Historic East Australia Rainfall

Australia’s rainfall event: A titanic blocking high-pressure ridge south-southeast of Australia during the past 5+ days forced a deep upper trough to form along the southern Australia Coast this past weekend and into this week. Tropical moisture entrained into the upper trough from a warmer-than-normal water surface north and northeast of the continent lead to the 60-year flooding episode in Sydney and surrounding areas. The event was an example of the combination of cold upper troughs interacting with a warmer than normal ocean to produce excessive low atmospheric moisture and attendant rainfall. The event is also related to the fading La Nina episode. The excessive rainfall event was forecast by Australia Bureau of Meteorology in their warm season outlooks issued late last year.