Delta is forecast to make landfall along the Louisiana coast on Friday, then track across Mississippi, Tennessee, and eastern Kentucky through Sunday. The cloud shield on the outer fringes of the hurricane will start to spread over Charlotte on Friday. The morning will start with mostly sunny skies, but high clouds will increase through the day. Rain should hold off until after the evening IMSA practice session.
Some of the outer rain bands from Delta will start to spread into the area late Friday night or Saturday morning. Through the day, there will be numerous showers around the track, but they will be on and off - it doesn't look like a washout at all. I expect that the majority of this rain will be light, with the total amount of rain expected all day being around one or two tenths of an inch. When I made Monday's forecast I was afraid that heavy rain would be possible, but due to the westward shift of the forecast track, I am much less concerned about that now. This is why I have lowered the Impact rating to low. It will make for some interesting tire strategy during the racing, but it should all be able to be held as scheduled. It will be breezy on Saturday, with a southeast wind at 10-20 mph, gusting up to 30 mph at times.
On Sunday, there will still be showers in the area, mostly in the morning, but they should be scattered and occur less frequently than on Saturday. It is possible that showers could end in time for the Cup race in the afternoon, but I can't say I'm very confident in that yet. An isolated thunderstorm can't be ruled out, but the chance of one at the track is low.