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 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
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.
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.
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.
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%.
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.
There's a fair amount of uncertainty in the forecast for Mid-Ohio late this week, so the finer details are hazy, but the general pattern appears to be a bit unsettled. This will result in some chance of rain each day for the Trans Am event Thursday through Saturday. But it will not be a washout by any means.
Thursday is expected to have some showers and thunderstorms in the area that develop in the afternoon. Most of the day should be mostly sunny and dry, with comfortable temperatures around 80 degrees.
On Friday there will be a low pressure system tracking east across the upper Great Lakes, so there will probably be increasing moisture over Ohio. An upper level disturbance may also be crossing the area, so I think the chance of rain on Friday is probably the highest of any day of the event. But coverage is expected to be scattered, so there will still be plenty of opportunity for dry racing.
On Saturday there may be some dry air building into the area behind the exiting upper level disturbance, but the models don't completely agree on this. While I think a dry day is most likely, I will have to keep a small chance of rain in the forecast as it can't be ruled out completely at this point.
By Scott Martin - @RaceWx4You
Looking at the latest GFS model trend for this weekend, we'll have moisture in the Central Indiana area throughout each day, but I believe we may be able to squeeze at least two days of racing action without any interruption from Mother Nature. Even though I do have a small chance of rain for Friday, I believe we can make it throughout the day completely dry. The reason for the 20% chance is that models do not handle convective pop-up showers and storms well.
Just about the same can be said for Saturday but had to up the risk a little bit as precipitable water values will be higher, around 1.75 inches. There will be scattered shower and storm development, but I believe those will come later in the afternoon. Crossing my fingers that the on-track activity will be completed by the time those form.
More available moisture will be in the area on Sunday, with precipitable water values up around 2.00 inches. Showers and storms will be able to develop easier with the heating of the day, so there will be scattered to numerous showers around especially during the afternoon hours.
It is still early in the forecast game, but I'll be able to have a better look at what to expect when the higher resolution models come out this week. Radar will be up by Thursday on the site.
The forecast for Detroit this week has been a moving target, but the pattern is starting to come into better focus as we get closer to the weekend. There are still some uncertainties about the timing of rain chances at Belle Isle, but the latest data point toward a better weekend for racing than previously indicated.
Friday looks like a nice day at the track, with mostly sunny skies and highs in the mid 70s. A cold front will be pushing south toward Belle Isle on Friday, but it isn't expected to move across the area until Friday night. The front will have very little moisture to work with, so there may not be any rain with it when it moves through.
High pressure will be building over the area on Saturday, and the front will be to the south of Detroit, across northern Ohio. Most of the day will be very nice, with mostly sunny skies and highs in the mid 70s. However, as a low pressure system approaches from the west, a southerly flow will develop, spreading greater moisture into the area and pushing the front back to the north. While I think the majority of the rain with this will come after Saturday's racing ends, there is some uncertainty about timing, so I have just a 20% chance of rain late in the day, but with very low impact on the IndyCar race at 3:30 pm. No impact is expected for the Trans Am and IMSA races that will be held earlier in the day.
Showers and thunderstorms are likely on Saturday night into Sunday morning as low pressure track east across Michigan, but the big question is, when will it end? There is a lot of uncertainty about this, but what I can say is that conditions should be improving through the day. The most likely sessions to be impacted by rain will be IndyCar qualifying and Trans Am Race 2. It is possible that there could be enough rain to cause some delays to these sessions, depending on how well water drains off the track.There will still be a chance of rain through the afternoon, but the chance will be lower than in the morning. I'd put the chance of rain in the morning at 60%, but closer to 40% in the afternoon. The Stadium Super Trucks and IndyCar Race 2 will probably have a wet track to deal with, but I don't think the conditions at that time will be bad enough to cause major delays or cancellations.
We'll have our live radar feed going through the weekend - just use the Radar link at the top of the website. I'm going on a beach vacation with my family this weekend, so my weather updates on Twitter will be limited, but Scott (@RaceWx4You) will help to keep you informed of the latest weather conditions at Belle Isle.
The forecast graphics for IMSA and Trans Am (Impact level differs based on the timing of races and expected rainfall):
There have been some big shifts in how the models depict the weather pattern evolving over Detroit this weekend. I have very low confidence in this forecast, due to the models changing their tune back and forth between dry and wet. With so much uncertainty, I cannot make the forecast very detailed or specific in regard to timing of rain. But based on the latest model runs, it looks like there will be at least a chance of rain at the track each day. I wish I could make a forecast with greater confidence one way or the other, but sometimes we just have to admit that we don't know what will happen.
The Detroit Grand Prix is always a big event packed with racing action, as IndyCar, IMSA WeatherTech Championship, and the Trans Am Championship will all be racing on the streets of Belle Isle Park. The weather could cause some problems on Friday, but the rest of the weekend is looking good so far.
On Friday, the Detroit area will be in a warm and moist south to southwesterly flow, while a cold front will be pushing south across the upper Great Lakes. In the warm, moist air mass ahead of the front, there will likely be showers and thunderstorms. The question of timing is too uncertain this far out to be very specific, but I think the afternoon will have better rain chances than the morning. At this time, I have the impact on racing as moderate, meaning there will be wet conditions and possibly some delays in the schedule. I could see the impact becoming high with later forecast updates if the rain will be heavy, but that is too uncertain right now.
The cold front will move through Friday night, bringing a drier and cooler air mass to the area from the north. Saturday looks like great racing weather, with mostly sunny skies and highs in the upper 60s.
There is a little uncertainty about Sunday, but I'm going with a dry and mostly sunny forecast. Some previous model runs had shown the cold front lifting back to the north and bringing more rain on Sunday, but the latest models are in better agreement with each other that the front will remain to the south of Detroit. I'll feel more confident in the dry forecast with additional model runs that continue to show this trend.
Here are the forecast graphics for the other series that will be in action at Belle Isle:
The forecast for Trans Am at Road Atlanta today through Saturday is panning out pretty much as expected, but I've made a few small changes today.
Today's weather will start off mostly cloudy, and there are a few light sprinkles showing up on radar this morning, but much of it is not reaching the ground. I can't rule out a few drops of rain this morning, but since it won't be enough to measure, I'm not forecasting any chance of rain today. There will be some clouds remaining through the day, but the afternoon should see more sunshine than the morning. Highs will be warm, in the upper 80s, and winds will be from the west at 10 to 15 mph this afternoon.
Friday will likely see more cloud cover than today as a low pressure system approaches from the west. This will keep temperatures cooler, in the lower 80s. Showers and thunderstorms are expected to arrive at the track after activities are done, mainly 5 pm or later. So even though I have a 50% chance of rain in the forecast, no impact on racing is expected on Friday.
Showers and thunderstorms will move through on Friday night with the passage of a cold front, but some showers may linger into Saturday morning until the upper level trough exits. Scattered light showers will be around the track through the morning, and the track will likely remain wet for the morning's TA/TA3/TA4 race. The chance of showers will be gone by noon, and the rest of the day should have improving conditions with some sunshine breaking through at times. Winds will shift to the northwest on Saturday, bringing cooler temperatures in the mid 70s.
Road Atlanta will host the third round of the Trans Am Championship this weekend, and although the forecast graphic has a chance of shower and storms mentioned on two out of the three days, I don't expect that the weather will be too bad for racing.
A large high pressure ridge will be over the Southeast on Thursday, which will provide sunny skies and warm temperatures. Highs will reach the upper 80s, with no chance of rain.
The high pressure ridge will give way on Friday as a low pressure system approaches from the northwest. Friday will start off mostly sunny, but clouds will be increasing through the afternoon. There are some timing differences in the models right now regarding the time that showers and storms could arrive, but I think the most likely time is after 3 pm - after on-track activities have ended for the day. The weather impact on Friday is green, as the day's activities should go through with no problems.
There will likely be showers and thunderstorms on Friday night as the cold front associated with the low pressure system moves through. Around a quarter inch of rain will be possible Friday night. But the upper level trough will drag behind the front, which could keep some scattered showers going into Saturday morning. The TA/TA3/TA4 race begins at 8:55 am, and there is a chance that it will be affected by rain. I could see a wet start to the race, or perhaps a delay to the race, so I have a yellow flag for low impact. Any rain on Saturday morning should be light, just a tenth of an inch or less. Conditions will be improving through the day, and there could be some sunshine breaking through in the afternoon.
I plan on having another forecast update posted either Thursday or Friday, depending on how much the outlook changes.
By Doug Schneider
All signs continue to point toward nice weather this weekend for the Trans Am season opener at Sebring. The main weather issue will be winds. North winds today will be sustained at 15 to 25 mph, with gusts of 30 to 35 mph. This will produce a pretty strong cross wind on the Ullman straight. Here's a track map for reference:
Saturday and Sunday will continue to have breezy conditions, but not quite as strong as today, with sustained winds between 10 and 20 mph, gusting up to 25 mph.
By Doug Schneider
The Trans Am Championship opens its season this weekend at Sebring, and overall, the weather looks good for the event.
The Pirelli tire testing sessions on Thursday will likely be the only chance of rain impacting the track. There is a cold front that will be moving southward across Florida on Thursday, and scattered showers will be possible ahead of it. At this time, the atmosphere does not appear to have a large amount of moisture or instability with the front, so I am expecting that if there are showers on Thursday, they should be light.
By Friday, the chance of showers should end as high pressure will be building over Florida behind the front. Temperatures will be a little cooler, but still very pleasant, in the upper 70s on Friday. Temperatures will gradually warm each day over the weekend, with highs in the lower 80s by Sunday.
Overall, it should be a great weekend for going to Sebring, with both Trans Am and SVRA providing plenty of action and awesome cars.
By Doug Schneider
No big changes were needed to the forecast at Daytona this weekend as Trans Am will have great weather for its season finale on Saturday. Friday's qualifying sessions will have full sunshine and highs in the upper 70s. Clouds will start to increase through Saturday as winds shift to the northeast, bringing more moisture off the ocean, but no rain is expected during the day. There is a slight chance of some light showers beginning Saturday night and into Sunday for the historic racing event. Winds will be picking up too on Sunday as a low pressure system takes shape off the coast.
By Doug Schneider
The finale of the Trans Am season should have great weather in Daytona this weekend.
A cold front will move through the area on Wednesday night, and there is a chance of some showers ahead of the front as teams arrive at the track on Wednesday. But once the front moves through, there will be plenty of sunshine and comfortable temperatures. Thursday will be a little breezy behind the front, with a northeast wind of 10 to 15 mph, gusting to 25 mph at times. Temperatures will warm into the upper 70s on Friday, with lighter winds as high pressure builds in. There will be another cold front approaching from the north on Saturday, but it will only increase clouds a little bit, and lower temperatures slightly. There will not be enough moisture for the front to produce any rain as it moves through, so I'm not worried about any rain for the race.
I'll have another update on Thursday, unless there is a significant change to the forecast before then.
Showers and thunderstorms are likely at COTA today, which may interrupt the scheduled practice sessions. A front will be moving into northern Texas late in the day, and push southward overnight. Compared to what was shown by the models on Monday, the front is moving a little slower, so I've added a slight chance of showers and thunderstorms on Friday.
There is some uncertainty about what will happen with the front on Saturday. I'm going with the models that show the front pushing through and being located south and west of COTA, which should mean a dry race day. But there is one model that is keeping the front near the track on Saturday, and producing some showers. I'm not confident enough to jump on that model yet. It does look like there will be more clouds than sun for the race, with comfortable temperatures in the upper 70s.
By Doug Schneider
The penultimate round of the Trans Am Series will be at COTA this weekend, and after a front moves through on Thursday, the weather looks like it will be nice in time for race day.
On Thursday, a front will be pushing southward across Oklahoma and northern Texas. This will bring a good chance of showers and thunderstorms at the track as teams load in and start to practice. Storms will be possible at any time of the day, but it looks like the afternoon will have the best chances. Indications are that this front will push through on Thursday night, and high pressure will build in behind it. A northeasterly flow of dry air around the high should provide dry and mostly sunny conditions on Friday and Saturday, with comfortable temperatures and humidity levels both days.
By Doug Schneider
Not much change to the forecast for Trans Am's weekend at NOLA Motorsports Park. High pressure will be firmly in control through Saturday. The chance of any rain on Saturday has dropped to virtually zero, and plenty of sunshine is expected through the whole event. Temperatures should be pretty comfortable too, reaching to the mid 80s.
By Doug Schneider
Trans Am has a quick turn around, going from Homestead to NOLA in back-to-back weekends. The good weather that the series enjoyed in Homestead will likely continue in NOLA this weekend.
The weather pattern through mid-week will feature a large high pressure ridge over the Mississippi and Tennessee Valley region, which will supply dry and stable air from the north into Louisiana. This will provide sunny to mostly sunny skies at the track on Thursday and Friday, and the humidity levels will be relatively comfortable for New Orleans. The high pressure area will be shifting east, becoming positioned near the Atlantic coast. This will result in a more southeasterly flow off the Gulf of Mexico into Louisiana, and higher humidity levels. The added moisture will bring more clouds, and possibly an isolated shower or thunderstorm on Saturday. At this point, it doesn't look like a big deal, and I only have the chance of rain at 20%. Most likely, the race will be run in dry conditions.
By Doug Schneider
Homestead-Miami Speedway was spared the brunt of Hurricane Matthew on Thursday. The maximum wind speed recorded at the airport, which is very close to the speedway, was a gust of 38 mph. The total rainfall from Matthew was 0.95 inches.
Today will be hot and humid, as highs will be in the lower 90s, and dewpoint temperatures will be in the mid to upper 70s. The humidity will make it feel like it is over 100 degrees. If you're at the speedway, stay hydrated and take frequent breaks in a shaded area.
Tomorrow should have slightly lower dewpoints, in the lower 70s, so it won't feel quite as muggy as today. Highs will be around 90, and winds will shift to the north at 5 to 10 mph.
By Doug Schneider
Trans Am has made a good call and delayed today's official load in at Homestead-Miami Speedway to tomorrow due to Hurricane Matthew., which is now a Category 3 hurricane with maximum sustained winds near the center of 125 mph. However, Matthew's path will stay east of Homestead, so winds are expected to stay below 50 mph there later today. Here's the latest forecast track:
By Doug Schneider
(Updated Tuesday 10/4 for the latest Matthew forecast)
It's going to be an interesting weather week across southeast Florida as Hurricane Matthew will be tracking near the area. The good news is that Matthew is expected to be gone by the time the on-track activity starts for Trans Am at Homestead-Miami Speedway.
Here's the latest forecast track from the National Hurricane Center for Hurricane Matthew (as of Tuesday morning, 10/4), which is now a strong Category 4 hurricane with winds around 145 mph:
By Doug Schneider
The weather still looks nice for Trans Am's visit to VIR this weekend. The low pressure system near the coast that I mentioned in my last post is staying nearly stationary, and most of the rain associated with it is staying near the coast or Eastern North Carolina. There's still a small chance of some showers reaching VIR on Thursday, but it should not amount to much if there is a shower. Friday and Saturday look great, with highs in the mid to upper 80s, and plenty of sunshine. I wish I could be there this weekend at my favorite track.
By Doug Schneider
Moisture associated with the remnant of the tropical storm formerly known as Julia could bring quite a bit of rainfall to central North Carolina this week, and possibly to VIR. There is some uncertainty about how far north the heavy rain will extend, so VIR could end up with a lot of rain or very little. The good news is that most of this rain will come on Tuesday, Wednesday, and Thursday, before the racing gets under way.
Here's what the weather map is expected to look like on Thursday:
By Scott Martin
Unfortunately, the forecast has not changed from Friday's update, and Saturday looks to be a pretty wet day for the Trans Am Series at Road America.As the shortwave approaches the area between midnight on Friday night and into early Saturday morning, rain will start falling, with heavy rain and thunder at some point. The latest run of the NAM 4k model has rain and thunderstorms staying in the area throughout the morning, with the shower activity becoming more scattered in nature for the afternoon hours. Afternoon highs will be in the mid 70s, but you will definitely need umbrellas and rain parkas to stay dry. Please seek shelter in a building if you see lightning or hear thunder. We've already lost too many people in the country to lightning strikes in 2016. Let's not add to that number. Radar will be running bu the time the morning rises.
Doug Schneider and Scott Martin are race fans and meteorologists dedicated to providing accurate forecasts and timely weather updates at racing venues around the world. We forecast for IndyCar, Indy Lights/MRTI, IMSA, Pirelli World Challenge, World Endurance Championship, and Trans Am Series races, as well as major SCCA and NASA events.