On the evening of July 9th, intense thunderstorms developed rapidly along a warm front draped from northwest to southeast across the area. There were two rounds of thunderstorms, the first being discrete, rotating storms called supercells. These supercell thunderstorms dropped large hail across portions of western Illinois (Mt. Sterling area) and also across the western St. Louis metro area. Hail in excess of 2 inches was noted in both of these supercells. Over time, the storms congealed into a large complex of thunderstorms known as a mesoscale convective complex (MCC). This line of storms contained damaging, sometimes destructive winds as they quickly pushed southeast across east-central Missouri into southwest Illinois. The worst damage was noted from Rensselaer, MO southward to Perry, MO, where straight-line winds of 90 mph were found. This same line of storms also affected the St. Louis metro area, bringing widespread 60-70 mph winds across the metro causing many large tree limbs to fall and many to be without power.

Thunderstorm Wind in ST. LOUIS (C), MISSOURI
From 09-JUL-21 23:51:00 to 09-JUL-21 23:54:00 (CST-6)
Location: ST LOUIS
Magnitude: 65.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Damaging winds were reported in an area from I-70 and Kingshighway Blvd. southeast into the heart of the city. At the intersection of Pine Street and N. 17th Street, the steeple on the Centenary United Methodist Church collapsed to the roadway below. Also, in a park area near 14th and Pine Street, a large healthy tree was blown over.

Thunderstorm Wind in WASHINGTON, MISSOURI
From 10-JUL-21 00:30:00 to 10-JUL-21 00:30:00 (CST-6)
Location: OLD MINES
Magnitude: 56.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Public

Several large tree branches were blown down.

Hail in LEWIS, MISSOURI
From 09-JUL-21 19:45:00 to 09-JUL-21 19:45:00 (CST-6)
Location: MAYWOOD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in ST. LOUIS, MISSOURI
From 09-JUL-21 20:10:00 to 09-JUL-21 20:47:00 (CST-6)
Location: HAZELWOOD
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A wide swath of large hail, up to two inches in diameter, fell across portions of St. Louis County including Bridgeton, St. Ann, Overland, Maryland Heights, Creve Coeur, and Brentwood.

Thunderstorm Wind in MADISON, MISSOURI
From 10-JUL-21 01:22:00 to 10-JUL-21 01:32:00 (CST-6)
Location: FREDERICKTOWN
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds blew down several large trees on the southeast side of Fredericktown to about 3 miles southeast of Fredericktown.

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 09-JUL-21 20:27:00 to 09-JUL-21 20:27:00 (CST-6)
Location: BRIDGETON TERRACE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in LINCOLN, MISSOURI
From 09-JUL-21 22:40:00 to 09-JUL-21 22:46:00 (CST-6)
Location: HAWK PT
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A swath of wind damage extended from Hawk Point to Troy. Numerous trees, tree limbs and power lines were blown down. Just southwest of Troy along Highway J, a tree was blown over onto a house causing moderate damage.

Thunderstorm Wind in WARREN, MISSOURI
From 09-JUL-21 22:42:00 to 09-JUL-21 22:52:00 (CST-6)
Location: WARRENTON O SLLVN AR
Magnitude: 61.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A swath of wind damage across portions of Warren County. Several manufactured homes sustained minor damage to underpinning, tie downs and supports, about 3 miles north northeast of Warrenton. In Warrenton, a large sign near a shopping center was damaged. Several trees were blown down in and around Warrenton, one of which was about 3 feet in diameter. Just southwest of Wright City, a tree was topped and a small shed was moved several feet.

Hail in ST. CHARLES, MISSOURI
From 09-JUL-21 22:43:00 to 09-JUL-21 22:43:00 (CST-6)
Location: JOSEPHVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in ST. CHARLES, MISSOURI
From 09-JUL-21 23:20:00 to 09-JUL-21 23:20:00 (CST-6)
Location: ORCHARD FARM
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in ST. CHARLES, MISSOURI
From 09-JUL-21 23:03:00 to 09-JUL-21 23:27:00 (CST-6)
Location: WENTZVILLE
Magnitude: 62.00 MG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Damaging thunderstorm winds moved from north to south across the western portions of St. Charles County. At the intersection of Highway T and Highway D, several power poles were snapped off. A large tree was blown down near the intersection of Lake St. Louis Boulevard and Locksley Manor Drive. A tree and power lines were knocked down near the intersection of Sonderen Street and E. Elm Street. Also, a large tree was blown down on to Highway 94 just northeast of Defiance.

Thunderstorm Wind in FRANKLIN, MISSOURI
From 09-JUL-21 23:25:00 to 09-JUL-21 23:36:00 (CST-6)
Location: LABADIE
Magnitude: 61.00 EG
Property damage: 7.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down numerous large tree limbs in Labadie. In Gray Summit, two trees were blown over onto structures near Highway 100, causing moderate damage.

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 09-JUL-21 23:30:00 to 09-JUL-21 23:30:00 (CST-6)
Location: GUMBO
Magnitude: 70.00 EG
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm winds blew down a steel highway sign at the intersection of I-64 and Boones Crossing.

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 09-JUL-21 23:30:00 to 09-JUL-21 23:44:00 (CST-6)
Location: ST ANN
Magnitude: 61.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: ASOS

A swath of damaging winds extended from about 2 miles north northwest of St. Ann to Richmond Heights.  A large tree was blown down on Dorsett Road west of Lindbergh Boulevard. Several large trees were blown down along Baltimore Avenue near Ronald Drive in St. Ann. Numerous large tree limbs and power lines were blown down in St. Ann, St. John, Vinita Park, and Richmond Heights.

Thunderstorm Wind in JEFFERSON, MISSOURI
From 09-JUL-21 23:50:00 to 09-JUL-21 23:50:00 (CST-6)
Location: PARKDALE
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several large trees were blown down just northwest of Parkdale.

Thunderstorm Wind in CALLAWAY, MISSOURI
From 09-JUL-21 22:45:00 to 09-JUL-21 23:00:00 (CST-6)
Location: TOLEDO
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds blew down several large tree limbs onto Highway O near intersection with County Road 111. Also, in Mokane a large maple tree was blown over onto a home causing moderate roof damage.

Thunderstorm Wind in AUDRAIN, MISSOURI
From 09-JUL-21 21:36:00 to 09-JUL-21 22:05:00 (CST-6)
Location: LADDONIA
Magnitude: 61.00 EG
Property damage: 12.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Widespread wind damage between Laddonia, Rush Hill and Mexico. One tree was blown down onto Route KK just west of Highway 19. Another tree was blown down onto Route B at 6th Street in Rush Hill. A two foot diameter tree was blown over onto Central Street in Mexico. Also, numerous tree limbs, power lines and power poles were blown over.

Thunderstorm Wind in MONROE, MISSOURI
From 09-JUL-21 21:01:00 to 09-JUL-21 21:45:00 (CST-6)
Location: MONROE CITY
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm winds blew down numerous trees, tree limbs and power lines around the county, especially between Monroe City and Paris. Also, several power poles were blown down along Highway W.

Thunderstorm Wind in MARION, MISSOURI
From 09-JUL-21 20:23:00 to 09-JUL-21 20:47:00 (CST-6)
Location: PALMYRA
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Widespread wind damage across the central sections of Marion County. Numerous trees, tree limbs and power lines were blown down. Some of the debris landed on roads blocking them.

Thunderstorm Wind in LEWIS, MISSOURI
From 09-JUL-21 20:20:00 to 09-JUL-21 20:30:00 (CST-6)
Location: EWING
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm winds blew down numerous tree limbs around town.

Thunderstorm Wind in RALLS, MISSOURI
From 09-JUL-21 20:47:00 to 09-JUL-21 21:30:00 (CST-6)
Location: RENSSELAER
Magnitude: 78.00 EG
Property damage: 1.30M
Crop damage: 0.00K
Reported by: NWS Storm Survey

An NWS storm survey discovered a macroburst that first initiated to the north of Rensselaer, MO. This macroburst caused extensive tree damage in town, especially on the western side of Rensselaer where several large branches and trees were snapped or uprooted and a few roofs sustained damage. Winds in this area were determined to be around 80 mph. The large swath of damaging winds then pushed south towards Mark Twain State Park. Extensive tree damage was noted in the state park. In addition, the Blackjack Marina sustained quite a bit damage from straight line winds around 80 mph. These winds were strong enough to cause damage to several boats, damage to the metal roofing of the marina, and the winds were even able to pull part of the marina off its mooring. The dollar amount damage to the marina is estimated to be around a million dollars.  The worst of the damage occurred to the south of the marina in the town of Perry, MO. Extensive tree damage was noted in this area along with some damage to roofs and siding to a number of residences. The degree of tree and structural damage was consistent with fairly widespread 80 mph winds across town, with localized areas of 90 mph present in some of the observed damage. Straight line wind damage continued to the south of Perry, but it became less intense and more scattered in nature south of town. No deaths or injuries were reported.