‘nothing illegal done’ by Scott Morrison amid calls to resign over secret ministries
I never thought I’d say this: I’m with Karen Andrews. #auspol #TinPotScott
— Julian Hill MP (@JulianHillMP) August 16, 2022
What is driving the 70% chance of a third La Niña in three years?
As noted in an earlier post, the Bureau of Meteorology has lifted its Pacific climate driver monitor to “alert” levels for another La Niña. Conditions now and forecast place the chance of a third La Niña in as many years as a 70% chance.
There are a couple of things of note from the fortnightly update of climate drivers from BoM ... one related to what’s going on in the Indian Ocean.
From today's @BOM_au update of climate drivers, a couple of things stood out. One is that all of the top five models used predict that the IOD will remain in its negative phase through November (ie up to summer)... pic.twitter.com/etHQBwiD3b— Peter Hannam (@p_hannam) August 16, 2022
Negative IODs, or Indian Ocean dipoles, typically mean more moisture than usual streaming across the continent in the form of north-west cloud bands, lifting rainfall in late winter and through spring in south-eastern Australia.
The Pacific, meanwhile, typically is more influential for eastern Australia from spring into summer, and another La Niña (or even a near-La Niña) would elevate the chance of above-average rainfall.
Also from @BOM_au's climate driver update, three of the seven models have La Nina thresholds being exceeded in the Pacific by September, and 4/7 by October. Would be only the fourth "three-peat" of three La Ninas in as many years since 1900. pic.twitter.com/K3cyHXayDS
Given the full dams and saturated catchments, above-average rainfall likely means more flooding, hence the warnings from the Queensland government this week.
Authorities made similar warnings last year ahead of the second La Niña, but whether that made sufficient difference (in NSW at least) will likely be known when the NSW floods inquiry report is released.
One other note from the BoM update today. The Southern Annual Mode, the other influence (from the Southern Ocean) on Australia’s climate is forecast to be in its positive phase for the next month or so. (Forecasting is limited.)