By Doug Schneider

Not much has changed in the expected weather pattern this weekend over Indiana. An upper level trough and a surface cold front are expected to cross the area Saturday night and Sunday. The frontal passage on Saturday night will bring some showers, and the upper trough will linger over the area through Sunday. This trough will create some instability that will produce scattered showers around central Indiana during the day. The chance of a shower at the track is about 30%. Showers are possible any time of the day, but the best chance is in the afternoon. I expect that any showers on Sunday will be light and short-lived, with low impacts on the racing. I don't expect any delays or red flag periods due to rain or lightning. 

By Doug Schneider

A nice weather weekend is expected as IMSA returns to Indianapolis Motor Speedway. A large high pressure system will be sitting over the area to start the event on Friday, providing mostly sunny skies and pleasant temperatures and humidity. Through the weekend, this high will shift east, and a low pressure trough in the mid and upper levels will approach the area on Sunday. This will bring an increase in cloud cover, and possibly a few showers. The good news is that moisture appears limited as the trough moves through on Sunday, so if there are any showers at all, they should be light and short-lived. I don't expect any significant impacts to the race at this time, but I'll keep an eye on it as we get closer to the weekend. Stay tuned for updates through the week.

By Doug Schneider

Some changes were made for this forecast update for IMSA's VIR weekend. While the chance of rain has lowered on Saturday, the chance has increased on Sunday. 

The models have not done a great job with how they handle a cold front that moves southward through Virginia and North Carolina this weekend. This makes for an uncertain forecast. What I am confident about is that temperatures on Friday will be hot, with highs in the mid 90s and a heat index around 100 to 105. Most of the day will be dry, but there is a slight chance of showers and storms moving into the area late in the day, mainly after 5 pm.

A weak front or low pressure trough will be associated with these showers, and will move through in the evening hours. It will shift winds to the north, and bring slightly lower humidity for Saturday. There will still be some instability in the afternoon that may allow for isolated showers and storms to develop. Again, most of the day will be dry, with only a small chance of showers late in the afternoon. 

Another front moves in from the north on Sunday, and may initiate showers and thunderstorms in the afternoon. With more cloud cover, temperatures will be cooler, in the 80s. 

By Doug Schneider

Mixed conditions are expected at VIR for Michelin GT Challenge weekend. It will start off hot and humid, followed by a frontal passage that will bring showers and storms, then cooler and drier air will build in behind the front.

Friday's chance of showers will be mainly in the afternoon, as the atmosphere heats up and creates instability. With winds from the southwest, temperatures will climb into the mid 90s, with a heat index approaching 100. Afternoon showers are expected to develop near or along the Blue Ridge and track east into the Piedmont. Coverage is expected to be scattered, and the chance of a shower or storm at the track is about 30% at this time.

The chance of rain increases on Saturday as a cold front moves southward across Virginia. There are some disagreements among the models regarding the coverage of showers with this front, and the timing of the best chance of rain is still uncertain this far out. The expected cloud cover and frontal passage will bring temperatures down from Friday's highs, but the humidity will still be quite high. 

The passage of the front on Saturday is expected to be followed by a more pleasant air mass on Sunday, as high pressure over the northeast builds southward into Virginia and the Carolinas. Under mostly sunny skies, highs will be in the lower 80s, with more comfortable humidity levels. 

By: Stephen McCoy

A cold front is expected to move through the region late Thursday evening into Friday. During the day on Thursday, ahead of the front, winds will largely be from the Southwest. These winds will bring warmer, above-average temperatures to the area, with afternoon highs approaching 90°. In addition, scattered showers are expected to develop along the front, which have a chance to enter the region in the late afternoon; a few thunderstorms may also be possible.

Once this front moves through, an area of high pressure will build in, shifting winds more towards the North. As a result, temperatures for Friday and Saturday will be expected closer to normal. Partly cloudy conditions will persist for much of this time period, mostly in the mid-to-upper levels as the result of an area of low pressure located over the Great Plains. Cloud cover will increase Saturday afternoon as the low begins to move into the Midwest.

The low pressure system will make its way over central Wisconsin on Sunday. Winds are likely to increase to 15-20 mph sustained with gusts approaching 30 mph out of the South/Southeast. A warm front will extend to the East from the center of the low, though the front will remain to the South of the track, which will keep temperatures a few degrees below normal, and the afternoon high the coolest of the weekend. There is a likely chance for showers and thunderstorms associated with the system, which is expected during Sunday afternoon; however exact timing of the rainfall is still a bit uncertain. What is somewhat certain is that if rainfall occurs during Sunday's race, it will likely be a full wet race, as the forecast models predict an average rainfall total around 1/2" for the day.

By: Stephen McCoy

A cold front will move through the region late on Friday as a low pressure system tracks eastward over southern Ontario. The front will bring cloudy conditions through the day with a likely chance for showers, especially in the afternoon. Some thunderstorms may also develop along the front, which may cause a halt in track activities if lightning gets too close. However, for now, it is still too uncertain where individual storms will track. Winds through the day will largely be from the South, with some stronger gusts reaching to 20 MPH.

As the front moves out of the region on Saturday, high pressure will build in, bringing more stable conditions during the day. Winds from the Northwest will result in slightly cooler temperatures for the morning low, but with drier air aloft creating clearer conditions, afternoon temperatures should reach higher than on Friday. A few stray isolated showers are possible during the morning, however no significant rainfall is expected. Dry conditions will continue into Sunday, which will see the warmest highs of the weekend.

By Doug Schneider

Not much has changed in the forecast for IMSA's visit to CTMP this weekend. A few showers are possible Friday morning, and again on Sunday, but overall I expect the conditions to be good. 

A cold front will move through southern Ontario Thursday night or early Friday morning. Expect a wet track as activities begin on Friday morning, but most of the rain should be gone by the time the first practice session begins at 9:15 am. The rest of the day will have clouds clearing out, with partly to mostly sunny skies. 

Saturday looks great, with pleasant temperatures and mostly sunny skies.

Sunday is still a bit uncertain, as one model is showing some light rain through the day, but other models show dry conditions. There is an upper level trough that will be approaching from the west, which will bring moist air northward into southern Ontario. However, most of the rain should stay south of Lake Ontario. I expect that if there is any rain, there would only be a little sprinkle now and then, and it would have very little impact on the race. I don't expect that it would cause any delays or interruptions, though it may wet the track slightly. If you're going to the track, it might be a good idea to bring some rain gear, just in case.

By Doug Schneider

The weather looks favorable for IMSA's weekend at CTMP, but there are some uncertainties to this forecast that may impact the event.

A cold front is expected to cross the area sometime between late Thursday through Friday morning. Model difference in the timing makes it uncertain, but I think the most likely timing will take showers out of the CTMP area before on-track activities begin Friday morning. It will be breezy through the day as wind shift to the northwest, and sustained winds will be between 10 and 20 mph with gusts up to 30 mph possible.

Saturday should be a very nice day, with mostly sunny skies and mild temperatures, thanks to high pressure building in that will supply dry air. 

Sunday is still uncertain, but I'm keeping it dry for now. Most models do the same with rain moving in on Monday, but a couple show showers spreading into the area through the day on Sunday. I will take the optimistic route on this one and keep Sunday dry, with the caveat that it could change with updated forecasts later in the week.