An extremely humid and unstable air mass on Saturday July 23 set the stage for strong to severe storms to develop mid to late afternoon along the I-90 corridor in far northern Illinois.  These storms ended up shifting very slowly southeast, bringing flash flooding to parts of Belvidere and Rockford, as well as near the Lake and Cook Counties border.  Severe winds with gusts around 60 mph were scattered within this area.  Another potent round of storms developed across northeast Iowa and moved eastward into northern Illinois around sunset.  These brought isolated severe winds in north central Illinois as well as additional heavy rainfall.

Flash Flood in COOK, ILLINOIS
From 23-JUL-16 16:40:00 to 23-JUL-16 22:45:00 (CST-6)
Location: KENILWORTH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Numerous stranded cars at the viaduct at Wilson St and Winnetka Rd.

Thunderstorm Wind in BOONE, ILLINOIS
From 23-JUL-16 15:58:00 to 23-JUL-16 15:58:00 (CST-6)
Location: BELVIDERE
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous large branches downed in the city.  Radar estimated time.

Hail in WINNEBAGO, ILLINOIS
From 23-JUL-16 16:32:00 to 23-JUL-16 16:32:00 (CST-6)
Location: CHERRY VLY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

There were also reports of 55 to 60 mph winds and very heavy rainfall with visibilities around 200 feet.

Thunderstorm Wind in COOK, ILLINOIS
From 23-JUL-16 17:42:00 to 23-JUL-16 17:42:00 (CST-6)
Location: EVANSTON
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A few large limbs downed.  Radar estimated time.

Thunderstorm Wind in COOK, ILLINOIS
From 23-JUL-16 17:42:00 to 23-JUL-16 17:42:00 (CST-6)
Location: EVANSTON
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A few large limbs downed.  Radar estimated time.

Thunderstorm Wind in KANE, ILLINOIS
From 23-JUL-16 18:08:00 to 23-JUL-16 18:08:00 (CST-6)
Location: ELGIN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Branches down Rt. 25 and Sunset Park Dr.

Flash Flood in BOONE, ILLINOIS
From 23-JUL-16 15:57:00 to 23-JUL-16 22:00:00 (CST-6)
Location: BELVIDERE
Flood cause: Heavy Rain
Property damage: 24.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple roads flooded and closed on the south side of town.  Belvidere Police Department had to replace a police car damaged by flood waters.

Thunderstorm Wind in OGLE, ILLINOIS
From 23-JUL-16 18:58:00 to 23-JUL-16 18:58:00 (CST-6)
Location: POLO
Magnitude: 55.00 EG
Crop damage: 0.00K
Reported by: COOP Observer

Old shed knocked down, with a portion of an old barn damaged and branches downed.  Radar estimated time.

Thunderstorm Wind in LEE, ILLINOIS
From 23-JUL-16 19:08:00 to 23-JUL-16 19:08:00 (CST-6)
Location: DIXON
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple power lines down in the town of Dixon.  Time estimated from radar.

Thunderstorm Wind in LEE, ILLINOIS
From 23-JUL-16 20:13:00 to 23-JUL-16 20:13:00 (CST-6)
Location: SCARBORO
Magnitude: 55.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy rain and continuous lightning.

Thunderstorm Wind in GRUNDY, ILLINOIS
From 23-JUL-16 21:39:00 to 23-JUL-16 21:39:00 (CST-6)
Location: MORRIS
Magnitude: 57.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Couple trees downed.  Numerous large branches downed.  Outbuilding damaged.  Radar estimated time.

Flash Flood in COOK, ILLINOIS
From 23-JUL-16 16:40:00 to 23-JUL-16 22:45:00 (CST-6)
Location: NORTHFIELD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Traffic standstill on Interstate 94 at Winnetka Rd.  Flooded roads have forced people onto roofs of cars.

Thunderstorm Wind in MCHENRY, ILLINOIS
From 23-JUL-16 16:15:00 to 23-JUL-16 16:15:00 (CST-6)
Location: MARENGO
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large tree blown down.  Time estimated by radar.

Thunderstorm Wind in COOK, ILLINOIS
From 23-JUL-16 17:15:00 to 23-JUL-16 17:28:00 (CST-6)
Location: EVANSTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several 6 inch diameter branches down in Evanston.  In Wilmette, IL lightning struck and downed a 30 ft long branch which took down power lines with an estimated 200 homes without power.  Winds estimated at 60 mph on Dempster St just west of Skokie Blvd in Skokie, IL.

Flash Flood in WINNEBAGO, ILLINOIS
From 23-JUL-16 15:57:00 to 23-JUL-16 22:00:00 (CST-6)
Location: PERRYVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Roads flooded with multiple vehicles stranded and flooded along Interstate 39 and Rt. 20.  A lane of traffic on Interstate 39 was closed near the Magic Waters water park in Cherry Valley.

Flash Flood in LAKE, ILLINOIS
From 23-JUL-16 16:05:00 to 23-JUL-16 22:45:00 (CST-6)
Location: FT SHERIDAN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Car stranded in two and a half feet of water at Green Bay and Burchell Ave.