By Doug Schneider

The forecast confidence for Sunday as been low all week, but I had been optimistic that the chance of rain would hold off until after the race ends. That no longer looks like it will happen, as the models today have come into better agreement that a line of showers and thunderstorms will cross Belle Isle on Sunday. 

There are some differences in timing of the storms, but it appears that the afternoon will be the most likely time for storms on Sunday. That's about as precise as I can be at this time. It could be enough heavy rain and lightning in the area for some delays that will affect the day's schedule. I may have to raise the Impact level to a Red Flag, but I'm not yet confident enough on the strength and speed of the storms to do that yet. 

By Doug Schneider

The remnants of the tropical system formerly known as Alberto will be dumping quite a bit of rain across the Detroit area through tonight. The abundant moisture associated with it will exit on Thursday, so it won't interfere with the on-track activity, which begins on Friday. 

There will be a cold front passing across the area on Friday, probably around noon, followed by an upper level trough passage in the evening. With the front and upper trough in the area, the forecast continues to have a 50% chance of showers through the day, with mostly cloudy skies. I think the coverage of showers will be scattered, with a 50/50 chance of a shower hitting the track. The wind will start from the southwest in the morning, then shift to northwest once the front moves through, and increase to around 10 mph. 

Behind the front, high pressure will build in from the north, and provide cooler and drier air for Saturday. It looks like it will be a great day to be at the track and enjoy some racing action, with partly cloudy skies and a high temperature around 70. There will be a northeasterly breeze at 10 to 15 mph. 

As I mentioned in my last post, Sunday is a little more uncertain. The models are showing the high pressure system exiting and another upper level trough approaching the area, which brings some rain late in the day. At this time I think it will hold off until the evening or overnight hours, and not have an impact on the race. This may change with my next forecast update, so stay tuned.

By Doug Schneider

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A big weekend of racing action is coming up this weekend on the streets of Belle Isle near Detroit, with IndyCar, IMSA, Trans Am, and Stadium Super Trucks all in action. After a chance of rain moves through on Friday, the weather pattern looks favorable for good conditions for racing over the rest of the weekend.

The models show a cold front moving through the Detroit area sometime on Thursday night or Friday morning. There is an upper level trough that lags behind the front, which moves through later in the day. While the majority of rain will come along the front, there will still be a chance of rain in the area until the upper trough moves through. 

High pressure to the north over Canada will start to settle southward over the Great Lakes on Saturday, with an upper level ridge building as well. This will usher some cooler temperatures into the area, and create a pressure gradient that will produce some breezy conditions. A north wind at 10 to 20 mph and partly sunny skies will keep temperatures in the 60s for most of the day. 

Some differences develop in the models for Sunday regarding the strength of the ridge and whether it gives way to a weak trough. For now I'm going with a forecast that maintains the ridge, as that seems to be the way most models are pointing. With a little more sunshine expected, high temperatures should rise into the 70s. 

A cold front will be passing through Ohio during the day on Friday bringing with it showers and thunderstorms. The good news is that severe weather does not look possible at this time. The bad news is that lightning will be possible with these storms, so you will need to stay weather aware if you are at the track. Winds will be quite breezy as well, averaging 15-20 MPH out of the southwest. The afternoon high should top out in the upper 60s to just at 70 degrees, and the chance of rain is 70%.

Once the cold front passes, the remainder of the weekend looks fantastic. Saturday will be mostly sunny with the high reaching the upper 60s to just at 70 degrees again. Winds will be out of the west at 5-10 MPH. Another cold front will move through the state late on Saturday that will bring even more dry air and cooler temperatures on Sunday. May need a jacket to start the day as temperatures are expected to be in the mid-40s, and the afternoon high will only reach the lower 60s. Winds will be out of the north to northwest at 5-10 MPH.

By Doug Schneider

While Scott deals with a wet forecast for Trans Am's event at Homestead this weekend, I have a nice easy Southern California forecast for the Grand Prix of Long Beach. 

No big changes are needed from my previous forecast, just a few adjustments to temperatures. Perfect racing weather is expected each day, with highs in the 70s. Friday will be a little breezy, with a northwest wind at 10 to 15 mph, gusting to around 20 mph at times. Saturday will be the warmest day, with a high in the upper 70s, then temperatures fall down a little for Sunday as high clouds will start to spread across the area. 

I will be taking a short vacation Friday and Saturday, so I don't plan to have another update in that time, but I don't think the forecast will need any updates through the rest of the weekend.