I live in Virginia and teach political science, and I have no idea who Warner might be running against.
Do you think Warner is going to ultimately win by this margin? I'm assuming that he will shed the remnants of his once strong support in Appalachian Virginia, and win with a map similar to Tim Kaine's, with massive margins coming out of the Northern Virginia, Richmond, and Virginia Beach/Hampton Roads metropolitan areas, with a boost from Charlottesville/Albermarle County.
Kaine won by 16 against a highly polarizing and unpopular opponent. It’s unclear whether an unknown opponent would do better or worse. I’d imagine it will be a similar margin, maybe slightly less since I don’t expect a lot of crossover voting in a presidential year and while I can certainly see Biden winning by 10-12 in VA, I don’t think he’ll win by 15.