What are mammo clouds?
Mammatus or mammo clouds resemble upside-down pans of biscuits or huge grapes, hanging from the underside of storm clouds like a cow’s udder. In fact, the cloud mamma derives its name from the Latin word for breast. In Scotland, they are called pocky clouds – pocky meaning baggy; and are also referred to as ‘rain balls’. These spectacular clouds are produced by pockets of cold, moist air descending from the main body of the cloud. For mammatus to form, the sinking pockets of air must stay more moist and cooler than the air around it. The pockets continue to sink until eventually their temperature and moisture characteristics become the same as the surrounding air. Although ominous in appearance and contrary to popular belief, mammatus clouds are not funnel clouds because they do not rotate and tornadoes do not emerge from one of these hanging pouches. However, they can be present with severe storms, and sometimes are not seen until after the storm is over.
