Tony,
The esteemed Mr. Harley wrote recently,
And I pretty much agree. B&W is already unreal and so you as the artist have full license to make the sky look however you want. Looks plausible enough, if one can call that “real.”
The question/reaction does come from the relationship to the mountains. I think that’s the challenge here. And honestly, I’m not sure which way to go - darker, or lighter? The light is diffused with no direct - which is consistent with the cloud cover.
Also, to me the sky is presented is quite dramatic, but maybe not ominous? I say because the ceiling looks pretty high and I don’t get the impression of a pending squall or something getting ready to unleash - like I would think if they were ominous.
And to come full circle, I quite like this as presented! I think the contrast in the clouds is close to the contrast in the mountains; maybe it’s the luminosity difference that’s throwing us off.
I’m afraid I haven’t been much help Tony.
Lon