Weather Warnings for Illinois

Issued by the National Weather Service

Current watches, warnings, and advisories for Illinois
Alerts Updated: August 13, 2026, 1:22 am  UTC


Special Weather Statement issued August 12 at 6:42PM CDT by NWS Quad Cities IA IL

Summary: Conditions are favorable for the development of funnel clouds, and possibly brief, weak tornadoes. At 545 PM, there was a funnel cloud reported near Ainsworth, Iowa. The National Weather Service will continue to closely monitor the situation, and may issue a Tornado Warning if the threat increases. If you see a funnel cloud or tornado, seek shelter indoors and then contact your local law enforcement agency for relay to the National Weather Service.
Severity:  Moderate    Effective:  August 12, 2026, 6:42 pm      Expires:  August 12, 2026, 9:00 pm
Area:  Keokuk; Washington; Louisa; Jefferson; Henry; Des Moines; Van Buren; Lee; Mercer; Henderson; Warren


Flood Advisory issued August 12 at 6:12PM CDT until August 12 at 9:15PM CDT by NWS Paducah KY

Summary: * WHAT...Urban area and small stream flooding caused by excessive rainfall is expected. * WHERE...Northern Franklin County in south central Illinois... Hamilton County in south central Illinois... Southern Jefferson County in south central Illinois... * WHEN...Until 915 PM CDT. * IMPACTS...Minor flooding in low-lying and poor drainage areas. * ADDITIONAL DETAILS... - At 612 PM CDT, Doppler radar indicated heavy rain due to thunderstorms. This will cause urban and small stream flooding. Between 1 and 2 inches of rain have fallen. - Additional rainfall amounts up to 1 inch are expected over the area. This additional rain will result in minor flooding. - Some locations that will experience flooding include... Mcleansboro, Rend Lake Area, Sesser, Ina, Dahlgren, Waltonville, Bonnie, Belle Rive, Ewing, Nason, Broughton, Macedonia and Belle Prairie City. - http://www.weather.gov/safety/flood
Severity:  Minor    Effective:  August 12, 2026, 6:12 pm      Expires:  August 12, 2026, 9:15 pm
Area:  Franklin, IL; Hamilton, IL; Jefferson, IL


Flood Warning issued August 12 at 2:48PM CDT until August 13 at 7:00PM CDT by NWS Chicago IL

Summary: ...The Flood Warning is extended for the following rivers in Illinois... Thorn Creek at Thornton affecting Cook County. For the Thorn Creek...including Thornton...Minor flooding is forecast. * WHAT...Minor flooding is occurring and minor flooding is forecast. * WHERE...Thorn Creek from Near Glenwood downstream to confluence with Little Calumet River, including the Thornton gauge. * WHEN...Until Thursday evening. * IMPACTS...At 11.0 feet, 187th Street threatened in Glenwood. * ADDITIONAL DETAILS... - At 2:30 PM CDT Wednesday the stage was 9.6 feet. - Recent Activity...The maximum river stage in the 24 hours ending at 2:30 PM CDT Wednesday was 10.6 feet. - Forecast...The river is expected to rise to a crest around 10 feet tonight. It will then fall below flood stage tomorrow afternoon. - Flood stage is 9.0 feet. - http://www.weather.gov/safety/flood
Severity:  Severe    Effective:  August 12, 2026, 2:48 pm      Expires:  August 13, 2026, 9:00 am
Area:  Cook, IL


Extreme Heat Warning issued August 12 at 1:14PM CDT until August 15 at 9:00PM CDT by NWS St Louis MO

Summary: * WHAT...Dangerously hot conditions with heat index values up to 111. * WHERE...Portions of south central and southwest Illinois and central and east central Missouri. * WHEN...Until 9 PM CDT Saturday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
Severity:  Severe    Effective:  August 12, 2026, 1:14 pm      Expires:  August 13, 2026, 4:15 am
Area:  Clinton; Washington; Randolph; Madison; St. Clair; Monroe; Boone; Moniteau; Cole; Osage; Callaway; Montgomery; Gasconade; Warren; St. Charles; Franklin; St. Louis; St. Louis City; Jefferson


Heat Advisory issued August 12 at 1:14PM CDT until August 15 at 9:00PM CDT by NWS St Louis MO

Summary: * WHAT...Heat index values up to 109. * WHERE...Portions of south central and southwest Illinois and central, east central, and northeast Missouri. * WHEN...Until 9 PM CDT Saturday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
Severity:  Moderate    Effective:  August 12, 2026, 1:14 pm      Expires:  August 13, 2026, 4:15 am
Area:  Greene; Macoupin; Montgomery; Bond; Fayette; Marion; Calhoun; Jersey; Monroe; Ralls; Pike; Audrain; Lincoln


Heat Advisory issued August 12 at 1:11PM CDT until August 13 at 11:00AM CDT by NWS Paducah KY

Summary: * WHAT...For the Heat Advisory, heat index values up to 107. For the Extreme Heat Warning, dangerously hot conditions with heat index values up to 110 expected. * WHERE...Portions of southern Illinois, southwest Indiana, western Kentucky, and southeast Missouri. * WHEN...For the Heat Advisory, until 11 AM CDT /noon EDT/ Thursday. For the Extreme Heat Warning, from 11 AM CDT /noon EDT/ Thursday to 8 PM CDT /9 PM EDT/ Sunday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
Severity:  Moderate    Effective:  August 12, 2026, 1:11 pm      Expires:  August 13, 2026, 4:15 am
Area:  Jefferson; Wayne; Edwards; Wabash; Franklin; Hamilton; White; Jackson; Williamson; Saline; Gallatin; Union; Johnson; Pope; Hardin; Alexander; Pulaski; Massac; Gibson; Pike; Posey; Vanderburgh; Warrick; Spencer; Fulton; Hickman; Carlisle; Ballard; McCracken; Graves; Livingston; Marshall; Calloway; Crittenden; Lyon; Trigg; Caldwell; Union; Webster; Hopkins; Christian; Henderson; Daviess; McLean; Muhlenberg; Todd; Perry; Bollinger; Cape Girardeau; Wayne; Carter; Ripley; Butler; Stoddard; Scott; Mississippi; New Madrid


Extreme Heat Warning issued August 12 at 1:11PM CDT until August 16 at 8:00PM CDT by NWS Paducah KY

Summary: * WHAT...For the Heat Advisory, heat index values up to 107. For the Extreme Heat Warning, dangerously hot conditions with heat index values up to 110 expected. * WHERE...Portions of southern Illinois, southwest Indiana, western Kentucky, and southeast Missouri. * WHEN...For the Heat Advisory, until 11 AM CDT /noon EDT/ Thursday. For the Extreme Heat Warning, from 11 AM CDT /noon EDT/ Thursday to 8 PM CDT /9 PM EDT/ Sunday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
Severity:  Severe    Effective:  August 12, 2026, 1:11 pm      Expires:  August 13, 2026, 4:15 am
Area:  Jefferson; Wayne; Edwards; Wabash; Franklin; Hamilton; White; Jackson; Williamson; Saline; Gallatin; Union; Johnson; Pope; Hardin; Alexander; Pulaski; Massac; Gibson; Pike; Posey; Vanderburgh; Warrick; Spencer; Fulton; Hickman; Carlisle; Ballard; McCracken; Graves; Livingston; Marshall; Calloway; Crittenden; Lyon; Trigg; Caldwell; Union; Webster; Hopkins; Christian; Henderson; Daviess; McLean; Muhlenberg; Todd; Perry; Bollinger; Cape Girardeau; Wayne; Carter; Ripley; Butler; Stoddard; Scott; Mississippi; New Madrid


Extreme Heat Warning issued August 12 at 1:11PM CDT until August 16 at 8:00PM CDT by NWS Paducah KY

Summary: * WHAT...Dangerously hot conditions with heat index values up to 112. * WHERE...Perry County Illinois. * WHEN...Until 8 PM CDT Sunday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
Severity:  Severe    Effective:  August 12, 2026, 1:11 pm      Expires:  August 13, 2026, 4:15 am
Area:  Perry