Arcus cloud

Rising air motion can often be seen in the leading (outer) part of the shelf cloud, while the underside can often appear as turbulent and wind-torn.

Cool, sinking air from a storm cloud's downdraft spreads out across the land surface, with the leading edge called a gust front.

In a severe case there will be vortices along the edge, with twisting masses of scud that may reach to the ground or be accompanied by rising dust.

[2] One of the most famous frequent occurrences is the Morning Glory cloud in Queensland, Australia, which can occur up to four out of ten days in October.

[3] One of the main causes of the Morning Glory cloud is the mesoscale circulation associated with sea breezes that develop over the Cape York Peninsula and the Gulf of Carpentaria.