Flash flooding a concern after constant rain in forecast

ST. LOUIS, MO — All systems are go for a major rainfall event across the Bi-State area. The storms we get today (Thursday) will be mainly in the afternoon and there will be breaks in the coverage. Consider it the "warm-up act" to the main event which really doesn't get rolling until late Friday, and will last through early Sunday.

This is a slightly different look at rainfall probabilities. Breaking it down into three categories:

  • There is a slim chance of seeing less than 2" of rain (about 10%)
  • There is a very good chance rainfall totals will range from 2" to 5"....(the most likely range).
  • However, there is still a decent shot at more than 5" of rain (30%).

So, I'm going to forecast 2" to 5" with a few spots exceeding 6". Which makes this a pretty significant rainfall event for the region.

The major rivers (Mississippi River and Missouri River) may reach at least moderate flood levels with some potentially significant high water on the smaller rivers, like the Cuiver, Meramec and Big Rivers, along with Dardenne Creek. A lot will depend on how fast the rain comes down and exactly where the heaviest totals end up.