The Bureau of Meteorology has declared Australia is in the grip of a looming El Niño.

Historically, when the criteria for an El Niño Alert have been met, an El Niño event has materialised roughly 70 per cent of the time.

However, the divergence in assessment between the Bureau of Meteorology and the World Meteorological Organization is a point of note, attributed to differences in their evaluation methodologies.

Despite the present lack of atmospheric response, the chances of El Niño development persist in the coming weeks, according to the Bureau's latest update. 

Sea surface temperatures (SSTs) in the tropical Pacific Ocean have surged beyond the El Niño thresholds, a trend projected to continue at least until the year's end as indicated by climate models. 

In contrast, atmospheric indicators such as wind patterns, cloud formations, and large-scale pressure trends have remained consistent with neutral ENSO (El Niño-Southern Oscillation) conditions. 

This signals that the Pacific Ocean and the atmosphere have not yet fully synchronised, a phenomenon typical of impending El Niño occurrences. 

Historically, El Niño has correlated with reduced rainfall during the winter-spring period in eastern Australia.

In parallel, the Indian Ocean Dipole (IOD) presently maintains a neutral state, but forecasts from climate models hint at the possibility of a positive IOD emerging later this winter or early in the spring.

A positive IOD has the potential to exacerbate the impact of El Niño by further diminishing winter-spring rainfall across Australia.

The current state of the Madden-Julian Oscillation (MJO) reveals a state of weakness, with the majority of climate models indicating a lack of significant intensification over the next fortnight. 

Meanwhile, the Southern Annular Mode (SAM) index has displayed a positive tendency, projected to return to neutral values in the upcoming week. 

It is anticipated that a neutral SAM state will have a minor influence on Australian climate conditions.

Despite these nuanced indicators, the overall long-range forecast for August to October maintains a vision of warmer and drier conditions across a significant part of Australia. 

The Bureau's sophisticated climate model accounts for a comprehensive range of oceanic and atmospheric factors in shaping its extended forecasts.