The El Niño – Southern Oscillation (ENSO) is currently neutral. However, current observations and model outlooks indicate El Niiño remains possible in 2018, according to the Bureau of Meteorology of the Australian Government (BOM).
Therefore, the Bureau’s ENSO Outlook remains at El Niño WATCH, meaning there is approximately a 50% chance of El Niño forming in the coming months; double the normal chance.
Surface waters of the central and eastern tropical Pacific Ocean are slightly warmer than average, and water below the surface is warming. Atmospheric indicators largely remain neutral, although the Southern Oscillation Index (SOI) has become more negative (El Niño-like).
International climate models surveyed by the Bureau predict further warming of the tropical Pacific is likely. All models suggest El Niño thresholds are likely to be reached by the end of spring.
El Niño during spring typically means below-average rainfall in eastern and northern Australia while daytime temperatures are typically above average over the southern two-thirds of Australia.
The Indian Ocean Dipole (IOD) is neutral. However, roughly half of international climate models suggest a short-lived positive IOD event may develop. A positive IOD during spring typically reduces rainfall in central and southern Australia, and can exacerbate any El Niño-driven rainfall deficiencies.
