By Doug Schneider

A cold front moving across Florida will bring a line of showers and thunderstorms to Daytona tomorrow. Over the past few days, the trend has been toward a later arrival of the showers, and now I expect that the chance of rain will fall mainly between 11 AM and 3 PM. During this time, showers may produce a tenth to a quarter inch of rain, as well as cloud-to-ground lightning. The good news is that the line should move through fairly quickly - it won't last all of the 4 hours of the time frame, but that is the window when I expect the showers to move through. I expect that the rain will last for about an hour, maybe two at most. The IMSA Prototype Challenge race is the event that is most likely to be affected. There may be a stoppage during the race for lightning in the area or brief heavy rain.

On Sunday, the main weather impact will be much cooler temperatures. Low temperatures in the morning will only be in the mid 40s, with a high struggling to reach 60 in the afternoon. It will be a little breezy, with a northwest wind at 10 to 15 mph, but at least there will be plenty of sunshine.

By Doug Schneider

The timing of a cold front has changed since Monday's forecast, shifting the chance of rain out of Friday and into Saturday. 

Friday at the Roar will be a sunny and warm day, with high temperatures reaching the mid 80s. Clouds will start to increase late in the day, and rain will likely begin to fall overnight. A cold front will move across the area on Saturday morning, and there could be a few thunderstorms with it. The front appears to move through fairly quickly, so while there could be some delays or cancellations in the practice sessions on Saturday morning, there should be enough time to get plenty of practice done through the afternoon. Rainfall is not expected to be heavy, with just a tenth to a quarter inch expected. Saturday will be a little breezy, with wind gusts between 20 and 25 mph.

Behind the front, temperatures will be much cooler. Lows on Sunday morning will only be in the mid 40s, with a high on Sunday in the lower 60s, despite abundant sunshine. 

By Doug Schneider

A cold front is expected to move across the Daytona area and bring showers to the Speedway on Friday and Friday night, but the good news is that the timing of most of the rain should allow for very little impact on the on-track activities. 

The Roar will open with warm temperatures and a good southwest breeze on Friday. Through the day, clouds will be increasing as a deep upper level trough and its associated cold front move across the Plains to the eastern United States. Ahead of this front, some scattered showers may develop around Daytona on Friday afternoon. I expect that only the late day practice session will have a chance of rain, and any rain that occurs will likely be light. The main band of showers with the cold front is not expected to move across Daytona until after dark on Friday night. 

By the start of practice on Saturday morning, the cold front should be east of the Speedway, and clouds will gradually be clearing out. The track may be wet in the morning, but it should dry out quickly with clearing skies and a bit of wind. Temperatures will be cooler compared to Friday, but still quite pleasant in the lower 70s. Winds will shift to the west and still be a little breezy at 10 to 15 mph. 

High pressure building over the area will bring a northwest winds and cooler temperatures for Sunday, with morning lows in the upper 40s and afternoon highs in the mid 60s. Still, there will be plenty of sunshine all day, along with low humidity. 

Over the past few days, the models have been in pretty good agreement on this pattern, and have not changed much from run to run, so my confidence in this forecast panning out is fairly high. Check back through the week for updates.

By Doug Schneider

There's no good news to report today about the weather forecast at Thunderhill Raceway this weekend. A deep and slow-moving low pressure system will be crossing Northern California, bringing periods of rain and breezy conditions from Thursday night through Saturday night. The only change change to the forecast worth mentioning is that the models are showing this system moving slightly slower than before, and to account for that, I have added a chance of rain to Sunday morning. So while the vast majority of the 25 Hours will be run in the rain, the final stages of the race, possibly the final 3-6 hours, may be rain-free. Through the event, I expect that rainfall amounts will likely be between 1 and 2 inches. Wind will also be a factor on Friday and Saturday, with sustained winds from the south to southeast at 15 to 25 mph, with gusts between 30 and 40 mph at times. 

By Doug Schneider

I wish I could bring better news of a dry and sunny forecast for the 25 Hours of Thunderhill, but unfortunately, it looks like it will be a very wet weekend in Willows, California. 

A strong low pressure system will be tracking west across the Pacific through the week, and arrive in northern California just in time for the on-track action. As teams set up and start to practice on Thursday, clouds will be increasing but most of the day will remain dry, with just a slight chance of rain possible late in the day. The chance of rain will be increasing Thursday night, and by Friday there will be periods of on/off rain as a flow of deep moisture spreads into the area ahead of the low pressure system. This system will be slow-moving, so rain will continue to spread across the area through Friday night and Saturday. There will also be a good southerly breeze on Friday and Saturday, with sustained winds between 15 and 25 mph, with higher gusts. The total amount of rainfall through Saturday could be between 1 and 2 inches. However, it's still a long way out in the forecast, so the forecast rain amounts will come into better focus as we get closer to the weekend.

Rain is expected to start tapering off on Saturday night. This far out, timing is uncertain, but right now I expect that by daybreak Sunday morning, all the rain should be gone. Clouds will start to decrease as drier air moves in, and there may be a mix of sun and clouds by the checkered flag. 

Check back for updates to the forecast through the week.