Hi folks, so sorry about the false alarm. Someone followed up on my bird report of Northern Parula and discovered that there was an Orange-Crowned Warbler making this parula-like call. I've seen/heard a lot of OC warblers but never heard this variation so I was pretty surprised by this but I have no doubt that this was the same bird. The individual created a recording that sounds identical to mine. Here's the flickr post if you're interested:
https://www.flickr.com/photos/jgunn/19618219355/in/photostream/

Sorry again. This is a good learning experience for me though, not to rely 100% on my ears, esp with rarities.

Matt