Humidity will return to the region today, setting the stage for an unsettled weekend for many areas. A boundary will develop across southeast South Dakota into western Minnesota by Friday night, moving only slightly southeastward through the weekend. This boundary will be a focus for storm development, mainly during the afternoon and nighttime hours, as waves of energy aloft interact with the boundary. Periods of moderate to heavy rainfall could produce total rainfall amounts from 1.5 to 3 inches from Friday night through Sunday, with locally higher amounts possible. Additional rainfall will be possible from another round of storms Sunday night into Monday, although location and amounts in that periods are less certain at this time. In addition to the potential for heavy rain, some strong to severe storms will be possible. The greatest threat of this will be Friday evening, mainly west of a line from Yankton to Sioux Falls to Marshall.
