This image is a bit vague - it's one of those in which the subject seems a bit generalised, and the viewer's not completely sure where they're meant to look within the frame - the eye roams about in a way that's not very focussed or structured. I'm not saying don't take such scenes - just try to feel your way into what you put in the frame and what it means visually.
I've seen far worse skies, but the blacks here look a bit blocked-up as well. It may sound as if I'm talking technicalities, but the essence is to do with how we may feel when we're looking at images. It's psychological at root. Normally, you can get away with far more outrageous tonal extremes in black and white than you can in colour ... generally, colour is the more literal medium, whilst mono is more of an abstraction, and hence freer.
What strikes me as odd is that there's a very strong sense of light and deep shade on the left and right of the picture, but none at all in the centre.
I'm not saying that's any kind of failure of technique on your part, just that maybe it wasn't a good time to press the shutter!