By: Stephen McCoy - @stephenmmcc

There are a few changes in this update to the forecast for the next two days at Sonoma Raceway. Some higher wind speeds are looking likely in the afternoon for both Saturday and Sunday as a result of a stronger pressure gradient at the surface. The slightly cooler temperatures seen for Saturday's high and Sunday's low are likely caused by these stronger winds as the cooler air moves into the region from the Pacific.

By: Stephen McCoy - @stephenmmcc

Clear conditions with warm temperatures continue to dominate the forecast for the Indycar Grand Prix of Sonoma at Sonoma Raceway. High temperatures for the weekend are expected to stabilize around the mid-to-upper 70's and with dew point temperatures in the upper 40's to low 50's, heat index values should remain close to the actual temperature. Some moisture in the upper levels could bring some light cloud cover to the region in the late afternoon to evening on Friday, but otherwise conditions will remain clear. Expect maximum wind speed of 5-10mph from the west to southwest each day.

By: Stephen McCoy - @stephenmmcc

A picture-perfect weekend is in store for Indycar for the season finale this weekend at Sonoma Raceway. The eastern edge of an upper level trough will be over the region through early next week with winds primarily from the southwest during this period. The winds will bring mostly dry air to the region during the weekend aside from the later hours on Friday, where some more moisture will cause light cloud cover into the evening and nighttime hours. Surface winds will be around 5-10 mph each day, generally from the west, but they could fluctuate between the northwest and southwest. With plenty of sunshine, temperatures will reach the mid to upper 70's each day, with dew point temperatures in the upper 40's to low 50's, keeping the heat index close to the air temperature.

On Sunday, some fog looks to be possible as saturated air at the surface will be present under a temperature inversion and dry air aloft, but it will erode into the late morning with clear conditions returning for the race.

By Doug Schneider

The forecast remains steady for the Monterey Grand Prix at Laguna Seca this weekend, with nice weather still expected. The only potential issue may be fog each morning, which is fairly standard for the Monterey peninsula this time of year.  The fog will burn off between 8 and 10 am, with sunny skies expected for the rest of the day. High temperatures in the low to mid 70s and low humidity will make for very pleasant conditions to take in some great racing action.