By Doug Schneider

I wanted to get a quick update on the weather situation this morning and what can be expected at Belle Isle Park this afternoon. It appears likely that there will be weather impacts during the racing this afternoon, especially the IndyCar race. 

Here's what's happening this morning on radar across the Great Lakes:

Low pressure is located over Wisconsin, with a stationary from stretching east across central Michigan. Showers are tracking E-SE along this front. For the morning hours, the shower and thunderstorm activity will stay to the north of Detroit, near the front.

Through the day, the low pressure area will track along the front, and the front will start to drift to the south. This will start to bring the showers and storms closer to Belle Isle in the afternoon. In addition, there will be a good amount of instability developing with daytime heating - it will be partly to mostly sunny for much of the morning and early afternoon. This instability will result in more showers and thunderstorms developing near the front the low pressure center, and some of these storms could become strong. 

Here is one model's (HRRR) depiction of what the radar will look like and where the low pressure center will be at 5 pm this afternoon:

Here's what I'm expecting at Belle Isle today - there may be a light and brief passing shower at any time during the day, but the chance of one is very low - maybe 20% or less. Then after 3 pm, the chance of showers and thunderstorms will start to rise (about 60%), with storms most likely to arrive sometime between 4 pm and 6 pm. The storms are expected to produce frequent lightning and heavy downpours. They may also be capable of producing gusty winds and hail. 

With the IndyCar race being run from 3:40 to 5:45 pm, it is likely that the race will be impacted. The extent of the impact will depend on how much rain falls, which can be highly variable depending on whether a storm tracks directly over the track or just skirts by. I do think that there will be lightning in the area, which will require a stoppage of the race. 

If you are going to Belle Isle today, stay aware of any storms that are approaching and take action when any calls to find shelter are announced. Have a plan ahead of time to get to a sturdy shelter. 

By Doug Schneider

The forecast graphic for the Detroit Grand Prix hasn't changed much from Wednesday, but there are some details on the timing of rain chances on Saturday that are coming into better focus today. More details on that below.

Today continues to look like a beautiful day at Belle Isle Park. There will be abundant sunshine and warm temperatures in the mid 70s. Admission is free today so get out and enjoy some great racing in perfect weather.

A cold front will be approaching Belle Isle from the north on Saturday, which will bring a chance of showers and thunderstorms. There could be showers in the area as early as the pre-sunrise hours of Saturday morning, but if these did occur they would be light and just wet the track a little. Scattered showers will be possible through the morning, but the chance of rain will be rising through the afternoon and evening, as will the threat of thunderstorms. This means that the IndyCar race, which is scheduled from 3:50 pm to 5:45 pm, will have the best chance of rain of Saturday's races. The exact timing of rain is too uncertain to say whether the race will be wet or dry at this time, but I would put the chance of at least part of the race being run in wet conditions at 40%. It is possible that rain could hold off until after the racing ends for the day, and I would put the chance of that happening at 60%. 

With thunderstorms being possible on Saturday, fans at the track should stay weather aware, and have a plan to find shelter, preferably in a building, when thunder is heard.

Showers and thunderstorms are likely after sunset Saturday evening as the cold front moves through. High pressure will build in from the north on Sunday, providing cooler temperatures and low humidity. It will be a beautiful day to take in a race, with mostly sunny skies and highs in the mid 60s. It will be a little breezy, with a north wind at 10 to 15 mph.

By Doug Schneider

The main change to the forecast for the Detroit Grand Prix with today's update is to shift the timing of rain chances on Saturday a little earlier. This could have the potential of impacting some races on Saturday, but which races will be impacted is still uncertain as there is not good model agreement on timing. 

Friday continues to look great as a cold front will move through the area on Thursday and a dry and cool air mass will follow it. With plenty of sunshine, highs on Friday will be in the lower 70s. 

Another low pressure system and its associated cold front will approach the area on Saturday. One model, the GFS, brings this front through on Saturday morning, which would put the chance of rain mainly in the morning and leave a dry afternoon. However, two other models that I have more confidence in, the NAM and ECMWF, have their rain chances with the cold front coming in the afternoon and evening. I think this later timing is more likely to occur than the earlier timing, but I can't rule out showers at any time of the day. With the afternoon timing of the cold front, there may be more instability available for thunderstorms, so I've added that to the forecast. This does not appear to be a rain-out situation at all - just scattered showers and possibly a thunderstorm in the area for a brief period, so I have the Impact as low. Even if a storms passes over Belle Isle, it should only produce around a tenth of an inch of rain. 

Behind the cold front on Sunday, there will be mostly sunny skies, low humidity, and cooler temperatures. Morning lows will be in the lower 50s, with highs in the upper 60s. 

By Doug Schneider

Overall, the weather looks really nice for the Detroit Grand Prix weekend. Don't let that rain chance on Saturday keep you away. With Trans Am, IMSA, and IndyCar in action, it should be a great event to attend. 

As teams set up at Belle Isle on Thursday, there will be rain in the area. A cold front will be pushing through the area, and while the heaviest rain will be to the south across Ohio, up to a quarter inch of rain may fall at Belle Isle on Thursday. 

Once the front exits Thursday night, a cool and dry air mass will build in from the north. Friday will be a beautiful day for racing, with sunshine and high temperatures in the lower 70s. Even better, Friday is Comerica Bank Free Prix Day, with no charge for admission. Free racing and nice weather - it doesn't get any better!

Saturday will have more cloud cover, but still a fair amount of sunshine, mainly in the morning. A southwest wind at 10 to 15 mph will raise temperatures into the mid 70s in the afternoon. Clouds will be increasing through the day as another cold front approaches from the north. However, at this time I expect that any rain with the front will hold off until after the racing is done for the day (the IndyCar race ends at 6 pm). There is a concert after the race which may have a chance of being impacted, but at this time I only have a 30% chance of rain during the daylight hours. Rain is most likely to arrive overnight. 

The cold front should be through the area by the time on track action starts on Sunday morning at 10:45. There is a chance of the timing changing with later forecasts, but for now I'm going with a dry and mostly sunny day. Winds will shift to the north behind the front, with temperatures topping out around 70. 

By Doug Schneider

The forecast graphic for Indy 500 qualifying hasn't changed much from yesterday, but some of the finer details are coming into better focus today, so I wanted to get an update out with what I'm thinking will happen on Sunday. 

As I mentioned yesterday, one scenario was that there would be two rounds of showers and storms on Sunday. I think that this is going to be the scenario that plays out. However, it's not all bad news!

I expect that a round of showers will move through central Indiana Sunday morning. These showers will be the remains of dying storms overnight that will move in from the west. This round will likely not be heavy, and while there may be some lightning possible with it, I don't think lightning will be frequent or widespread enough to be a big issue at the Speedway. There may be around a tenth of an inch of rain with this round of showers. The most likely time for these showers to occur will be between 9 am and noon. This may interfere with the morning practice sessions. It is possible that the decaying showers could die completely before reaching the Speedway. However, I think it is likely that there will be some rain occurring in the mid to late morning.

The second round is expected to be more significant than the first. The Storm Prediction Center has a Slight Risk of severe storms for central Indiana on Sunday afternoon, which means a 15% chance of severe storms in any location.  

If severe storms occur at the Speedway, damaging wind gusts and frequent lightning will be the main threats. Everyone at the track will need to stay weather aware on Sunday, and find shelter inside a building (I recommend the Museum!) when the PA system announces that storms are in the area. 

The big question with this second round is timing. The two qualifying sessions are scheduled to be held from 12:15 to 2:15 pm EDT. I expect that the second round will arrive after 2 pm at the very earliest, and more likely after 4 pm. If the first round doesn't drop too much rain and track drying does not cause too much of a delay, I think that qualifying can be completed. I do think that the practice session scheduled from 3:15 to 6:00 pm will be interrupted. The storms will move through quickly but they could dump some heavy rain in a very short time, possibly a quarter to a half inch. Again, strong winds and lightning will pose a real threat, so take any calls for action seriously.

I have changed the Impact to Moderate with a yellow flag, meaning that there may be some delays and possibly cancellations to the practice sessions, but qualifying should be able to get in as scheduled if the timing plays out as expected.

Of course, the weather doesn't always do what we expect, so we'll hope for the best and watch how it develops. I won't be able to provide regular radar updates on Sunday until the mid afternoon, but you can use our radar link at the top of the page to keep up with the weather.