Prosper in a dynamic world
Search

Strong signs that La Nina is breaking down

After three successive La Niñas, there are strong signs that the latest La Niña is quickly waning and will release its grip and move towards neutral in its effect on Australia in the second half of summer into autumn, as the previous two did.

This means we can expect an end to the relentlessly wet weather which has lashed large parts of Australia in recent summers, and for much of 2022 – with a return to drier, potentially warmer conditions as we move through summer.

How do we know this? The chart below tells you most of what you need to know.

  • The chart shows an ocean pattern called the Kelvin wave – which moves across the Pacific underneath the surface of the ocean – transporting the warmer-than-usual water that we’ve had in Australian waters back into the central Pacific.
  • At the same time, this is causing the colder waters in the eastern Pacific to retreat, slowly shutting down the cycle.

In simple terms, as those red blobs move west (or to the right of the chart), the effects of La Niña become less pronounced.

Why does warmer water moving away from our region signal the end of La Niña?

Because warm-than-usual water near Australia is La Niña’s fuel.

If you go back to the La Niña explainer piece which we wrote in September 2022, we told you that La Niña occurs when:

  • The temperature contrast that develops across the equatorial Pacific Ocean supports stronger trade winds blowing from east to west across surface of the Pacific.
  • These enhanced trade winds cause warmer-than-average water to pile up on the western side of the equatorial Pacific Ocean and cooler-than-average water to form in the central and western equatorial Pacific.
  • The pools of abnormally warm and cool water help air rise over the western Pacific Ocean and sink on the eastern side of the Pacific basin. This rising and sinking air causes enhanced convection and cloudiness near Australia. Or in other words, a much stronger likelihood of rain.

Here’s the super quick version if your concentration is waning (like La Niña) right now due to the common affliction known as end-of-year-itis:

The ingredients for La Niña are vanishing, and quite quickly.

Image: Hopefully we’ll see fewer scenes like this in the near future. Source: iStock.

Arguably we have already seen a glimpse of La Niña’s weakening influence over the last week or so in Australia, with a period of dryish weather in most parts of the country south of the tropics.

As La Niña continues to weaken, the rain taps will of course not totally turn off. The weather will still deliver its daily and weekly mix of conditions irrespective of underlying climate drivers which point towards broader wet or dry trends.

But overall, a drying trend realtive to average is now looking likely across much of the country. Whether we see the opposite of La Niña – El Niño – with its signature hot, dry summers in the near future is not yet clear.

WATCH: Our climate update video issued earlier this month which pointed to a drier second half of summer

Latest news

Satisfy your weather obsession with these news headlines from around the nation, and the world.

How is DTN APAC equipped to service the offshore wind farm industry?

Wind turbines are usually pictured on rolling hills far from cities and people, but what if they were on rolling swells off the coast of populated areas? Australia’s National Electricity Market (NEM) and WA renewable power network currently harnesses wind power from 115 wind farm facilities and a capacity of 15,617 MW, according to OpenNEM. […]

Quarter million lightning strike and heavy downpours smash southwest WA businesses

The southwestern tip of Western Australia is the latest corner of the country to see exceptionally heavy winter rainfall, with 24-hour totals topping 100mm at some locations, and over 250,000 lightning strikes causing costly shutdown procedures. Storms and heavy downpours pelted much of the South West Land Division on Wednesday as a cold front and […]

East Coast Low brings intense night of wind, rain and surf to NSW businesses

The East Coast Low lashed large parts of the NSW coastline in the 24 hours to Wednesday morning as damaging to destructive winds, intense rainfall and large waves disrupted industries from aviation to ports, and transport to power utilities. The stretch of NSW coastline from the Hunter region to the South Coast has been most […]

East Coast Low deepening near NSW coast disrupting aviation, transport and utility industries

Heavy rain, destructive winds and damaging surf will batter eastern NSW in the coming days following the explosive development of an East Coast Low leading to significant disruptions to transport, aviation and utilities. A coastal trough located off the southeast Queensland and northeast NSW coast rapidly intensified into a low pressure system overnight into Tuesday […]