I just finished looking over some of the new information regarding Tuesday's storm threat. It looks like there will be a slight risk of severe weather across the area, with an increased threat between Noon and 9pm. Before Noon and in the early morning hours a few storms from Western and Central Missouri may still be producing small hail as they weaken and move towards the Bi-state. So, while morning rain and storms are possible, the heaviest will be West of the St. Louis Metro and could impact areas like Gasconade County, MO.
In the afternoon there will be quite a temperature spread with cooler air North and warm moist air South of St. Louis. As the two air masses collide and energy rolls through the atmosphere, it could spark several strong storms with hail, damaging winds and possibly a tornado or two. Again, it appears the greatest risk for severe weather area wide is between Noon and 9PM tomorrow.
Also, there is a Flash Flood Watch that will go into effect for the News 4 viewing area Tuesday morning through Tuesday evening. There could be some areas that get hit repeatedly by isolated downpours. These downpours could result in flash flooding from generally a quick 1-2" of rain.
By late evening tomorrow and through Wednesday we get a break with some dry weather. But be prepared for more storms Thursday with the possibility of both heavy rain and severe weather.