EARLIER this week the Bureau of Meteorology (BOM) in a statement declared the El Niño has ended and the El Niño–Southern Oscillation (ENSO) has returned to neutral, with the expectation the indicator would remain stable until “at least July 2024”.
Following the announcement, The Nationals leader, David Littleproud said the reputation of the BOM appeared to be suffering following summer with the majority of the country having above average rainfall, despite a forecast in October last year of “below average rainfall across much of Australia excluding parts of the southeast”.
Locally there was an extremely dry end to summer with almost no rainfall in Hamilton from January 17 to the end of March, but the previous seven weeks had so much rain the summer total of 152 millimetres was still over 40mm above average for the season and in the top 20 per cent of 146 years of records.
The BOM has said oceanic and atmospheric indicators are now indicative of neutral ENSO with sea surface temperatures (SSTs) in the central Pacific steadily cooling since December 2023.
“There has been substantial cooling over the last fortnight, with the NINO3.4 index now within the historical thresholds for the neutral phase of ENSO,” their statement said.
“This surface cooling is supported by a significant amount of sub-surface cooling underneath the central and eastern Pacific, which is typical at the end of the El Niño phase of ENSO.
“Recent cloud and surface pressure patterns are indicative of short-term weather variability, rather than being influenced by ENSO.
“International climate models suggest ENSO is likely to continue to remain neutral until at least July 2024. While three out of seven international models are predicting central Pacific SSTs to reach La Niña thresholds in July, El Niño and La Niña predictions made in mid-autumn tend to have lower accuracy than predictions made at other times of the year.
“This means that current forecasts of the ENSO state beyond July should be used with caution.”
The BOM also addressed the Indian Ocean Dipole (IOD) index, which although at +0.57 °C - above the positive IOD threshold - the IOD was considered neutral.
But Mr Littleproud said there was a lot of scepticism from Australian farmers about the reliability of long-range forecasts.
“They said that we’re going to have a dry year and in fact there were many business decisions made,” Mr Littleproud said.
“There’s a lot of memory from what happened through the drought of 2018 through to 2020 where there wasn’t any feed and it was a really dry time. And so farmers took the pre-emptive step (in late 2023), took management decisions and productive decisions on their farms to actually sell down their livestock.
“That actually forced the price down. It simply flooded the market and it was nowhere near (as dry).”
Mr Littleproud said farmers needed seasonal forecasts to have better accuracy.
“I think farmers obviously look at it, they obviously make their decisions predicated on what’s just ahead of them because some of the advice that they’ve been getting hasn’t been the best and hasn’t given them the tools that they need to be able to make those decisions,” he said.
“There has been millions upon millions of dollars pumped in the Bureau of Meteorology and they need to make sure the accuracy - and I appreciate that we’re dealing with the weather - but their accuracy needs to be a lot better than what it is now because people are making financial decisions predicated on their advice and it’s important they get it as close as they can, but when they’re as far out as what they were this year, there’s still a lot of scepticism out there about the Bureau’s advice and where we may be heading.”
The BOM said El Niño events were followed by ENSO-neutral years about 50 per cent of the time, La Niña years about 40 per cent, and by another El Niño year about 10 per cent.
