The National Weather Service in Chicago has issued a * Flash Flood Warning for... Southeastern Cook County in northeastern Illinois... East Central Grundy County in northeastern Illinois... Northeastern Kankakee County in northeastern Illinois... Will County in northeastern Illinois... Lake IN County in northwestern Indiana... West Central Porter County in northwestern Indiana... * Until 945 PM CDT. * At 350 PM CDT, Doppler radar indicated thunderstorms producing heavy rain across the warned area. Between 1 and 3 inches of rain have already fallen over the past few hours across parts of the warned area, with additional thunderstorms producing torrential rain moving into the warned area. Flash flooding is ongoing or expected to begin shortly. HAZARD...Flash flooding. SOURCE...Doppler radar. IMPACT...Rapid-onset flooding of small creeks and streams, urban areas, highways, streets and underpasses, as well as other poor drainage and low lying areas. * Some locations that will experience flash flooding include... Chicago, Joliet, Hammond, Gary, Orland Park, Tinley Park, Oak Lawn, Calumet City, Portage, Merrillville, Chicago Heights, Roseland, Englewood, South Shore, East Chicago, Schererville, Hobart, Lansing, Oak Forest and Crown Point. Additional rainfall amounts of 1 to 3 inches are possible in the warned area over the next 1 to 2 hours. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Warning means rapid-onset flooding is imminent or may already be occurring. Persons along creeks, drainage ditches, and other waterways should take immediate precautions to protect life and property. Expect flash flooding of creeks, ditches, canals, and storm sewers, as well roadways, underpasses, farmland, and other poor drainage areas.