A frontal system over the area brought two rounds of showers and thunderstorms to the mid Mississippi Valley on June 18. The first was during the midday to early afternoon hours, quickly followed by the second round in the late afternoon and evening. While there were scattered reports of hail, heavy rain and damaging winds were reported across much of the area. As a result of the torrential rains, flash flooding was rather widespread.  Rainfall totals through mid evening were widely varied; ranging from a couple tenths of an inch to well over 2 inches in some locations. A few lightning strikes also caused some damage. Afternoon highs were mainly in the 80s, with a few low 90s south of highway 34.

Thunderstorm Wind in JO DAVIESS, ILLINOIS
From 18-JUN-10 12:55:00 to 18-JUN-10 12:55:00 (CST-6)
Location: GALENA
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: COOP Observer

Wind gusts estimated to be 70 mph blew a tree down onto a house in Galena, IL at 155 pm June 18.  The local utility company also reported several outages due to trees on power lines and trees down in the right-of-way.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 12:55:00 to 18-JUN-10 12:55:00 (CST-6)
Location: USTICK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 60 mph were observed about 2 miles west of Ustick, IL at 155 pm June 18.  Some small branches were blown down in the area.

Thunderstorm Wind in CARROLL, ILLINOIS
From 18-JUN-10 13:00:00 to 18-JUN-10 13:00:00 (CST-6)
Location: THOMSON
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Newspaper

Wind gusts estimated to be 70 mph blew trees and power lines down in Thomson, IL around 100 pm CST June 18.  Some power outages were also observed.  A large  tree fell onto a camping trailer at Thomson Causeway.

Thunderstorm Wind in CARROLL, ILLINOIS
From 18-JUN-10 13:05:00 to 18-JUN-10 13:05:00 (CST-6)
Location: MT CARROLL
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 65 mph were observed in Mount Carroll, IL at 205 pm June 18.

Thunderstorm Wind in JO DAVIESS, ILLINOIS
From 18-JUN-10 13:05:00 to 18-JUN-10 13:05:00 (CST-6)
Location: SCALES MOUND
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Wind gusts estimated to be 70 mph blew a roof off a house in Scales Mound, IL around 205 pm June 18.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 18-JUN-10 13:10:00 to 18-JUN-10 13:10:00 (CST-6)
Location: KENT
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Wind gusts measured to be 60 mph were observed near Kent, IL at 210 pm June 18.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 18-JUN-10 13:55:00 to 18-JUN-10 13:55:00 (CST-6)
Location: FREEPORT
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Newspaper

Trees and power lines were downed by severe thunderstorm wind.

Thunderstorm Wind in PUTNAM, ILLINOIS
From 18-JUN-10 14:37:00 to 18-JUN-10 14:37:00 (CST-6)
Location: GRANVILLE
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Wind gusts estimated to be 65 mph blew down some power lines in the Granville, IL area at 337 pm June 18.  Heavy rain and lightning was also reported.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 18:30:00 to 18-JUN-10 18:30:00 (CST-6)
Location: FULTON
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 65 mph blew down some large tree limbs about 4 miles east northeast of Clinton, IA in Whiteside County Illinois around 730 pm June 18.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 18-JUN-10 18:38:00 to 18-JUN-10 18:38:00 (CST-6)
Location: MOLINE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts measured to be 60 mph were observed in Moline, IL at 738 pm June 18.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 18-JUN-10 18:49:00 to 18-JUN-10 18:49:00 (CST-6)
Location: RAPIDS CITY
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 60 to 70 mph were observed 6 miles northeast of East Moline, IL at 749 pm June 18.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 18:52:00 to 18-JUN-10 18:52:00 (CST-6)
Location: ALBANY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 60 mph were observed 2 miles south of Albany, IL at 752 pm June 18.

Thunderstorm Wind in WARREN, ILLINOIS
From 18-JUN-10 19:35:00 to 18-JUN-10 19:35:00 (CST-6)
Location: LITTLE YORK
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 70 mph were observed in Little York, IL at 839 pm June 18.  Some large trees were bending over.

Flash Flood in MERCER, ILLINOIS
From 18-JUN-10 19:49:00 to 18-JUN-10 22:00:00 (CST-6)
Location: ALEDO
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy rains resulted in flash flooding in Aledo, IL during the evening of June 18.  Several streets were flooded and Highway 17 had water covering it.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 19:49:00 to 18-JUN-10 19:49:00 (CST-6)
Location: ROCK FALLS
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 65 mph blew down several tree limbs in Rock Falls, IL at 849 pm June 18.  A power outage was observed in half of the town.

Hail in HENRY, ILLINOIS
From 18-JUN-10 19:55:00 to 18-JUN-10 19:55:00 (CST-6)
Location: GALVA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Quarter-sized hail fell on the north side of Galva, IL at 855 pm June 18.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:30:00 to 18-JUN-10 13:30:00 (CST-6)
Location: ROCK FALLS
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 60 mph blew down a 4 to 5 inch diameter tree limb onto a gas station in Rock Falls, IL at 230 pm June 18.  Widespread tree debris was observed in the area.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 18-JUN-10 12:45:00 to 18-JUN-10 12:45:00 (CST-6)
Location: PORT BYRON
Magnitude: 75.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Newspaper

A roof was torn from a building and tossed onto nearby power poles, causing one of the poles to fall and smash the attached transformers into a passing van and setting the van on fire.  The occupants of the van escaped without major injury.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:18:00 to 18-JUN-10 13:18:00 (CST-6)
Location: STERLING
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Wind gusts estimated to be 70 mph blew down 10 large trees at Emerald Hill Golf Course about 4 miles east northeast of Sterling, IL around 118 pm CST June 18.  This report was relayed by a Rockford area television station.

Lightning in ROCK ISLAND, ILLINOIS
From 18-JUN-10 13:00:00 to 18-JUN-10 13:00:00 (CST-6)
Location: HAMPTON
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Newspaper

Lightning struck a house, setting fire to the attic.  Time is estimated.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:39:00 to 18-JUN-10 13:39:00 (CST-6)
Location: STERLING
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated to be 60 mph blew down some large tree limbs in Sterling, IL at 239 pm June 18.

Thunderstorm Wind in STEPHENSON, ILLINOIS
From 18-JUN-10 13:30:00 to 18-JUN-10 13:30:00 (CST-6)
Location: PEARL CITY
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Wind gusts estimated to be 70 mph blew down several trees and wires in Pearl City, IL around 230 pm June 18.  This report was relayed by emergency management.

Thunderstorm Wind in HENRY, ILLINOIS
From 18-JUN-10 13:00:00 to 18-JUN-10 13:00:00 (CST-6)
Location: GENESEO
Magnitude: 70.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Newspaper

Severe thunderstorm winds downed several trees, flipped over a rooftop air conditioner unit on city hall, and blew in a plate glass window.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:30:00 to 18-JUN-10 13:30:00 (CST-6)
Location: ROCK FALLS
Magnitude: 65.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Newspaper

Wind gusts estimated to be near 70 mph blew the roof off of a mobile home on Harbor Drive.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:18:00 to 18-JUN-10 13:18:00 (CST-6)
Location: YEOWARD ADDITION
Magnitude: 65.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Newspaper

Severe thunderstorm winds blew a semi trailer carrying pretzels onto its side on westbound Interstate 88. Both the driver and passenger suffered minor injuries.

Thunderstorm Wind in WHITESIDE, ILLINOIS
From 18-JUN-10 13:15:00 to 18-JUN-10 13:15:00 (CST-6)
Location: ROCK FALLS
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Newspaper

One-third of the roof was torn off a steel warehouse at a trucking company.

Thunderstorm Wind in ROCK ISLAND, ILLINOIS
From 18-JUN-10 12:45:00 to 18-JUN-10 12:45:00 (CST-6)
Location: ILLINIWEK PARK
Magnitude: 70.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Newspaper

Several vehicles at a campground suffered damage from falling tree limbs.

Thunderstorm Wind in CARROLL, ILLINOIS
From 18-JUN-10 13:00:00 to 18-JUN-10 13:00:00 (CST-6)
Location: MILLEDGEVILLE
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Newspaper

Wind gusts downed tree limbs in Milledgeville.

Thunderstorm Wind in CARROLL, ILLINOIS
From 18-JUN-10 13:00:00 to 18-JUN-10 13:00:00 (CST-6)
Location: LANARK
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Newspaper

Wind gusts downed tree limbs in Lanark.