More about how 538’s model has a weakness. From Nate’s description:

Our models also project the turnout in each race, based on factors such as the eligible voter population and turnout in past midterms and presidential races. Competitive races tend to produce higher turnout than noncompetitive ones. Projecting turnout is important in understanding the relationship between the national popular vote and the number of seats that each party might gain or lose.

If turnout is much larger than he has parametrized, then his model is likely going to show a non-trivial error.

I’ve been following twitter all morning and it is really hard to guess what the final turnout will be, because I don’t know if the reported long lines at polling places is a simple consequence of having fewer polling places and/or fewer voting booths/machines.