By Doug Schneider
There's no good news to report today about the weather forecast at Thunderhill Raceway this weekend. A deep and slow-moving low pressure system will be crossing Northern California, bringing periods of rain and breezy conditions from Thursday night through Saturday night. The only change change to the forecast worth mentioning is that the models are showing this system moving slightly slower than before, and to account for that, I have added a chance of rain to Sunday morning. So while the vast majority of the 25 Hours will be run in the rain, the final stages of the race, possibly the final 3-6 hours, may be rain-free. Through the event, I expect that rainfall amounts will likely be between 1 and 2 inches. Wind will also be a factor on Friday and Saturday, with sustained winds from the south to southeast at 15 to 25 mph, with gusts between 30 and 40 mph at times.
By Doug Schneider
I wish I could bring better news of a dry and sunny forecast for the 25 Hours of Thunderhill, but unfortunately, it looks like it will be a very wet weekend in Willows, California.
A strong low pressure system will be tracking west across the Pacific through the week, and arrive in northern California just in time for the on-track action. As teams set up and start to practice on Thursday, clouds will be increasing but most of the day will remain dry, with just a slight chance of rain possible late in the day. The chance of rain will be increasing Thursday night, and by Friday there will be periods of on/off rain as a flow of deep moisture spreads into the area ahead of the low pressure system. This system will be slow-moving, so rain will continue to spread across the area through Friday night and Saturday. There will also be a good southerly breeze on Friday and Saturday, with sustained winds between 15 and 25 mph, with higher gusts. The total amount of rainfall through Saturday could be between 1 and 2 inches. However, it's still a long way out in the forecast, so the forecast rain amounts will come into better focus as we get closer to the weekend.
Rain is expected to start tapering off on Saturday night. This far out, timing is uncertain, but right now I expect that by daybreak Sunday morning, all the rain should be gone. Clouds will start to decrease as drier air moves in, and there may be a mix of sun and clouds by the checkered flag.
Check back for updates to the forecast through the week.
By: Stephen McCoy
Springtime conditions are in full swing in South Africa this weekend for the Kyalami 9 Hours. The race weekend will kick off with some lingering showers possible during the early morning on Thursday after showers and thunderstorms are present on Wednesday as an upper level trough moves eastward over the region. As upper level winds return to zonal flow, an area of high pressure is expected to build in at the surface, diminishing chances for precipitation during the remainder of Thursday; some moisture will remain in the lower levels, causing partly to mostly cloudy conditions.
Conditions will wane overnight with mostly clear skies anticipated for Friday morning. Warming air temperatures and dew point temperatures near 16°C (60°F) will allow CAPE values in the afternoon to approach 1000 J/kg, providing an environment for possible thunderstorm development. Similar conditions are likely for Sunday, and may bring a chance for isolated showers in the early afternoon once again.
By Scott Martin
There is really not much change in the forecast for the season finale for the Blancpain GT World Challenge America series at Las Vegas. Skies will be sunny to mostly sunny throughout the entire event weekend with temperatures starting off rather warm on Thursday and becoming more mild by Sunday. Winds will be the only weather issue we'll have to deal with as we could see gusts up to 30 MPH on Thursday, 20 MPH on Friday, and 25 MPH on Sunday. With the wind, you may need a light jacked throughout the day on Friday and Sunday.
By Scott Martin
You probably couldn't ask for a better forecast to end off the racing season than what looks to happen this week at Las Vegas Motor Speedway. While Friday and Saturday look nearly picture perfect with mild temperatures and plenty of sunshine, we'll have to contend with some gusty winds on the first day of practice on Thursday.
Winds will be increasing through the morning hours and will be averaging around 5-15 MPH out of the south, but gusts up to 25-30 MPH will be possible during the late morning and into the afternoon hours. Other than the wind, no weather problems should occur as skies will be sunny with no rain expected. Temperatures start off in the lower 60s at 8:00 am and warm into the mid-80s for the afternoon high.
Friday and Saturday will nearly be identical in the weather department... There will be plenty of sunshine on both days with only a few passing clouds. Once again no rain in the forecast and afternoon highs will be mild. While both days will top out in the upper 70s, Friday will start off a little warmer near 60 degrees at 8:00 am with Saturday starting off in the mid-50s.
Sunday looks to be a great day at the track as well as skies will be sunny with maybe a cloud or two, but we'll stay dry and mild. Temperatures start off in the mid-50s at 8:00 am and top out in the mid-70s. Winds will be out of the north at 6-12 MPH.
Doug Schneider, Scott Martin, and Stephen McCoy 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, Pro Mazda, USF2000, IMSA, Blancpain World Challenge America, and World Endurance Championship, as well as major SCCA and NASA events.