A cold front triggered scattered thunderstorms across central Illinois during the late afternoon and evening of May 20th.  Many of the storms dropped dime to quarter-sized hail, while a couple cells produced damaging downburst winds. In addition, isolated, slow moving thunderstorms developed along the I-57 corridor. One of these thunderstorms produced very heavy rain and flash flooding in Effingham County.

Thunderstorm Wind in SANGAMON, ILLINOIS
From 20-MAY-12 16:25:00 to 20-MAY-12 16:30:00 (CST-6)
Location: WILLIAMSVILLE
Magnitude: 52.00 EG
Property damage: 12.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A tree fell onto a vacant house in Williamsville.

Thunderstorm Wind in LOGAN, ILLINOIS
From 20-MAY-12 16:40:00 to 20-MAY-12 16:45:00 (CST-6)
Location: ELKHART
Magnitude: 61.00 EG
Property damage: 7.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A power pole was blown down and two trees were damaged in Elkhart.

Thunderstorm Wind in SANGAMON, ILLINOIS
From 20-MAY-12 16:08:00 to 20-MAY-12 16:13:00 (CST-6)
Location: SHERMAN
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Power lines were blown down west of Sherman.

Thunderstorm Wind in MENARD, ILLINOIS
From 20-MAY-12 17:54:00 to 20-MAY-12 17:59:00 (CST-6)
Location: PETERSBURG
Magnitude: 63.00 MG
Property damage: 14.00K
Crop damage: 0.00K
Reported by: Mesonet

A few trees were blown down and roofing was torn off a home.

Flash Flood in EFFINGHAM, ILLINOIS
From 20-MAY-12 16:00:00 to 20-MAY-12 21:30:00 (CST-6)
Location: DEXTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Rural areas of central Effingham County accumulated nearly 4.00 of rain in two hours during the early evening of May 20th. An isolated, slow moving thunderstorm was responsible for the heavy rainfall. Many rural roads south of I-70 and west of I-57, between Altamont and Watson, were inundated.

Hail in SANGAMON, ILLINOIS
From 20-MAY-12 16:42:00 to 20-MAY-12 16:43:00 (CST-6)
Location: MECHANICSBURG
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in MORGAN, ILLINOIS
From 20-MAY-12 16:45:00 to 20-MAY-12 16:46:00 (CST-6)
Location: FRANKLIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LOGAN, ILLINOIS
From 20-MAY-12 16:55:00 to 20-MAY-12 16:56:00 (CST-6)
Location: MT PULASKI
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in SANGAMON, ILLINOIS
From 20-MAY-12 17:05:00 to 20-MAY-12 17:06:00 (CST-6)
Location: (SPI)SPRINGFIELD ARP
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in MENARD, ILLINOIS
From 20-MAY-12 17:27:00 to 20-MAY-12 17:28:00 (CST-6)
Location: ATHENS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in CHAMPAIGN, ILLINOIS
From 20-MAY-12 17:43:00 to 20-MAY-12 17:44:00 (CST-6)
Location: PHILO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in VERMILION, ILLINOIS
From 20-MAY-12 18:10:00 to 20-MAY-12 18:11:00 (CST-6)
Location: WESTVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in VERMILION, ILLINOIS
From 20-MAY-12 19:20:00 to 20-MAY-12 19:21:00 (CST-6)
Location: FAIRMOUNT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in SANGAMON, ILLINOIS
From 20-MAY-12 15:35:00 to 20-MAY-12 15:40:00 (CST-6)
Location: PLEASANT PLAINS
Magnitude: 61.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several trees were blown down. The front of a garage was pulled out, and the roof was torn off an outbuilding.