BOM warns that the chance of a La Niña forming in the next few months has increased from 50 to 70 percent.
A La Niña weather alert was issued on Tuesday by Australia’s Bureau of Meteorology (BOM), making it three times as likely that Australia’s summer will be affected by storms and flooding.
This update will come as particularly distasteful news for most Australians hoping to enjoy some post-lockdown sunshine.
BOM climatologist Dr Lynette Bettio said, “This is roughly three times the normal likelihood of an event forming in any year, but does not guarantee a La Niña will form.”
According to Bettio, the weather phenomenon increases the chance of “above average rainfall for northern and eastern Australia during spring and summer.”
Australia experienced a La Niña event last year which resulted in our coldest summer in 9 years. Weatherzone meteorologist Ben Domensino said: “If we do see a fully-fledged La Niña forming in the next few months, this would be the first back-to-back La Niña event in a decade.”
The Bureau's ENSO Outlook has been raised to La Niña ALERT.
Historically, when La Niña ALERT criteria have been met, La Niña has then developed around 70% of the time, around 3 times the normal likelihood.
Learn more in our Climate Driver Update: https://t.co/tNdIBloaPb pic.twitter.com/gOdC8wJf1v
— Bureau of Meteorology, Australia (@BOM_au) October 12, 2021
The chances were upped by the bureau following the continued cooling throughout the tropical Pacific Ocean in September and a subsequent increase in water temperatures nearer Australia.
Consequently, BOM’s ENSO outlook was raised on Tuesday from ‘watch’ to ‘alert’.
Responding to this alert, Carlene York, NSW State Emergency Service Commissioner has pleaded for residents to prepare.
She warned that with La Niña last summer, “We experienced major floods right across the state,” encouraging citizens that “the more you can do now to prepare, the less likely you’ll end up needing emergency assistance from our volunteers when these weather events hit.”
Looking at a cross-section of water-temperature anomalies across the equatorial #Pacific there is clear evidence of a developing #LaNina starting back in late boreal summer/austral winter. pic.twitter.com/MG6By476hp
— Jason Nicholls 💙 (@jnmet) October 12, 2021
In a recent blog post, BOM stressed that the new alert is not a guarantee, rather it is an “indication that most of the typical precursors of an event are in place.”
