Overall, it looks like the weather will not be a significant factor during the Roar, but there could be some pesky light showers in the area, mainly on Saturday afternoon and on Sunday.
A cold front is expected to pass through Daytona on Friday morning. It should be a dry frontal passage, as moisture will be very limited. However, a brief sprinkle can't be ruled out entirely, but the chance of one is very low. Behind the front, winds will shift to the northwest, but temperatures will remain pleasant, with highs in the mid 70s.
On Saturday, the front is expected to stall south of Daytona, then lift back to the north Saturday night. The exact position of this front, and how quickly it lifts northward, will determine the rain chances for Saturday. This makes the forecast rather uncertain, but at this time, I expect that the late afternoon hours will have a slight chance of showers. Any showers should be light, with low impacts.
On Sunday, the front will be north of the area, and a warm southerly flow will develop. This will warm temperatures up into the upper 70s, and south winds will be breezy and gusty. Gusts up to 30 mph will be possible. Like Saturday, the chance of rain will depend on the position of the front. Some models keep it near the FL/GA border, and have higher rain chances in Daytona, while others push it much farther north and have no rain in Daytona. For now, I will have a just slight chance of showers in the forecast. If shower occur, they should be light with little impact. I expect gusty winds will be the bigger impact on Sunday.