Weather Alerts For Markham, IL

# HEADLINE -------------------- FLOOD ADVISORY IN EFFECT UNTIL MIDNIGHT CDT TONIGHT # DETAILS -------------------- WHAT Rivers to remain near bankfull and may result in localized flooding near streams and rivers. WHERE Portions of northeast Illinois, including the following county, Cook and northwest Indiana, including the following county, Lake IN. WHEN Until midnight CDT tonight. IMPACTS Creeks and streams may rise to near bankfull. ADDITIONAL DETAILS - At 659 PM CDT, Gauges report rising streams and rivers due to earlier heavy rainfall. - SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE - Hammond, Gary, Tinley Park, Calumet City, Portage, Merrillville, Chicago Heights, East Chicago, Schererville, Hobart, Lansing, Oak Forest, Harvey, Highland, Munster, Dolton, Park Forest, Homewood, Matteson and Frankfort. - http://www.weather.gov/safety/flood ISSUED AT Wednesday, June 17, 2026 at 7:02 PM CDT ISSUED BY National Weather Service Chicago IL HEADER Flood Advisory # PRECAUTIONARY/PREPAREDNESS ACTIONS -------------------- A Flood Advisory means minor flooding along waterways and other poor drainage areas is imminent or may already be occurring. Persons in the advisory area should use caution and avoid flood waters. # AREAS AFFECTED -------------------- Cook IL, Lake IN IN

There is a Marginal Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS SOUTH-CENTRAL PORTIONS OF ILLINOIS AND INDIANA THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ALONG THE NORTHERN GULF COAST SUMMARY A corridor of tornado, damaging hail and wind threat persists from south-central Illinois into Indiana this evening. A broader zone of severe hail and wind extends from southeast Kansas into western Ohio. IL...IN...MO...OH The greatest tornado threat corridor extends from south-central IL into parts of central/southwest IN this evening, where air mass recovery continues out of the southwest. Supercells in this region have been tornadic at times, also producing large damaging hail. Given the extreme shear downstream, and continued low-level theta-advection, the environment remains conditionally favorable for a couple strong tornadoes through this evening over a small portion of IL and IN. The threat may extend as far east as western/central OH later tonight, with tornado potential depending on instability. For more information see mesoscale discussion 1171. Northern Gulf Coast A moist and unstable environment exists across LA and into southern MS/AL ahead of Arthur. Low-level shear may increase further this evening, with periodic mini-supercell potential and tornado risk. For more information see mesoscale discussion 1172.