Storms developed along an outflow boundary that was laid out along the I-70 corridor.  The storms produced wind damage, large hail as well as 9 tornadoes.  Two of the tornadoes were rated EF3 as they moved through the St. Louis metro area.

Tornado in MONTGOMERY, ILLINOIS
From 31-MAY-13 20:02:00 to 31-MAY-13 20:06:00 (CST-6)
Location: WAGGONER
Tornado F-scale: EF1
Crop damage: 0.00K
Reported by: NWS Storm Survey

A tornado touched down half a mile north of the intersection of County Road 100E and 2200N or 3.5 miles south-southwest of Waggoner, Illinois.  Several large tree limbs 6 to 10 inches in diameter were blown down by the tornado. The tornado path at this location was 30 yards wide. The tornado traveled northeast and damaged one barn and a few outbuildings on Goby Avenue, about 1.5 miles west of I-55.  The roof of two outbuildings were uplifted and tossed 100 to 150 yards to the northeast.  Another outbuilding was severely damaged on Coalfield Avenue, half a quarter of a mile west of I-55. Damage intensity was rated EF1.  Debris from this machine shed was tossed across a corn field and across I-55. The tornado then crossed I-55, blowing over three tractor trailers.  No injuries were reported.  The tornado then damaged a third farmstead on County Road 2500N approximately a quarter of a mile east of I-55. Windows were blown inward on a two story farm home and two machine sheds were severely damaged. The damage intensity was rated EF1 and damage was 40 yards wide. The tornado continued to move northeast and downed large tree branches 6 to 10 inches in diameter on East Waggoner Road, about 2 miles east southeast of Waggoner, Illinois.  The tornado then lifted and dissipated.  The tornado path length was 4.3 miles with a max path width of 50 yards.  The damage was rated EF1 with max wind speeds estimated between 90 and 100 MPH.

Thunderstorm Wind in MONTGOMERY, ILLINOIS
From 31-MAY-13 20:04:00 to 31-MAY-13 20:05:00 (CST-6)
Location: FARMERSVILLE
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A wide swath of wind damage occurred over far northern Montgomery County.  Several outbuilding sustained minor to moderate damage.  Five grain bins were blown off their foundations into a field on Thomasville Trail, about half a mile west of I-55.  Also, several large trees and numerous tree limbs were blown down.

Thunderstorm Wind in BOND, ILLINOIS
From 31-MAY-13 20:05:00 to 31-MAY-13 20:11:00 (CST-6)
Location: SORENTO
Magnitude: 78.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Thunderstorm winds snapped several power poles in Sorento.  Just north of Greenville, several large trees were snapped and numerous tree limbs were blown down.

Hail in ST. CLAIR, ILLINOIS
From 31-MAY-13 20:15:00 to 31-MAY-13 20:15:00 (CST-6)
Location: O FALLON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in FAYETTE, ILLINOIS
From 31-MAY-13 20:40:00 to 31-MAY-13 20:40:00 (CST-6)
Location: VANDALIA
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds blew down a large tree limb onto U.S. Highway 51 about a mile north of Vandalia.

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 19:38:00 to 31-MAY-13 19:38:00 (CST-6)
Location: (ALN)STL RGNL ARPT A
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 19:30:00 to 31-MAY-13 19:30:00 (CST-6)
Location: MITCHELL
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down a large tree blocking the door to a house, trapping the occupant briefly.  There was only minor structural damage to the house.

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 19:36:00 to 31-MAY-13 19:36:00 (CST-6)
Location: BLUFF JCT
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down several very large trees around the 1000 block of both Grand Avenue and Randle Street near North Elm Street.  One of the trees went through the roof of a house on Grand Avenue causing major damage.  Another large tree on Randle Street pulled down several power lines.

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 19:31:00 to 31-MAY-13 19:31:00 (CST-6)
Location: OLDENBURG
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Thunderstorm winds caused minor roof damage to a home at the intersection of New Poag Road and Illinois Route 111.

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 19:50:00 to 31-MAY-13 19:50:00 (CST-6)
Location: BARNETT SIDING
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds blew over several tractor trailers along Interstate 55 between mile markers 31 and 28 on the southbound side of the highway.  No injuries were reported.

Thunderstorm Wind in MADISON, ILLINOIS
From 31-MAY-13 20:00:00 to 31-MAY-13 20:00:00 (CST-6)
Location: ALHAMBRA
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm winds blew down several trees around town as well as several fences.

Thunderstorm Wind in MACOUPIN, ILLINOIS
From 31-MAY-13 19:58:00 to 31-MAY-13 20:04:00 (CST-6)
Location: VIRDEN
Magnitude: 78.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A wide swath of wind damage occurred over northern Macoupin County.  Numerous trees and tree limbs were blown down.  Also, an outbuilding on the west side of Virden had part of its roof blown off.

Tornado in MADISON, ILLINOIS
From 31-MAY-13 19:29:00 to 31-MAY-13 19:37:00 (CST-6)
Location: OLDENBURG
Tornado F-scale: EF3
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado crossed the Mississippi River from St. Louis County Missouri into Madison County Illinois, about 1.1 miles northwest of the intersection of Illinois Routes 3 and 203.  It blew down several trees once it made landfall.  As it traveled to the east northeast, it took about a quarter of the roof off of a business on the northwest corner of the intersection of Illinois Route 3 and Piasa Lane.  On the east side of Illinois Route 3, a gas station sustained minor damage.  Damage in this area was rated EF1.  Further northeast, several power poles were snapped along S. Delmar Avenue.  Just south of the intersection of Robbins Road and Illinois Route 111, 5 large wooden power poles were snapped and there was a convergent pattern in the tree damage to the north.  As it crossed the far southern portions of South Roxana, there was minor damage to several homes, then the tornado crossed Highway 255. It buckled in a wall on a large steel framework building and twisted the roof steel girders just south of Old Alton Edwardsville Road, about a quarter of a mile east of the intersection of Old Alton Edwardsville Road and Section Line Road.  On the same property, another very large and well-built wood framed metal sided storage building was completely destroyed by the tornado.  Damage was rated EF3 in this location.  The tornado continued to the northeast crossing Illinois Route 143 just north of the intersection with N. University Dr.  Before lifting and dissipating, the tornado crossed Illinois Route 159, just south of Fox Creek Golf Club and snapped off several large fir trees as well as a wooden power pole.  The tornado path length in Madison County was 8.6 miles with a max path width of 150 yards.  The damage in this segment was rated EF3 with max wind speeds of 160 MPH.  Overall, the entire tornado path length was 10.6 miles with a max path width of 150 yards.  The tornado was rated EF3 with max wind speeds of 160 MPH.

Tornado in MACOUPIN, ILLINOIS
From 31-MAY-13 19:49:00 to 31-MAY-13 19:52:00 (CST-6)
Location: GILLESPIE
Tornado F-scale: EF2
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado began on the west side of Gillespie, causing minor damage to an apartment complex on the southwest side of the intersection of Broadway Street and LJ Avenue.  It blew out several windows on one of the apartment buildings.  It then caused major damage to the north end of a brick gymnasium at Gillespie High School.  The damage to the gymnasium was rated EF2.  Then it proceeded to travel northeast, blowing the roof off of a house just northeast of the high school.  Also, a large pine tree was snapped off at the base next to the house.  The tornado continued to the northeast.  There was extensive damage to trees and roofs along a west southwest to east northeast path through the town.  The tornado destroyed a garage at the corner of Henry Street and Fulton Street.  The tornado lifted and dissipated just north of the intersection of Harding Avenue and Illinois Route 16.  The tornado path length was 1.5 miles with max path width of 150 yards.  The damage was rated EF2 with max wind speeds of 115 MPH.