Is green lightning possible?

Ok, I’m down here waiting for Hurricane Jeanne to make landfall. I stayed for Frances and observed, several times, what I would swear was green lightning flashing in the sky. It wasn’t like a deep forest green, more like minty green with a hint of yellow.

I want to see if I can see it again this time. My question is whether that’s actually what I saw, or is it possible for a blowing transformer to light up an entire sky? Anyone else ever seen lightning that color?