Thanks! TBH, I really wouldnt of known what I was looking for, that cloud just come out of no where in mins, it was nice and bright outside, then went dark all of a sudden, so I went out and saw that, so I just took 2 pics and come back in again, I didnt want to hang about because 1 it was right over head, and 2 I thought it was a thunder cloud so didnt want to be standing their if it decided to throw a bolt at me, so I went back in. All I rememeber was it was very quiet out but went very very windy.