Here is the Qualitative Precipitation Forecast (QPF) for the next 7 days, according to the National Weather Service. This shows the potential amounts of rainfall, your mileage may vary. The area in shades of violet and purple are 1.5 to 2.5 inches. Shades of blue are 1 to 1.5 inches. Most of this is expected to fall in the next 3 days.
Here is how much rain has fallen so far in May across the Midwest.