Much of the on-track activity will be dry on Friday, but rain chances creep back into the forecast after 3:00 pm, which could affect the qualifying sessions. The good news is that the rainfall appears to be light but may be just enough to bring out the rain tyres. It will be partly cloudy throughout the day and the afternoon high will be in the mid-50s. Rain chances are nearly 0% through much of the day, but increases to 30% after 3:00 pm.
The good news for the main event, The USAF NASA 25 Hours of Thunderhill, should be dry for at least 21 out of the 25 hours. A few light showers may dampen the track during the morning and into the early afternoon hours on Saturday, but those rain chances will only be around 30%. After 3:00 pm, the remainder of the race will be dry, but temperatures will be very cool to pretty chilly. Saturday's high will be in the lower 50s, then falling into the mid-30s for the early morning low on Sunday morning, before warming back into the upper 40s by the checkered flag.
I'll have radar up and running before 10:00 am PST today.