From 538
In several states that report turnout by party registration, the share of registered voters has been getting bluer over the course of the day. In Broward County, Florida, for instance, Democrats led by 4 points in votes cast between 7 and 1030 a.m., by 8 points in votes cast between 10:30 a.m. and 12:30 p.m., by 11 points in votes cast between 12:30 p.m. and 3 p.m., by 15 points in votes cast between 3 and 4, and by 21 points in votes cast between 4 and 6. Among other things, this may make exit polls even less reliable than usual for predicting the vote, because if you’re only surveying people who have voted by a certain point in the afternoon, you’re not getting a representative sample of Election Day turnout.