Heavy downpours, severe storms and a flash flood threat are looming over parts of the Upper Midwest and Great Lakes heading into the work week ahead, including several major cities from Chicago to Pittsburgh. Monday's level 2 of 5 severe storm threat shifts east slightly, and covers major cities, including Chicago, Detroit, Cleveland and Pittsburgh. However, storms that track over the same area over and over again also pose a flash flood threat. Rain forecast Great Lakes Sunday-Wednesday(FOX Weather)A 2 out of 4 flash flood threat is in place along the southern Great Lakes starting Sunday and continuing through Wednesday, according to the FOX Forecast Center. Stick with FOX Weather as we continue to track the storms and give you the latest forecast and information.