Heatwaves and Heavy Rainfall in Southeastern Australia during the Austral Summer

Summer weather patterns in southeastern Australia are subdivided into seven groups. These are used to study heatwaves and heavy rainfall by comparing them with other days in these groups that do not produce these extreme weather types. Both heatwaves and heavy rainfall are linked to atmospheric waves that propagate eastward through the southern Indian Ocean and amplify over Australia. These waves propagate equatorward over Australia during heatwaves, which are better forecast at 7-day lead times than non-heatwave days. Heavy rainfall, which is less well forecast, occurs when these waves break and form a pressure trough several kilometres above the surface.