Although the El Niño−Southern Oscillation (ENSO) remains neutral, latest model outlooks and recent warming in the tropical Pacific, mean the likelihood of El Niño developing in spring has increased to around a 50% chance.
This is roughly double the normal probability of an El Niño developing.
Ocean indicators are currently neutral but show some signs of potential El Niño development. Sea surface temperatures in the eastern Pacific Ocean, though currently neutral, have been slowly warming since April, while waters below the surface of the tropical Pacific are now warmer than average, a common precursor to El Niño events.
The Bureau’s acting Manager of Long Range Forecasting Services Robyn Duell said the majority of international climate models surveyed by the Bureau forecast the tropical Pacific Ocean will continue to warm but remain in the neutral range during July and August.
“Five out of eight models indicate that the ocean warmth is likely to reach El Niño thresholds in the southern hemisphere spring, while a sixth model falls just short,” Ms Duell said.
During El Niño, rainfall in eastern Australia is typically below average during winter and spring. A neutral ENSO phase has little effect on Australian climate.
The Indian Ocean Dipole (IOD) another of Australia’s key climate drivers remains neutral. Five out of six climate models indicate the IOD is likely to remain neutral in the coming months and one model suggests a positive IOD.