Key Points
- The Bureau of Meterology has declared Australia is experiencing its third consecutive La Niña
- La Niña conditions were blamed for devastating flooding in southeast Queensland and the NSW Northern Rivers this year
Another summer of heavy rainfall and humid, sticky nights is ahead for much of Australia as forecasters declare a rare third consecutive La Niña weather event.
The outlook for the rest of 2022 has been raised to an established La Niña, according to atmospheric and oceanic indicators, which inform the Bureau of Meteorology's (BoM) La Niña alert system, the El Nino–Southern Oscillation (ENSO).
The BoM observed cooling in the central tropical Pacific Ocean in recent months, along with trade wind strength and equatorial cloudiness - all typical La Niña indicators.
It comes after months of reports of a likely third appearance of the weather pattern, which leads to heavier than usual rainfall, and cooler temperatures across the north and east coast.
"Models indicate this La Niña event may peak during the spring and return to neutral conditions early in 2023," the BoM said.
La Niña conditions were blamed for devastating flooding in southeast Queensland and the NSW Northern Rivers this year.
Three consecutive years of La Niña is an unusual event, and has only occurred three other times since 1900.
Professor Julie Arblaster, deputy director of the ARC Centre of Excellence for Climate Extremes, said another La Niña would be "very concerning" due to the potential wet weather conditions it could bring to eastern Australia this spring.
"Many regions are still recovering from flooding events earlier this year and additional rainfall in already saturated catchment areas could impede this recovery," she said.
The BoM said global warming is continuing to influence climates locally and around the world, with Australia's temperatures risingg by about 1.47 degrees Celsius for the 1910-2020 period.
Australia's south has experienced an overall 10 to 20 per cent reduction in cool-season rainfall in recent decades.
There has also been a trend towards high-intensity rainfall events that occur over a short period of time, especially in northern Australia.
