Pumpkins may be frosted on Saturday morning, and it's not out of the question that some of the region's highest points see their first flakes Friday evening.
A vigorous cold front will be pushing eastward through the area on Friday. It doesn't have a ton of moisture to work with, but there will probably be some showers as it moves through. Light amounts of rain, under 1/4 inch, probably under 1/10 inch, are expected.
Behind the front, the coldest air we've seen this season will be ushered in, with temperatures falling into the 40s during the day on Friday and widespread upper 20s to mid 30s lows by Saturday morning. Winds may calm down enough for a few hours on Saturday morning to allow frost to form. Highs won't make 60 for most in the Roanoke and New River valleys.
It is possible that the cold air will catch up to the meager moisture enough that a few snowflakes could fall on the highest elevations, mainly in West Virginia, but maybe even into the higher peaks of the western fringe of Virginia, by late Friday afternoon and early evening. This will not be a big deal, just a novelty, if it happens.
Temperatures will not be quite as cold on Sunday morning, highs will return to the 60s and eventually 70s early in the coming week, lows will recover into the 40s and lower 50s, and the cool-mornings, warm-afternoons, dry pattern continuing that will spread the fall foliage show south and east and into lower elevations.