I think the key to PA is the Western part of the state. Trump is going to lose ground in the eastern suburbs. If Trump matches his total out here then he can keep it close. But if he loses ground then you get a Biden win of about 6-8 points. From what I can tell here on the ground is that he has lost some ground how much I don't know.
What makes you say he's losing ground in the west?
Have you noticed any positive signs for Biden in that part of the state?
Where I live there were no Clinton signs at all. Trump signs were everywhere. Fast forward to today and while Trump still dominates with signs, there are two distinct differences:
1. Several houses that had Trump signs before don't have anything.
2. Biden signs have popped up in the area. With specifically 7 in my town.