By Doug Schneider

Beautiful California weather can be expected this weekend as IMSA heads to WeatherTech Raceway Laguna Seca. 

A large high pressure ridge will be over the west coast for the second half of this week. Through the weekend, this ridge will shift to the east, and a low pressure trough in the upper levels will approach from the west. The main affect of this will be temperatures that will trend warmer each day of the event, and a slight increase in high clouds on Sunday. 

Morning fog is often an issue at Laguna Seca, and while it can't be ruled out, it is too far out in the forecast to mention it as a problem at this time. Forecasting fog is difficult even a few hours in advance, so I'm not going to try to do it 4 to 6 days in advance. We'll see how that develops in later forecast updates.

By Doug Schneider

Not much has changed in the weather pattern shown by the models for this weekend in St. Petersburg, so the forecast that I made on Monday still appears on track (no pun intended). A low pressure system will be over the Gulf of Mexico, with a high pressure system over the eastern United States. While I can't rule out an isolated shower or thunderstorm in the area both Saturday and Sunday, I don't expect that they are likely to have an impact on the racing. Pop-up showers along the Florida coast are difficult to predict days in advance, so while they are possible in the St. Pete area, their coverage should be isolated enough to make the chance of one occurring at the track very low. Overall, it should be a good weekend for racing. 

By: Stephen McCoy

Much like was stated in the initial forecast, a trailing front from a surface low pressure system centered over Scandinavia will sit mostly stationary over the region on Thursday and into Friday. South to southwesterly winds along the frontal boundary will bring a likely chance for precipitation during the day, with some of the heaviest rainfall occurring in the later hours, near qualifying and/or the night practice session. Low level winds from the south to southwest will cause mostly cloudy to overcast conditions through much of the weekend.

A cold front extending from a low pressure system north of the British Isles is expected to move through the region on Friday, bringing another chance for showers ahead of it around mid-day. The front will weaken as it passes through, however low temperatures for Saturday morning are still expected to cool from Friday's, though not as severely as initially thought.

The weekend will round out with another cold front approaching the region from the west. Winds continuing from the south to southwest ahead of the front will bring slight chances for isolated showers on both Saturday and Sunday, though with lighter rainfall than seen earlier in the weekend. However, the front itself will bring heavier rainfall as it passes through Sunday, which could impact conditions in the final hours of the race, depending on the timing of the passage.

By: Stephen McCoy

It certainly won't be the conditions that the teams are typically used to for the 24 Hours of Spa. Temperatures for the weekend are looking to be in the upper 50's °F, or low teen's °C with chances for showers during the practice and qualifying days before somewhat clearer conditions move in for the race.

On Wednesday, a surface low pressure system is expected to move northeastward through mainland Europe, bringing warmer temperatures, strong winds and a likely chance for precipitation to the region. Entering Thursday, the system will be located over Scandinavia, with a front trailing behind to the southwest. The front is expected to sit mostly stationary over the region during the day, resulting in a chance for precipitation along the boundary. South to southwesterly winds will cause temperatures to be relatively consistent through the day, with a high only a few degrees warmer than the morning low. In addition, conditions will be mostly cloudy to overcast in the low levels through the day. The stationary front will move eastward out of the region overnight Friday, however a cold front from a low pressure system north of the British Isles will move into the region Friday afternoon, bringing a chance for scattered showers. South to southwesterly winds continuing overnight will keep temperatures relatively consistent with Thursday before the cold front passes and cools temperatures into Saturday.

After Friday's cold front passage, drier and slightly cooler conditions will move in for the 24 hour. Winds will shift towards the south to southeast for the race as another cold front begins a lengthy approach towards the region, passing through late Sunday or early Monday. Current model output is mixed on the passage time, though an earlier passage could mean heavier cloud cover for the race ahead of the front, with a later passage resulting in clearer conditions. An earlier frontal passage could also bring a slight chance for isolated showers, however for now there isn't enough to definitively say if rainfall will occur.

By Doug Schneider

The INDYCAR season finale at St. Peterburg is expected to have general good weather conditions, although an isolated shower or thunderstorm can't be ruled out.

The general weather pattern across Florida and the Gulf of Mexico later this week will feature a weak low pressure area over the Gulf that will be slowly tracking toward Florida. Over the weekend, it will be located just off the Florida coastline. It is a weak and poorly-defined low, which adds some uncertainty to the forecast. But it may be enough of a factor to produce some showers and thunderstorms near the St. Pete area, or maybe just offshore. This far out in the forecast, there is enough uncertainty about their location to warrant a small rain chance. However it doesn't look like they should have much impact if they do occur. 

​Check back through the week for forecast updates.