9:15 pm Update: Light to moderate rain beginning to move into northwest Illinois and southern Wisconsin. Rain will continue to spread northeast through the night. Heavy rain has already fallen in Iowa with over an inch being reported in places like Cedar Rapids and Belle Plaine.
Gulf moisture will continue to lift north through the Southern Plains and into the Midwest this evening and overnight. Heavy rain will move from southwest to northeast through Missouri, Iowa and Wisconsin this evening before spreading east into Northern Illinois later tonight and by dawn Sunday morning. Rainfall amounts over an inch to an inch and a half will be possible with the bulk of rain coming early Sunday and then possibly again by Sunday afternoon as a secondary low lifts into northwest Illinois. Light showers and drizzle will persist through Sunday evening until colder air funnels in from the northwest late Sunday night with a change over to slushy snow by mid-day Monday.
With the expected rain tonight and Sunday it's possible minor flooding may occur along streams, creeks and local rivers may rise. You'll also likely notice standing water in ditches and low lying areas. The snow depth continues to dwindle away but it still looks like the snow/water equivalent remains between 1"-2". This means if we were to melt the current snow cover on the ground we would get roughly between half an inch to an inch of water. Also, the ground remains frozen beneath the snowpack and any heavy rain that does occur will likely runoff rather than infiltrate into the soil. It's possible that some of the local rivers may approach flood stage by early next week.