Ask HN: A great mobile screenflow app?

What do you folks use for mobile screenflows?

I'm familiar with software such as Balsamiq or the Pencil plugin for Firefox, but it's my understanding that they mostly work with one screen at a time. I'd like to have the option to build a state flow diagram with these screens and be able to keep it updated as the app evolves, so that the team is always up to speed with the latest changes.

Thank you!