A line of severe thunderstorms moved across northern Illinois late in the evening of May 17th and overnight into the early morning of May 18th. There were numerous reports of damaging winds occurring with these thunderstorms along with a few reports of hail up to the size of golf balls. An EF-1 Tornado also occurred touching down approximately two miles south of Poplar Grove and dissipating approximately 3 miles northwest of Harvard.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 17-MAY-17 22:00:00 to 17-MAY-17 22:00:00 (CST-6)
Location: UTICA
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple large trees were blown down.

Thunderstorm Wind in DU PAGE, ILLINOIS
From 17-MAY-17 22:17:00 to 17-MAY-17 22:17:00 (CST-6)
Location: (DPA)DUPAGE CO ARPT
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in WILL, ILLINOIS
From 17-MAY-17 23:21:00 to 17-MAY-17 23:26:00 (CST-6)
Location: LOCKPORT LEWIS ARPT
Magnitude: 56.00 MG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Official NWS Observations

Winds gusted 60 to 64 mph at NWS Chicago.  A power pole was snapped on Renwick Road.

Thunderstorm Wind in COOK, ILLINOIS
From 17-MAY-17 23:33:00 to 17-MAY-17 23:33:00 (CST-6)
Location: LEMONT
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A large section of a tree was blown down.

Thunderstorm Wind in COOK, ILLINOIS
From 18-MAY-17 00:00:00 to 18-MAY-17 00:00:00 (CST-6)
Location: OAK LAWN
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A four inch diameter tree branch fell through a windshield and a six inch diameter branch fell onto a car.  Near 97th and Kenneth, a one foot diameter branch from a healthy maple tree was blown down.  Scattered tree limbs of varying sizes were blown down throughout town.

Thunderstorm Wind in KANE, ILLINOIS
From 17-MAY-17 22:10:00 to 17-MAY-17 22:10:00 (CST-6)
Location: NORTH AURORA
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A large tree was blown down in a backyard in North Aurora.

Thunderstorm Wind in OGLE, ILLINOIS
From 17-MAY-17 17:05:00 to 17-MAY-17 17:05:00 (CST-6)
Location: MT MORRIS
Magnitude: 60.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Sheet metal was stripped off of a farm building.  Trees six to twelve inches in diameter were blown down.

Thunderstorm Wind in OGLE, ILLINOIS
From 17-MAY-17 17:08:00 to 17-MAY-17 17:08:00 (CST-6)
Location: LEAF RIVER
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees that were approximately 12 inches in diameter were blown down.

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:10:00 to 17-MAY-17 17:10:00 (CST-6)
Location: RCKFRD COTTONWOOD AR
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A 65 mph wind gust was recorded at WTVO.

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:15:00 to 17-MAY-17 17:15:00 (CST-6)
Location: PECATONICA
Magnitude: 60.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous mature trees were snapped and uprooted.  Some of the trees were up to four feet in diameter.  Trees and limbs fell onto power lines.  Power poles were blown down. A 10 foot by 8 foot chicken coop was blown into a nearby field.

Thunderstorm Wind in KENDALL, ILLINOIS
From 17-MAY-17 23:05:00 to 17-MAY-17 23:05:00 (CST-6)
Location: PLATTVILLE
Magnitude: 62.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:17:00 to 17-MAY-17 17:22:00 (CST-6)
Location: WEST END
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:30:00 to 17-MAY-17 17:30:00 (CST-6)
Location: ROCKTON WGN WHEEL AR
Magnitude: 83.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A large outbuilding was destroyed and another suffered roof damage.  Numerous large branches were snapped and a couple large trees were blown down.

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:17:00 to 17-MAY-17 17:17:00 (CST-6)
Location: WEST END
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A tanker truck was blown off of US-20.

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:31:00 to 17-MAY-17 17:31:00 (CST-6)
Location: ROSCOE
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Multiple large trees were uprooted.

Thunderstorm Wind in LEE, ILLINOIS
From 17-MAY-17 20:52:00 to 17-MAY-17 20:52:00 (CST-6)
Location: SWISSVILLE
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Multiple trees and power lines were blown down.  A parked police car was pushed four to five feet by the wind.

Hail in WINNEBAGO, ILLINOIS
From 17-MAY-17 21:09:00 to 17-MAY-17 21:09:00 (CST-6)
Location: EAST ROCKFORD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in LEE, ILLINOIS
From 17-MAY-17 21:19:00 to 17-MAY-17 21:19:00 (CST-6)
Location: HENKEL
Magnitude: 78.00 EG
Crop damage: 0.00K
Reported by: NWS Storm Survey

Sporadic wind damage was noted over eastern Lee County.  Several wooden power poles were broken on route 52 northwest of Mendota.  Several hardwood trees were snapped on Route 251 near Cottage Hill Road.  An irrigation pivot was toppled in the same area.

Tornado in MCHENRY, ILLINOIS
From 17-MAY-17 21:31:00 to 17-MAY-17 21:34:00 (CST-6)
Location: CHEMUNG
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This is a continuation of a tornado that began in Boone County two miles south of Poplar Grove.  The tornado crossed into McHenry County south of Hunter Road.  Softwood trees were snapped on Hunter Road. Hardwood trees were snapped or sheared on White Oaks Road.

Tornado in BOONE, ILLINOIS
From 17-MAY-17 21:21:00 to 17-MAY-17 21:31:00 (CST-6)
Location: BELVIDERE ARPT
Tornado F-scale: EF1
Property damage: 100.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado touched down approximately two miles south of Poplar Grove.  Tree branches were broken on Poplar Grove Road where the tornado touched down. A large softwood tree trunk was snapped on Beaver Road.  Trees were debarked on Beaverton Road.  A small outbuilding was destroyed on Edson Road. Hardwood trees were snapped at the trunk on Russellville Road and again on Capron Road.  On the east side of Capron, A garage was destroyed and shingles were peeled off the north side of a home and dozens of trees were snapped. Another small outbuilding was destroyed on County Line Road with debris strewn about three quarters of a mile downstream.  The tornado passed into McHenry County on County Line Road south of Hunter Road.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 17-MAY-17 21:23:00 to 17-MAY-17 21:23:00 (CST-6)
Location: MENDOTA
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A few large trees were blown down in Mendota.

Thunderstorm Wind in MCHENRY, ILLINOIS
From 17-MAY-17 21:37:00 to 17-MAY-17 21:37:00 (CST-6)
Location: BIG FOOT
Magnitude: 74.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Straight line wind damage occurred in Big Foot Prairie.  A few large trees and large tree limbs were blown down.

Thunderstorm Wind in DE KALB, ILLINOIS
From 17-MAY-17 21:49:00 to 17-MAY-17 21:49:00 (CST-6)
Location: DE KALB
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Numerous four to six inch diameter branches were blown down blocking streets.  A 10-inch diameter tree branch was blown down at the intersection of 7th Street and Roosevelt Street.

Hail in BOONE, ILLINOIS
From 17-MAY-17 21:25:00 to 17-MAY-17 21:25:00 (CST-6)
Location: POPLAR GROVE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in DE KALB, ILLINOIS
From 17-MAY-17 21:52:00 to 17-MAY-17 21:52:00 (CST-6)
Location: HINCKLEY
Magnitude: 60.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Straight line winds caused isolated tree damage and destroyed a farm outbuilding.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 17-MAY-17 21:55:00 to 17-MAY-17 21:55:00 (CST-6)
Location: PERU
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in WINNEBAGO, ILLINOIS
From 17-MAY-17 17:30:00 to 17-MAY-17 17:30:00 (CST-6)
Location: LATHAM PARK
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Large trees 18 to 20 inches in diameter were uprooted.