A series of slow-moving lines and clusters of thunderstorms moved east-southeast across southern Illinois from the midday hours through the early evening hours. The storms produced flooding rains and isolated strong wind gusts. The storms intensified during peak afternoon heating within a region of unstable southwest flow ahead of a mid-level disturbance. The disturbance rotated eastward near St. Louis, Missouri just ahead of a cold front. The soil across southern Illinois was saturated from an early morning round of thunderstorms. Runoff from the afternoon storms caused very large rises on area creeks, mainly north of a line from Carbondale to Harrisburg. One fatality was associated with record flooding of Rayse Creek near Mount Vernon.

Flash Flood in HAMILTON, ILLINOIS
From 16-JUL-21 15:43:00 to 16-JUL-21 17:30:00 (CST-6)
Location: MC LEANSBORO
Flood cause: Heavy Rain
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Law enforcement rescued a woman whose suv was stranded in high water on Highway 14.

Flash Flood in FRANKLIN, ILLINOIS
From 16-JUL-21 12:15:00 to 16-JUL-21 13:20:00 (CST-6)
Location: BENTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Water was over the road on both the on and off ramps on Illinois Highway 14 near Interstate 57, extending into the town of Benton.

Flood in JACKSON, ILLINOIS
From 16-JUL-21 16:11:00 to 16-JUL-21 17:15:00 (CST-6)
Location: MURPHYSBORO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Street flooding occurred in Murphysboro, with about three inches of water flowing across streets in places. Rainfall of 2.25 inches was measured during the day.

Flash Flood in WABASH, ILLINOIS
From 16-JUL-21 14:00:00 to 16-JUL-21 19:00:00 (CST-6)
Location: MT CARMEL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash flooding was reported, with water over a lot of roadways in and around Mount Carmel. 1.38  inches of rainfall was measured in the first round of storms, followed by another round of storms later in the afternoon.

Flood in JACKSON, ILLINOIS
From 19-JUL-21 22:00:00 to 24-JUL-21 12:00:00 (CST-6)
Location: MT CARBON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Minor flooding occurred on the Big Muddy River. Some low-lying woods and fields near the river were flooded.

Thunderstorm Wind in FRANKLIN, ILLINOIS
From 16-JUL-21 12:10:00 to 16-JUL-21 12:10:00 (CST-6)
Location: BENTON
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A tree was downed just east of Benton. The tree fell onto a trailer.

Flood in JEFFERSON, ILLINOIS
From 16-JUL-21 14:15:00 to 17-JUL-21 06:00:00 (CST-6)
Location: MT VERNON
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Social Media

Several streets on the south side of Mt. Vernon had standing water over them. Record flooding occurred on Rayse Creek in southwest Jefferson County. A motorist drowned after driving into the creek flooding on a county road south of Woodlawn. The incident occurred during the early morning hours of the 17th following the heavy rain on the 16th. The vehicle and driver were swept away in the creek. Both were recovered a couple days later. The storm total rainfall southwest of Mount Vernon was 6.0 inches, both at Scheller and Marcoe.

Flash Flood in PERRY, ILLINOIS
From 16-JUL-21 14:24:00 to 16-JUL-21 17:10:00 (CST-6)
Location: DU QUOIN
Flood cause: Heavy Rain
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several streets in Du Quoin and elsewhere around the county were flooded. Emergency management reported several parts of U.S. Highway 51 in and north of Du Quoin were flooded with one to two feet of water, and cars were stalled out. Portions of Route 51 remained closed in and around Du Quoin into the early evening hours. Homes and businesses were surrounded by water. The 24-hour storm total rainfall at Tamaroa was reported to be 7.0 inches by a local television weather observer.