Heat Advisory issued September 17 at 4:44PM CDT until September 18 at 8:00PM CDT by NWS St Louis MO
Issue date: 2026-09-17T21:44+00:00
* WHAT...Heat index values up to 103. * WHERE...In Illinois, Fayette IL, Montgomery IL, Calhoun IL, Greene IL, Jersey IL, and Macoupin IL Counties. In Missouri, Boone MO, Callaway MO, Lincoln MO, and Montgomery MO Counties. * WHEN...Until 8 PM CDT Friday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses.
