Mike that's happening all across the NE. The cold winter damaged the top and you will need to form a new tree from that strong new growth down low. There's nothing unusual about this it happens here each winter and I'm listed zone 8a by new USDA system. Your tree isn't dying it's just wounded. Cut off the dead and nurture the new growth.

Thank you Fruitnut for your advise. Do you have any advise as to fertilizing and a watering schedule for the new growth after I cut off the dead growth?

At this point in the year I wouldn't fertilize, you want the growth to start hardening off for fall. I doubt you need to water either, looks plenty established. Just cut out the dead wood and call it a day.

There's no harm in leaving the dead wood till you can prune it w/o hurting the new growth. You can prune anytime from now till spring....on the dead wood.

I doubt you'd have any problem knowing what was dead...

An easy way to check for dead is to start pruning the the tip and clip. If the center of the branch is not dead then stop. Dead wood will be brown. Keep going until you see healthy core.

Still, it is best to do this in the spring though....