As we get ready for a fun night, or at least a fun couple of hours, of following Virginia primary results, there's a simple but important point to remember about the "turnout percentages" for the state and particular locations that you will be hearing about (as, indeed, we have been hearing about sporadically all day).
Virginia does not have party registration. So "turnout" is measured against total voter registration. That's why Virginia's primary turnout percentages always look so incredibly low (e.g., today's anticipated turnout of 5% or less) as compared to party registration states. Moreover, this factor makes comparison of "turnout" in various jurisdictions perilous. Heavily Democratic jurisdictions (e.g., Arlington County and most of the state's independent cities) will naturally tend to show much higher turnout percentages than more competitive areas. But that does not mean Democrats are turning out there at higher rates.
This is obvious if you think about it for a minute, but some of the "reports" kicking around today contrasting "high" turnout in parts of NoVa to abysmal turnout in SW VA garble this key point. The percentage of the statewide primary vote cast in different parts of the state is indeed a very big deal, and we'll be looking at that when the votes start coming in.