Australia's BOM declares La Nina through to at least Jan. 2021

Australia’s Bureau of Meteorology (BOM) has officially declared a La Nina weather pattern has established in the Pacific Ocean, and expects the phenomenon to persist until at least January of 2021, according to an update published Tuesday. 

The agency has maintained a 70% likelihood of a La Nina being established in late 2020 since mid-August, with the BOM saying that “all key indicators… have now reached or exceed La Nina thresholds.” 

The bureau shifted its ENSO Outlook from ‘Alert’ to ‘La Nina’ for the first time since November 2017, with that weather pattern deemed to have lasted until February 2018.

La Nina events in the Pacific Ocean are known to shift rainfall patterns globally, with wetter-than-average conditions expected in Australia – which could boost the country’s wheat production.

Northern parts of India, Indonesia, northern Brazil as well as parts of southern Africa also typically receive more than average rainfall as part of the phenomenon.

Drier than average rainfall is more likely to hit southern states in the US – which could negatively affect the wheat crop there – as well as southern areas of South America, such as Argentina and southern Brazil, both of which are already struggling with dry conditions.

“While models agree La Nina will continue well into [the southern hemisphere’s] summer 2020–21, around half the models predict a strong event, while 3 of 8 models suggest moderate strength,” the BOM said.

Weather models surveyed by the BOM currently do not indicate that the event will be as strong as the La Nina of 2010-2012 – which was the fourth-strongest La Nina on record.

However, all models agree that the event will last until at least January 2021.