By Scott Martin - ​@RaceWx4You

By Doug Schneider - @Race4caster

It will be a great weekend to head to beautiful Virginia International Raceway to take in some awesome race cars. Trans Am will have a shared weekend with SVRA's Heacock Classic Gold Cup Historic Races, and the schedule is jam packed with action. A large area of high pressure will be stationary over the Great Lakes and Mid Atlantic region, and it will keep dry and sunny weather across Virginia later this week. Temperatures will be pretty warm too under the high pressure ridge, between 4 and 8 degrees above normal for late September in southern Virginia. There's good agreement among the models on this pattern, so I don't expect that there will be many changes needed to this forecast through the week. Check our social media feeds on the right for updates.

By Scott Martin - ​@RaceWx4You

Click on images to enlarge.

By Doug Schneider - @Race4caster

The main weather story for the Six Hours of COTA late this week will be the heat. A large high pressure ridge through the mid and upper levels of the atmosphere will be sitting over Texas, resulting in mostly sunny skies each day and high temperatures reaching well into the 90s (mid 30s C). These temperatures are 3-5 degrees warmer than normal for Austin this time of year. Everyone at the track will need to take precautions to beat the heat - drink plenty of water, take frequent breaks in the shade or in a air conditioned building, and use sunscreen. 

By Scott Martin - ​@RaceWx4You

It's a championship-quality forecast for the final weekend of the season for the Verizon Indycar Series, as they visit the majestic Sonoma Raceway. Mornings will start off cool each day, but maximum sunshine will allow the temperatures to climb nicely to near 80 degrees each day. Wind will not be an issue for Friday and Saturday, but will be picking up to 10 MPH by Sunday afternoon. We won't even mention rain in this forecast.

By Doug Schneider - @Race4caster

By Doug Schneider - @Race4caster

The SVRA and Trans Am event at Watkins Glen will start off with some wet weather, but conditions will be improving over the weekend.

There will be a large upper level trough across the area on Thursday and Friday, which will produce cloudy and cool weather with scattered showers. Thunderstorms do not appear to be a threat at the track, and at this time I do not expect that the rain on Friday will be very heavy. It looks like there will be mainly light showers that are on and off at times through the day, perhaps occurring with more frequency in the afternoon than the morning.

The chance of rain will continue Friday night, but I expect that the trough will be moving fast enough that the chance of rain will end before the TA2 race on Saturday morning at 10:55 am. This is one part of the forecast that I'm not very confident about right now - it is possible that a few showers could linger into Saturday morning, but I'm going with a dry day for now because I don't think it will have an impact while there is action on the track. Clouds will be decreasing through the day, with mostly sunny skies developing in the afternoon. Despite the sunshine, a north wind will keep temperatures cool, with highs in the mid 60s. 

Sunday looks great as a strong high pressure ridge builds into the area. While morning temperatures will be quite cool, in the 40s, sunny skies will bring temperatures up to the upper 60s in the afternoon. 

By Scott Martin - ​@RaceWx4You

For much of the week I thought that the remnants of Harvey would be swept out of here before the race weekend at Watkins Glen for the Verizon Indycar Series, but the forecast has changed drastically today.

Saturday will not be too bad at the track with partly cloudy skies throughout much of the day. Morning temperatures will start off pretty chilly and may bring a slight delay to morning on-track activities, but it will warm quickly into the mid 60s for the high. There is a very slight chance of a shower passing over the track after the noon hour, but the better rain chance will come during the late afternoon and early evening hours.

Sunday will be a pretty soggy day for the track, especially during the morning and into the early afternoon hours. It will be quite breezy at times as well, as the surface low formerly known as Harvey, passes nearby to the track. We do not expect any severe weather or lightning at this time, but definitely keep posted to the weather conditions through the day. Rain coverage should diminish for the mid-afternoon through the early evening hours, and maybe we can get a dry track for a little while. Afternoon highs will top out in the upper 60s.

By Scott Martin - ​@RaceWx4You

It now looks like the remnants of Harvey will be pushed away from the area before it has a chance to rain on the Indycar weekend at Watkins Glen. Therefore, nice weather can be expected throughout the weekend. Mostly sunny to sunny skies can be expected each day, with highs starting off in the mid-60s on Friday and warming into the upper 70s by Sunday. No rainfall is expected on any day, so Firestone can keep those rain tires in the hauler.

By Doug Schneider - @Race4caster

There hasn't been a big change in what I'm thinking the weather will be in Mexico City this weekend for the WEC event, but my confidence is rising that the racing will be impacted by rain each day. A low pressure system will be taking shape in the Gulf of Mexico, just off the east coast of Mexico. This will produce an easterly flow through the low and mid levels of the atmosphere that will pump moisture toward the track all weekend, but especially Saturday and Sunday. With mountains all around the city, the moisture rising up the mountains slopes will produce showers and thunderstorms each day, and mainly in the afternoon hours. I've raised the chance of rain with the forecast update to reflect my higher confidence, and I've raised the Impact to High, as I think there's a good chance of the rain being heavy enough at times to require a stoppage in the action. Rain amounts are likely to be between a quarter and a half inch each day, but amounts could be higher than that if a storm moves directly over the track. 

The Weather Channel has a pretty good interactive radar display for Mexico here -
​ ​https://weather.com/weather/radar/interactive/l/19.43,-99.13

By Doug Schneider - @Race4caster

The remnants of Hurricane Harvey will be pulling out of Texas by Thursday, and high pressure will build over the state behind it. The high pressure system will bring drier and and stable conditions. This should provide nice weather for Pirelli World Challenge at COTA this weekend. Temperatures will be close to normal for Austin this time of year, with highs in the lower 90s and lows around 70. With a lot of sunshine each day and very little shade at the track, it will be important to stay hydrated and to use sunscreen. 

As the high pressure system over the Plains shifts to the east near the Mississippi River on Sunday, winds near and just above the surface will shift to a more easterly direction. This will transport a little more moisture inland on Sunday, which is why I have a slight chance of showers and thunderstorms in the forecast. I think that most of the activity will stay closer to the Texas coast, well east of COTA, but there is some uncertainty about how far inland storms may develop this far out in the forecast. There is just a very low chance that the racing could be impacted by storms. I'll be keeping an eye on this through the week, so check back here for updates and follow me on Twitter - @Race4caster.

By Doug Schneider - @Race4caster

It looks like the WEC weekend in Mexico City could be a wet one, as there's a good chance of showers and thunderstorms each day at the track. The weather pattern doesn't change very much through the weekend, as there will be a good amount of moisture in the atmosphere. There may be a slightly better chance of rain on Saturday as a low pressure system in the midlevels of the atmosphere develops, producing an stronger easterly flow of moist air off the Gulf of Mexico. But for the most part, the showers and storms will be driven by afternoon instability. It is possible that a heavy shower could stop racing action, but rain amounts are too uncertain this far out to put the Impact rating any higher than Moderate. 

I'll keep an eye on how the models change as we get closer to the event, and I'll post an update when any changes are needed.

By Scott Martin - ​@RaceWx4You

By Scott Martin - ​@RaceWx4You

Not much change in the forecast for the Bommarito Automotive Group 500 at Gateway Motorsports Park...

FRIDAY
Great weather throughout the afternoon hours, with mostly sunny skies and highs in the lower 80s. That is how it will be for the first practice session at 4PM. Qualifying temperatures will be down in the mid to upper 70s, and final practice temperatures at 9PM will be in the lower 70s and dropping into the upper 60s by the end of the session.

SATURDAY
Almost a near repeat of Friday's weather... Sunny skies throughout the day with temperatures topping out in the lower 80s. Temperatures will be dropping down into the mid 70s by the start of the main event at 8PM, and down into the lower 70s by the end of the race around the 10PM hour.

By Scott Martin - ​@RaceWx4You

Well a lot has changed since my last forecast for this weekend's events at Road America for the Trans Am Series Presented By Pirelli. We now will have a chance of showers and thunderstorms to end out the race weekend.

FRIDAY
Definitely the best day of the event weekend when talking about the weather. We'll have sunny skies throughout the day today with cool temperatures for late August. Afternoon highs will warm up in the upper 60s after temperatures will be starting off at 50 degrees at 7:00AM. No rain for today, and winds will start off out of the north at 5-10 MPH and shift out of the east by the early afternoon hours.

SATURDAY
There will be a warm front approaching from the west during the day that will bring an increase of clouds to the area, along with slightly warmer temperatures. It will still be rather cool at 7:00 AM with temperatures starting off in the lower 50s, but afternoon highs will make it to near 70 degrees. Winds will be out of the east at 5-10 MPH to start with, but will shift out of the southeast by the afternoon hours. With the shift in the wind direction, this could bring an isolated shower or two to the area, but with a dry airmass at the surface, you may not see much rain at all. Rain chance will only be at 20% for the late afternoon hours.

SUNDAY
The warm front will have moved through the area and a center of low pressure will be approaching the state from the west. Along with that, an upper level trough will move into the state from the north allowing that low to deepen. This will increase the chance of showers and thunderstorms throughout the day, especially the early morning through the early afternoon hours. Skies will be cloudy throughout the day, and afternoon highs will be in the upper 60s. The best chance of rain will be during the 1:00 AM - 11:00 AM time frame, with scattered showers possible after that. The chance of rain during event times will be at 50%.

By Doug Schneider - @Race4caster

The forecast for VIR this weekend is still looking good, but I've made a few small changes for this update, mainly to Saturday.

A large high pressure area will be tracking from the Great Lakes to New England over the weekend, and as it extends southward on the eastern side of the Appalachians, there will be a slight increase in moisture on Saturday. This could result in more cloud cover, and a light sprinkle cannot be ruled out entirely. The chance of measurable rain is too low to mention a percent chance of rain (less than 10%), but a few drops of rain may be felt at the track. It shouldn't have any impact on the racing at all. 

Temperatures all weekend are expected to be below normal for late August in southern Virginia, and humidity levels will be quite comfortable too.

​I hope to see you at the track!

By Scott Martin - ​@RaceWx4You

A great looking forecast for the event weekend out at Gateway Motorsports Park. Temperatures will top out in the low-80s for the daytime highs on both Friday and Saturday. The very good news is there is no rain in the forecast.

FRIDAY
Temperatures will be in the low-80s for the first practice session at 4PM, then down into the mid to upper 70s for qualifying. The last practice session for the day will be at 9PM and the temperatures will be in the low-70s and into the upper 60s.

SATURDAY
Temperatures will be dropping down into the mid 70s by the time the green flag drops on Saturday night. When the checkers fly around 10pm, temperatures will have made it down into the low-70s. No rain is expected, just a few clouds overhead.

By Scott Martin - ​@RaceWx4You

I don't believe you can ask for a better forecast for the race weekend at Road America for the combo event featuring the NASCAR Xfinity Series and The Trans Am Series Presented by Pirelli.

Not much to say about the weather except for nice and cool weather, especially for late August. We'll have plenty of sunshine on Friday and Saturday, but don't let the cooler temperatures fool you. Grab the sunscreen and shades because the sunburn factor will still be rather high. Temperatures will be near 70 degrees on both days.

Sunday won't be that much different. We'll have a few more clouds with slightly warmer temperatures. highs will be in the lower 70s. The main story for this whole weekend is no rain chance.

By Doug Schneider

Virginia International Raceway is about a five hour drive from my house, but it's the track I consider my "home track". If you've never been there, it is a gorgeous facility with a ton of great viewing spots, and you should definitely put it on your list of tracks to visit. I will be at the track this weekend, so I'm very pleased that I can make a forecast that calls for beautiful weather each day. 

A cold front is expected to move through the area on Wednesday night, which will bring some storms. Behind it, a large area of high pressure at the surface will be tracking across the Great Lakes and into New England through the weekend, and extend southward along the east coast. In the upper levels of the atmosphere, there will be a trough located near the coastline, producing a northwesterly flow aloft. The upshot of these features will be dry weather with plenty of sunshine, temperatures cooler than normal, and comfortable humidity levels.

There is one caveat to this forecast that I have to mention. One model (the GFS) does produce some afternoon showers each day, mostly near the mountains to the west, but it does show some precipitation reaching the track. My experience with this model is that it sometimes overplays the chance of afternoon showers in the summertime. Other models and the forecast from the NWS favor a dry weekend. At this time, I'm going with a dry forecast, expecting that this wetter model will change as we get closer to the weekend.

By Doug Schneider - @Race4caster

Not much change has been needed to the forecast I made on Monday, as I'm still expecting nice weather for the ABC Supply 500 on Sunday.

A cold front will move across the area on Friday, which will bring a good chance of storms that day. More stable air will build in at the surface behind the front, but an upper level trough will lag behind it and keep a slight chance of showers going into Saturday. There is a possibility of some isolated light showers around the track for the final practice session late in the day, but the showers should be so sparse and short-lived that I don't expect much, if any, impact. I think the timing of possible showers favors the late afternoon and evening hours, mainly 4 pm or later.

The models differ on how fast the trough will exit, and there may continue to be some showers into Saturday night. But I'm confident that any chance of showers will be gone by sunrise. Race day will be mostly sunny with pleasant temperatures in the upper 70s, and a northwest wind at 5 to 10 mph. Overall, a great day to be at the track. 

By Doug Schneider - @Race4caster

Overall, the forecast looks favorable for a nice weekend of IndyCar racing at Pocono Speedway. Hopefully this forecast will hold up as we get closer to the weekend. 

There will be a good chance of showers and thunderstorms in the area on Friday, and a cold front is expected move through on Friday night. The upper level trough is delayed a little behind the front, which is why I've included a slight chance of showers on Saturday. A dry day is most likely, but I can't entirely rule out an isolated shower until the trough exits the area on Saturday night. 

As the trough exits, dry air aloft will build into the region from the northwest, along with surface high pressure. This should provide a nice day for the race on Sunday. There should be a good amount of sunshine, and temperatures will be pretty comfortable too, with highs in the mid 70s.

Unless there's a major shift in the forecast, I should have another update posted on Wednesday afternoon.

​By Scott Martin - ​@RaceWx4You

Not really much change for the Grand Prix of Utah for the Pirelli World Challenge at Utah Motorsports Campus. Hot with a mix of sun and clouds for both Saturday and Sunday, with a very slight risk of an isolated shower or thunderstorm. Highs will be in the lower 90s.

By Scott Martin - ​@RaceWx4You

By Doug Schneider - @Race4caster

The forecast for Mid-Ohio is coming into better focus today, and the good news is that race day for the Trans Am Series is looking pretty nice. But there could be some rain before that.

Today will begin mostly sunny, but clouds will increase in the late morning and early afternoon. Showers and thunderstorms are expected to develop across central and eastern Ohio as moisture spreads up from the south, but the coverage of showers should be scattered. The chance of rain at the track today is around 30%, and any showers that may occur should be brief, so there should be plenty of dry track time for practice sessions.

The chance of rain rises on Friday as there will be a cold front approaching from the west that will result in greater coverage of showers and storms in the afternoon. Expect the timing of storms on Friday to be 2 pm or later, so the qualifying sessions could be impacted. If a storm occurs at the track, it could produce a quick quarter of an inch of rain, in addition to cloud-to-ground lightning. Those at the track will need to stay weather-aware and take shelter when thunder is heard. 

The front is expected to move through Friday night, and drier air will build in behind it. This should give a nice day for racing on Saturday, with partly cloudy skies and highs in the upper 70s.

By Scott Martin - ​@RaceWx4You

This is really a plain and simple forecast for this week out in Tooele, Utah, as the Pirelli World Challenge Series visits the grand Utah Motorsports Campus. Throughout the entire weekend you can expect mostly sunny skies, with the exception of a very small risk of an isolated shower or thunderstorm on Sunday. Highs will be in the upper 80s to just at 90 degrees. Winds will start out of the southeast on each day at 5-10 MPH, but will shift by the afternoon hours. The only thing that I would recommend is to stay hydrated and keep the shades and sunscreen handy.