By Doug Schneider
A high pressure system will be over the Great Lakes region on Thursday and Friday, which should provide nice weather those days. However, an upper level trough will move into the northern Great Plains on Saturday. A southerly flow on the west side of the high pressure system will supply increasing moisture into the St. Louis area ahead of this trough. Showers and thunderstorms are expected to develop over Iowa and northern Missouri on Saturday afternoon, and track toward the southeast. There is a chance that they could arrive at WWTR during the race. Exact timing is still uncertain this far out, but I would put the chance of a shower or storm during the race at 40%. Check back for updates later in the week as the timing becomes more clear.