Scattered thunderstorms moved across northern Illinois during the afternoon and evening of July 10th producing heavy rain and isolated flooding.
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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.
Scattered thunderstorms moved across northern Illinois during the afternoon and evening of July 10th producing heavy rain and isolated 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 Chicago, IL wrote its last area forecast discussion before the first event at Jul 10, 5:50 PM CST, 0 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 650 PM CDT Wed Jul 10 2024 .KEY MESSAGES... - Scattered non-severe thunderstorms in the area this afternoon and again tomorrow afternoon. - Hot and humid conditions expected early next week. Heat indices may approach or exceed 100 degrees. - Periodic thunderstorm chances Saturday through mid next week, including the potential for a couple nocturnal/early AM t-storm complexes. && .DISCUSSION... Issued at 339 PM CDT Wed Jul 10 2024 Through Thursday Night: Convection has sprouted this afternoon along a surface convergence axis extending from near Freeport, IL to near Danville, IL. Convective coverage should continue to increase heading into this evening as large-scale forcing for ascent increases with the approach of a mid-level disturbance currently twirling its way across southern Minnesota and into Iowa, with outflow boundaries also helping to kick-start new convection. A consistent signal in recent runs of both the HRRR and WoFS lends relatively high confidence in the convective footprint remaining maximized generally near and west of a Rockford, IL to Watseka, IL line, but radar and satellite observations suggest that at least isolated showers and possibly storms remain probable through this evening farther to the east. Mediocre mid-level lapse rates and deep layer shear should prevent any of today's storms from becoming severe, and a warm nose near 600 mb will also likely play a role in curtailing overall thunderstorm coverage and longevity, particularly east of the aforementioned line. That being said, the strongest convective cores can still be expected to produce locally torrential rainfall, small hail, and gusty winds (possibly up to around 45-50 mph). With the relatively slow storm motions and presence of multiple surface boundaries, wouldn't be entirely surprised if any favorable cell-boundary interactions led to an isolated funnel cloud or two being spotted somewhere -- though any actual touch-downs occurring would be highly unlikely. The same air mass will remain in place into tomorrow, and thus similar conditions to today can be expected. High temperatures will likely end up being in the low 80s/near 80F at most locations, though onshore flow should cause locations closer to the lakeshore to remain in the 70s. The aforementioned Minnesota/Iowa disturbance will likely be near or directly over our forecast area come tomorrow, and with similarly moist near- surface conditions remaining in place, isolated to scattered diurnal convection thus is likely to blossom once again. Current thinking is that convective coverage tomorrow may not be quite as widespread as it should be today, and it appears that it may end up focusing near and south of I-80, but the QPF spread in the latest suite of forecast guidance warrants carrying at least a slight chance PoP mention across our forecast area. Once again, lackluster mid-level lapse rates and deep layer shear should curtail a threat for severe weather, but we'll have to keep an eye on the potential for localized minor flooding with the expectation that any storms that develop will be slow-moving, efficient rainfall producers. The likelihood of any hydrologic concerns arising would be greatest wherever the rainfall amounts from today and yesterday were highest. Also couldn't rule out some additional funnel cloud funny business given the likelihood of a mid-level vorticity maximum gyrating directly over our CWA. Ogorek Friday through Wednesday: Friday will be primarily quiet and seasonably warm (mid 80s inland), except cooler (mid-upper 70s) near the lake. Following the exit of mid-upper level low pressure into the central and eastern Great Lakes, very dry air aloft and persistent mid- level height rises of 4 DaM/12 hour should effectively cap most of if not all diurnal convective development. With lingering higher dew points south of I-80 (upper 60s to around 70F), erosion of MLCINh and subtle convergence may be enough for widely isolated showers and maybe a thunderstorm, if any updrafts can survive pronounced dry air entrainment. Surface high pressure will remain over the area through Friday night, making for a quiet and seasonably mild night. The first potential episode of convection in the humid and at times stormy pattern expected this weekend through early next week may arrive Saturday morning in parts of the area, probably in a weakening state. This will occur in concert with a warm front lifting north and a large instability reservoir advancing eastward across the mid and upper MS Valley. Large scale forcing mechanisms will be lacking through the afternoon, though any convectively induced impulses, and convergence tied to lingering outflow and the northward advancing warm front may be enough for widely scattered afternoon pulse-type thunderstorms (30-40% PoPs). Highs on Saturday will be in the mid to upper 80s, except slightly cooler lower 80s along the Illinois shore due to lake influence backing winds east- southeasterly. Dew points in the upper 60s to lower 70s at peak heating will yield peak heat indices in the low-mid 90s, a harbinger of things to come Sunday through Tuesday. Expansive mid-upper 500s DAM 500 mb ridging centered over the inter-mountain west and mean troughing centered over Hudson Bay will set up a hot and humid northwest flow aloft locally in the Saturday night-Tuesday timeframe. Unlike previous occurrences this warm season of overnight arriving convection weakening quickly as instability diminishes, the impressive instability reservoir (3000-4000+ J/kg of MUCAPE) will largely remain in place through the period. This entails a period of "ring of fire" conditions, where our position on the northeast flank of the ridge puts us in the threat zone for southeastward moving convection, including potentially well-organized severe MCSs, and episodes of flash flooding due to PWATs up in the ~1.75-2" range at times (150-200% of normal). Aside from operational and ensemble members hinting at the likelihood of this type of activity, specific timing predictability in these types of patterns are commonly low confidence. This maxes out PoPs only in the chance (30-40% range) during windows of MCS favorability at this lead time. The first window may be Saturday night, prior to stronger deep layer shear being present, followed by Sunday night into early Monday when 40+ kt of deep layer bulk shear is forecast. Monday night into early Tuesday could end up being another window for parts of the area as well. Classic in these type of patterns, there will be many dry hours, and a relative daytime lull/capping Sunday and Monday PM will support highs in the lower to possibly mid 90s with dew points in the 70s yielding peak heat indices flirting with heat advisory (105+F) criteria. Tuesday afternoon will be similar thermally to Sunday and Monday, though perhaps less capped with a bit better chance of widely scattered PM thunderstorms as a weak cold front advances south. It's unclear whether the appreciable instability axis will be shunted far enough south by Wednesday to limit another round of convection, especially south of I-80, as the cold front takes on back door characteristics. What is of higher confidence is an end to the hot and humid conditions, with forecast high temps on Wednesday in the low-mid 80s inland and upper 70s near Lake Michigan. Castro && .AVIATION /00Z TAFS THROUGH 06Z FRIDAY/... Issued at 650 PM CDT Wed Jul 10 2024 Forecast concerns include... Chance of showers this evening and again on Thursday. Possible fog overnight. Scattered thunderstorms are mainly focused across west and central IL early this evening and this looks to be the area where they will continue into the evening as they slowly weaken. Additional showers will be possible across northern Il along with possibly an isolated thunderstorm in the next hour or so as various outflow boundaries interact with each other. There will be another chance for showers and possibly isolated thunder on Thursday with better chances southwest of the terminals. Along with isolated coverage, confidence is too low to include any precip mention in this forecast. Fog is possible overnight into early Thursday morning and mainly south and west of the Chicago terminals. There may also be some mvfr or possibly ifr cigs across central IL, where the current rains are the heaviest. Overall confidence for fog is low and maintained mention at RFD and GYY. Trends will need to be monitored through the night. Wind directions have been problematic with the various outflow boundaries. Eventually, they should settle on a light southeast direction this evening or become light and variable. Winds may favor a more light north/northeast direction by daybreak and then remain northeasterly on Thursday. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && Visit us at weather.gov/chicago
Hazardous Weather Outlook National Weather Service Chicago/Romeoville IL 413 PM CDT Wed Jul 10 2024 ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002- 010-011-019-112115- 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- 413 PM CDT Wed Jul 10 2024 /513 PM EDT Wed Jul 10 2024/ This Hazardous Weather Outlook is for portions of north central Illinois...northeast Illinois and northwest Indiana. .DAY ONE...Tonight. Weather hazards expected... Limited Thunderstorm Risk. DISCUSSION... Scattered non-severe thunderstorms are expected through the mid to late evening, primarily across inland portions of northern and central Illinois. Flooding is possible along portions of the Kankakee and Iroquois River basins. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday and Saturday... Limited Thunderstorm Risk. Sunday through Tuesday... Limited Thunderstorm Risk at times. Limited daytime Excessive Heat Risk. DISCUSSION... Hot and humid conditions look poised to return this weekend into next week, along with periodic thunderstorm chances. Heat indices may approach or exceed 100 degrees Sunday through Tuesday. Flooding will remain possible along portions of the Kankakee and Iroquois River basins. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be necessary through tonight. GENERAL STORM MOTION OF THE DAY: Moving toward the east-southeast at 15-25 mph. LMZ740>745-112115- 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- 413 PM CDT Wed Jul 10 2024 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...Tonight. Weather hazards expected... Limited Thunderstorm Risk. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday... Limited Thunderstorm Risk. Saturday through Tuesday... Limited Thunderstorm Risk at times. Castro 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
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
A photo showed a car stuck in approximately one foot of water on Route 23.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2024Every state in 2024This day in weather historyWarnings in Illinois, July 2024
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: 1183523.