Scattered thunderstorms developed over parts of northeast Illinois during the afternoon of July 8th producing isolated wind damage.
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 LOT wrote it up.
Scattered thunderstorms developed over parts of northeast Illinois during the afternoon of July 8th producing isolated wind damage.
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 8, 2:03 PM CST, 2 hours 22 minutes earlier.
Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 303 PM CDT Wed Jul 8 2020 .SHORT TERM... 303 PM CDT Through Thursday night... Isolated to widely scattered thunderstorms are ongoing across the parts of the area early this afternoon due to the presence of little to no capping. This will continue to be the trend through the afternoon before the activity abates with sunset. While no severe weather is expected, the storms will produce some gusty outflow winds in and near their vicinity. Storm motions are also less than 10 mph, so some highly localized heavy down pours will be possible. The primary weather concern following this afternoons thunderstorm activity is the threat for a period of strong to possibly severe thunderstorms over the area late Thursday/Thursday evening. Another hot and humid day is expected on Thursday, with temperatures in the low 90s, and heat indices up around 100. Similar to today, capping will remain weak, so increased cumulus development is likely by late morning, with some isolated to scattered thunderstorms possible during the afternoon. While deep layer flow will remain weak during the day, thus limiting the threat for more severe convection, it appears things could change Thursday evening. Going into Thursday evening forecast guidance continues to advertise a convectively enhanced mid-level disturbance approaching the area. An associated localized increase in the deeper layer flow looks to potentially drive a more organized area of thunderstorms across northern IL Thursday evening. Strong damaging winds and heavy torrential downpours will be the primary threats with these storms. The best timing for severe storms looks to be roughly 5 to 10 PM Thursday evening. Some scattered showers and storms could linger across the area Thursday night, but it appears the threat of more substantial storms should wane overnight. KJB && .LONG TERM... 239 PM CDT Friday through Wednesday... Gradually drier air is forecast to move into the area Friday into Saturday under temporary northwest flow aloft resulting from a short lived Great Lakes trough. A weak sheared short wave is forecast in global guidance to scoot just west of the area Saturday afternoon. Have most places dry though Saturday and that very well could be the case Sunday, with the EC continuing to be drier than the GFS in the backside of the trough depiction. Sunday is forecast to have northerly surface winds and thus the potential to have highs only at normal (mid 80s). The forecast interest in mid-late next week will probably start to increase due to the likelihood of at least an upstream heat wave in the Plains to mid-Mississippi Valley that could build into the Lower Great Lakes. The upper level ridge is forecast to build eastward by most guidance into the midweek period, though as is often the case with increasingly hot and humid airmasses, so will the zone of active convection (e.g. "Ring of Fire"). Ensemble forecast data suggest 850 mb temperatures may make a run toward 22- 24C+ with deterministic counterparts hinting at even higher, which would translate to highs at least in the lower 90s. With increasing humidity levels, apparent temperatures would be even higher. Yet as previously hinted, active clusters of thunderstorms love these patterns and may try to sneak into our area which, while perhaps presenting other problems, may alleviate heat concerns. Again this is 6-10 days out, so plenty of time for things to shift. So for now, something to keep an eye on given the time of year. Borchardt/MTF && .AVIATION... For the 18Z TAFs... Light winds will continue at all terminals with an easterly component becoming the norm at ORD/MDW in the wake of a weak leak breeze within a few hours of the TAF issuance. Widely scattered showers and thunderstorms are expected to develop over the next few hours with a peak in activity generally between 19-23Z. The inherited VCTS groups looked great. Similar to yesterday, wind gusts in excess of 30 kts and brief reductions in visibility are possible should a thunderstorm cell develop directly over a terminal. Will follow the strategy of issuing AMDs if/when a thunderstorm develops near/over a TAF site, with the expectation for less coverage today than yesterday. All convective activity is expected to wane toward sunset at the loss of diurnal heating. Winds may become somewhat erratic (but still light) in the wake of any thunderstorm activity tonight. After daybreak, winds should become south/southwesterly and increase to 5-10 kts. At ORD/MDW on Thursday, a lake breeze is expected to develop during the early afternoon hours but current indications are the southwesterly winds should keep it east of the terminals. Additionally, scattered thunderstorms with gusty winds are expected to develop from 20Z (Thursday) onward. For now, have introduced a PROB30 group keeping in mind later TAF packages will likely feature a stronger mention. Borchardt && .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 316 PM CDT Wed Jul 8 2020 ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002- 010-011-019-092030- 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- 316 PM CDT Wed Jul 8 2020 /416 PM EDT Wed Jul 8 2020/ 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. Limited Excessive Heat Risk. DISCUSSION... Expect hot and humid conditions inland of Lake Michigan through early evening. Isolated to widely scattered thunderstorms will continue abate with sunset this evening. The storms will be capable of locally heavy downpours and wind gusts potentially strong enough to down small tree limbs. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Thursday... Elevated Severe Thunderstorm Risk. Limited Flooding Risk. Limited Excessive Heat Risk. Friday... Limited Thunderstorm Risk. Limited Excessive Heat Risk. Saturday and Sunday... Limited Thunderstorm Risk. Tuesday... Limited Thunderstorm Risk. DISCUSSION: Hot and humid conditions will continue Thursday with heat index readings potentially topping 100 degrees. Scattered thunderstorms are probable Thursday afternoon that could increase in coverage into Thursday evening and persist overnight. A few storms, mainly over northern Illinois into Thursday evening, could be severe with strong damaging wind gusts. Also locally heavy rainfall is likely, and this could result in some localized flooding threat. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be necessary through tonight. GENERAL STORM MOTION OF THE DAY: Moving toward east around 5 mph. LMZ740>745-092030- 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- 316 PM CDT Wed Jul 8 2020 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... Elevated Severe Thunderstorm Risk. Friday through Sunday... Limited Thunderstorm Risk. Tuesday... Limited Thunderstorm Risk. KJB Visit us at http://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
218 PM CDT Wed Jul 8 2020
ILZ003-004-081945-
Boone IL-Winnebago IL-
218 PM CDT Wed Jul 8 2020
...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL WINNEBAGO AND WEST
CENTRAL BOONE COUNTIES UNTIL 245 PM CDT...
At 218 PM CDT, Doppler radar was tracking a strong thunderstorm near
Cherry Valley, or near Loves Park. This storm was nearly stationary.
Pea size hail and wind gusts up to 50 mph will be possible with this
storm. A brief funnel cloud is also possible.
Locations impacted include...
Rockford, Belvidere, Loves Park, Machesney Park, Poplar Grove,
Candlewick Lake, Cherry Valley, Timberlane and Caledonia.
Including the following interstates...
I-39 between mile markers 122 and 123.
I-90 between mile markers 9 and 20.
This includes... Rock Cut State Park, Rock Valley College, and
Rockford Rivets Baseball.
LAT...LON 4223 8902 4229 8906 4236 8902 4239 8895
4234 8883 4227 8886 4223 8891
TIME...MOT...LOC 1918Z 268DEG 4KT 4229 8895
BorchardtSpecial Weather Statement
National Weather Service Chicago/Romeoville
344 PM CDT Wed Jul 8 2020
ILZ003-008-082100-
Winnebago IL-Ogle IL-
344 PM CDT Wed Jul 8 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL OGLE AND
SOUTHWESTERN WINNEBAGO COUNTIES UNTIL 400 PM CDT...
At 342 PM CDT, Doppler radar was tracking a strong thunderstorm near
Winnebago, or 7 miles north of Byron, moving south at 10 mph.
Half inch hail and winds in excess of 40 mph will be possible with
this storm. This storm may intensify quickly, so stay tuned and be
prepared should a warning be needed.
Locations impacted include...
Byron, Winnebago, Pecatonica, Stillman Valley, Leaf River and Seward.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4220 8945 4220 8940 4232 8940 4228 8916
4208 8915 4213 8948
TIME...MOT...LOC 2042Z 011DEG 8KT 4223 8931
DonofrioSpecial Weather Statement National Weather Service Chicago/Romeoville 411 PM CDT Wed Jul 8 2020 ILZ033-039-082145- Iroquois IL-Ford IL- 411 PM CDT Wed Jul 8 2020 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN FORD AND SOUTHWESTERN IROQUOIS COUNTIES UNTIL 445 PM CDT... At 411 PM CDT, Doppler radar was tracking a strong thunderstorm near Paxton, moving north at 5 to 10 mph. Penny size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Paxton, Buckley, Loda and Roberts. Including the following interstate... I-57 between mile markers 262 and 274. PRECAUTIONARY/PREPAREDNESS ACTIONS... Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4044 8803 4049 8826 4065 8819 4061 8788 TIME...MOT...LOC 2111Z 197DEG 5KT 4054 8812 Donofrio
Special Weather Statement National Weather Service Chicago/Romeoville 419 PM CDT Wed Jul 8 2020 ILZ008-082200- Ogle IL- 419 PM CDT Wed Jul 8 2020 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL OGLE COUNTY UNTIL 500 PM CDT... At 419 PM CDT, Doppler radar was tracking a strong thunderstorm over Stillman Valley, or near Byron, moving south at 5 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Byron, Oregon, Mount Morris, Davis Junction, Stillman Valley and Chana. This includes... Lowden State Park and Ogle County Fairgrounds. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4218 8935 4213 8908 4193 8914 4200 8945 TIME...MOT...LOC 2119Z 016DEG 6KT 4209 8923 Donofrio
Special Weather Statement National Weather Service Chicago/Romeoville 514 PM CDT Wed Jul 8 2020 ILZ106-082245- Northern Will IL- 514 PM CDT Wed Jul 8 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN WILL COUNTY UNTIL 545 PM CDT... At 514 PM CDT, Doppler radar was tracking a strong thunderstorm over Shorewood, or near Joliet. This storm was nearly stationary. Winds in excess of 40 mph will be possible with this storm. Locations impacted include... Joliet, Romeoville, Plainfield, Lockport, Crest Hill, Shorewood, Fairmont and Crystal Lawns. Including the following interstates... I-55 between mile markers 251 and 260. I-80 between mile markers 123 and 125. This includes... Joliet Junior College and Lewis University. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4159 8803 4146 8825 4159 8825 4165 8812 TIME...MOT...LOC 2214Z 033DEG 2KT 4156 8818 Donofrio
Special Weather Statement
National Weather Service Chicago/Romeoville
520 PM CDT Wed Jul 8 2020
ILZ106>108-082245-
Eastern Will IL-Southern Will IL-Northern Will IL-
520 PM CDT Wed Jul 8 2020
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL WILL COUNTY UNTIL 545 PM
CDT...
At 519 PM CDT, Doppler radar was tracking a strong thunderstorm near
Frankfort. This storm was nearly stationary.
Winds in excess of 40 mph will be possible with this storm.
Locations impacted include...
Joliet, New Lenox, Homer Glen, Mokena, Frankfort, University Park,
Manhattan, Ingalls Park and Preston Heights.
Including the following interstates...
I-57 between mile markers 337 and 338.
I-80 between mile markers 135 and 143.
I-355 near mile marker 1.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4137 8792 4150 8807 4157 8794 4149 8779
4147 8779 4147 8775 4146 8773
TIME...MOT...LOC 2219Z 332DEG 1KT 4148 8791
DonofrioThe Chicago radar (KLOT), 20 km away, was scanning. The volume nearest the first event began at 22:24 UTC.
2 thunderstorm wind. Local standard time, as filed.
Two large trees were blown down blocking a road and a fair amount of corn was laying down near Cedar and Baker Roads.
A large tree limb was blown down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2020Every state in 2020This day in weather historyWarnings in Illinois, July 2020
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: 904141, 904142.