The positive Indian Ocean Dipole (IOD), which contributes to dry weather in eastern Australia, is likely past its peak, while an El Nino event is continuing in the Pacific, the Bureau of Meteorology says in a climate driver update. 

The combination of an El Nino, which the bureau declared in September, and a positive IOD had reinforced the outlook for warmer and drier conditions for much of Australia during spring and into summer. 

All international climate models surveyed by the bureau suggest the positive IOD is likely to ease this month, while the El Nino influence on Australian rainfall usually reduces during summer, especially in the east, the bureau says. 

The long-range forecast for Australia indicates December to February rainfall is still likely to be below median across much of northern and western Australia, with warmer days and nights very likely for almost all of the country. 

At the same time, “high impact rainfall events” can occur during El Nino years, particularly during October to April when severe storm frequency peaks, the bureau says. 

Tropical Pacific sea surface temperatures are expected to remain well above El Nino thresholds until early into the second quarter of next year.