Pacific-origin air surged into the Dakotas Friday with Bismarck, North Dakota hitting 51° and Pierre, South Dakota topping out at 53°—readings some 20° above normal. Westerly flow will bring that same air mass into northern Illinois this weekend. Some of the warmth Saturday will be used to melt the remaining snow cover, but high temperatures will still end up some 10° warmer than Friday.
A cold front will move out of Minnesota, sagging to the south end of Lake Michigan before becoming stationary later tonight, and then moving slowly north on Sunday. Cloudiness and scattered showers will be associated with this frontal boundary. Southerly winds will eventually pull very moist, high dew point (50°) air into this area Sunday into Monday giving a mild humid “feel”. Clouds and showers will keep temperatures from approaching the 60° mark.
