Lightning effect for halloween using dimmer

Have a generic dimmer controlling the high hats on my porch. Was just playing with it, and by hand I can generate a cool lightning-like effect by alternating "start level change" and "set level" commands.

Would love to program this in somehow so every X seconds (variable between 3 and 10) it did a pre-set lightning effect that went something like:

lights to 100
fast dim (something like 600ms)
lights to 80
faster dim (something like 200ms)
lights to 80
medium dim (something like 1s)

Ideally, all those numbers would be random variables in distinct ranges such that it seemed more realistic and organic.

Also, I'm running Echo Speaks and have speaker drops on my porch to a house-wide received in the basement with an Echo Link. Ideally, every time the above happened it'd fire appropriate thunder sounds.

Thoughts on the best way of accomplishing this?

While I haven't coded in years, I was CIS undergrad and later did a bunch of C#/VB/Java/etc work.