The timing of rain on Friday is coming into better focus, with the morning having the best chance of seeing showers and maybe a few thunderstorms. The coverage of showers will decrease in the afternoon, but there could still be some on/off showers through the afternoon. Total rainfall amounts around a quarter of an inch are expected on Friday, but again, most of that will be in the morning. I think it will be hard to get the track dry for practice in the afternoon, but that will depend on the frequency of showers hitting the track. There could be enough of a break to get some practice in.
Colder air with a high pressure system will build into the area on Saturday. There will be more clouds around in the morning, but they will clear by the afternoon, leaving mostly sunny skies. Highs will only be in the lower to mid 60s, with a north wind at 10 to 15 mph.
Race day looks about as nice as you can hope for. Sunny skies, high temperatures around 70, and a northeast wind at 5-10 mph. Bring a jacket to wear in the morning as the day will start off in the upper 40s and 50s.