The Northern VA suburbs which will be won by Biden by 250K is key to Biden holding serve in the state. Trump had a crack at VA before last yrs shutdown, but the GOP cratered in VA after that
Biden will win NOVA by way more than 250K. Hillary had a 200K margin out of Fairfax County alone. She had more than 100K out of Arlington and Alexandria.
I predict Biden nets close to 250K out of Fairfax alone. 100-150K out of Arlington and Alexandria. The main improvements will be in Loudoun and Prince William due to population growth and increased turnout which will all go to Biden. I wouldn't be surprised if Biden wins NOVA by about 500K. I also see him winning Richmond and its suburbs big and the Virginia Beach region slightly. I think Virginia will be a blowout and it wouldn't surprise me if he won the state by double digits.