On the morning of July 13, a strong, individual thunderstorm developed over northwestern Illinois.  During the late morning and early afternoon hours, this storm tracked southeastward, strengthened and developed into a cluster of strong storms.  This storm cluster moved through Ogle, Lee, La Salle and Ford Counties.  The eastern and western extremes of the storm cluster also affected portions of Livingston and Iroquois Counties.  Lee and La Salle Counties were primarily hit with large hail, with up to 4 inch hail observed near Sublette.  However, there were isolated incidents of wind damage, primarily to trees and power lines.  By the time the storms got to Ford County, strong winds were the major concern.  Windspread wind damage was observed in and around Paxton.

Thunderstorm Wind in FORD, ILLINOIS
From 13-JUL-04 14:12:00 to 13-JUL-04 14:12:00 (CST)
Location: PAXTON
Magnitude: 70 EG
Property damage: 100K
Reported by: NWS STORM SURVEY

Widespread damage from the west side of Paxton where small and medium size tree limbs were down to about State Road 115, 4 miles west of Paxton.  Numerous large limbs were down, some large trees snapped ot uprooted.  Shed roofs and doors were torn off and barns collapsed.  A building was damaged at the airport west of town.  Damage extended several miles north and south of State Road 9, but the worst damage appeard to be along SR 9 between County Roads 1500 and 1700.

Thunderstorm Wind in LEE, ILLINOIS
From 13-JUL-04 11:35:00 to 13-JUL-04 11:45:00 (CST)
Location: AMBOY
Magnitude: 60 EG
Property damage: 20K
Reported by: EMERGENCY MANAGER

A roof was blown off the addition of a house and into a barn.  Many rows of corn were knocked down.  These events occurred at Bryer Knoll and Rocky Ford.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 13-JUL-04 12:10:00 to 13-JUL-04 12:10:00 (CST)
Location: PERU
Magnitude: 70 EG
Reported by: GENERAL PUBLIC

Wind gust estimated by co-op observer, knocking down trees.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 13-JUL-04 12:40:00 to 13-JUL-04 12:40:00 (CST)
Location: LEONORE
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

Large limbs torn off of trees by strong wind gusts.

Thunderstorm Wind in IROQUOIS, ILLINOIS
From 13-JUL-04 14:00:00 to 13-JUL-04 14:00:00 (CST)
Location: LODA
Magnitude: 55 EG
Reported by: NWS STORM SURVEY

Large limbs torn off of trees.

Hail in LA SALLE, ILLINOIS
From 13-JUL-04 11:44:00 to 13-JUL-04 12:05:00 (CST)
Location: MENDOTA
Magnitude: 1.75 
Reported by: TRAINED SPOTTER

Several reports of large hail, up to 1.75 inches were observed in Mendota by trained spotters.

Hail in LA SALLE, ILLINOIS
From 13-JUL-04 12:20:00 to 13-JUL-04 13:05:00 (CST)
Location: UTICA
Magnitude: 2.75 
Reported by: AMATEUR RADIO

A swath of hail cut across La Salle county from North Utica to 5 miles WSW of Kangley.The following reports were received:1.75 inch hail at North Utica0.75 inch hail at South Utica1.25 inch hail 2 miles east of Leonore0.75 inch hail at Leonore1.00 inch hail 3 miles SW of Grand Ridge2.00 inch hail 5 miles W of Streator at County Road 18.1.75 inch hail at Streator2.75 inch hail 5 miles WSW of Kangley

Hail in LEE, ILLINOIS
From 13-JUL-04 10:40:00 to 13-JUL-04 12:00:00 (CST)
Location: DIXON
Magnitude: 4.00 
Reported by: TRAINED SPOTTER

A swath of hail cut across Lee County, beginning at 6 miles south of Polo or 6 miles northwest of Dixon, through Dixon, Amboy, Sublette to 1 mile south of Sublette.  Large hail was observed throughout this path.  The following reports were received:4.00 inches in diameter, was observed by a Farm Service Agent 1 mile south of Sublette.  2.00 and 1.25 inch hail was observed in the town of Sublette.  1.00 inch hail in Amboy2.75 inch hail in Amboy by law enforcement0.88 inch hail 6 miles south of Polo0.75 inch hail in Dixon

Thunderstorm Wind in LEE, ILLINOIS
From 13-JUL-04 11:20:00 to 13-JUL-04 11:20:00 (CST)
Location: AMBOY
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

Wind gust was estimated by a trained spotter.

Hail in LIVINGSTON, ILLINOIS
From 13-JUL-04 13:20:00 to 13-JUL-04 13:25:00 (CST)
Location: MANVILLE
Magnitude: 2.00 
Reported by: GENERAL PUBLIC

a co-op observer located 1 mile south of Streator, or 5 miles northwest of Manville reported 2.00 inch hail.

Hail in LIVINGSTON, ILLINOIS
From 13-JUL-04 13:45:00 to 13-JUL-04 13:50:00 (CST)
Location: CHATSWORTH
Magnitude: 1.00 
Reported by: GENERAL PUBLIC

Hail in LIVINGSTON, ILLINOIS
From 13-JUL-04 13:09:00 to 13-JUL-04 13:14:00 (CST)
Location: MANVILLE
Magnitude: 1.75 
Reported by: LAW ENFORCEMENT

Hail in OGLE, ILLINOIS
From 13-JUL-04 10:37:00 to 13-JUL-04 11:42:00 (CST)
Location: POLO
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Hail in LIVINGSTON, ILLINOIS
From 13-JUL-04 13:50:00 to 13-JUL-04 13:55:00 (CST)
Location: FORREST
Magnitude: 1.00 
Reported by: AMATEUR RADIO

Thunderstorm Wind in LA SALLE, ILLINOIS
From 13-JUL-04 13:15:00 to 13-JUL-04 13:20:00 (CST)
Location: STREATOR
Magnitude: 60 EG
Reported by: TRAINED SPOTTER

Power lines were torn down and large limbs were torn off of trees.  Trees up to 12 inches in diameter were knocked down.

Hail in LA SALLE, ILLINOIS
From 13-JUL-04 12:54:00 to 13-JUL-04 12:59:00 (CST)
Location: OTTAWA
Magnitude: 1.25 
Reported by: TRAINED SPOTTER