A warm front across the region was the focus of thunderstorm development.  A mesoscale convective system developed during the evening of June 25th and moved east across the region.  There were numerous reports of large hail, damaging winds and flash flooding.

Thunderstorm Wind in ST. FRANCOIS, MISSOURI
From 25-JUN-11 22:05:00 to 25-JUN-11 22:05:00 (CST-6)
Location: BONNE TERRE
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. FRANCOIS, MISSOURI
From 25-JUN-11 22:05:00 to 25-JUN-11 22:05:00 (CST-6)
Location: BONNE TERRE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in GASCONADE, MISSOURI
From 25-JUN-11 22:17:00 to 25-JUN-11 22:17:00 (CST-6)
Location: TEA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. LOUIS, MISSOURI
From 25-JUN-11 22:15:00 to 25-JUN-11 22:15:00 (CST-6)
Location: ROBERTSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 25-JUN-11 22:20:00 to 25-JUN-11 22:20:00 (CST-6)
Location: FLORDELL HILLS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down a large tree branch, which knocked down a few power lines, then landed on a house causing minor roof damage.  This was near the intersection of Jennings Station Road and Hord Avenue.

Hail in ST. CHARLES, MISSOURI
From 26-JUN-11 00:02:00 to 26-JUN-11 00:02:00 (CST-6)
Location: COTTLEVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. CHARLES, MISSOURI
From 26-JUN-11 00:05:00 to 26-JUN-11 00:05:00 (CST-6)
Location: WELDON SPG
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 26-JUN-11 00:04:00 to 26-JUN-11 00:04:00 (CST-6)
Location: VIGUS
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Flash Flood in ST. CHARLES, MISSOURI
From 26-JUN-11 02:15:00 to 26-JUN-11 05:30:00 (CST-6)
Location: PERUQUE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Up to six inches of rain fell onto already saturated soils causing flash flooding.  Numerous roads were flooded including Highway N between Weiss Road and Dardenne Farms Drive.  Several locations in St. Charles had to be evacuated due to flash flooding.  Residents of an 80 unit apartment complex on Cole Boulevard were evacuated after basement and ground floor apartments flooded with more than 2 feet of water.  Also, houses on Hawthorn Avenue were evacuated as flood waters rose very quickly.

Flash Flood in LINCOLN, MISSOURI
From 26-JUN-11 03:00:00 to 26-JUN-11 05:30:00 (CST-6)
Location: MILLWOOD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Up to four inches of rain fell in a short amount of time onto already saturated soils causing flash flooding.  Numerous roads were flooded including Highways C and H, as well as Gravens Road and South Chantilly Road.

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 25-JUN-11 22:45:00 to 25-JUN-11 22:45:00 (CST-6)
Location: OAKLAND
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down several large tree limbs.

Thunderstorm Wind in ST. LOUIS, MISSOURI
From 25-JUN-11 22:50:00 to 25-JUN-11 22:50:00 (CST-6)
Location: SAPPINGTON
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down a two foot diameter tree near the intersection of Lindbergh Blvd. and Watson Road.

Hail in FRANKLIN, MISSOURI
From 25-JUN-11 18:35:00 to 25-JUN-11 18:35:00 (CST-6)
Location: SULLIVAN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in WASHINGTON, MISSOURI
From 25-JUN-11 19:20:00 to 25-JUN-11 19:20:00 (CST-6)
Location: RICHWOODS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. LOUIS, MISSOURI
From 25-JUN-11 19:42:00 to 25-JUN-11 19:42:00 (CST-6)
Location: ROBERTSON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in WASHINGTON, MISSOURI
From 25-JUN-11 21:47:00 to 25-JUN-11 21:47:00 (CST-6)
Location: CANNON MINES
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHINGTON, MISSOURI
From 25-JUN-11 21:49:00 to 25-JUN-11 21:49:00 (CST-6)
Location: OLD MINES
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. CHARLES, MISSOURI
From 25-JUN-11 23:52:00 to 25-JUN-11 23:57:00 (CST-6)
Location: FT ZUMWALT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ST. CHARLES, MISSOURI
From 26-JUN-11 00:00:00 to 26-JUN-11 00:00:00 (CST-6)
Location: DARDENNE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Flash Flood in ST. LOUIS (C), MISSOURI
From 26-JUN-11 02:00:00 to 26-JUN-11 05:30:00 (CST-6)
Location: BADEN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Up to five inches of rain fell onto already saturated soils causing flash flooding.  Numerous roads were flooded including Interstate 70 at Shreve Avenue, so the interstate was closed for a time. Also, as section of Interstate 70 was damaged due to a sewer line collapse near the West Florissant Avenue exit.  Several cars stalled in high water on Interstate 64/Hwy 40 near Grand Boulevard.  Flooding also closed Interstate 55 at Loughborough Avenue for a time.  Several homes in the 4400 block of Dryden Avenue and Dryden Court had to be evacuated due to flooding.  Basements had several feet of water in them.

Flash Flood in ST. LOUIS, MISSOURI
From 25-JUN-11 23:20:00 to 26-JUN-11 05:30:00 (CST-6)
Location: NORTHWOODS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Up to five inches of rain fell in a short amount of time onto already saturated soils causing flash flooding.  Numerous roads were flooded including the intersection of Lindbergh Boulevard and Huntleigh Woods Drive.  Manchester Road was closed in both directions east of the intersection with Brentwood Boulevard.  Also, Highway 141 was flooded where it goes under Interstate 44.

Hail in WASHINGTON, MISSOURI
From 25-JUN-11 21:54:00 to 25-JUN-11 21:54:00 (CST-6)
Location: BELLEFONTAINE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter