The National Weather Service in Chicago has issued a * Severe Thunderstorm Warning for... Northern Livingston County in central Illinois... Southern La Salle County in north central Illinois... Southern Will County in northeastern Illinois... Southern Grundy County in northeastern Illinois... Northern Kankakee County in northeastern Illinois... Southeastern Cook County in northeastern Illinois... Porter County in northwestern Indiana... Lake County in northwestern Indiana... * Until 915 PM CDT. * At 822 PM CDT, severe thunderstorms were located along a line extending from Ogden Dunes to near Wilmington to near Wenona, moving east at 55 mph. HAZARD...70 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect considerable tree damage. Damage is likely to mobile homes, roofs, and outbuildings. * Locations impacted include... Hammond, Gary, Portage, Merrillville, Valparaiso, Chicago Heights, Schererville, Hobart, Lansing, Crown Point, Highland, Munster, Park Forest, Matteson, Frankfort, Griffith, St. John, Streator, Chesterton and Lake Station. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building.