We will see a spray of some clouds and maybe a fading thundershower late Friday night into early Saturday morning. After the morning, spot thundershowers; much of Saturday will be rain free, but hot and humid.
That will change Saturday evening.
Sometime between 6 p.m. and midnight, a fast moving line of severe thunderstorms will drop rapidly southeast across eastern Missouri and western Illinois. This line of storms will have the potential to produce strong winds, large hail, and possibly a quick spin-up tornado or two. This line will eventually impact pretty much everyone in the viewing area by late Saturday night.
So while the storm threat (and severe threat) will be very limited during the day Saturday, the evening will be a time to pay close attention to that northwest horizon for fast approaching severe storms.