Lightning
Ive seen one too, over the med...suspect it wasnt a sprite but rather a blue jet...
The subject of lightning appears to be cleaverly avoided in meteorology classes...the basics of negative lightning formation are covered and thats it...
I did however find this program to be very informative about the very zoological makeup of our atmosphere...
for instance, ever known that there is negative lightning AND positive lightning? Positive lightning lasts 10 times longer and is 6 times more powerful than negative on average...its been known to down some of our late colleagues in the past (wait? Death by lightning strike? you bet!)
Sprites appear harmless, but seem to be directly related to postive lightning...perhaps an electric discharge from the earths magnetic field through a storm cloud?
There is obviously a lack of knowledge and research into this field, and seeing that there are occasions when the tropopause WILL allow us to overfly such cells, maybe we should be getting a bit more aware of these dangers!