A cold front and upper level trough is expected to move through upstate New York sometime late Wednesday night or early Thursday morning. By sunrise, the front should be to the east, but there will still be a chance of scattered showers around Watkins Glen. The chance of any impact on racing is low, but it could affect the Porsche GT3 Cup practice if it lingers a little longer. Clouds will be decreasing through the day as the upper trough moves away and drier air builds in on a northwest flow.
A large high pressure ridge from the surface through the upper levels of the atmosphere will be building over New York for Friday and Saturday. The result will be sunny skies wand warming temperatures. Highs on Friday will be in the upper 80s, then reach the lower 90s on Saturday. The normal high temperature for this time of year is around 80 degrees, so it will be much warmer than normal.
Sunday will continue to have hot temperatures, and humidity levels will be increasing. The increase in moisture may produce a little more cloud cover, but it will still be mostly sunny and hot, with highs well into the 90s. Some models hint at a chance of an afternoon shower developing, but I'm not confident enough in that happening yet to mention it in the forecast. I think the high pressure system will maintain stable conditions through Sunday.