Discussion of medical Droids in Star Wars and why the Rebel has the nondescript 2-1B while the Emperor’s choice for surgery on Vader is a pitch-black room full of shiny black monster droids and smoke. In a thunderstorm.
It was obviously meant to evoke Frankenstein, but the revival there needed a storm to work. Here it just seems to be mood lighting.
In this case, the storm could be the result of the Emperor’s mood. (Only he and R2-D2 shoot lightning in the original trilogy, proving that both are embodiments of their sides of the Force. Ahem.)
But it got me thinking, a planet like Coruscant probably has weather control...
“Weather Control, this is the Emperor. Yes, Emperor. Haven’t you been watching the news? It’s been almost a day! Anyway, I want a storm over my palace. Yes, thunder, lightning, the whole deal. Sets the mood. No? Well then, I’ll have to do it by hand.”