Dan Hirschhorn at Politico sums up the Pennsylvania senate contest with this little gem tucked deep into today’s article:

Democrats win elections in Pennsylvania by racking up big margins in blue Philadelphia and performing well in the purple suburbs. That’s how Rendell won two terms as governor, despite capturing only a small fraction of the state’s 67 counties.
Pollsters say that well over 40 percent of Democrats need to come out for Sestak to have a shot – a turnout significantly higher than the likely voter models have predicted so far.

Update (10:24am) — A Battle ‘10 reader writes:

Went to the polls at about 9am today in Perkiomen in Montgomery County, PA and my neighbor, a GOP committeeman, told me that 400 had already showed up, which was already about 20 percent turnout…