The weather pattern across southeast Australia will feature high pressure off the coast, and low pressure over central Australia, with a trough of low pressure extending into New South Wales. The position of this trough will be the main factor in the chance of showers and thunderstorms at Mount Panorama. Here's what the pattern is expected to look like around midday on Friday, Saturday, and Sunday, according to one model (the image is moisture, the arrows are winds at the surface, and the lines are pressure contours):
Bathurst, Australia is 16 hours ahead of EST, and 11 hours ahead of GMT. The race starts at 5:45 am local time Sunday, which is 6:45 pm Saturday GMT, and 1:45 pm Saturday EST.
Here's the forecast in Celsius and km/h: