A line of severe thunderstorms moved across all of northern Illinois during the evening of April 17th producing several tornadoes and wind damage. Large hail occurred across parts of northwest Illinois and flooding occurred across parts of northeast Illinois.
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.
A line of severe thunderstorms moved across all of northern Illinois during the evening of April 17th producing several tornadoes and wind damage. Large hail occurred across parts of northwest Illinois and flooding occurred across parts of northeast Illinois.
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 Apr 17, 2:03 PM CST, 1 hour 32 minutes earlier. Its key messages:
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
303 PM CDT Fri Apr 17 2026
.KEY MESSAGES...
- Another round of showers and thunderstorms is expected later
this evening into tonight. Some of the storms could be
severe. Locally heavy rainfall could result in flooding
issues.
- Windy and unseasonably warm weather today will be replaced by
much colder weather over the weekend into early next week.
- Frost/freeze conditions are expected many areas Sunday and
especially Monday mornings.
&&
.MESOSCALE...
Issued at 303 PM CDT Fri Apr 17 2026
Latest radar and satellite trends indicate that storms are
following a mostly discrete supercell structure in the vicinity
of far northwest Illinois. Recent model guidance has also
trended to favor this scenario, suggesting the bulk of
convection through at least 5pm in our area will remain
generally northwest of a Dixon to Boone County line. A less
favorable environment highlighted by diminishing theta-e from
modest diurnal mixing and limited near-term upstream moisture
advection does raise some questions about how far east the more
organized convection will survive over the next couple hours.
However, modestly favorable low-level hodographs amid slightly
less-backed flow do support the potential for supercell modes to
survive with any convection that does clip the far northwest
CWA. Primary threat will be large hail and possibly a tornado.
Focus then turns to an expected expansion of convection along
the cold front (currently from just east of Des Moines to Kansas
City) as it quickly moves eastward into a more favorable
environment. As this convection marches eastward through late
afternoon, increasing coverage of pre-frontal convection
associated with deeper low-level moisture over Missouri will
surge toward west-central Illinois. This should result in a
well-formed QLCS with the potential for damaging winds and
embedded brief tornadoes across a large swath of Illinois this
evening. Will need to closely monitor any bowing segments,
particularly around and after sunset, as low-level flow
increases and lengthens hodographs.
Kluber
&&
.DISCUSSION...
Issued at 136 PM CDT Fri Apr 17 2026
For near term details on the convective threats through this
evening, see the mesoscale discussion (and/or additional future
discussions) above. Additional concerns for tonight will be
centered on heavy rainfall and localized flash flooding.
Precipitable water values still lie at the upper echelon of
typically observed values for Mid April, and this coupled with
some enhanced forcing should lead to areas of 1-1.5" rainfall
in a relatively short window of time. We cannot rule out any
higher overall totals (pushing 3"), given that we have several
windows of forcing both in the open warm sector and along the
cold front. Much of this rain will go immediately into runoff.
In addition to any urban locations, it is hard to pinpoint the
more favored areas in the watch area, however the most
susceptible areas overlapping with higher confidence rainfall
would be in the Rock River Basin, and then extending eastward
into the Fox and Des Plaines River Basins across northern
Illinois. A secondary heavy rain axis may setup south, but if we
have a forward propagating system, that may limit the duration
of heavy precipitation.
A taste of reality will return to the lower Great Lakes region
behind tonight's strong cold front. High temperatures will
reached at midnight. While some temperature recoveries will
occur as clouds break through the morning, rather stout cold air
advection through the day will prevent temperatures from
plateauing higher than the mid 40s to low 50s area wide. Normal
highs for mid April are right at 60. A stiff northwest breeze
will make it feel even less pleasant, with "wind chill" readings
in the lower 40 in many areas in the afternoon. This will set
the stage for a cold night Saturday night.
Cold advection gets reinforced as the upper trough axis will be
shifting overhead. The center of the surface high will be off to our
southwest Saturday night, thus we will maintain a bit of a wind
component, however things look to decouple enough to suggest some
areas of frost.
Reinforced northwest flow on the backside of the upper trough will
maintain a similar airmass on Sunday and provide a carbon copy day
from Saturday. With high pressure nearby Sunday night, a widespread
frost appears increasingly likely, with some area in outlying areas
heading for a potential hard freeze.
Upper heights recover nicely and warm advection on the back side for
the departing surface high will encourage temperatures to rebound
back above normal through mid week with generally dry
conditions. There will be periods of onshore flow keeping cool
readings near the shore.
KMD
&&
.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 116 PM CDT Fri Apr 17 2026
Key Messages:
- High confidence in a line of thunderstorms impacting the
terminals late this afternoon and evening. Localized wind
gusts in excess of 50 kts may occur in some portions of the
line of storms.
- Southerly winds this afternoon will gust to around 30 kts at
times before a gusty westerly to northwesterly wind shift
occurs with both the line of storms and again with a trailing
cold front later tonight.
- Post-frontal MVFR ceilings are expected tonight.
Confidence remains high in all terminals being affected by
thunderstorms today. Uncertainty remains with the precise timing
of the storms, but this evening still appears to the most likely
time frame for storms at the Chicago metro terminals, while RFD
could see storms as early as the mid-late afternoon. The storms
will likely affect the terminals as a solid line, though some
potential exists for RFD to be affected by more cellular or
supercellular convection before storms grow upscale into a line
with time. A gusty westerly to northwesterly wind shift and
localized wind gusts in excess of 50 kts may occur in some
portions of the thunderstorm line, and some hail and tornado
threat exists too -- primarily at RFD. The storms should last
for about 2-3 hours at any one location (possibly longer at RFD
if multiple rounds of storms materialize there) with rain then
continuing for a bit longer until a cold front pushes across
the area.
Prior to the arrival of the storms, southerly winds will gust
to around 30 kts at times this afternoon. Another gusty
northwesterly wind shift is expected behind the aforementioned
cold front with blustery post-frontal west-northwesterly winds
then continuing through the remainder of the TAF period.
Lastly, MVFR (and potentially IFR) ceilings are likely to occur
during the thunderstorms and again behind the cold frontal
passage. A return to VFR conditions is then likely to occur
sometime tomorrow morning.
Ogorek
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch through late tonight for ILZ003-ILZ004-ILZ005-
ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-ILZ019-ILZ020-
ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-ILZ103-ILZ104-ILZ105-
ILZ106-ILZ107-ILZ108.
IN...Flood Watch through late tonight for INZ001-INZ002-INZ010-
INZ011-INZ019.
LM...Small Craft Advisory until 10 PM CDT Saturday for the IL and
IN nearshore waters.
&&
Visit us at weather.gov/chicagoHazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
1218 PM CDT Fri Apr 17 2026
ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-181730-
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-
1218 PM CDT Fri Apr 17 2026 /118 PM EDT Fri Apr 17 2026/
This Hazardous Weather Outlook is for portions of north central
Illinois...northeast Illinois and northwest Indiana.
.DAY ONE...This Afternoon and Tonight.
Weather hazards expected...
Significant Thunderstorm Risk...with an associated:
Level 3 of 5 Damaging Wind Risk...up to 70 mph.
Level 2 of 5 Tornado Risk.
Level 1 of 5 Large Hail Risk...up to one inch in diameter.
Elevated Flooding Risk.
DISCUSSION...
A line of thunderstorms is expected to work across northern
Illinois this evening. Thunderstorms may be severe with damaging
wind gusts, hail, and perhaps a few tornadoes. Heavy rain may
also lead to instances of flash flooding.
.DAYS TWO THROUGH SEVEN...Saturday through Thursday.
Saturday...
Elevated Frost and Freeze Risk.
Sunday...
Significant Frost and Freeze Risk.
.SPOTTER INFORMATION STATEMENT...
Spotters will likely be needed this evening.
GENERAL STORM MOTION OF THE DAY:
Moving toward the northeast at 45 mph and then becoming east.
LMZ740>745-181730-
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-
1218 PM CDT Fri Apr 17 2026
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...This Afternoon and Tonight.
Weather hazards expected...
Hazardous conditions for small craft.
Elevated Thunderstorm Risk...with an associated:
Thunderstorm Waterspout Risk
Level 3 of 5 Thunderstorm Wind Gust Risk...up to 60 knots.
.DAYS TWO THROUGH SEVEN...Saturday through Thursday.
Saturday...
Hazardous conditions for small craft are likely.
Monday and Tuesday...
Hazardous conditions for small craft are likely.
KMD
Visit us at www.weather.gov/chicagoThe Milwaukee radar (KMKX), 95 km away, was scanning. The volume nearest the first event began at 21:36 UTC.
27 thunderstorm wind, 12 tornado, 7 flood, 6 hail, 2 heavy rain, 1 funnel cloud. Local standard time, as filed.
Storm chaser video showed a brief tornado touched down in an open field three miles from north of Pecatonica. The tornado was only on the ground for about two minutes and caused no known damage.
Several photos were received of broken windows and damaged siding from in and around Durand due to a combination of severe winds and hail.
A few hail reports came from south of Durand ranging in size from 1.25 to 2.25 inches in diameter.
A high-end EF-1 tornado began near Meridian Road between Favor Road and Steward Road southeast of Harrison, initially causing damage to trees and an outbuilding. Video footage from storm chasers documented the tornado becoming fully condensed and growing in size and intensity as it tracked east-northeastward across Favor Road and impacted two farmsteads, causing significant damage to a few outbuildings and snapping and uprooting multiple trees. Additional storm chaser footage showed the tornado intensifying again as it tracked northeastward across Gummow Road and then reaching peak intensity as it impacted a property along Freeport Road. At this property, the majority of an older two-story house's roof was removed, several trees were snapped, and an old barn was destroyed. The footage then captured the tornado making a sharp turn to the southeast and crossing Freeport Road once again before roping out and eventually dissipating in open fields near Owen Center Road.
Softwood trees were snapped near the intersection of Task Bridge Rd and Best Rd north of Pecatonica.
A personal weather station recorded 2.31 inches of rainfall in Rockford between 6:00 and 7:00 PM CST.
A personal weather station recorded 1.81 inches of rainfall near Timberlane between 6:00 and 7:00 PM CST.
An EF-1 tornado began near the intersection of Freeport Road and Bates Road southeast of Harrison, initially downing several tree branches at and near a small cemetery. The tornado produced additional tree damage as it tracked eastward along Roscoe Road before entering the west side of Roscoe and reaching its peak intensity as it tracked through the Hawks Point, Crystal Hills, and Oxford Commons subdivisions. There, multiple homes had portions of their roofs torn off or damaged and had sections of siding and fascia peeled off. A few homes also had their garage doors blown in, leading to parts of their garage walls getting blown out in a few cases. Numerous trees were also uprooted or damaged in these subdivisions. The tornado then continued eastward, knocking down several power poles along Gleasman Road and damaging a nearby farm outbuilding before crossing the Rock River. East of the Rock River, the tornado continued to cause extensive tree damage. Multiple additional houses sustained roof and fascia damage from the tornado as well. The tornado appeared to dissipate just as it reached the Winnebago-Boone County line. Extensive straight-line wind damage was also observed in close proximity to the tornadic circulation, particularly along its southern flank.
McHenry County emergency management reported a funnel cloud near Capron.
Standing water was reported on IL-173 near Oak Grove Rd in Alden.
An EF-1 tornado with peak winds near 95 mph appeared to have started just south of County Road 2200 N in Bureau County, where a barn structure sustained roofing damage. The tornado then moved northeastward into LaSalle County, producing damage to trees and farm outbuildings. Several wooden power poles were damaged just southeast of Mendota before a semi truck was blown over on I-39 as the tornado continued northeastward. The tornado then passed near Meriden, causing additional damage to trees and farm outbuildings before dissipating in an open field northwest of Earlville.
Multiple reports were received of around six inches of standing water across IL-23 south of Harvard.
Photos shared via social media showed doors blown out of a farm outbuilding near Earlville.
Metal roofing was damaged on a building north of Leland.
A two foot diameter tree was down and blocking the southbound lane of Somonauk Rd just north of Pratt Rd in Sandwich.
Flooding was reported along Rollins Rd in Fox Lake.
Three power poles were blown over (not snapped) west of Cornell.
Flooding was reported at US-45 and Washington St in Third Lake.
Flooding was reported at US-41 and Buckley Rd in North Chicago.
Power lines were downed causing a tree to catch fire at IL-38 and Kirk Rd in Geneva.
An EF-1 tornado with peak winds around 90 mph dropped in rural northeast McLean County before crossing into Livingston County southwest of Fairbury. In the few minutes the tornado survived in Livingston County, it damaged trees and a machine shed.
Several power lines were downed along IL-17 west of I-55 near Dwight.
An EF-1 tornado touched down on the west side of Gibson City, producing significant roofing damage to several buildings along 8th Street. The tornado continued ENE for several miles, producing primarily tree damage before lifting approximately three miles ENE of Gibson City.
A tree roughly two feet in diameter was snapped in Rolling Meadows.
An EF-1 tornado with peak winds near 95 mph touched down west of Loda with initial damage consisting of the collapse of two empty grain bins. The tornado continued ENE crossing into Iroquois County southwest of Buckley, downing and uprooting trees and blowing over semi-trucks on Interstate 57. Near the end of the damage track, the roof of a large outbuilding was removed, while nearby trees were snapped near the base and deposited in various directions.
An EF-1 tornado with peak winds near 95 mph touched down west of Loda with initial damage consisting of the collapse of two empty grain bins. The tornado continued ENE crossing into Iroquois County southwest of Buckley, downing and uprooting trees and blowing over semi-trucks on Interstate 57. Near the end of the damage track, the roof of a large outbuilding was removed, while nearby trees were snapped near the base and deposited in various directions.
An eight inch diameter tree limb was broken near the intersection of Oak St and American St in Paxton.
Photos shared via social media showed downed power poles and trees in Bonfield.
Tree damage was reported around Manteno.
Extensive tree damage was noted around Kankakee, including downed branches up to one foot in diameter.
Emergency management reported extensive tree damage around Watseka, particularly the southeast part of town. Numerous uprooted trees and snapped trunks were reported. Two separate personal weather stations on the south and southeast sides of town recorded a 72 mph and a 73 mph gust.
A brief EF-0 tornado caused damage to trees and outbuildings near and northeast of Woodland.
An EF-1 tornado appeared to touch down in an open field southwest of the intersection of E 1200 North Road and N 2450 East Road and impacted a farm, leading to damage to several structures. The tornado then continued northeastward, causing damage to trees and farm outbuildings. The peak intensity of the tornado occurred near the end of the path along the Iroquois and Newton County border, where over a dozen new wooden power poles were snapped at their base. The tornado then appeared to lift just northeast of US-24 in southwestern Newton County.
A brief EF-0 tornado started near Farr Creek in the small community of Eldridge within unincorporated Momence. Along the path, a combination of scattered tree damage and outbuilding roof damage was noted. As the tornado tracked north of the center of Momence, multiple power poles were downed along IL-1, with additional tree damage noted near 5500N. The tornado appears to have dissipated just northeast of Trimm Creek.
Photos shared showed snapped softwood trees and damaged fences in Momence.
Power poles and trees were downed in Beecher. A fire was started when one branch fell onto a power line.
This tornado began just west of the Illinois-Indiana state line near CR 9000N in northeast Kankakee County. The first instances of damage included uprooted softwood trees, downed large branches from hardwood trees, and minor structural damage noted near Stateline Rd on either side of the border. The storm continued northeast into Lake County, Indiana where it caused additional damage to trees and a handful of structures.
The gauge on Buffalo Creek at Wheeling quickly rose to minor flood stage amid heavy rain and thunderstorms.
The gauge on the north branch of the Chicago River at Deerfield quickly rose to minor flood stage amid heavy rain and thunderstorms.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2026Every state in 2026This day in weather historyThe tornado archive for Illinois, 2026Warnings in Illinois, April 2026
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: 1333713, 1333766, 1333810, 1333776, 1333770, 1333779, 1333715, 1333782, 1333785, 1333815, 1334330, 1334331, 1333717, 1333817, 1333818, 1333819, 1333821, 1333824, 1334304, 1333719, 1334305, 1333857, 1333863, 1333870, 1334306, 1333914, 1334307, 1334308, 1333909, 1333826, 1333712, 1333916, 1333721, 1333923, 1333727, 1333728, 1333926, 1333930, 1333945, 1333933, and more.