Fractus Cloud - Significance in Thunderstorms

Significance in Thunderstorms

In rainstorms, scud often form in the updraft area where the air has been cooled by precipitation from the downdraft, thus condensation occurs below the ambient cloud deck. If scud are rising and moving towards the main updraft, sometimes marked by a rain-free base (RFB) or wall cloud, then the thunderstorm is still developing. Scud are common and are usually insignificant. However, scud precede wall clouds, which often form from rising scud.

In addition to forming in inflow, fractus also form in outflow. Scud are very common on the leading edge of a thunderstorm where warm, moist air is lifted by the gust front. Scud are usually found under shelf clouds.