File:“Wagon Wheel” Clouds Drift Toward Hawaii (NESDIS 2020-07-02 1963 tirosV actinoform).jpg

English: Actinoform clouds are usually so large that they are near impossible to recognize from the ground. They were first observed from images taken by the Television Infrared Observation Satellite (TIROS) V satellite, in August of 1963. One of these was impressive enough to become the very first feature of the Monthly Weather Review's "Picture of the Month" series that year. As early as 1961, TIROS satellites observed shallow hexagonal convective systems of cloud cells that were organized into differing degrees of cloudiness; a phenomenon that became known as “mesoscale cellular convection” or MCC. Two basic types of MCC include open- and closed-cell cloud systems, depending on whether the center of the cell is clear or cloudy. Actinoform clouds are a third class of MCC, which don’t fit into either of those categories—and we are still continuing to learn about these mysterious types of clouds.