US NOAA climate forecast: ’Increasing odds of La Nina’

The odds of La Nina conditions returning to Australia are increasing, according to a US agency, but the BOM says it is “too soon” to make that forecast for 2024.

The chances of another wet spring have risen on the back of the US NOAA forecast.

The odds of a shift to wetter than average La Nina conditions in late winter and spring have hit 65 per cent, according to the US National Oceanic and Atmospheric Administration’s latest climate outlook.

NOAA predicts “there are also increasing odds of La Nina in the seasons following a shift to ENSO-neutral”.

The forecast is that by late spring the probability of La Nina will reach 65 per cent, while the odds of neutral conditions falls to 30 per cent and El Nino 5 per cent.

US NOAA probability forecast showing the odds of a La Nina in late winter/spring are on the rise.

Commenting on the NOAA forecast, an Australian Bureau of Meteorology spokesman said “at this stage it is too soon to forecast a La Nina event in 2024”.

“Historically, La Nina has developed around 40-50 per cent of the time after an El Nino. La Nina tends to begin closer to autumn,” he said.

But the spokesman said at this stage the BOM was forecasting El Nino would continue to autumn.

Given the recent high rainfall across eastern Australia in the midst of the current El Nino, The Weekly Times asked the BOM if rising sea surface temperatures, as a result of climate change, were affecting the assumptions underpinning ENSO forecasting models.

The BOM spokesman said “record high global sea surface temperatures since April 2023 along with the lowest formation of sea ice in Antarctica, are likely having an impact on comparing current weather and climate events with similar past events that occurred within a cooler climate system.

“A significant concern is that a warming trend in both deep ocean and sea surface temperatures will cause changes to climate variability in the future compared to past experience.

“We haven’t seen these set of circumstances before and it will take time to evaluate and understand the data to determine the impacts of a warming climate on forecast accuracy.”