Alert archive / Illinois / Tornado Watches in 2026

Tornado Watch 340

June 17, 202646 counties in Illinois

The Storm Prediction Center issued this tornado watch at Jun 17, 2026, 7:49 AM CDT for 46 counties in Illinois. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jun 17, 2026, 7:49 AM CDT (12:49 UTC)
Expired
Jun 17, 2026, 2:18 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
75 kt
All 46 counties

Adams County, IL, Brown County, IL, Bureau County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Hancock County, IL, Iroquois County, IL, Jersey County, IL, Knox County, IL, LaSalle County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 58 km from the middle of the area, began a volume at 12:52 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
50%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
95%
One or more gusts of 65 knots or more
50%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 17, 7:57 AM CDTSevere Thunderstorm Warning Considerable damage threatDVNHancock, Henderson, McDonough, Mercer, Warren63 min
Jun 17, 8:14 AM CDTSevere Thunderstorm WarningILXFulton, Knox, Peoria, Stark61 min
Jun 17, 8:25 AM CDTSevere Thunderstorm Warning Considerable damage threatDVNBureau, Henry, Mercer, Rock Island, Whiteside65 min
Jun 17, 8:43 AM CDTSevere Thunderstorm Warning Considerable damage threatDVNHancock62 min
Jun 17, 8:54 AM CDTSevere Thunderstorm Warning Considerable damage threatDVNHancock, Henderson, McDonough, Warren66 min
Jun 17, 9:01 AM CDTSevere Thunderstorm WarningLSXAdams, Brown, Pike30 min
Jun 17, 9:03 AM CDTSevere Thunderstorm Warning Considerable damage threatILXFulton, Marshall, Peoria, Stark, Tazewell, Woodford57 min
Jun 17, 9:08 AM CDTFlash Flood WarningDVNMcDonough, Warren6 hr
Jun 17, 9:13 AM CDTSevere Thunderstorm WarningDVNBureau, Putnam47 min
Jun 17, 9:45 AM CDTSevere Thunderstorm WarningILXLogan, Mason, Menard, Sangamon60 min
Jun 17, 9:54 AM CDTSevere Thunderstorm WarningILXMcLean, Woodford66 min
Jun 17, 10:02 AM CDTSevere Thunderstorm WarningLOTLivingston58 min
Jun 17, 10:09 AM CDTSevere Thunderstorm WarningILXDeWitt, Macon, Moultrie, Piatt66 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 0.8 hours before the alert went out and 111 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2026-06-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2026-06-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 138 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2139 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
138 m²/s²
0-3 km storm-relative helicity
239 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

343 
WWUS20 KWNS 171247
SEL0  
SPC WW 171247
ILZ000-MOZ000-172000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 340
NWS Storm Prediction Center Norman OK
750 AM CDT Wed Jun 17 2026

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and Northern Illinois
  Far Northeast Missouri

* Effective this Wednesday morning and afternoon from 750 AM
  until 300 PM CDT.

* Primary threats include...
  A few tornadoes and a couple intense tornadoes possible
  Widespread damaging winds expected with isolated significant
    gusts to 85 mph possible
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter possible

SUMMARY...An intense line of storms with history of significant wind
gusts across Iowa will continue to quickly progress
east-southeastward into and across central/northern Illinois early
today. This includes a significant potential for wind damage aside
from an increasing risk for tornadoes, as well as bouts of large
hail.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 20 miles south southwest of
Burlington IA to 35 miles east of Champaign IL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 339...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 75 knots. A few cumulonimbi with maximum tops to 600. Mean
storm motion vector 30045.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 17, 3:55 AM CDTSevere Thunderstorm WatchSPCCarroll, Henderson, Henry, Jo Daviess, Mercer, Rock Island and 2 more7 hr
Jun 17, 5:42 AM CDTMesoscale DiscussionSPCCarroll, Henderson, Henry, Jo Daviess, Knox, Mercer and 3 more2 hr
Jun 17, 8:16 AM CDTMesoscale DiscussionSPCBrown, Bureau, Cass, Champaign, Christian, Clark and 37 more59 min
Jun 17, 10:43 AM CDTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Coles, Crawford and 19 more2 hr
Jun 17, 1:03 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Cass, Champaign, Christian and 24 more117 min
Jun 17, 2:14 PM CDTTornado WatchSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 45 more11 hr
Jun 17, 4:00 PM CDTMesoscale DiscussionSPCAdams, Bond, Brown, Calhoun, Cass, Champaign and 37 more60 min
Jun 17, 6:50 PM CDTMesoscale DiscussionSPCChristian, Clark, Coles, Crawford, Cumberland, Montgomery and 2 more115 min
Jun 16, 11:28 PM CDTMesoscale DiscussionSPCBuena Vista, Cherokee, Clay, Dickinson, Lyon, O'Brien and 3 more2 hr
Jun 17, 2:36 AM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Benton, Black Hawk, Boone and 74 more2 hr
Jun 17, 12:37 PM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Floyd, Howard, Mitchell, Winneshiek and 1 more83 min
Jun 17, 1:17 PM CDTSevere Thunderstorm WatchSPCAllamakee, Chickasaw, Floyd, Howard, Mitchell, Winneshiek4 hr
Jun 17, 4:45 PM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Clayton, Delaware, Dubuque, Fayette and 2 more2 hr

Nearby

Tornado Watches in Illinois, 2026Every tornado watch in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.