Expectations are that we will have record turnout, which raises the age-old question of whether that helps one of the candidates more than the other.

Barack Obama's biggest strength is in the southeast part of Pennsylvania around Philadelphia. That urban and suburban core is typical of the voters that have backed Obama by solid margins in most states.

Hillary Clinton will get most of her support from northeast and northwest Pennsylvania and basically everything between Pittsburgh and Philly.

As always, it's hard to get a good read on what will happen in a state like this. Both sides claim that they have great ground organizations which will spur a turnout advantage.

Clinton had the machinery in place to do that in New Hampshire, which led to a surprise win there. She has some of those same ingredients in place here in Pennsylvania, but then again, so does Obama.

Mayors are very important today, mainly because they are so attuned to what's going on in their wards and precincts, that they can deliver a little more than maybe a Senator.

The late polls continue to favor Clinton, but the average remains in that 6-point range. That would be the worst outcome possible for Democrats, because Hillary Clinton would argue that she won, while others would say it's time for her to get out of the race.

I'll have more from the road later today!