By Doug Schneider - @Race4caster

There have been some big shifts in how the models depict the weather pattern evolving over Detroit this weekend. I have very low confidence in this forecast, due to the models changing their tune back and forth between dry and wet. With so much uncertainty, I cannot make the forecast very detailed or specific in regard to timing of rain. But based on the latest model runs, it looks like there will be at least a chance of rain at the track each day. I wish I could make a forecast with greater confidence one way or the other, but sometimes we just have to admit that we don't know what will happen.

By Doug Schneider - @Race4caster

The Detroit Grand Prix is always a big event packed with racing action, as IndyCar, IMSA WeatherTech Championship, and the Trans Am Championship will all be racing on the streets of Belle Isle Park. The weather could cause some problems on Friday, but the rest of the weekend is looking good so far.

On Friday, the Detroit area will be in a warm and moist south to southwesterly flow, while a cold front will be pushing south across the upper Great Lakes. In the warm, moist air mass ahead of the front, there will likely be showers and thunderstorms. The question of timing is too uncertain this far out to be very specific, but I think the afternoon will have better rain chances than the morning. At this time, I have the impact on racing as moderate, meaning there will be wet conditions and possibly some delays in the schedule. I could see the impact becoming high with later forecast updates if the rain will be heavy, but that is too uncertain right now.

The cold front will move through Friday night, bringing a drier and cooler air mass to the area from the north. Saturday looks like great racing weather, with mostly sunny skies and highs in the upper 60s.

There is a little uncertainty about Sunday, but I'm going with a dry and mostly sunny forecast. Some previous model runs had shown the cold front lifting  back to the north and bringing more rain on Sunday, but the latest models are in better agreement with each other that the front will remain to the south of Detroit. I'll feel more confident in the dry forecast with additional model runs that continue to show this trend. 

Here are the forecast graphics for the other series that will be in action at Belle Isle:

By Scott Martin - ​@RaceWx4You

The latest model runs are in and I believe that the 101st Running of the Indianapolis 500 will remain dry throughout the entire event. There will be storms during the pre-dawn hours but will be out of the area well before 8AM. The skies will be mostly cloudy throughout the day, but conditions will be favorable for dry weather until around 2PM when a few scattered showers and thunderstorms will begin to develop. I do believe that those will stay west of the track until after the checkered flag falls, but I'm going to leave a 10% chance of a shower reaching the track before the end. It is almost not worth mentioning in the forecast, but this is racing on an oval with slick tires... any moisture could cause a problem. Therefore the 10%. The afternoon high will be around 80 degrees, and winds will be out of the southwest at 5-8 MPH.

Radar is up and running, and you can view it on your smart phone as well. I'm crossing my fingers that the forecast holds up throughout the night. I'll have another update in the AM.

By Scott Martin - ​@RaceWx4You

Believe it or not, I think Mother Nature is going to cooperate with us and allow Legends Day today and the Indianapolis 500 tomorrow to go on without any major delay or disruptions. We will have to deal with strong to possibly severe storms tonight through the overnight hours, but those will be gone in enough time for the big race on Sunday.

TODAY
There should be no problems at all during the day at Indianapolis Motor Speedway as far as the weather is concerned. Skies will be mostly cloudy throughout the day, which will bring a little relief to those who are sensitive to the sun, and the afternoon high will be around 80 degrees. Winds will be light out of the northwest at 1-3 MPH.

As far as tonight is concerned, there is the possibility of some strong to severe storms that could move through the area after 11PM associated with a mesoscale convective system. The Storm Prediction Center has the Indianapolis area in a slight risk for severe storms throughout tonight and into the morning hours on Sunday. The good news is that the storms will be on a weakening trend as they reach Central Indiana, but the threat of damaging winds and hail are still possible. The threat of tornadoes will be rather low, but not zero. Please stay weather aware tonight, especially if you are camping at the speedway.

SUNDAY
The line of storms should diminish around sunrise, and much of the daytime hours should remain dry on Sunday at the speedway. There could be an isolated shower or two pop up during the afternoon hours, but a relatively strong cap will be in place keeping any storms from developing. So I'm thinking optimistically and going with the race starting on time and racing to full distance. Skies will be mostly cloudy throughout the day, and the afternoon high will top out around 79 degrees. Winds will be out of the south-southwest to the west-southwest at 5-10 MPH. If a shower pops up and moves over the track, it should not last long and the rain amount will be light. The chance for rain at the track is 20%.

Most of the models are agreeing and keeping Indianapolis dry throughout the day, but the GFS is keeping moisture around. Normally the GFS model is not the best at guessing convective activity, so I'm sticking with the NAM-3k mainly for the forecast. I'm crossing my fingers that I am right.

By Scott Martin - ​@RaceWx4You

I think today is going to be a great day in Indianapolis, Looking at the latest HRRR, rain stays away from the area throughout the day, but storms look to move into the area around or just after 7PM tonight and will be quick out of the area around or just after 2AM Saturday morning. There is a potential for these storms to be strong to severe, and the Storm Prediction Center has a marginal risk for severe storms up for the area throughout the day until 8AM Saturday. If you're out and about, or if you're camping out, keep weather aware. For during the daytime hours at the track, there will be no problems. Skies will be mostly sunny, and the high will be around 79 degrees. Winds will be out of the south at 3-6 MPH.

Saturday is going to turn out to be another great day at the track, as skies will be partly to mostly cloudy throughout the day. The afternoon high will be around 79 degrees. Winds will be out of the north-northwest at 2-5 MPH. For the night time hours, there is a slight risk for severe storms in the Indianapolis area, mainly for another line of storms that is expected to move through during the overnight hours around or just after 1AM. The main threats will be from damaging winds and large hail, and there is a possibility for a few tornadoes as well. The latest NAM-3k model run is keeping the storms just south of Indianapolis, but not far enough to be comfortable to say there is no risk. Once again, stay weather aware, especially if you're camping out.

I may have some good news for Sunday for the Indianapolis 500. The latest run of the NAM-3k is keeping the main bulk of the rain and storm activity well to the south of Indianapolis. There will be another wave of storms that will be approaching the area, but it looks like it won't reach the area until well after the race is over. Now I am not ruling out a scattered shower or a brief thunderstorm to move over the track during the day, but as of now, it doesn't look all that bad. So my official forecast would be: Storms ending before 8AM, then skies will be mostly cloudy throughout the day. A passing shower or thunderstorm is possible during the day, but the likelihood of that is small at this point. The afternoon high is expected to be around 77 degrees, and the winds will be out of the south at 5-8 MPH. Chance of rain from 10AM-4PM will be around 20%.

Radar is up and running on the site, so feel free to use it at anytime. It refreshes every 60 seconds, so it will update the latest radar image in from the NWS Indianapolis as soon as it is uploaded. I'll have more updates throughout the weekend, especially on Sunday if rain develops around the track area.

By Doug Schneider - @Race4caster

Light rain has been around Lime Rock Park today, with around two tenths of an inch recorded at a nearby rain gauge. An upper level low pressure system is located to the west today, and will track east overnight. It will be positioned near Boston by Friday morning.

Some moisture will continue to wrap around the counter-clockwise circulation of the low into Friday, which will keep a good chance of showers in the forecast as cars hit the track. The good news is that any rain on Friday is expected to be light. It may only be on/off sprinkles. The total amount of rain on Friday will likely be under a tenth of an inch, so I expect that the impact on racing will be low. Some wet tires will probably have to be used at some point, probably for the morning sessions, but I don't foresee significant weather delays or cancellations. If you're attending the race, you may want to bring an umbrella. With a northwest wind and cloudy skies, temperatures will be pretty cool all day, mainly in the 50s.

Saturday looks like a great day to be at the track, and any chance of rain will end as the low moves farther away. Pleasant temperatures in the upper 60s are expected, with sunshine peeking through the clouds at times. 

By Scott Martin - ​@RaceWx4You

FRIDAY
The good news is that I have removed any rain chances out of the forecast for the Carb Day Festivities and the running of the Freedom 100. Skies will be mostly cloudy and the high will top out around 78 degrees. Winds will be out of the south at 3-7 MPH. Storms will move in for the evening, but well after the Steve Miller Band completes their show.

SATURDAY
Storms from the overnight and pre-dawn hours should be coming to a end before 8AM when the gates open at the track. Skies will be mostly cloudy throughout the day, as there will be a break throughout the morning into the early afternoon hours. Shower and storm chances begin to rise after 2PM, but just slightly. Good news is that the main bulk of the storms will move in after 8PM, well after the track closes for the day. The afternoon high will top out around 80 degrees, and winds will be out of the south to southwest at 3-8 MPH. The chance of rain throughout the day at the track is 30%.

SUNDAY
Here is where we may have some gnashing of teeth due to the weather. Looking at the latest model runs of the NAM and the GFS, there will be moderate to heavy rain/storms throughout the morning hours until 7-8AM. Then there will be a dry slot that opens of for Central Indiana from then until at least 2PM on both models (NAM-left, GFS-right), and the GFS keeps it dry until 8PM. So according to these model runs, the track should be dry for the scheduled race time. Double-checking with the NWS Indianapolis office, there are keeping the rain chances in throughout the day. Even though the amounts will be light, there is a possibility of a few delays. I'm going to side with the NWS right now until I can see when the high-resolution models come in to play. Skies will be mostly cloudy, and there will be a chance of rain throughout the day. The high will top out around 77 degrees, with winds out of the west to northwest at 5-7 MPH. Chance of rain as of now will be at 50%.

Once the timeframe for the high-resolution models come in to play, I can only cross my fingers and hope that the GFS and NAM models are correct. I will be able to nail the forecast down within 24 hours. Radar is up and running, so please feel free to use it and stay up to date with where the rain is happening.

By Scott Martin - ​@RaceWx4You

This weekend at the Indianapolis Motor Speedway for the 101st running of the Indy 500 is starting to get that "iffy" look to it. There will be a system moving through the area starting on Friday evening and will not leave until the late afternoon hours on Sunday. We should be able to get the race in on Sunday at full completion, but will we have some delays? That is the main question. Here is the forecast as of now...

Friday
The day will start off with mostly clear skies, but clouds will be on the increase during the day. It will be dry during the morning and early afternoon hours, but the chances of an afternoon shower/storm rises to about 1 in 5 for the remainder of the daytime hours due to the approach of an upper wave. Good news is that if any rain occurs, the amounts will be very light, and delays will be short if any at all. Afternoon high will be around 76 degrees, and winds will be out of the southwest to the south at 3-6 MPH.

Saturday
That upper wave will have the possibility of bringing some strong storms to the area during the evening on Friday into the day on Saturday. An unstable airmass with the wave will allow for robust convection, and the highest threat for strong to severe storms will be across Central Indiana. There will be a wave of storms moving through before 8AM, then a lull in the action until the mid afternoon hours, and scattered storm development picks back up throughout the rest of the day. Too early to know what the strength or what threats will be, but Saturday needs to be a day to stay weather aware. The high will top out around 80 degrees. Rain chances are over 50% to start with, then drop to around 20% during the lull in action, and finish off near 50% for the late afternoon into the night time hours. Rain totals of 1/2 inch will be possible.

Sunday
As the wave moves through the area, rain and storm chances will begin to drop throughout the day. Skies will start off mostly cloudy, but will begin to clear out some as the afternoon progresses. The high should top out around 76 degrees, with winds out of the west-southwest at 5-10 MPH. Rain chances start off at 40% during the morning, and drops to around 30% by noon. Good news is that if any rain occurs, the amounts will be very light, and delays will be short if any at all.