Extract from ABC News
Thankfully for Australia, a record El Niño does not also suggest record drought or heat is on the cards. (ABC News: Che Chorley)
The Pacific Ocean's continued rapid warming towards El Niño has firmed up the odds that Australia faces a warm and dry second half to 2026.
And forecasts continue to upgrade El Niño's potential strength, with the Bureau of Meteorology's (BOM) latest modelling tipping a record event.
But thankfully for Australia, a record El Niño does not suggest record drought or heat, with previous events showing only a weak relationship between strength and severity of impacts.
Pacific warming at a near record rate
Analysis from the central Pacific, El Niño's engine room, shows water temperatures have already climbed more than 1 degree Celsius since January, the greatest rate of warming this century and the most rapid transition from La Niña to El Niño since 1976.
But in 1976, warming eventually stalled, and it became only a weak or borderline event, which the BOM does not even classify as a fully-fledged El Niño.
This year, however, El Niño has the potential to break records.
The NIÑO3.4 index, the most commonly used yardstick for the state of the Pacific, is now +0.23C and could reach the BOM's El Niño threshold of +0.8C within weeks, although a declaration will not be made until there is clear evidence the atmosphere has responded.
This would represent a much earlier emergence of El Niño compared to normal. For example, during the 2023 El Niño, the 0.8C mark was not exceeded until September.
Because El Niños follow a standard seasonal cycle, an autumn or early winter onset allows more time for strengthening before a peak arrives in spring or summer.
"Climate models are now strongly aligned and there is high confidence in the onset of El Niño, followed by further intensification in the months that follow," chief of climate prediction at the World Meteorological Organization, Wilfran Moufouma-Okia said.
The BOM's model ACCESS-S is tipping the Niño3.4 index will soar to an unprecedented +2.9C in October, comfortably a new record for the oceanic strength of the El Niño signal.
And while the BOM's model is one of the more aggressive, a survey of leading global forecasts shows the general consensus also favours a significant event in 2026 with a NIÑO3.4 peak of around +1.5C to +2C, still considered a strong or very strong (super) El Niño.
But stronger events do not necessarily mean more severe impacts in Australia, according to University of New South Wales climate scientist Andrea Taschetto.
One of the strongest El Niño events in 1997/98 only had a modest impact on Australian rainfall, while the weak El Niño event of 2002/03 coincided with severe drought.
Why do we care about El Niño?
El Niño is one of the world's most influential climate drivers, helping to rearrange weather systems around the globe.
"Australia, it's very close to where El Niño happens, so the impacts for Australia are really significant," Dr Taschetto said.
Every event is different, with a number of factors working to pull the strings on the weather and climate.
But, in general, El Niño events see drier and warmer weather across northern and eastern Australia, particularly from June to November.
El Niño has been linked to some of the worst droughts in modern history, including the millennium drought between 1997 and 2010. This photo from the time is titled "Drought, Continuing Drought'. (Supplied: Julie Millowick)
Nine of the 10 driest winter–spring periods on record for eastern Australia occurred during El Niño years, according to the BOM.
This influence means it is often associated with drought, extreme heat and bushfires.
Driest April in decades drops soil moisture
This drying influence means good rains in autumn become more critical. However, a wet March is now a distant memory for much of Australia.
Much of Australia has failed to see significant rainfall in April, especially across the interior and eastern inland. (ABC News)
About a third of the country has failed to receive even a millimetre this month, and for several regions of eastern Australia April is on track to become the driest in decades.
In Gippsland, Bairnsdale has only picked up 5mm, the lowest April total since 1943.
Lithgow in central NSW has only received 2mm, the driest April since 1899, while Glen Innes in the state's north is stuck on 0mm for the first time since 1942.
The lack of rain in the New England region follows below average precipitation through summer, leading to record low soil moisture and the emergence of drought.
In southern Queensland, Texas and Toowoomba have both seen their driest April's since the 1990s.
Uncertainty of autumn as oceans undergo reset
But it is not all doom and gloom as forecasts early in the year can be inaccurate, and a dry April in isolation is not a reliable indication of a dry winter or spring.
Climate scientists and the BOM are notably cautious talking about El Niño's potential arrival or influence at this time of year.
This is because of something known as the "autumn predictability barrier", where just one unexpected weather event in the Pacific, such as a late-season cyclone or a strong burst of winds, can disrupt the development of a looming El Niño.
The ocean undergoes a 'reset' during autumn, which makes it susceptible to small fluctuations in the weather than during the other months (ABC: Chris Lewis)
"It's a really hard time of the year to be predicting those things just because it's a transition season," Dr Taschetto said.
In 2014, for example, early forecasts were projecting a strong El Niño event.
Then a persistent stream of easterly winds over the Pacific stopped it from happening.
"Then next year, 2015 and 16, was a massive El Niño event that came in the end," Dr Taschetto said.
No strong dry signal in winter outlook yet
While El Niño is a big player in the world of weather, current forecasts do not paint a dramatic picture of Australia's climate in the months to come.
The BOM's latest long range forecast for the winter months shows a slightly increased chance of "unusually dry" conditions for parts of south-eastern Australia and south-western Australia.
Despite early signs of an El Niño, the BOM's long-range outlook for winter rainfall does not look overly dry across Australia. (Supplied: BOM)
Elsewhere, there is no clear dry signal.
The strongest sign in the outlook is for winter daytime temperatures, which are very likely to be warmer than normal for most of the country outside the tropics.
Daytime temperatures in winter are highly likely to be warmer than normal, according to early long-range forecast from the BOM (Supplied: BOM)
El Niño gives hints beyond the outlook
There is no official long-range forecast beyond August, but typically El Niño favours lower spring rainfall for most of the country's east, and warmer than normal temperatures.
"[The El Niño Southern Oscillation] accounts for up to 40 per cent of the precipitation variability from September to November. So, it's a significant number," Dr Taschetto said.
Unlike its 'sister', La Niña, El Niño's influence on rainfall doesn't typically extend into our summer, but warmer conditions lag until at least January or February.
However, since every event is different, the BOM encourages people to watch the long-range forecast, which captures the specific nuances of all climate drivers, a far more accurate measure of potential weather than El Niño alone.
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