This morning I woke up on a beautiful day in NYC, spring whirring in the distance, to these spectacular clouds outside my window. It's only 30 minutes since I saw them and they've since disappeared. In any event, there are many KINDS of clouds and this kind is called "Altocumulus" characterized by the ominpotent wikipedia as, "a class characterized by globular masses or rolls in layers or patches, the individual elements being larger and darker than those of cirrocumulus and smaller than those of stratocumulus. Like other cumulus clouds, altocumulus signifies convection. It is usually white or gray, and often occurs in sheets or patches with wavy, rounded masses or rolls. Altocumulus often are seen preceding a cold front, and their presence on a warm, humid, summer morning frequently signals the development of thunderstorms later in the day. Alto means high and these clouds may cause rain if they are higher up."