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.

By: Stephen McCoy

It'll be a nice weekend to be in California for the INDYCAR season finale, though a bit cooler than this previous weekend's IMSA race at WeatherTech Raceway Laguna Seca. A cold front moving through the region on Monday and a second cold front moving through on Wednesday will cool temperatures to the mid 70's F for the weekend as surface winds bring air in from the northwest off the Pacific. Conditions will be clear for much of the event due to dry air, also from the northwest, entering into the region through the mid-to-upper levels.

Fog is possible each day, but largely depends on the direction of the surface winds. If they come off the mountains to the east and southeast, nothing to worry about. But northwesterly winds during the morning will bring moisture off Monterey Bay and could result in fog during the morning. Friday currently looks more likely than the rest of the weekend as light to no wind will be present before increasing into the afternoon.

By Doug Schneider

Not much has changed in the forecast for WeatherTech Raceway Laguna Seca this weekend. No rain is expected through the event, with temperatures starting off warm on Friday but getting cooler each day. The one change to the forecast is to bring in more cloud cover on Sunday, associated with the upper level trough that will be approaching the area. It does not appear that there will be enough moisture for rain, just some partial cloud cover. This trough will also help cool temperatures to the lower to mid 70s on Sunday. It should be a great weekend for racing.

By Doug Schneider

Beautiful California weather is expected this weekend as IMSA visits WeatherTech Raceway Laguna Seca. Sunny skies are expected each day, with pleasant temperatures. There will be a cooling trend each day, with Friday reaching the mid 80s, cooling to highs in the mid 70s on Sunday. This is due to an upper level trough that will be approaching, although it won't have enough moisture to produce rain, or even clouds. 

One thing to watch for as we get closer to the weekend will be morning fog or low clouds. Fog can be pretty common at Laguna Seca if the wind direction and ocean-land temperature difference are right. At this time I think it is unlikely to have any impact, so I'm keeping it out of the forecast.

By: Stephen McCoy

The forecast for Sunday at Watkins Glen has remained mostly consistent with the rest of the week's forecasts. Partly to mostly cloudy conditions will be present through much of the day, varying in height as the air aloft begins to saturate; westerly winds are expected to bring in moisture above the region. South to southeasterly winds at the surface will keep temperatures in the upper 60's to low 70's, but will also allow dew point temperatures to approach 60 °F as moisture moves in from the Atlantic. The saturated atmosphere coupled with minor lifting could result in some scattered showers through the region in the afternoon; a surface trough approaching from the northwest is expected to bring a larger chance for precipitation overnight.