I have been going over the latest model runs, and main shield of rain appears to stay north of the speedway for most of the morning and the early part of the afternoon hours. Around 4PM today is when it looks like scattered showers and thunderstorms start to arrive at the speedway. Now I can't rule out that there may be a few passing showers before hand, but it looks like the bulk of the rain doesn't move in until approximately 4PM. Winds will by gusty at times, up to 20 MPH. Tonight will feature much of the same. Scattered showers and thunderstorms, with winds gusting up to 25 MPH at times.
I'm going to be optimistic for the start of the Rolex 24 tomorrow. I know I put a 60% chance of showers and thunderstorms before 4PM in the forecast graphic, but I do believe that all the action will have passed through by 2PM and will only have to use rain tires for the first stint. But that is being optimistic. The high temperature will be reached at midnight, and will steadily fall throughout the day. Winds are still expected to be gusty, up to 30 MPH at times. Skies will start to clear after 5PM. Saturday night through the early morning hours of Sunday will be mostly clear skies and cold, reaching a low of near 40. Be sure to bundle up.
Sunday looks like a great day for the finish of the Rolex 24. Skies will be mostly clear, with only a few passing clouds. Highs will struggle to reach the mid 60s. No chance of rain.
Be sure to stay weather aware today while at the track, especially if you hear thunder in the area. I will be doing some maintenance work on the radar page today, so I'll have another radar page up in its place until the maintenance is finished. That should be done by 1pm. I'll tweet weather updates during the race today, so keep the smart phone handy. Have a great day.