Multiple rounds of heavy rain producing storms moved across the region during the day and evening of June 15th, with an especially intense area of extreme rainfall rates during the mid-afternoon through early evening centered on the I-88 and I-290 corridors from the IL/IA state line through Chicago.  This rain resulted in widespread flash flooding, including the closure of a portion of I-290 (Eisenhower Expressway).  Across the metro area, there were reports and photos of cars stranded, though no injuries were reported to the NWS.  The heavy rainfall and widespread storm coverage resulted in the cancellation or delays of hundreds of commercial flights in and out of Chicago.  A downburst occurred in Mendota, Illinois with winds estimated to be around 80 mph resulting in mainly tree damage.  While the environment was not conducive for long-lived or powerful tornadoes, a tornado threat existed with a few supercells. This included two storms in central Cook County, primarily west of downtown Chicago. Each of these had funnel cloud reports.  There was also a tornado reported near the Will/Kanakakee County border, not far from I-57.  An EF-1 tornado was confirmed near Symerton Illinois.  The highest rainfall amounts reported were two and a half to five inches in parts of Cook, DuPage, Kane, and Will Counties, which include a large majority of Chicago and the metropolitan area.

Flash Flood in KANE, ILLINOIS
From 15-JUN-15 17:40:00 to 15-JUN-15 21:30:00 (CST-6)
Location: LOVEDALE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Approximately a foot and a half of flowing water was reported near Illinois Avenue and Constitution Drive.  A car was stranded in the high water.

Flash Flood in DU PAGE, ILLINOIS
From 15-JUN-15 17:15:00 to 15-JUN-15 21:30:00 (CST-6)
Location: WEST CHICAGO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Around three feet of standing water was reported on Ann Street west of Joliet Street near Community High School.

Flash Flood in COOK, ILLINOIS
From 15-JUN-15 16:23:00 to 15-JUN-15 21:30:00 (CST-6)
Location: SCHILLER PARK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Media reported that 25th Avenue between Belmont and Irving Park Road was flooded and closed.

Flood in OGLE, ILLINOIS
From 15-JUN-15 15:00:00 to 15-JUN-15 21:30:00 (CST-6)
Location: ROCHELLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Standing water one to two feet deep was reported near the intersection of Route 38 and Turkington Terrace.

Thunderstorm Wind in LA SALLE, ILLINOIS
From 15-JUN-15 16:18:00 to 15-JUN-15 16:18:00 (CST-6)
Location: MENDOTA
Magnitude: 70.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Employee

Severe winds blew down around half a dozen trees on the southwest side of Mendota.  One tree fell onto a home causing damage.  A few utility poles were also blown down.  Some homes had shingle damage.

Flash Flood in WILL, ILLINOIS
From 15-JUN-15 10:15:00 to 15-JUN-15 16:00:00 (CST-6)
Location: WILMINGTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Several roads were flooded and closed including Route 53 at Kankakee Street and Main Street, as well as Main Street and River Street.  An observer in nearby Manhattan measured 3.25 inches of rain.

Flash Flood in GRUNDY, ILLINOIS
From 15-JUN-15 09:45:00 to 15-JUN-15 15:30:00 (CST-6)
Location: MORRIS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several roads in Morris were flooded and closed.  Nearby in Coal City, 1.49 inches of rain was measured in 35 minutes.

Flash Flood in COOK, ILLINOIS
From 15-JUN-15 17:30:00 to 15-JUN-15 21:30:00 (CST-6)
Location: MAYWOOD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Both directions of I-290 were flooded and closed between Harlem Avenue and Desplaines Avenue.

Tornado in WILL, ILLINOIS
From 15-JUN-15 18:32:00 to 15-JUN-15 18:39:00 (CST-6)
Location: SYMERTON
Tornado F-scale: EF1
Property damage: 100.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado touched down approximately 1.4 miles east of Symerton snapping large tree limbs west of Warner Bridge Road.  The tornado moved east and downed trees and a power pole along Peotone-Wilmington Road just west of Gougar Road.  The tornado turned southeast and impacted a Kennel and an adjacent residence where EF-1 damage was noted due to roof and tree damage.  This included multiple snapped or uprooted trees.   The tornado moved toward Tully Road and flipped multiple 320 lb grain bins over a garage and into a field across Tully Road.  Damage was noted to metal outbuildings.  The tornado continued southeast and impacted two farmsteads near Kennedy and Cedar Roads  where EF-1 damage occurred to trees and a machine shed.  Metal siding and additional debris from the shed was thrown a half mile downstream where the tornado dissipated in a field.