From the National Weather Service in Blacksburg:
Flash Flood Watch in effect from Tuesday evening through Wednesday evening.
Several rounds of showers and thunderstorms with heavy rainfall will result in a potential for flash flooding Tuesday through Wednesday.
A large and slow moving storm system will draw very moist air into the Appalachian region from the Gulf of Mexico through Wednesday. A series of upper level waves will pass across through Tuesday night…and then the passage of a cold front on Wednesday…will result in two to three rounds of heavy rain with embedded thunderstorms for most of the region.