By Doug Schneider

The main change to the forecast today has been to add a mention of a light sprinkle or shower on Sunday morning.

A west to northwest flow will bring the marine layer into the Monterey Peninsula each night, resulting in low clouds forming. These clouds will linger through the morning, and dissipate by noon, leaving mostly sunny skies on Friday and Saturday afternoons. On Sunday, the moisture will get a little deeper as a cold front approaches from the northwest. This could squeeze out a little rain, probably just a couple hundredths of an inch at most. Rain could fall during the Sunday morning warm-up session, but again, the light nature of the rain should not have much of an impact. For the race, it will be partly sunny with temperatures in the 60s.

By: Stephen McCoy

Conditions for this weekend at Watkins Glen have remained mostly as expected, with a shift of precipitation from Friday to Saturday. A surface low pressure system located off the Atlantic coast will cause winds to be largely from the south to southeast on Friday, bringing moisture off the ocean and resulting in mostly cloudy to overcast conditions. The increased moisture may also cause a slight chance for isolated showers in the region, especially in the afternoon. On Saturday, a cold front extending south from a surface low located over Canada is expected to move through the region, bringing a higher chance for precipitation during the afternoon. Winds behind the front will shift to the west to northwest, cooling temperatures into Sunday with cloud cover decreasing through the day as drier air moves in.

By: Stephen McCoy

Mixed conditions will start the event off on Friday and will improve as the weekend progresses.

Around mid-week, a low pressure system will move eastwards over Canada to the north of the region. This system will bring a cold front through the area with a high percentage of rainfall and a drop in temperatures expected Wednesday into Thursday. A second low will take a similar route as the first during the early part of the weekend with its warm front moving northward through New England Thursday into Friday morning. This will allow temperatures to warm again into the upper 70's, which will remain largely consistent through the next few days. Of note: the National Hurricane Center has identified a disturbance in the Atlantic which has a 50% chance to develop into a tropical system within the next 5 days. Current model guidance suggests the system will curve along the east coast before moving out into the northern Atlantic. This has been brought up as its location at the beginning of the weekend will bring moisture from the Atlantic to the region, resulting in a chance for scattered showers through the day, especially during the afternoon. As mentioned, conditions will improve for the remainder of the weekend as the low and potential tropical system move further eastward. Winds shifting to the west/northwest on Sunday will bring slightly cooler temperatures and clearer conditions. Saturated air at the surface and a temperature inversion just above the surface will result in a potential for fog for both Saturday and Sunday morning.

By Doug Schneider

Aside from some clouds and fog each morning, nice weather is expected for IndyCar's visit to WeatherTech Raceway Laguna Seca. 

All this week, a large area of high pressure will be located off the California coastline. This high will produce a west to northwest flow off the Pacific Ocean. In this setup, it is common for the Monterey Peninsula to experience fog and low clouds overnight due to the marine layer - moist air off the ocean spreads inland, and as temperatures cool overnight, fog can form. This past weekend at the IMSA event, fog and low clouds formed each morning, and usually cleared out between 10 am and noon. I expect a similar pattern this weekend. Some of the early morning sessions may be impacted due to low visibility. ​Once the clouds and fog lift, sunny skies will prevail. Thanks to the cool air off the ocean, temperatures will only reach to around 70 degrees in the afternoons. 

By Scott Martin

Other than a few tweaks to the temperatures and dewpoints, the forecast remains the same for the Grand Prix of Portland. Both days will start off mostly cloudy, but clouds will decrease throughout each day and skies will become mostly clear by the afternoon hours. Highs will top out in the mid to upper 70s.

By Doug Schneider

No big changes to the forecast for IMSA weekend at WeatherTech Raceway Laguna Seca. Overall, the weather will be very nice for racing, with mostly sunny skies each afternoon and pleasant temperatures.

Expect clouds to spread in overnight, and linger into the morning each day. This is due to a northwest wind that will persist all weekend, bringing in a marine layer of moisture, resulting in low clouds forming overnight. The clouds should lift around the late morning and early afternoon.  

By Scott Martin

While there will be plenty of excitement on the track at Portland International Raceway, the weather department will be rather uneventful as the forecast is really similar for each day of the event weekend. Each day will feature a mix of sun and clouds, with temperatures starting off around 60 degrees in the morning and topping out in the lower to mid-70s. Winds will be out of the northwest ranging from 2-8 mph, and we'll remain dry throughout the weekend.

By Doug Schneider

Nice weather is expected for the IMSA weekend at WeatherTech Raceway Laguna Seca. Through this week, high pressure will be drifting east across California, eventually settling over the Rockies by the weekend as a weak trough moves into the west coast. This trough will bring cooling temperatures over the weekend, and maybe some high clouds. Overall, skies will be mostly sunny. As is typical for the Monterey Peninsula, moring fog may develop. At this time, it is too early to forecast fog with any confidence. With a west wind off the ocean, fog will be possible, but I will wait until we get closer to the weekend to add it to the forecast.