The day will start off cloudy, with temperatures for practice in the upper 60s and high humidity. By late morning, I expect to see some breaks in the clouds that will allow temperatures to rise through the 70s by early afternoon. The main question at this time is how early the thunderstorms develop in the afternoon. I'm seeing some conflicting signals in the models about this. My best estimate is that the chances of seeing showers and thunderstorms will start ramping up around 2 pm, with showers likely by 6 pm. Keep your fingers crossed that the coverage of showers will be sparse enough before all the on-track action is done. There is some potential for strong to severe thunderstorms in the evening, but I think this threat will come after qualifying has ended.
If there are delays in qualifying, Monday's weather looks like it might cooperate, at least for part of the day. Most of Monday morning and early afternoon look dry, but the chance of showers and thunderstorms will once again be rising through the afternoon. Highs on Monday will be in the lower 80s.
While it's still a little early to pin down the Indy 500 forecast with much confidence, I'll give you a general idea of what I'm seeing from the models. The weather looks nice and dry for the middle of the week, with high pressure over the region through Saturday. Temperatures will be getting warmer each day, with highs in the 60s on Wednesday, then around 70 on Thursday, and near 80 by Saturday. Right now, it looks like there will be a chance of rain on Sunday. It's too early to be much more precise than that at this point as there are some timing differences in the models. I'll have a more detailed forecast posted tomorrow evening, and hopefully things will be a little more clear.