BoM to declare La Niña the first tropical cyclone of the summer | Australia weather
The Australian Bureau of Meteorology is expected to declare on Tuesday that a La Niña event is underway in the Pacific, underlining the prospect of a relatively cool, humid and stormy summer for much of the north and east.
The statement will come a day after the office confirmed that the first tropical cyclone of the season had formed in the Australian region. Cyclonic rice developed near Christmas Island and reached the grade stretch on a Monday, but will weaken within days without making landfall.
A La Niña declaration is widely awaited by the office of its bimonthly update of the main climatic drivers for Australian weather Tuesday afternoon. There has been a La Niña alert in place for weeks, and most models desktop users have indicated that such an event will last until at least January 2022.
“You can see the model is already La Niña and you can see the impacts,” said Agus Santoso, senior research associate at UNSW’s Climate Change Research Center. “It’s not strong but it’s not that weak either.”
The Bureau of Meteorology has been approached for comment.
People living in eastern Australia, in particular, hardly need further confirmation that conditions have recently turned wet and cool. While the above-average precipitation experienced by many regions during winter and spring was more related to Indian Ocean conditions, the Pacific tends to have more influence in summer.
During the La Niña years, the trade winds from east to west blowing over the equatorial Pacific become stronger. These effectively push rain systems westward and increase the risk of flooding, and also raise the relative sea level in the western Pacific.
These years also tend to have more cyclones than usual. Last month, the office estimated that there were two out of three chances The Australian region is reportedly more than the seasonal average of 11.
Last year also included a La Niña and experts say there is about a 40% chance of having back-to-back events. The last double fight spanned 2010-11 and 2011-12.
“I suspect it will be neutral next year,” Santoso said, adding “that it is not impossible to have three years in a row” as the period 1998-2000 shows.
Ben Domensino, senior forecaster at Weatherzone, noted that the United States’ National Oceanic and Atmospheric Administration (Noaa) said a double La Niña dip last month. It uses a lower threshold to rate such an event, or its opposite, an El Niño.
“Although this has not been technically stated [in Australia], we’ve been in a very La Niña-like state for a few weeks now, ”Domenino said.
The recent widespread and heavy falls have resulted in minor to moderate flooding in many inland rivers, especially in New South Wales. The Lachlan River, which last week threatened the town of Forbes in west-central New South Wales, remains at major flood levels.
Another belt of precipitation – fed in part by moisture from Cyclone Paddy – is heading east. This is expected to bring 40 to 60mm of rain over a large area from Queensland to Victoria, with isolated falls of 100mm. Since the watersheds are already saturated, more flood watches will be issued, Domensino said.
Farmers struggling to get crops before the fields are saturated are among those looking to the sky for relief from the rain. Insurers will also be watching closely, as damage from floods typically exceeds that from droughts and even bushfires.
During the last La Niña and its aftermath from December 2020 to April 2021, the Insurance Council of Australia declared three disasters. These triggered around 65,000 insurance claims for damages totaling just over $ 1 billion, the CIA said.