Altocumulus lenticularis

Altocumulus Lenticularis have the shape of lenses or almonds, usually quite elongated and whose contours are usually well defined; sometimes have iridescence and corona. These clouds often appear in the formation of clouds of orographic origin (near mountains), but they can also be seen in regions without marked relief, although less frequently. Typically, these "lenses" are almost stationary and indicate approaching thunderstorms, especially if accompanied by iridescence.