitude: 50 MG
Property damage: 5K
Reported by: BROADCAST MEDIA

Hail in CALHOUN, IOWA
From 04-JUL-03 22:39:00 to 04-JUL-03 22:39:00 (CST)
Location: SOMERS
Magnitude: 0.75 
Crop damage: 5K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in GRUNDY, IOWA
From 05-JUL-03 01:16:00 to 05-JUL-03 01:16:00 (CST)
Location: GRUNDY CENTER
Magnitude: 50 EG
Property damage: 5K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in STORY, IOWA
From 04-JUL-03 23:31:00 to 04-JUL-03 23:36:00 (CST)
Location: AMES
Magnitude: 50 EG
Property damage: 5K
Reported by: AMATEUR RADIO

Hail in CRAWFORD, IOWA
From 04-JUL-03 23:48:00 to 04-JUL-03 23:48:00 (CST)
Location: DELOIT
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: EMERGENCY MANAGER

Hail in CALHOUN, IOWA
From 04-JUL-03 22:19:00 to 04-JUL-03 22:25:00 (CST)
Location: POMEROY
Magnitude: 0.75 
Crop damage: 5K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WRIGHT, IOWA
From 05-JUL-03 00:30:00 to 05-JUL-03 00:30:00 (CST)
Location: DOWS
Magnitude: 61 EG
Property damage: 5K
Reported by: NEWSPAPER

Thunderstorm Wind in STORY, IOWA
From 04-JUL-03 22:51:00 to 04-JUL-03 22:51:00 (CST)
Location: AMES
Magnitude: 50 EG
Property damage: 2K
Reported by: AMATEUR RADIO

Thunderstorm Wind in BUTLER, IOWA
From 05-JUL-03 02:00:00 to 05-JUL-03 02:00:00 (CST)
Location: PARKERSBURG
Magnitude: 61 EG
Property damage: 20K
Reported by: NEWSPAPER

Hail in CALHOUN, IOWA
From 04-JUL-03 22:10:00 to 04-JUL-03 22:10:00 (CST)
Location: POMEROY
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: UNKNOWN

Hail in SAC, IOWA
From 04-JUL-03 22:02:00 to 04-JUL-03 22:02:00 (CST)
Location: EARLY
Magnitude: 0.75 
Crop damage: 5K
Reported by: TRAINED SPOTTER

Hail in HUMBOLDT, IOWA
From 04-JUL-03 21:55:00 to 04-JUL-03 21:55:00 (CST)
Location: HUMBOLDT
Magnitude: 1.00 
Property damage: 5K
Crop damage: 2K
Reported by: BROADCAST MEDIA

Hail in CALHOUN, IOWA
From 04-JUL-03 22:15:00 to 04-JUL-03 22:15:00 (CST)
Location: ROCKWELL CITY
Magnitude: 1.75 
Property damage: 10K
Crop damage: 10K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in TAMA, IOWA
From 05-JUL-03 00:10:00 to 05-JUL-03 00:10:00 (CST)
Location: GARWIN
Magnitude: 50 EG
Property damage: 2K
Reported by: UNKNOWN

Thunderstorm Wind in BREMER, IOWA
From 05-JUL-03 00:10:00 to 05-JUL-03 00:10:00 (CST)
Location: JANESVILLE
Magnitude: 56 EG
Property damage: 5K
Reported by: UNKNOWN

Hail in WEBSTER, IOWA
From 04-JUL-03 23:15:00 to 04-JUL-03 23:15:00 (CST)
Location: DAYTON
Magnitude: 0.88 
Property damage: 2K
Crop damage: 5K
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in GRUNDY, IOWA
From 04-JUL-03 23:45:00 to 04-JUL-03 23:45:00 (CST)
Location: GRUNDY CENTER
Magnitude: 74 EG
Property damage: 30K
Crop damage: 10K
Reported by: NEWSPAPER

Thunderstorm Wind in CRAWFORD, IOWA
From 04-JUL-03 23:15:00 to 04-JUL-03 23:15:00 (CST)
Location: CHARTER OAK
Magnitude: 61 EG
Property damage: 5K
Reported by: NEWSPAPER

Thunderstorm Wind in CRAWFORD, IOWA
From 04-JUL-03 23:15:00 to 04-JUL-03 23:15:00 (CST)
Location: RICKETTS
Magnitude: 61 EG
Property damage: 5K
Reported by: NEWSPAPER