I think we would need more context to be 100% sure about why 'cloudy' is wrong here, but to me I think it is wrong because cloudy is an adjective describing something as being cloudy,
e.g. this lemonade is cloudy (i.e. not clear in colour)
the sky is cloudy today (i.e. there are lots of clouds in the sky)
You should instead use 'cloud', but even then I am not sure this sentence makes sense. Perhaps 'cloud movement' would be better? But it is hard to be certain without more context.