There is a surface boundary that is forecast to stall out over the Wisconsin/Illinois border, and this may bring showers and thunderstorms to the area on Thursday, especially during the afternoon hours. There is a possibility that the weather on Wednesday could make the storms form farther to the south on Thursday, we'll just have to wait and see on that part. By Friday, all of the shower activity will have moved out of the area, and the day is setting up to be nice and dry with mild temperatures.
We'll have a slightly active weather pattern setting back up over the area for Saturday as troughing starts to form and begins to move near the area. This will allow several waves to move through the area, but as of now, rain chances will be small and mainly during the afternoon hours. Same story on Sunday, but rain chances will be even smaller, and I wouldn't be surprised if I will be able to remove those rain chances out of the forecast within the next day or two.
Bottom line: We'll mention the chance of rain on both Saturday and Sunday, but more than likely it will stay dry at the track. I'll have a really good idea by Wednesday night on what the weather will hold for us at Road America.