By Doug Schneider

By Doug Schneider

A cold front is expected to move through the Detroit area on Thursday, which will bring a good chance of showers and thunderstorms. It is possible that the storms with the front will move through Wednesday night, so the timing is a little uncertain, so I'm putting a chance of rain in for load-in day on Thursday. Fortunately,, there is no on-track action scheduled that day.

An upper level low pressure system will be sitting over Ontario for the rest of the weekend. This will bring cooler temperatures on Friday and Saturday, with highs in the lower 70s.  

Another upper level disturbance rotating around the low will bring the possibility of some showers and storms on Sunday. With the timing still uncertain this far out, I only have a 30% chance of rain. I'll be keeping an eye on this for the next few days. 

By Doug Schneider

It has been difficult to think about the weather today due to the terrible accident today in PWC practice at Lime Rock Park, as our thoughts and prayers are with Andrew Palmer and Jorge de la Torre. 

The past few days, I've been optimistic about getting the entire Indy 500 in without rain. I'm feeling more and more confident about that happening with the latest data this morning. Most of the moisture that has been over the Midwest and Indiana the past few days will be shifting east, with drier air aloft moving in from the west tonight. With this dry air above the surface, it will be difficult for storms to develop tomorrow afternoon. There will be a cold front approaching the area, which will result in some isolated to scattered storms developing in Indiana, but I expect that they will hold off until after the race ends. I'd put the chance of getting the entire race done with no rain delays at 90%. The day will likely start off with some clouds, but these clouds should gradually decrease through the morning, leaving partly cloudy skies by the start of the race. Temperatures will reach the lower 80s, and winds will be between 8 and 12 mph, generally from the south-southwest. 

Enjoy the race, it's going to be epic.

Today will be a warm day at the track, and with dewpoints rising up into the 60s today, the mid 80s forecasted for today's highs will feel uncomfortable to some. There is a boundary located near the region and is expected to lift to the northeast as a warm front. Isolated convective showers and thunderstorms will form across the area this afternoon, but coverage could be limited due to weak forcing. As the day progresses, humidity levels rise and so will the chance for showers and thunderstorms. Rainfall should not last too long, and amounts should average around a tenth of an inch.

On Saturday, the warm front will stay west of the area, but a cold front starts to move into northern New York and northern New England. A chance for convective showers and thunderstorms to develop over the area during the afternoon and evening hours. Also, with highs reaching the upper 80s, dewpoints will reach the upper 60s to near 70, and this will mean that the heat index will be in the 90s. Once ahain, rainfall shouldn't last too long, and amounts should average around a tenth of an inch.

Stay hydrated and in the shade when possible. Also remember that when you hear thunder, you are close enough to be struck by lightning. So when thunder roars, go indoors. Radar will be up and running on the Pirelli World Challenge website. Just click the link posted beneath the Racecast Weather logo. I'll also have updates on our Twitter feed.

By Doug Schneider

Unfortunately, showers and thunderstorms washed out qualifying for the Indy Lights Freedom 100 today. The weather pattern for tomorrow and Saturday looks much the same as it did today, so the chances of seeing additional showers and thunderstorms on Carb Day and Legends Day will be 50/50 or higher. In a moist air mass like this one, it is difficult to pin down the timing of showers in advance. Showers are possible at any time of the day Friday and Saturday, so if you're at IMS or at Lucas Oil Raceway for the Carb Night Classic, you should stay weather-aware. You can click the IMS Radar link at the top of the page to see where storms are in relation to IMS, along with lightning strikes. The range rings that are displayed mark 8, 12, and 16 miles from the Speedway. Remember - if you can hear thunder, you are close enough to be struck by lightning. Have a plan in advance of where to seek shelter, and move there as soon as you hear thunder. Remain sheltered until 30 minutes after the last thunder is heard.

Sunday continues to look more promising for racing as a ridge of high pressure will develop over the southeast, which will cut off the flow of moisture from the Gulf of Mexico. Still, there will be a small chance of showers and thunderstorms due to an upper level disturbance that will move through. The key will be the timing. It looks like the atmosphere will be capped for most of the day, which means that showers will not be able to develop until this cap breaks. Forecasting the timing of this is always tricky, but right now, I expect that storms will hold off around the Speedway until late in the afternoon (around 3 pm or later). I'm optimistic that the race will be done before any storms develop. The 30% chance of rain in the forecast is for the chance of rain before 4 pm. I'd put the chance of rain after 4 pm closer to 50%. Even if the storms hold off until after the race, they could add to the traffic problems leaving the Speedway.