During the afternoon of May 31st, a cluster of thunderstorms produced locally damaging winds across parts of the Chicago metro as well as a landspout in west-central McHenry County.
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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 LOT wrote it up.
During the afternoon of May 31st, a cluster of thunderstorms produced locally damaging winds across parts of the Chicago metro as well as a landspout in west-central McHenry County.
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 Chicago, IL wrote its last area forecast discussion before the first event at May 31, 2:04 PM CST, 3 minutes earlier.
Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 304 PM CDT Wed May 31 2023 .SHORT TERM... Issued at 304 PM CDT Wed May 31 2023 Through Thursday Night... Thunderstorms continue to develop across much of northeastern and central Illinois this afternoon and are expected to linger through early evening. While instability is more than sufficient (around 1000 J/kg MLCAPE and 9+ C/km low-level lapse rates), the lack of synoptic scale forcing has confined the thunderstorm activity to a variety of mesoscale surface boundaries (lake breeze and outflow) scattered across the area. The expectation is for storms to continue to pulse along these boundaries into the early evening hours where the waning instability should allow convection to finally come to an end. Given that these boundaries are fluid, the coverage of storms will continue to be of an isolated to widely scattered nature meaning that some areas may not see rain. However, any areas that do see storms could see periods of heavy rainfall and possibly some small hail and/or gusty winds upwards of 40 mph especially from more robust cores. Regardless, widespread severe weather is not expected given the aforementioned lack of upper-level dynamics and wind shear. Once storms fizzle this evening, dry and clearing conditions are expected for tonight with temperatures dropping into the mid-60s. Temperatures will once again warm into the upper 80s to lower 90s on Thursday with partly cloudy skies. Chances for storms are expected to materialize Thursday afternoon given the similar environment to today, however; drier air is expected to be advecting into the area from the east. This dry advection should help keep thunderstorm activity confined to areas nearest the I-39 corridor where better moisture and some upper-level influence is forecast to establish. Regardless, I have maintained an isolated to scattered mention of storms for the entire reason given this potential but suspect that eastward extent should be somewhat limited. Any storms that do develop on Thursday are expected to taper during the early evening as instability wanes leaving us with dry conditions overnight once again. Yack && .LONG TERM... Issued at 304 PM CDT Wed May 31 2023 Friday through Wednesday... Key Forecast Messages: * Very warm/hot inland Friday through the weekend but with lower humidity levels * Continuation of the primarily dry pattern On Friday, drier easterly low level flow up to 850 mb and inland footprint of drying influence of high pressure centered over the Great Lakes will shunt the instability axis well inland and likely preclude the threat for any showers outside of the CWA. Limited any slight chance PoPs to far interior sections and with the thunder threat looking even lower than the chance for measurable rain, removed thunder mention from the gridded database. The main story will be the hot temperatures inland, reaching the lower to locally mid 90s. Saving grace will be lower humidity levels, as dew points mix out the upper 40s and lower 50s during the afternoon. Lakeside locales will reach the lower to mid 70s thanks to onshore flow through the day. Saturday will be quite similar to Friday temperature wise, except with no precip. chances even far inland and somewhat stronger northeast flow, possibly featuring gusts up to 20 to 25 mph. The semi-permanent Rex block pattern will then return into next week as a closed upper low parks over the northeast. Gradual "cool" advection emanating from the Hudson Bay to Great Lakes surface high will bring slightly lower temperatures Sunday, and especially next work week, though inland highs should still generally average above normal. Overnights will go from mild to comfortably cool outside of Chicago later in the weekend into next week. Unfortunately for areas that miss out on the pop-up convection today (Wednesday) and Thursday, there's little hope for meaningful drought relief through day 7 (next Wednesday). Other than maybe a few spotty diurnal showers with a backdoor front sometime in the Tuesday-Wednesday timeframe, dry conditions will prevail. Longer range pattern guidance offers *some* hope of a more active pattern arriving by mid June, but until then, expect drought conditions to worsen for most areas. Castro && .AVIATION... For the 18Z TAFs... Aviation Forecast Concerns include... * Isolated to scattered thunderstorms through mid afternoon with another chance Thursday afternoon. * Wind direction trends with approaching lake breeze and potential influence from thunderstorm outflow. An inland moving lake breeze has begun to assist development of isolated showers near ORD and MDW as of 1740z while higher coverage of thunderstorm cells remains to the south of the terminals. Expect that the lake breeze will reach ORD/MDW by 20z if not sooner which will keep the chance for thunderstorms near these terminals. Expect that the potential will decrease as along as the lake breeze boundary continues westward. Thunderstorm outflow may interrupt this but would also act to stabilize things so am fairly confident that the thunderstorm threat will diminish at ORD/MDW by 20/21z, though activity may be ongoing to the west. This will also result in a longer potential for storms at DPA/RFD which may linger until closer to sunset, though think the main window will be prior to 22/23z or so. GYY looks to have a lesser chance for storms as the lake breeze should largely remain to the southwest but storms may drift off the boundary and affect the terminal at times. Winds will remain southerly inland of the lake breeze and be southeasterly behind it. Thunderstorm outflows will upset the wind field and likely result in a window of variable winds before the prevailing direction returns. Light southeast winds will occur tonight with an increase in speeds Thursday morning. More isolated to scattered showers and thunderstorms are expected Thursday afternoon. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && Visit us at weather.gov/chicago Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSChicago www.twitter.com/NWSChicago www.youtube.com/NWSChicago
Hazardous Weather Outlook National Weather Service Chicago/Romeoville IL 318 AM CDT Wed May 31 2023 ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002- 010-011-019-010830- Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage- La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford- Northern Cook-Central Cook-Southern Cook-Northern Will- Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton- 318 AM CDT Wed May 31 2023 /418 AM EDT Wed May 31 2023/ This Hazardous Weather Outlook is for portions of North Central Illinois...Northeast Illinois and Northwest Indiana. .DAY ONE...Today and Tonight. Weather hazards expected... Limited Thunderstorm Risk. DISCUSSION... Isolated to scattered slow moving thunderstorms are expected to develop across portions of the area this afternoon. Focus for storm initiation will likely be the inland moving Lake Michigan lake breeze across northeast Illinois and northwest Indiana, though isolated storms will also be possible in other areas. While severe weather is not expected, any thunderstorms will be capable of producing at least occasional cloud to ground lightning, brief downpours and localized brief wind gusts up to 45 mph. Storms may linger into early evening before dissipating with the loss of daytime warmth. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday and Friday... Limited Thunderstorm Risk. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be necessary through tonight. GENERAL STORM MOTION OF THE DAY: Moving toward the northwest at 10 mph. LMZ740>745-010830- Winthrop Harbor to Wilmette Harbor IL- Wilmette Harbor to Northerly Island IL- Northerly Island to Calumet Harbor IL- Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN- Burns Harbor to Michigan City IN- 318 AM CDT Wed May 31 2023 This Hazardous Weather Outlook is for portions of the Illinois nearshore waters of Lake Michigan and the Indiana nearshore waters of Lake Michigan. .DAY ONE...Today and Tonight. Weather hazards expected... Limited Thunderstorm Risk. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday... Limited Thunderstorm Risk. Tuesday... Limited Thunderstorm Risk. Ratzer Visit us at www.weather.gov/chicago Follow us on Facebook, Twitter, and Youtube at: www.facebook.com/nwschicago www.twitter.com/nwschicago www.youtube.com/nwschicago
Special Weather Statement National Weather Service Chicago/Romeoville IL 156 PM CDT Wed May 31 2023 ILZ006-013-019>021-023-032-103>108-INZ001-312100- Lake IL-DuPage-La Salle-Kendall-Grundy-Kankakee-Livingston- Northern Cook-Central Cook-Southern Cook-Northern Will- Southern Will-Eastern Will-Lake IN- Including the cities of Waukegan, Buffalo Grove, Mundelein, Gurnee, Naperville, Wheaton, Downers Grove, Lombard, Carol Stream, Ottawa, Streator, La Salle, Mendota, Marseilles, Oswego, Yorkville, Plano, Morris, Coal City, Minooka, Kankakee, Bourbonnais, Bradley, Pontiac, Dwight, Fairbury, Evanston, Des Plaines, Schaumburg, Palatine, Northbrook, Chicago, Cicero, Oak Lawn, Oak Park, La Grange, Calumet City, Oak Forest, Lemont, Orland Park, Park Forest, Joliet, Bolingbrook, Plainfield, Mokena, Channahon, Manhattan, Wilmington, Crete, Peotone, Beecher, Gary, Hammond, and Merrillville 156 PM CDT Wed May 31 2023 ...Isolated Strong Thunderstorms through Mid Afternoon... Through 4 PM, widely scattered pop-up thunderstorms will continue to develop across portions of the area, and move off to the northwest at about 10 to 15 mph. A few of these thunderstorms will be strong, capable of producing wind gusts up to 50 mph and small hail. All thunderstorms will produce lightning strikes and heavy downpours. Near Lake Michigan, most of the thunderstorm activity will likely remain several miles inland of the lake. Move indoors if you hear thunder or see lightning. Use caution when driving in heavy rain. RC
Special Weather Statement
National Weather Service Chicago/Romeoville
305 PM CDT Wed May 31 2023
ILZ020-312030-
Kendall IL-
305 PM CDT Wed May 31 2023
...A strong thunderstorm will impact portions of northern Kendall
County through 330 PM CDT...
At 305 PM CDT, Doppler radar was tracking a strong thunderstorm over
Yorkville, moving northwest at 10 mph.
HAZARD...Wind gusts of 50 to 55 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Oswego, Yorkville, Plano, Montgomery and Bristol.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4159 8828 4156 8850 4172 8854 4172 8837
TIME...MOT...LOC 2005Z 145DEG 10KT 4165 8844
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH
IzziThe Chicago radar (KLOT), 31 km away, was scanning. The volume nearest the first event began at 20:04 UTC.
2 thunderstorm wind, 1 tornado. Local standard time, as filed.
Pictures received from the public showed multiple large tree limbs down near Yorkville High School. Time was estimated based on radar.
A 61 mph wind gust was reported through Cocorahs. 0.5 inch hail was also noted.
A brief landspout tornado was visible in an open field based on two public photos, including one from a drone, west of Woodstock. Timestamps from photos indicate that the landspout may have spanned over a period of a few minutes. The storm's path was estimated from the drone image and storm motion.
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, May 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: 1102928, 1102930, 1102925.