Rain-inducing La Nina likely near peak
Rain-inducing La Nina likely near peak
18 January 2022
The La Nina weather pattern is likely “near or at its peak” with a return to neutral conditions expected in the autumn, the Bureau of Meteorology says in its Climate Driver Update.
La Nina increases the chance of above average rainfall across much of northern and eastern Australia during summer, leading to greater risk of property damage from flooding.
The bureau says the climate pattern remains active in the tropical Pacific Ocean but models are pointing toward the end of the event.
“Five of the seven international climate models surveyed by the Bureau indicate La Nina thresholds are likely to be met during February,” today’s update says. “By April, only two models continue to exceed the threshold, with the other five returning to neutral.”
Other climate drivers may help drive wet weather around Australia in the coming weeks.
The Southern Annular Mode (SAM) index has briefly dipped to negative levels, but is forecast to approach positive levels during the remainder of January and into the first week of February.
A positive SAM during summer typically brings wetter weather to eastern parts of Australia, but drier than average conditions for western Tasmania.
Rainfall last month was above average for the Top End of the Northern Territory and Cape York Peninsula, much of eastern and parts of northern NSW, eastern Victoria, and some parts of Queensland’s tropics.
Rainfall across much of Greater Sydney was 10-40% above average, while Observatory Hill and three nearby inner Sydney sites had their highest totals for December since 1992. The heaviest falls for the region fell from December 8-10.
Greater Melbourne was drier than average last month after heavy storms at the start of December saw suburban Maribyrnong receiving 37mm in 30 minutes.
For the country as a whole December rainfall was 6% below average, with drier areas including WA and parts of SA and Victoria. Tasmania recorded its sixth-driest December on record.
