For now, Thursday will be a mainly dry day with only a very small chance of a shower during the afternoon and early evening hours, with rain chances picking up after on-track activity has concluded for the day. Rain will be likely during the late-night hours on Thursday night and will continue through the pre-dawn hours on Friday. While much of the activity will have ended by the time the gates open on Friday morning, we'll continue to have a very small chance of a stray shower or two through the afternoon hours. The good news is that rain chances during on-track times on both days will only be 20%.
While Saturday will be a near-perfect day for races at "America's National Park of Speed," Sunday will be an "iffy" day weather-wise as a surface low will be approaching the area. The European forecast model has shower and storm activity moving into the area during the mid to late afternoon hours, while the GFS model has the activity arriving earlier during the late morning hours. To be on the safe side, I went with the shower and thunderstorm potential to start during the late morning hours and through the remainder of the day. As long as there is no lightning close to the track, that means we may have to see the world's greatest drivers try to conquer the course in the wet. Rain chances for now is set at 40%. We can get a better idea on the rainfall potential once the higher-resolution models come into view by Friday morning.