High Quality Content by WIKIPEDIA articles! National Weather Service Chicago, currently based in Romeoville, Illinois, is a weather forecast office responsible for monitoring weather conditions for 23 counties in Northern Illinois, the Chicago metropolitan area and Northwest Indiana. The Army Signal Service established the first federal weather office in the region in Chicago on October 15, 1870. During May 1894 the Chicago Weather Bureau was given a new forecast area extending from the Great Lakes region all the way to the Rocky Mountains. The current National Weather Service Chicago is located in Romeoville and is in charge of issuing local forecasts and weather warnings for the Chicago area. It is one of only two National Weather Service offices in Illinois, the other being National Weather Service Central Illinois in Lincoln, Illinois. The National Weather Service Chicago forecast office is located adjacent to the Lewis University Airport in Romeoville, Illinois.