A strong storm system for mid-June brought two rounds of thunderstorm on Wednesday June 17th. The strongest round of storms occurred during the morning hours that brough damaging winds (some significant), heavy rain, and two EF-1 tornadoes in Illinois which occurred in Monmouth and Warsaw.
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 DVN wrote it up.
A strong storm system for mid-June brought two rounds of thunderstorm on Wednesday June 17th. The strongest round of storms occurred during the morning hours that brough damaging winds (some significant), heavy rain, and two EF-1 tornadoes in Illinois which occurred in Monmouth and Warsaw. |Many trees fell and power lines were damaged, along with several reports of flash flooding. There were also 4-5 train cars that were pushed off the railroad just south of Monmouth, IL in Warren County due to significant straight-line winds (estimated near 100 mph). Additional train cars derailed as a result of these cars being blown off.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Jun 17, 5:48 AM CST, 1 hour 22 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Quad Cities IA IL 648 AM CDT Wed Jun 17 2026 .KEY MESSAGES... - Slight/Enhanced Risk (level 2/3 of 5) for severe storms early this morning around sunrise, lasting through mid morning.The primary threat with these storms will be large to very large hail. - Late this morning and through the afternoon, much of the area will have a threat for more severe storms, with the whole area under a severe threat ranging from a Slight Risk (level 2 of 5) in our northwest to a Moderate Risk (level 4 of 5) in our extreme southeast/east. - High moisture content over the area will allow for heavy rainfall with any storms through today. Flash flooding will be possible in areas that see repeating rounds of storms, especially in areas that recently saw heavy rainfall. Flood Watch remains in effect for areas in West-Central Illinois. - Quiet weather will be seen through the second half of the work week, with the pattern becoming active again this weekend and beyond. && .SHORT TERM /THROUGH TONIGHT/... Issued at 215 AM CDT Wed Jun 17 2026 Severe weather is expected today as a seasonably strong system moves through the region. This will bring two rounds of storms to eastern Iowa, northwest Illinois, and northeast Missouri: a first round in the morning hours (4-9 AM) and second round in the afternoon hours (12-7 PM). Morning storms are anticipated to have a primary threat of large hail and low damaging wind potential, while afternoon storms will be capable of all hazards, including tornadoes. In addition, heavy rain will lead to localized flash flooding, especially in areas that see repeated rounds of storms. A strong shortwave will move from the Northern Plains into the Upper Midwest this morning. Pressure heights are near or at the NAEFS climatological minimum for mid-June, while winds aloft are near or at their maximum. This can be seen in a strong (50-60 kts) zonal jet at 500 mb sampled upstream with today's 00Z soundings. As this system translates into the Upper Midwest early this morning, southerly to southwesterly flow across the central Plains will provide warm air advection and moisture, which will amplify with the LLJ towards sunrise. As a result, dewpoints are forecast to rise into the mid to upper 60s within a few hours after sunrise, creating a sharp gradient between the northern and southern halves of the CWA. Lift along this WAA wing will provide the focus for morning convection, with showers and storms across the area. For the morning, the greatest risk for severe storms is along and south of Interstate 80, though there is some uncertainty given a strong cap over the region. If storms are able to develop, shear magnitude and direction suggests a mixed storm mode with multicell and supercells storms. A favorable severe environment of high lapse rates (7.5-8.5 degC/km) and up to 2000 J/kg of MUCAPE will support a primary risk of large hail. In addition to the risk of large hail, heavy rain will be possible with these these storms. This should be a soaking rain this morning and flash flooding threat should be limited, save for areas that have a long residence time with storms. This would primarily occur with cells that move over the same areas, as storms in this first round will be moving quickly towards the east at 40-50 kts. By mid- to late morning, these storms will move east into central Illinois, giving the airmass time to recover. At this point, strong southwesterly flow will continue to feed in moisture and instability, providing the energy necessary for the second round of storms. The greatest area of uncertainty is in how much recovery time will be possible, as morning storms and showers could persist longer than anticipated. If the atmosphere is able to recover following morning storms, an environment favoring supercells will develop, leading to the potential for all hazard severe thunderstorms. Around 12 PM, forcing along the cold front will plow into a region of 2000 (north) to 4000 (south) J/kg of CAPE, providing the forcing necessary for convective initiation. These storms will be fast moving, with a storm motion of 50 kts to the east. Large hail and damaging winds are possible with all storms. Tornado threat will be more limited, with the best low level shear supporting the highest tornado threat in west-central Illinois. These storms will exit into central Illinois around 6-7 PM. Once these storms move off to our east, CAA advection behind the front will support westerly to northwesterly winds up to 20-25 mph, leading to a breezy night. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 215 AM CDT Wed Jun 17 2026 Several pleasant, mainly dry days will follow our big system today. This will lead to temperatures below normal for highs and lows Thursday and Friday. Dry air should keep any rain threat low, though some energy skirting by aloft could bring some sprinkles or even a tiny thunderstorm as early as Friday night. Warm begins to spread northward again towards Saturday, as the flow aloft shifts towards a more active zonal flow regime. Models remain consistent in showing a warm front developing over the Midwest Saturday night, and having at least one significant wave of rain and thunderstorms/ potentially an MCS Sunday and Sunday night. There is latitude differences in the latest deterministic guidance, with the GFS shifting that axis a bit south, and the EC and GEM maintaining a more northerly frontal zone. Regardless, that will be the next period for us to focus on for both heavy rainfall and a thunderstorm risk. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 648 AM CDT Wed Jun 17 2026 A severe, bowing line of storms is bearing down on KCID around 12Z and will quickly track southeast through KMLI and KBRL in the 13Z to 14Z timeframe. There have been several reports of 50-60+ kt gusts with this line and expect that threat, along with heavy rain, hail, lightning, and IFR conditions to accompany the line of storms. Additional storms are following in the wake of this line, so expect scattered to widespread storms through early afternoon, with some strong to severe thunderstorm development again possible at KMLI and KBRL in the early afternoon with potential for damaging winds, hail, and possibly tornadoes. Farther north, KDBQ will remain north of the severe line of storms in more stratiform rain with embedded thunderstorm activity and occasional lightning through around 18-19Z. Additional isolated storms are possible with the cold frontal passage late this afternoon into early evening for KCID, KDBQ, and KMLI, and a lower potential (less than 30%) at KBRL. Winds remain breezy throughout the day outside of storms, with breezy winds and VFR conditions behind storms this afternoon and evening. Low-level wind shear develops at most terminals again for a few hours this evening. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...None. IL...Flood Watch through this evening for ILZ009-016>018. MO...None. && SHORT TERM...Ellingworth LONG TERM...Ervin AVIATION...NWS
Hazardous Weather Outlook National Weather Service Quad Cities IA IL 321 AM CDT Wed Jun 17 2026 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-180830- Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson- Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson- Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll- Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson- Warren-Hancock-McDonough-Scotland-Clark- 321 AM CDT Wed Jun 17 2026 This Hazardous Weather Outlook is for portions of north central Illinois...northwest Illinois...west central Illinois...east central Iowa...northeast Iowa...southeast Iowa and northeast Missouri. .DAY ONE...TODAY AND TONIGHT The Wapsipinicon River is experiencing flooding. Please see the latest Flood Statements and Flood Warnings for details. A strong system will bring the potential for severe thunderstorms today. A Moderate, level 4 of 5, risk is forecast for central Illinois, with an Enhanced, level 3 of 5, risk of severe thunderstorms south of Highway 30 and the remainder of the area under a Slight, level 2 of 5, risk. The first round of thunderstorms will continue through late morning today, with a primary risk of large hail. After 12 PM, a second round of thunderstorms is expected along and ahead of the cold front, with all severe weather hazards possible, including tornadoes. Localized flash flooding will be possible during both rounds, especially in areas that see multiple rounds of storms. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY The next chance for thunderstorms will be Sunday and Sunday night. .SPOTTER INFORMATION STATEMENT... Spotter activation is expected this morning and this afternoon. Ellingworth/Ervin
Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
728 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0711 AM Tstm Wnd Dmg 1 SE Walford 41.88N 91.83W
06/17/2026 Linn IA Emergency Mngr
Firework sales tent collapsed.
&&
argPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
730 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0729 AM Flash Flood 3 WSW Cedar Rapids 41.95N 91.73W
06/17/2026 Linn IA Trained Spotter
2 to 3 feet deep water with a car stuck at
location.
&&
argPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
732 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0701 AM Tstm Wnd Dmg 2 SE Atkins 41.97N 91.83W
06/17/2026 Benton IA Emergency Mngr
tree snapped at location.
&&
argPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
738 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0715 AM Tstm Wnd Gst 3 E Cedar Rapids 41.97N 91.61W
06/17/2026 E70 MPH Linn IA Trained Spotter
Estimated wind gust. Torrential rainfall
also occurring at time of report.
&&
12Preliminary Local Storm Report
National Weather Service Quad Cities IA IL
757 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0740 AM Tstm Wnd Gst Lowden 41.86N 90.93W
06/17/2026 E60 MPH Cedar IA CO-OP Observer
&&
argPreliminary Local Storm Report
National Weather Service Quad Cities IA IL
801 AM CDT Wed Jun 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0751 AM Rain 2 NE Muscatine 41.44N 91.05W
06/17/2026 M1.39 Inch Muscatine IA Trained Spotter
&&
argThe Quad Cities radar (KDVN), 76 km away, was scanning. The volume nearest the first event began at 13:08 UTC.
14 thunderstorm wind, 2 tornado, 2 flash flood. Local standard time, as filed.
A public report that several large trees were uprooted, some over 2 ft in diameter. Likely 80 mph or higher wind gusts based on degree of damage.
A trained spotter estimated thunderstorm wind gust of 60 MPH.
The ASOS at the Moline-Quad Cities Airport measured a peak thunderstorm wind gust of 60 knots.
An NWS Storm Survey found widespread thunderstorm damaging winds of 80 to 100 mph occurred across Warren County, starting near Little York, where 14 utility poles on the south side of Little York were downed and snapped. Tree damage was also noted throughout town.
A personal weather station near Rozetta Illinois measured a thunderstorm wind gust of 50 knots.
A trained spotter reported trees snapped at this location.
A trained spotter reported thunderstorm wind gusts of 60 MPH.
A short-lived EF-1 tornado developed in Monmouth Illinois and tracked southeast through town for 1.3 miles, with estimated maximum winds of 100 mph. Along the tornado path, structural damage was observed in the heart of Monmouth, with a few buildings seeing roofing damage, many windows blown out, and part of their brick walls damaged. Some houses also saw loss of shingles. Otherwise, a lot of damage was observed to trees along a clear convergent path, with numerous snapped, uprooted, and a lot of trees with downed large branches throughout. Some of these large tree sections were downed on houses as well.
A personal weather station north of New Windsor measured a thunderstorm wind gust of 52 knots.
An NWS Storm Survey found widespread thunderstorm damaging winds of 80 to 100 mph occurred across Warren County, starting near Little York and tracking southeast through Ormonde. Through this stretch, widespread tree and utility pole damage was noted.
A public report of multiple derailed double stack train cars by thunderstorm winds.
The Emergency Manager reported a thunderstorm wind gust of 72 MPH.
Spotter reported widespread tree damage across northern Warren County with many whole trees down and large branches down.
A brief EF1 tornado uniquely tracked across three states. This developed just inside Lee County, Iowa, with peak winds of 105 mph, and tracked southeast through Clark County, Missouri. It then continued across the Mississippi River into Hancock County, Illinois, impacting northern parts of Warsaw damaging primarily trees.
A public report of trees down in town.
Law Enforcement reported that 77th St West was closed due to flooding. The time of the report was estimated based on radar.
A trained spotter reported that ditches are full, creeks out of their banks between Colchester and Adair across the south central portion of the county with 3 to 5 inches of water on many of the back roads.
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, June 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: 1337548, 1337536, 1337537, 1337538, 1337546, 1337539, 1337540, 1337545, 1337524, 1337541, 1337547, 1337535, 1337542, 1337543, 1337534, 1337544, 1337550, 1337549.