Black nor'easter

A black nor'easter is a persistent and potentially violent north-easterly storm that occurs on the east coast of Australia, particularly from southeastern Queensland to southern New South Wales, usually between late spring and early autumn, about two days a year (or more, depending on the intensity).

[1] Developing offshore as a deep coastal trough, the storm is heralded by the rapid build-up of dense black cloud that brings heavy rainfall and strong northeasterly winds along the east coast of Australia.

[2] Although not convection-driven, the north-east wind field leading warm moist tropical air to the subtropics and mid-latitudes can combine with a higher level cut off low from the Southern Ocean.

"[5] They can also be formed by a cool pool of air that arrive from the Great Australian Bight, whereby spurring a low-pressure system over the southeast simultaneously as a moisture-rich coastal trough (fueled by warm sea temperature) – This can cause higher evaporation, thereby raising the amount of liquid in the atmosphere.

[5] Due to the strong winds caused by the Black Nor'easterly storms, a number of people in New South Wales (especially in Sydney) have been killed by falling trees.