A cold front will move through the area today, which will bring a chance of showers and thunderstorms. Behind the front, temperatures will be cooler - highs today will be in the upper 80s, but Friday will be about 10 degrees cooler. As high pressure builds in from the northwest, winds will be blowing from the north at 10 to 20 mph, with gusts above 20 mph possible at times. As the high pressure becomes centered over the Florida Panhandle on Saturday, winds will be lighter, and sunny conditions will continue. Humidity will be low both days.
The high pressure center will move off the east coast on Sunday, which will turn the low level flow toward the east. This will transport some moisture off the Atlantic Ocean into South Florida, and the humidity will be a little higher. It looks like the moisture will remain shallow enough that it will only bring some clouds to the track, and not bring any rain. I think this is the most likely scenario, and I'm sticking with a dry forecast. However, there are a couple models that squeeze out a little light rain on Sunday. Even if those models are right, there should not be a significant impact to the racing. Pleasant temperatures in the upper 70s will continue into Sunday.