A vigorous short-wave trough interacted with an approaching low pressure system and associated warm frontal boundary to trigger clusters of strong to severe thunderstorms across west-central Illinois during the late afternoon of August 6th. Due to enhanced low-level wind shear along and north of the warm front, many of the cells began rotating and spinning up occasional funnel clouds.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS ILX wrote it up.
A vigorous short-wave trough interacted with an approaching low pressure system and associated warm frontal boundary to trigger clusters of strong to severe thunderstorms across west-central Illinois during the late afternoon of August 6th. Due to enhanced low-level wind shear along and north of the warm front, many of the cells began rotating and spinning up occasional funnel clouds. One of the cells intensified as it pushed into Sangamon County, producing a long-track tornado that was on the ground for over 25 miles from just north of Pawnee in far southeastern Sangamon County to southeast of Stonington in Christian County. The tornado produced EF-1 damage along much of its path, peaking with EF-2 damage just south of Willeys in Christian County. This particular thunderstorm cell dropped 2-inch diameter hail north of Taylorville and went on to produce a downburst with 80 mph wind gusts in far eastern Shelby County near Lake Mattoon. The storms eventually congealed into a line as they pushed into eastern Illinois later in the evening, with scattered wind damage, hail, and flash flooding.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Lincoln, IL wrote its last area forecast discussion before the first event at Aug 6, 1:30 PM CST, 3 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service Lincoln IL 230 PM CDT Sun Aug 6 2023 .SYNOPSIS... Issued at 230 PM CDT Sun Aug 6 2023 Severe storms and localized flash flooding are possible into the evening and overnight hours. Lows tonight should hover in the mid-to- upper 60s. Showers and cloudy conditions to linger into Monday. More chances for showers and thunderstorms return by mid week. Temperatures remain seasonable through the week. && .DISCUSSION... Issued at 230 PM CDT Sun Aug 6 2023 -------------------[Discussion]------------------- Today's main story is the severe weather risk this evening. Models are trending to agree that the timing of this system should be 4PM to approximately midnight. There is sufficient moisture in the atmosphere, but dewpoints aren't all that impressive. The effective bulk shear shown on the NAM 3km and HRRR models 12z.6 runs have values of 40-55 kts. The CAPE values are not all that impressive. The surface is slightly capped, which the surface heating will be minimized by the cloud moving overhead. There was a short break in the clouds between last nights MCV circling to our northeast and the incoming low pressure system. The MLCAPE shows 1500-2200 J/kg along and south of a Schuyler Co to Crawford Co line. North of this line has the higher values of CIN. The storms that develop will be supported mainly by the high shear values. This is a classic case of a high shear / low CAPE day in central Illinois. SPC has the majority of the CWA in a slight risk for severe weather. Part of the CWA in a 15% hatched area for sig hail. After looking at the environment and hail parameters. It may be difficult, but not impossible, to get any sig hail. Lapse rates aren't supportive of large hail. The area they have circled with a 5% tor is about where I believe will be the area of interest this evening for severe weather. There is a 15% risk for wind. DCAPE values of near 1000 J/kg support that there may be some strong, and potentially destructive, wind gusts within the storms. Today has a risk for some flash flooding on top of the severe threat. The area of interest for any localized flash flooding is primarily north of I-72, however if there is a cell that is proficient in rainfall can cause localized flooding south of I-72. NAM model soundings for several locations in central/southeastern Illinois show a long, skinny CAPE profile, PWAT values of 1.9 to 2.2 inches, and a deep warm precip process layer. There was sufficient precipitation yesterday, that there may some issues in the urban areas of the CWA, especially the northern half of the CWA. The ground is well saturated. The low-level jet is expected to strengthen which will push more moisture into central Illinois. If we get rain rates of greater than 1.5"/hr or 2.5" in 6 hours, problems may arise for localized areas. WPC has the majority of Illinois in a slight risk for excessive rainfall. After today, showers and cloudy conditions linger into Monday as the surface low finishes moving through the area. Tuesday looks to be dry before wetter conditions return for the remainder of the week. Temperatures remain seasonable through the forecast, with highs in the 80s and lows in the 60s. Delaney && .AVIATION... (For the 18z TAFs through 18z Monday Afternoon) Issued at 1242 PM CDT Sun Aug 6 2023 It's a complex forecast today, with a mix of MVFR and VFR ceilings early this afternoon across the east associated with an MCV centered in northern Indiana and multiple waves of storms expected through the late evening. The first round is just a broken line of showers that has produced an occasional strike of lightning, while the round that arrives after about 22z/5pm will have the potential to produce frequent lightning, strong wind gusts, and localized hail. Overnight tonight, northerly flow behind the surface low will advect cooler air across a moistened boundary layer to result in areas of fog (locally dense) and low stratus. Bumgardner && .ILX WATCHES/WARNINGS/ADVISORIES... Flood Watch through Monday morning for ILZ027>031-036>038. &&
Hazardous Weather Outlook National Weather Service Lincoln IL 331 PM CDT Sun Aug 6 2023 ILZ027>031-036>038-072045- Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean- 331 PM CDT Sun Aug 6 2023 This Hazardous Weather Outlook is for central Illinois and west central Illinois. .DAY ONE...Tonight. Another round of thunderstorms is expected late this afternoon through tonight. Some of these storms could be severe with damaging wind gusts, large hail, and an isolated tornado possible. In addition, heavy rain is possible, which when factoring in the saturated ground conditions from Saturday's rainfall, could result in flooding. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Additional storms are possible Wednesday and Friday. It is too early to determine the severe threat at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed from 4 pm to 11 pm. Expected storm motion is toward the east southeast around 25 to 30 mph. ILZ040>057-061>063-066>068-071>073-072045- Schuyler-Mason-Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard- Scott-Morgan-Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar- Shelby-Cumberland-Clark-Effingham-Jasper-Crawford-Clay-Richland- Lawrence- 331 PM CDT Sun Aug 6 2023 This Hazardous Weather Outlook is for central Illinois, east central Illinois, southeast Illinois and west central Illinois. .DAY ONE...Tonight. Another round of thunderstorms is expected late this afternoon through tonight. Some of these storms may be severe with damaging wind gusts, large hail, and an isolated tornado possible. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Additional storms are possible Wednesday and Friday. It is too early to determine the severe threat at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed from 4 pm to 11 pm. Expected storm motion is toward the east southeast around 25 to 30 mph. Delaney
The Lincoln radar (KILX), 49 km away, was scanning. The volume nearest the first event began at 22:56 UTC.
13 thunderstorm wind, 10 hail, 4 flash flood, 2 tornado. Local standard time, as filed.
A power line was blown down on East Lakeshore Drive.
A tornado touched down 3 miles north of Pawnee at 6:09 PM CDT. It caused minor roof damage and blew down several trees before it crossed into Christian County just north of the intersection of Pawnee-New City Road and Skaggs Road at 6:13 PM CDT.
This tornado crossed from Sangamon County into far western Christian County just north of the intersection of Pawnee-New City Road and Skaggs Road at 6:13 PM CDT. It continued east-southeastward across Sangchris Lake, damaging a home near the lakeshore and causing extensive tree damage before passing just north of Tovey and Kincaid. The tornado crossed Route 29 southeast of Sharpsburg and tracked over mainly open fields between Routes 29 and 48. It then strengthened and caused EF-2 damage 2 miles south of Willeys along 1600 East Road just south of 1600 North Road where it demolished about 2/3 of a house. The tornado continued east-southeastward, then dissipated near North 2300 East Road about a half mile north of 1500 North Road at 7:03 PM CDT.
A farmstead was damaged near the intersection of Cotton Hill Road and Galloway Road. The roof was damaged and a few trees were blown over.
An outbuilding was damaged and a few trees were blown over near the intersection of Pawnee-New City Road and Zion Road.
Several large trees and power lines were blown down.
Several 2 to 4-inch diameter tree branches were blown down.
A trained spotter estimated a 60 mph wind gust.
An emergency manager estimated sustained winds of 50 mph with gusts to around 60 mph.
A large tree was snapped.
The roof of a house suffered significant damage.
Downburst winds of 80-85 mph caused significant damage around Lake Mattoon. One home on the east side of the lake lost half its roof, while a home on the west side of the lake had a tree blown onto it. Extensive tree damage was noted in a concentrated area south of Shelby County Road 975 North.
Downburst winds of 80-85 mph caused significant damage around Lake Mattoon. Extensive tree damage was noted in a concentrated area south of Cumberland County Road 1250 North.
Water was 1 to 2 feet deep on some streets in Pana.
A power pole was blown down and caught on fire.
Several tree branches were blown down.
US-45 was flooded south of Watson near Salt Creek.
Water was flowing across Main Street in Clay City.
Water was flowing across several streets in Flora.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2023Every state in 2023This day in weather historyThe tornado archive for Illinois, 2023Warnings in Illinois, August 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1130582, 1130541, 1130559, 1130550, 1130586, 1130574, 1130560, 1130561, 1130562, 1130563, 1130575, 1130564, 1130565, 1130566, 1130576, 1130577, 1130578, 1130579, 1130583, 1130584, 1130585, 1130573, 1130580, 1130581, 1130569, 1130567, 1130568, 1130572, 1130570.