This map of early voting in Virginia (from non-partisan VPAP) is fascinating.
The darker blue—more votes already in—are mostly heavily Democratic areas. The yellow areas in the west and the “panhandle” are the Republicans. Early voting was huge, six times’ the last gubernatorial election in 2017. Of course, that was pre-covid, and perhaps the exigencies of 2020 cause a permanent shift in voting patterns. [EDIT: I have learned that early voting in 2017 required an excuse.]
It’s reasonable to conclude that the Democrats have banked a big lead here.
We are certainly going to see a “red shift” if these early votes are announced before the day-of votes. [EDIT: Most of these votes have been counted and will be reported before the day-of votes. However, with the day-of votes, the Republican areas, less dense, report faster. Expect a red shift; and then a smaller blue shift back.] The question is how much. I don’t know at what point we can be certain of the results, but one clue will be turnout in those Republican areas. If historical trends continue, this is about 40% of the total vote for the election. Republicans need very big turnout tomorrow: twice as many people as they got to vote early. Democrats only need about 1 for 1 (one voter tomorrow for every voter who voted early). I know which phone bank I would rather be at.