Morning glory

From Glossary of Meteorology

morning glory

A wind squall or succession of wind squalls, frequently accompanied by a spectacular low roll cloud or a series of such clouds, that occurs early in the morning, mainly in the late dry season (September–October) at places around the southern coast of the Gulf of Carpentaria region of northern Australia.

The cloud lines may be up to a few kilometers across in the direction of travel, usually from the east or northeast, and are of considerable lateral extent, often stretching from horizon to horizon with a remarkably uniform cross section.