Our guess is that quite a few runners will be in attendance at GTH, and some might be looking for some jogging paths, or tips on where to jog.
We can tell you that Downtown St. Louis is a relatively gentle area, with minimal, small rolling hills. If you've gone on the road and thought, "wow, this city is hilly," that's probably not an idea that'll hit you in the STL.
You can find some maps for the area at walkjogrun.com. When typing in America's Center, we found this map and link.
The St. Louis Track Club offers a pretty complete selection of the running paths favorited by area runners. Many are a bit outside of the City of St. Louis, let alone Downtown, but there are some nice paths here.
A nice blog on STL running can also be found at runstlouis.com. Another useful resource.
For weather forecasts, click on the website for the area's largest metro paper, the Post-Dispatch. It's at STLtoday.com, and you'll want to look at the upper right-hand corner of the homepage for weather info.
May your miles be smooth, our runner friends!