Expect more days with near-record humidity & moisture
The all-time highest values in those cities are around 2.4". You can see that South Bend wasn't far off from those historical values. And, it's values like these that are becoming more common during the spring and summer. Even in the winter, Michiana is seeing more moisture and heavier rain events.These air masses with extremely high amounts of moisture and humidity are allowing more and more heavy rain events to occur. According to the current 30-year climatological average, South Bend sees just over 38" of rain per year. If we take a look at the most recent data between 1991 and 2017, though, South Bend's average has jumped to nearly 40" per year. That is a substantial change in just a handful of years. At that pace, the city could be averaging 50" of rain per year by the end of the century. That same story exists for the rest of Indiana and all of Michigan as well. Average annual rainfall amounts are on the rise from Evansville and Indianapolis to Detroit, Grand Rapids and the Upper Peninsula of Michigan.
For more information on this topic, please take a look at this slideshow prepared by the National Weather Service in North Webster, Indiana. In the meantime, expect additional moderate to possibly heavy rain by Friday and Saturday after a brief break late Wednesday and Thursday.