Its perfect in black and white. Its putting the right message across.
The whole point i work in greyscale is i don't want too many colors destracting people from what i want them to look at. Ie; the sky.
Clouds look fantastic, very sharp and clean
IMHO i would have made it darker, i just increase sharpness and brought the brightness down in photoshop and the clouds are well emphasised
I like greyscale