I was out in my back yard looking at the mountains when I notice a cloud formation in the NE all alone, no other clouds around, oval shaped, whitish, grayish like a cloud, it was unusual being up there and no other clouds in sight. It caught my attention, I observed it for just a few minutes, 5 minutes or less, it slowly started getting smaller and smaller until it disappeared completely within 1 to 2 minutes, then I called my daughter she came out and saw it appear again getting larger and larger then stopped for a few moments then started getting smaller and smaller until it disappeared again completely, very weird. Observed a few more planes in the area more than usual, stayed out for another 30 minutes with nothing else happening. Just wondering if anybody else saw it. October 28. 2012 at about 2:30 pm just outside Albuquerque, NM. I have read that UFO's hide behind clouds????