My 99 was doing the same thing a few years ago. Turned out to be a bad head gasket.
Pressure from cyl 2 was pushing into a nearby coolant channel. That caused coolant to escape from the overflow tank.
Hope it's not that...

 

Thank you to all of your replies. I went ahead and ordered a new radiator cap and a new reservoir cap as well. Since doing so, I have not had any coolant barfing issues. Again, I really appreciate all of this input. Y'all are helpful. My case is closed!