Australia’s Bureau of Meteorology has declared a La Niña weather event is under way in the Pacific, bringing the country in line with other agencies, and underscoring the prospect of a relatively cool, damp and stormy summer for much of the north and east.
The declaration, made at a media conference in Melbourne on Tuesday, confirmed a Guardian Australia report. The bureau said it had shifted its outlook for La Niña on its main climate drivers forecast.
“Key atmospheric and oceanic indicators of the El Niño-Southern Oscillation (ENSO) show an established La Niña,” the bureau said.
It made the call based on sea-surface temperatures that were close to La Niña thresholds in a key region of the tropical Pacific, with models indicating further cooling was likely. The indicators they watch include the amount of cloud buildup and the strength of trade winds.
“The current model outlooks suggest this La Niña will persist until the late southern hemisphere summer or early autumn 2022,” the bureau said, extending the longevity of the event from earlier predictions that it would begin to dissipate by the end of January.
A majority of the models used by the bureau now predict La thresholds will be met by February 2022.
Andrew Watkins, head of the bureau’s Operational Climate Services, said the La Niña would also increase the likelihood of cooler than average daytime temperatures for large parts of Australia.
“The last significant La Niña was 2010–12. This strong event saw large impacts across Australia, including Australia’s wettest two-year periods on record, and widespread flooding,” Watkins said.
This year’s event is not predicted to be as strong as the 2010-12 event and may even be weaker than in 2020-21 La Niña event, he said.
One difference compared with a year ago, however, is that soils are far more saturated, and many dams are close to or at full capacity.