A fast-moving complex of thunderstorms raced east-southeast from east central Missouri into southern Illinois. Clusters of thunderstorms organized into a squall line over southern Illinois, producing increasingly organized swaths of wind damage. The environment over southern Illinois was characterized by moderately strong instability, with most-unstable layer cape values from 2000 to 3000 j/kg. A strong 500 mb shortwave moved southeast from the upper Mississippi Valley into the western Great Lakes region, likely helping to initiate the storm complex over Missouri. Once it was initiated, the storm complex accompanied an elevated cold front at 850 mb, which was preceded by a southwest wind flow near 30 knots.

Thunderstorm Wind in JEFFERSON, ILLINOIS
From 23-JUL-17 03:33:00 to 23-JUL-17 03:33:00 (CST-6)
Location: DIX
Magnitude: 56.00 EG
Property damage: 6.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Power lines were down, and trees were damaged in the area.

Thunderstorm Wind in JEFFERSON, ILLINOIS
From 23-JUL-17 03:52:00 to 23-JUL-17 03:52:00 (CST-6)
Location: MT VERNON ARPT
Magnitude: 51.00 MG
Property damage: 6.00K
Crop damage: 0.00K
Reported by: Airplane Pilot

A peak wind gust of 59 mph was measured at the Mount Vernon airport on Route 15. There was minor damage to a plane. The 59 mph wind measurement was at a site separate from the automated weather observing system.

Thunderstorm Wind in EDWARDS, ILLINOIS
From 23-JUL-17 04:21:00 to 23-JUL-17 04:30:00 (CST-6)
Location: WEST SALEM
Magnitude: 70.00 EG
Property damage: 85.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Scattered straight-line wind damage was observed across much of the northern half of the county. Within the overall area of scattered damage, more concentrated damage was located in West Salem. In West Salem, numerous large tree limbs were broken, and a couple of trees were uprooted. Elsewhere around northern Edwards County, hundreds of tree limbs and about a half-dozen trees were blown down. Downed trees and limbs damaged a couple of homes, garages, and a pickup truck. Two barns were blown down between West Salem and Bone Gap. Several power poles were blown over.  Peak winds were estimated near 80 mph. The damaging wind event continued east into Wabash County.

Thunderstorm Wind in WABASH, ILLINOIS
From 23-JUL-17 04:30:00 to 23-JUL-17 04:45:00 (CST-6)
Location: BELLMONT
Magnitude: 70.00 EG
Property damage: 80.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This damaging wind event continued east from Edwards County into Wabash County. Scattered straight-line wind damage was observed across much of central Wabash County from Mount Carmel west. Within the overall area of scattered damage, more concentrated damage was located in Bellmont. Hundreds of tree limbs and about a half-dozen trees were blown down. Downed trees and limbs damaged a couple of homes, barns, and garages. Several power poles were blown over. The only damage in Mt. Carmel itself consisted of a few large limbs down on the western edge of the city. Peak winds were estimated near 80 mph.

Thunderstorm Wind in WAYNE, ILLINOIS
From 23-JUL-17 04:05:00 to 23-JUL-17 04:14:00 (CST-6)
Location: GEFF
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported the severe winds persisted for up to ten minutes.

Thunderstorm Wind in WHITE, ILLINOIS
From 23-JUL-17 04:35:00 to 23-JUL-17 04:35:00 (CST-6)
Location: CROSSVILLE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter measured a wind gust to 60 mph.