Fog occurs when stratus clouds are in touch with the ground surface. Very uniform cloud bases. These clouds contain more water and the cumulus puffs are larger than altocumulus. Appears in rows, patches or in rounded masses with blue sky visible between cloud elements. Sometimes occurs with the spreading out of cumulus clouds later in the day.
Color ranges from white to dark gray.
Little or no precipitation expected. To distinguish from altocumulus, hold your hand at arm's length. Stratocumulus cloud elements will be larger than the size of the ball of your thumb up to about the size of your balled fist. It is not characterized by thunder, lightning or hail. No sun or moon visible through cloud mass.