By Doug Schneider

There has been a pretty big shift in the forecast for Sunday at VIR, and it now appears that there will be a good chance of seeing rain during the day. 

A cold front is expected to move into the area Saturday night, which is in line with the previous forecast thinking. However, the models are now showing this front slowing down and stalling as it moves into the Piedmont of NC and VA. It is expected to be located just southeast of VIR on Sunday. Meanwhile, an upper level disturbance will be approaching, and its interaction with this front will produce some showers in the area. Rain is possible any time of the day on Sunday, but it appears that the best chance of rain will come in the afternoon. Rain amounts in the neighborhood of a tenth of an inch can be expected. Since this isn't expected to be a heavy rainfall, and no lightning is expected, I kept the impact as low.

By: Stephen McCoy

A cold front moving through the region on Saturday will bring more cloudy conditions than the rest of the weekend, with slightly cooler temperatures. Surface winds are expected from the west to southwest during the morning, but will shift to the west to northwest behind the front. Temperatures will be about the same as the previous few days, but will cool behind the front; temps by the end of the race will be in the low to mid 60's. There is a slight chance for isolated showers ahead of the front near the early to mid afternoon; model output suggests maximum totals during the race around a few hundredths of an inch should precipitation occur.

By Doug Schneider

The forecast that I posted on Sunday appears to be holding up pretty well as we get closer to the weekend, as there has been little change to that forecast with today's update. Nice weather is expected each day as high pressure extends across Virginia and North Carolina Piedmont region. Temperatures will be trending warmer each day through Saturday, then a cold front is expected to move across the area Saturday night.

The majority of rain with this front should pass to the north, and I'm keeping my forecast dry. However, there is a model (GFS) that shows some rain occurring Saturday night. So if there is any rain, I expect it won't affect the racing on Saturday or Sunday. With the passage of the front, temperatures will get cooler again on Sunday, with highs in the lower 70s.

By: Stephen McCoy

Warm and pleasant conditions will welcome the WeatherTech SportsCar Championship series for its season finale at Road Atlanta this weekend. The main thing of note in this forecast is the possibility of a cold front moving into the region on Saturday that could bring a slight chance for isolated showers, though at this point the models are subjective as to the location of the front.

Conditions for Wednesday, Thursday, and Friday are very similar in terms of the overall atmospheric set-up. A surface high pressure system will move into the Midwest region behind a cold front on Tuesday. The anticyclonic rotation around the system will cause winds over the Southeast to be largely from the east to northeast, slightly amplified by a possible tropical cyclone in the Atlantic. An upper level ridge will keep the surface system fairly stationary over the following days, finally relegating its influence over the region Friday into Saturday. Cloud cover on Friday may be slightly higher than earlier in the week as low level winds bring moisture from the Atlantic to the area as they are directed more from the east.

Meanwhile, an upper level trough is expected to move eastwards across the US and allow a surface low pressure system to develop on the eastern side of the Rockies around mid-week. The deepening of the trough will force the system towards the Midwest Thursday into Friday with a cold front extending southwards into the Gulf of Mexico. The trough is anticipated to move over the surface low, causing it to stall over the Midwest Friday night into Saturday. However, the cold front from the system will continue to move eastward, approaching Georgia sometime during the day. The models at this point are split on when a frontal passage may occur. An earlier passage will bring a slight chance for showers during the morning and a cooler afternoon high temperature while a later passage would allow temperatures closer to those seen earlier in the week and precipitation further towards the evening. The front would also change wind direction, coming mainly from the south ahead of the front and shifting to the west to northwest behind the front. With the amount of subjectivity to the forecast this far out, it will likely change in the coming updates during the week.

By: Stephen McCoy

Minor changes to temperature in this update with warmer weather expected for Saturday. Sunday's conditions will begin mostly clear, though as the day progresses cloud cover will slowly move in due to southwesterly winds in the upper levels ahead of an upper level trough. Partly cloudy skies are anticipated for the Grand Prix, though heavier cloud cover will move in for the remaining on-track sessions. Northwesterly winds overnight and into the morning on Sunday will cause a cooler high for the day relative to the rest of the weekend. Fog remains a possibility for all three days, though Friday remains the most likely for foggy conditions during the morning.