Given that many areas (see below) have received 2" or more of rain in just the last four days, additional heavy rains will cause a multitude of problems.
If you are interested in details, please allow me to break it down step-by-step.
Soils Are Saturated
The area in yellow (4-day rainfall) is already experiencing flooding. That includes "moderate" flooding on the Missouri.
The two week rainfalls are even more impressive. Some spots have received more than ten inches.
"Normal" Storms Plus a Hurricane
We have a front quasi-stationary across the region which will trigger periodic thunderstorms the next five days or so, especially at night.
Then, the remains of Hurricane Blanca threatens to move into the Central Plains bringing even more heavy rain. Again, a qualifier, since we are talking at least five days, the exact path is not certain.
Some Good News
There happens to be a major weather research program in progress in the Central Plains called PECAN (everything in meteorology has to have an acronym!). So, if this event does occur, the data being collected will help meteorologists make better, and more certain, forecasts of these types of events in the future.
Of course, I'll be updating on this from time to time.