By Doug Schneider

Ideal weather conditions can be expected at Road Atlanta this weekend for Petit Le Mans. A front is currently located well south of the area, near the Georgia/Florida border. This will act like a barrier to Hurricane Milton, which will track across central Florida, and stay well away from northern Georgia. High pressure along the East Coast will continue to build over northern Georgia through the rest of the week, and provide dry conditions with pleasant temperatures. It will get a little chilly at night if you're camping at the track, especially Saturday morning when lows will drop into the 40s. Lows on Saturday night will be around 50 degrees. 

By Doug Schneider

Beautiful weather is expected this weekend at VIR. If you have never been to one of the prettiest race courses in the country, this is a great year to go. High pressure will be over New England through the weekend, and extend southward along the East Coast. This will supply cooler than normal temperatures to VIR (the normal high is around 87), along with low dewpoints for comfortable humidity levels. There will be a gradual warming trend through the weekend, from low 80s on Friday to upper 80s by Sunday. Can't ask for better racing weather in southern Virginia in late August.

By Doug Schneider

A chance of rain has entered the forecast today for Sunday. A complex of thunderstorms is expected to develop over the northern Plains on Saturday, and track east-southeast toward Wisconsin. The main questions with this system are the timing and location. Some models show a more southward track that misses Road America completely, and I think this is the most likely scenario. However, some take it on a more northern track, and bring rain to the event, but at different times of the day. So there is a lot of uncertainty about Sunday's weather. The chance of impacts on the race is low, but that depends on the timing and track of this system. 

If you're going to the race on Sunday, it is a good idea to be prepared for showers and thunderstorms. Follow our X account (@RacecastWx) for forecast and radar updates during the race.

By Doug Schneider

Although there will be rain in eastern Wisconsin to start the event, the conditions will improve through the weekend, with very nice weather expected for Saturday and Sunday. 

A low pressure system will be tracking across northern Wisconsin on Thursday, which will bring numerous showers and thunderstorms to Road America during the day. The two practice sessions that afternoon are likely to be impacted. This system will be east of Wisconsin by Friday, but there may be some lingering showers in the area as the upper level trough remains overhead. These should just be scattered to isolated light showers, so the impact risk is very low. 

High pressure starts to build over the region on Saturday, providing mostly sunny skies for Saturday and Sunday. Temperatures will be on the warm side for Saturday, but humidity levels will be comfortable with a north wind. Sunday may be a few degrees cooler, with slightly lower humidity levels. 

By Doug Schneider

Not much has changed in the expected weather for IMSA's visit to Watkins Glen International. Sunday continues to have high chances of showers and thunderstorms that are likely to impact the race.

This morning, the radar is quiet, but as daytime heating increases, showers and thunderstorms are expected to develop in the Finger Lakes region. Coverage is expected to be scattered, so there's about a 40% chance of one of the storms hitting the track. There may be a brief downpour and lightning, which may cause a delay for a short time and require wet tires. Saturday looks similar to today, with scattered afternoon showers and thunderstorms. It will be hot and muggy both days, and the National Weather Service has issued at Heat Advisory for today and Saturday. Drink plenty of water and take breaks in the shade if you're at the track.

Sunday will have a higher chance of rain as a cold front approaches from the west. Showers and thunderstorms will be numerous ahead of this front. Showers are possible any time of the day, but the bulk of the thunderstorms are expected to come in the afternoon, mainly from 2 PM and later. It is likely that there will be heavy rain and frequent lightning in the closing half of the race, so I would not be surprised if there is a period when the race is red flagged. If you are at the track, stay weather aware and have a place to seek shelter from lightning, either in a vehicle or a building. The Storm Prediction Center has the area in a Marginal Risk of severe thunderstorms, so some strong wind gusts and hail cannot be ruled out. 

By Doug Schneider

It is setting up to be a wet weekend at Watkins Glen. A large high pressure ridge will be located across the Ohio Valley and central Appalachian region, south of New York. A front will be lingering near the Finger Lakes region through the end of this week, which will be a focus for showers and thunderstorms. With afternoon heating creating some instability, scattered showers and thunderstorms will develop each afternoon near the front. 

The best chance of showers and thunderstorms appear to be on Sunday, when another front and low pressure system will push toward the area from the west. This should bring greater coverage of showers and storms during the race. There may be some stronger storms that produce heavy rain and frequent lightning, and may result in some delays or stoppages during Sunday's race. 

​Be sure to follow @RacecastWx on X for radar updates over the weekend.

By Doug Schneider

Not much has changed since my initial forecast for the Detroit Grand Prix, but the timing of rain has come into better focus. 

A cold front will be approaching the area on Saturday, but I expect that all the racing can be done in the dry that day. Showers are expected to move into Detroit late in the day, around or after 6 pm. The IMSA race is scheduled to end at 5 pm, so the chance of impacts is very low. Of course, the rain may arrive a little earlier than expected, but I think the chance of that is low. 

Saturday night will have rain showers moving through, with a tenth to a quarter inch of rain expected. This rain is expected to exit Sunday morning, mainly by 8 or 9 am. The INDYCAR morning warm-up session is at 9:30, so there is a chance of running it in wet conditions if the showers are slower to exit that expected. After the rain exits, clouds will gradually decrease, and the weather for the race looks good, with partly sunny skies and temperatures in the 70s.

By Doug Schneider

Overall, the Detroit Grand Prix should have good weather, with just a slight chance of a shower on Sunday. 

A large high pressure ridge will be over the Great Lakes region on Friday, providing mostly sunny skies and comfortable temperatures and humidity levels. This ridge moves east on Saturday, which will bring increasing clouds through the day, and warmer temperatures with a southerly flow. There is a small chance that some showers could spread into the area in the evening, but most of this should hold off until after the on-track activity has ended for the day. There's a good chance of showers on Saturday night as an upper level trough moves through the region. For Sunday, the models begin to differ, with some keeping the trough over the area, which could lead to some showers. Other show the trough moving away quickly, resulting in a dry day. For this initial forecast, I will have just a slight chance (20%) of rain due to the uncertainty of timing with this system. Overall, I think there will be a very low chance of impacts on the racing. 

Check back later in the week for updates, and follow @RacecastWx on X and RacecastWeather on Facebook and Instagram.