Common Buckeye (Junonia coenia). While not especially rare, I've only seen a few this year, and didn't get many chances to take photos, but this one was very cooperative.
However, I'm pretty sure I saw one of these flit by, a Zebra Heliconian (Heliconius charithonia). The black and yellow bars and the wing shape were absolutely correct. The thing is, this butterfly shouldn't be anywhere near here, being a native of the deep southeastern coast, as far up as South Carolina.
Did one get swept up by Tropical Storm Karen and deposited up here? Could happen.