Forest-City based Winnebago Industries Inc. is planning to expand its manufacturing operations to nearby Lake Mills, the company said Wednesday. Winnebago and the city of Lake Mills have come to an agreement on a five-year lease of the 100,000-square-foot plant formerly owned and operated by Cummins Filtration. The Lake Mills facility will be used for the production of Winnebago's Class B motor homes. The expansion also will allow the company to transition its current Class B production facility in Charles City to additional subassembly operations. Winnebago Chairman and CEO Randy Potts said the company plans to start the process of staffing and equipping the Lake Mills facility immediately with a goal of starting initial production by early February.