By Doug Schneider

The main change to the forecast since Tuesday is a shift in the timing of the best chance of showers and thunderstorms on Saturday. Fortunately, this change is for the better, as the majority of rain is expected to pass through south-central Virginia on Friday night and early Saturday morning, with a low chance of impacts on the racing action. 

Some pop-up afternoon showers and thunderstorms will be possible on Friday, mainly near the higher terrain to the west of Danville. They will be moving east, but the chance of one of them reaching VIR before the end of the day's sessions is unlikely.

A passing trough and cold front are likely to bring showers and thunderstorms overnight and into early Saturday morning. There is a chance that some of the morning sessions could be impacted by these showers, possibly the GT qualifying from 8:30 to 9 am, and possibly the GT4 Sprint race at 9:25 am. Through the rest of the day, clouds will clear out and it will be mostly sunny, with high temperatures around 90 degrees. 

Drier air behind the departing trough will keep Sunday dry and sunny, with a high temperature around 90 again. 

By Doug Schneider

The season opener for GT World Challenge at VIR may be affected by some showers and thunderstorms, particularly on Saturday, but the vast majority of the racing action should be completed in dry conditions. 

A low pressure system is expected to be moving northeast across South Carolina and eastern North Carolina on Thursday. Even though it's just a couple days away, there are some big differences between the models in their placement of this low, and how much rain it brings to VIR. I'm going to be optimistic with my forecast, and only have a 30% chance of afternoon showers and thunderstorms. This is how most of the models are leaning, but the NAM shows much greater shower coverage. Hopefully it's an outlier. 

On Friday the low pressure system will be moving up the East Coast, and will no longer affect southern Virginia. With a lack of any significant high or low pressure systems in the area, I expect that Friday will be a typical summer day, with a few isolated showers or a thunderstorm possible in the afternoon, and a high around 90 degrees. 

Saturday appears to have the best chance of rain as an upper level trough and a surface cold front approach from the west. This system will provide lift and instability that will favor the development of showers and thunderstorms, mainly in the afternoon. There is a little uncertainty about the timing of the trough passage, and if it comes earlier there could be some morning showers as well. But the afternoon will be the more likely timing. 

Drier air aloft will build across the area behind this system, and which should result in a dry and mostly sunny day on Sunday. It will still be rather hot, with a high around 90.

By Doug Schneider

Showers and thunderstorms are likely in the Daytona area on Friday and Saturday afternoon and evening, which may have an impact on the IMSA WeatherTech240. Not much has changed in the expected weather pattern since my initial forecast on Monday. There will be a slow-moving low pressure system across the Deep South with a weak front near northern Florida. Since Daytona will be on the southern side of this system, hot and humid conditions can be expected during the event. Not too surprising for Daytona in July.

The chance of rain has increased a little on Friday as it looks like the front will be closer to Daytona than the models previously showed. Highs will reach the lower 90s, with a heat index around 100. Afternoon showers and thunderstorms are expected to develop in the area, and any of them could produce a brief heavy downpour. The only on track activity on Friday is a practice session from 6:15 to 7:15 pm, which is during the time frame when storms are possible. If a storm passes over the Speedway, a quick quarter to half inch of rain will be possible, along with gusty winds and frequent lightning. 

Saturday looks pretty similar to Friday, although there may be a little more cloud cover to hold temperatures down a little bit, but it will still reach 90 degrees. Like Friday, numerous showers and thunderstorms will develop in the afternoon and linger into the evening. Heavy downpours, gusty winds, and lightning are possible with any storms that pass over the Speedway. 

If you're at the track, stay weather aware and have a plan to find sturdy shelter before storms reach the Speedway. 

By Doug Schneider

The IMSA season resumes this weekend where it left off in January, at Daytona International Speedway. Unfortunately, it does not look like the weather will cooperate for the race. The weather pattern across the United States will feature a large trough over the east coast, and a large ridge over the Plains. As a result of this pattern, a front will be pushing south across the Southeast states on Friday, and stall across northern Florida on Saturday. This front will be the focus for showers and thunderstorms.

Friday at Daytona will be a hot and humid day. Most of the day will be rain-free with scattered clouds, then as daytime heating increases in the afternoon, scattered showers and thunderstorms will pop up in the area. Since the wind will be from the southwest, the sea breeze won't push inland enough to help cool temperatures, and highs will be in the lower to mid 90s. The practice session scheduled for 6:15  to 7:15 pm may have to deal with showers and thunderstorms in the area. I'd put the chance of rain during this time frame at 40%. 

The approaching front is expected to stall somewhere across northern Florida on Saturday, The exact position is uncertain this far out, but right now it looks like it will remain north of Daytona. This will keep hot and muggy conditions at the Speedway for race day, as drier air remains north of the front. The front will also provide lift that will enhance the chance of showers and thunderstorms. Timing is too uncertain to be specific at this time, and showers and thunderstorms will be possible at any time during the day. I put the impact at Moderate for now, but it is possible that could be raised to High with later forecasts, depending on how much rain is expected to fall. That will come into better focus through the week, so stay tuned for updates. 

By: Stephen McCoy

Nothing unexpected in the raceday forecast for Indycar's return. Current temperatures in Fort Worth are in the low-to-mid 90's with heat index values approaching 100 F. Conditions will begin to cool as the race gets underway; air temperatures around 90 F will be present around the green flag. By the end of the race, temperatures are expected to be down to the low 80's, though with dew point temperatures near 70 F, heat index values will still register around 90 F. Winds are currently directly from the east due to Cristobal's approach towards the Gulf shore, and will likely stay that way through the rest of Saturday. Partly cloudy conditions are anticipated through the race, though some of the clouds could begin clearing closer to the checkered flag.