Shooting during a rainy night (how to make it seem like a thunderstorm)

Hello everybody,

I’m shooting a movie that takes place in the 1940s and there is a scene where a guy hides a body in the woods during a thunderstorm.

I read a previous threat about everybody warning to not shoot during an actual thunderstorm so I’m not gonna do that. But how do you fake it? We have proper equipment for rain shoots (except a rain rig).

The guy comes in a classic car from the era and is also holding a traditional oil lamp (the one you might know from Django Unchained). He exits the car gets the body out. Drags him into the woods. Rolls him down a bit and then leaves.

So there should be enough light for the camera (Sony FX-30 and multiple T 1.5 lenses)

But how do I fake lightning? In post? Or using an LED Panel flashing? Technically it doesn’t have to visible but I really like that sudden brightness that you get.

What is the current way to do it?