Ordinary-cell convective storms - Severe Convective Storms and Tornadoes: Observations and Dynamics - page 132

Figure 3.32. Mammatus under the anvil of a cumulonimbus cloud which are attached to
striations or are organized in lines. (Top) Boulder, CO, June 27, 2010. The striations appear
to be two-dimensional, linearly symmetric features, as if an individual mammatus pouch were
extended into a line. (Bottom) May 8, 2005, Norman, OK (photographs by the author).
mammatus is sometimes preceded by linear striations under the anvil ( Figure
3.32 ), which suggests that gravity waves near the tropopause in the anvil may
sometimes trigger mammatus. These gravity waves may be triggered when
updrafts near the EL hit the stable tropopause. Aircraft penetrations have found
both turbulence and relatively smooth airflow, though turbulence has been found
aloft inside the anvil.
There are a number of theories for the generation of mammatus and some
combinations of them may be responsible for their appearance. (a) If the air in