A fairly typical weather pattern for north Texas is expected this weekend as IndyCar moves to Texas Motor Speedway, which should mean dry conditions with warm temperatures for the end of the week.
On Friday there will be a southerly flow in the low levels, which will bring some moisture off the Gulf of Mexico. However, there will be a ridge in the mid and upper levels of the atmosphere, which should provide stable conditions over north Texas that will suppress thunderstorms. There will be a dryline developing over west Texas in the afternoon, but it does not appear that there will be a lot of storms developing along it, and if they do, they will stay well to the west of TMS. I'm not 100% confident that there won't be an isolated storm on Friday evening, but the chances of rain at the track appear too low to mention right now.
I'm more confident that Saturday will be dry, as the atmosphere looks like it will be drier and more stable than Friday. A dry northwesterly flow in the mid and upper levels will continue, and if storms are able to form on the dryline, they will stay well to the west.