So I cracked it open and sure enough all of the coolant was boiling off, but I noticed the radiator fans weren't turning. Sure enough I waited for it to cool down a bit and started the engine, the fans span for a second and cut out.
Clearly the thermostat is gone! Not a big deal in itself, but being 30 miles from home and requiring a tow certainly wasn't pleasant. It hurt my wallet and my pride in my machine.

What's worse is I noticed today that my oil level has peculiarly dropped to about half and there's a some fresh looking oil coming from underneath the manifold. When it rains it pours!