A low pressure system tracked from Missouri across central Illinois on May 21st, triggering scattered strong to severe thunderstorms along and east of I-57.  Enough wind shear was present near the track of the low to create supercell thunderstorms with large hail, damaging winds and areas of flash flooding.  In addition...two brief tornado touchdowns were reported in Edgar County as the storms tracked further eastward toward Indiana.

Flash Flood in CLARK, ILLINOIS
From 21-MAY-10 12:00:00 to 21-MAY-10 16:30:00 (CST-6)
Location: CASEY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Heavy rainfall with rates of 2.00 to 2.50 inches per hours produced flash flooding in a narrow stretch of northern Clark County. Most roads were inundated with water including U.S. Route 40 in Martinsville where there was 2 feet of standing water. In Marshall, 3.00 to 4.00 inches of rain fell in about 90 minutes which flooded most roads in the town.

Flash Flood in VERMILION, ILLINOIS
From 21-MAY-10 13:15:00 to 21-MAY-10 18:00:00 (CST-6)
Location: CATLIN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Training thunderstorm cells produced an area of flash flooding in southwest Vermilion County. Rainfall rates of nearly 2.00 inches per hour were reported. Many rural roads were inundated because of the flooding, particularly near Indianola.

Flash Flood in CHAMPAIGN, ILLINOIS
From 21-MAY-10 13:30:00 to 21-MAY-10 19:00:00 (CST-6)
Location: PENFIELD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Training thunderstorm cells produced an area of flash flooding in northeast Champaign County. Rainfall rates of nearly 1.50 inches per hour for more than three hours were reported. Many rural roads were inundated by the flooding, particularly U.S. Route 136 east of Gifford.

Flash Flood in VERMILION, ILLINOIS
From 21-MAY-10 13:30:00 to 21-MAY-10 19:00:00 (CST-6)
Location: RANKIN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Training thunderstorm cells produced an area of flash flooding in northwest Vermilion County. Rainfall rates of 1.50 inches per hour for nearly 2.5 hours were reported. Many roads were inundated, particularly Illinois Route 49 and U.S. Route 136 west of Potomac.

Flash Flood in EDGAR, ILLINOIS
From 21-MAY-10 12:30:00 to 21-MAY-10 18:00:00 (CST-6)
Location: HILDRETH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Training thunderstorm cells produced an area of flash flooding in northwest Edgar County. Rainfall rates of nearly 2.00 inches per hour were reported. Many rural roads were inundated by the flooding, particularly between the towns of Hume and Metcalf.

Hail in CLARK, ILLINOIS
From 21-MAY-10 12:20:00 to 21-MAY-10 12:21:00 (CST-6)
Location: MARSHALL
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLARK, ILLINOIS
From 21-MAY-10 12:22:00 to 21-MAY-10 12:23:00 (CST-6)
Location: MARSHALL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CLARK, ILLINOIS
From 21-MAY-10 12:22:00 to 21-MAY-10 12:23:00 (CST-6)
Location: MARSHALL
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in LAWRENCE, ILLINOIS
From 21-MAY-10 13:04:00 to 21-MAY-10 13:05:00 (CST-6)
Location: BIRDS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in LAWRENCE, ILLINOIS
From 21-MAY-10 12:50:00 to 21-MAY-10 12:51:00 (CST-6)
Location: CHAUNCEY
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

A few trees were blown down south of Chauncey.

Tornado in EDGAR, ILLINOIS
From 21-MAY-10 11:20:00 to 21-MAY-10 11:21:00 (CST-6)
Location: HUME
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A tornado briefly touched down 1 mile south of Hume.  No damage was reported.

Tornado in EDGAR, ILLINOIS
From 21-MAY-10 11:40:00 to 21-MAY-10 11:41:00 (CST-6)
Location: MORTIMER
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A tornado briefly touched down northeast of Metcalf.  No damage was reported.

Hail in CLARK, ILLINOIS
From 21-MAY-10 12:22:00 to 21-MAY-10 12:23:00 (CST-6)
Location: MARSHALL
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public