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!