By Doug Schneider - @Race4caster
 |  Forecast in Celsius and km/h. Click to enlarge |
Here's a look at the radar and surface observations across Ontario this morning:
CTMP is located at the red dot northeast of Toronto. I've drawn the approximate position of a cold front with the blue line. There are showers across Michigan and Lake Huron this morning, but I'm not too concerned with these affecting the track - the storms in Michgan will pass south, and the shower over Lake Huron is dissipating. I do expect that as the cold front tracks into southern Ontario late this morning, additional showers and thunderstorms will develop. I expect that there will be scattered storms in the area around CTMP between 2 pm and 6 pm. The chance of one of them hitting the track is about 50%. I have lowered the chance of rain from the previous forecast, as the coverage of showers does not look as great as it did a couple days ago. The Prototype Challenge and WeatherTech practice sessions are the ones most likely to be affected. Rain amounts around a tenth of an inch can be expected if a shower or storm hits the track, with an additional tenth of an inch possible tonight.
The cold front will move through the area tonight, and I expect the rain to exit with it. In the previous forecast, there was a small chance of a shower lingering into Saturday morning as the upper level trough moved through, but the timing of that looks faster today, so I've removed that small rain chance from Saturday morning. It should be a really nice day to be at the track, with cool temperatures in the 70s, low humidity, and a breezy northwest wind.
Unfortunately, Sunday is moving in a wetter direction. Another cold front will be approaching the area, and since it looks to arrive sooner than previously projected by the models, I've had to raise the chance of rain. The 30% chance of rain in the forecast graphic is the chance of rain during the race, which will be held between 12:05 pm and 2:45 pm. There is a higher chance of rain after the race ends. I expect that any rain that might fall during the race will be light, so I have the impact ranked as Low. It could just be some sprinkles that barely even wet the track, like we saw at the end of the Watkins Glen race. Heavier rain may arrive in the late afternoon or evening hours.
The cold front will move through the area tonight, and I expect the rain to exit with it. In the previous forecast, there was a small chance of a shower lingering into Saturday morning as the upper level trough moved through, but the timing of that looks faster today, so I've removed that small rain chance from Saturday morning. It should be a really nice day to be at the track, with cool temperatures in the 70s, low humidity, and a breezy northwest wind.
Unfortunately, Sunday is moving in a wetter direction. Another cold front will be approaching the area, and since it looks to arrive sooner than previously projected by the models, I've had to raise the chance of rain. The 30% chance of rain in the forecast graphic is the chance of rain during the race, which will be held between 12:05 pm and 2:45 pm. There is a higher chance of rain after the race ends. I expect that any rain that might fall during the race will be light, so I have the impact ranked as Low. It could just be some sprinkles that barely even wet the track, like we saw at the end of the Watkins Glen race. Heavier rain may arrive in the late afternoon or evening hours.
