Here's a pic of the whole tree.
See how some leaves are green and others are yellow-orange-ish. I don't remember them doing this till fall before.

Here is a link that might be useful:

It's not easy to tell from a photo, but this is most likely anthracnose. This fungal infection occurs most readily after cool, wet weather in the spring. I'm not sure what your weather has been like in your area of PA, but cool and wet certainly decribes what most of New England has experienced. Anthracnose infection is prevalent here in ME, especially on maples of all species.
Although severe infections can cause an entire tree to lose its leaves, it's unlikely to be fatal unless it happens in several consecutive years. The spores for antracnose over winter on fallen leaves so autumn clean up, as well as maintaining good air circulation around the tree, are keys to prevention. There are fungicidal sprays which will control anthracnose, but prevention is much easier than cure, although there is little we can do about weather patterns.

Thank you soooo much for the information.
I will continue to keep an eye on it. Up to this point it's been a very healthy little tree.
But we're in this very strange weather pattern and it's true that there's nothing we can do about that.
Becky