Lightning fade out

[#1]

Hey guys, I had some footage of an incoming storm and I wanted to spice it up a bit with some lightning.

I downloaded a .mov of lightning and it looks ok but I'm really struggling trying to get the lightning to fade out to look more realistic. See attached clip of what I'm going for. Is it achievable with a .mov and using something like fractal noise and a luma matte? Any advice is appreciated, thanks!

[#2]

Hey guys, I had some footage of an incoming storm and I wanted to spice it up a bit with some lightning.

I downloaded a .mov of lightning and it looks ok but I'm really struggling trying to get the lightning to fade out to look more realistic. See attached clip of what I'm going for. Is it achievable with a .mov and using something like fractal noise and a luma matte? Any advice is appreciated, thanks!

[#3]

Realistic is such a relative term, given that the clip is slowed down at least 20 times from its actual speed. And this isn't even the only way a lightning bolt can collapse. You know, physics. So whatever you have in mind quite likely can sufficiently be faked using Fractal Noise, Roughen Edges, Turbulent Displace and applications of glow, even more so if it's moving faster than the reference clip. Either way, if you want more specific advise, you have to explain in more detail and show us at least a screenshot of the actual clip.

Mylenium