How can randomness be powerful in any meaningful sense of the word?
Capability of action? Pretty sure they're talking about the whole infinite possible worlds thing, without limit to stuff such as physical laws or logic or whatev'. That would indeed be more powerful than anything posited by mainstream religions, as those things would be explicitly capable of spawning an infinite number of beings infinitely more powerful than the noted posits (and things more powerful than them, and things more powerful than them, and...). They would also just have a jackton of beings equivalent to the mainstream divinities floating around... a genuinely infinite randomness would diminish deities by its very existence, because it would perforce render them no longer unique.
Though ant, you probably want to add "and everything that can't" to that. Theologians have long solved the problem of dealing with a unique deity in a multiverse of infinite possibilities-- it's actually something that some proofs/arguments for the existence of gods
predicate themselves on. Mostly, they just propose a limit to what
is possible. Generally, "nothing can be more powerful than god" is held as an axiomatic truth that cannot have a disproving example, ever, no matter how many possibilities are generated and tested. It's just held to not be in the achievable realm of possibilities, no matter how many goes you have at it. If you literally cannot, under any circumstances, make a circle (being more powerful than) a square (god), it doesn't matter how infinite your randomness is -- the circle will never be made a square.
... also weather isn't an infinitely random system. It's just beyond our currently capability to know in full. Probably argue a bit on whether it being a god-like power is a nonstarter, too. By and large, weather has literally shaped the world (primary influence on what formed the atmosphere, shaped geological formation, etc., etc.), is a key component to what made life, and has destructive and constructive powers on par or greater than those attributed to pretty much any god (hell, a lot of the times those powers of weather are
attributed to gods). Weather, taken as a whole, is as god-like in power as pretty much any god. Made the world, made life, freakishly and capriciously destructive... it fits pretty much all the check boxes for an abrahamic deity.