Even if the polls show Obama and Clinton almost tied (like in Ohio) Obama will still lose by like 10 points (like in Ohio)
Jay Cost of RCP's Horse Race Blog has said that Clinton, more or less, should, given the demographics, win PA by much the same margin as she did OH
From
http://www.realclearpolitics.com/horseraceblog/Keep an eye on Bucks and Montgomery counties. Frequently, Philadelphia and its suburbs report their returns before the rest of the commonwealth. If that holds true for the April 22nd primary - the results here should give us a sense of what kind of night we are in for. If Obama scores big wins in one or both, the final results might be close. If Clinton pulls roughly even with him, or beats him outright - she should have a good night. His analysis covers the whole state and how he expects each congressional district will go
Dave