The near-record El Nino underway in the Pacific is expected to intensify during spring while an Indian Ocean climate indicator is also moving towards levels associated with drier weather in parts of Australia.

The bureau says in its latest update that all models forecast the tropical Pacific will continue warming through the southern hemisphere spring, likely peaking in late spring or summer, and persisting into autumn. 

The relative Nino3.4 index values are forecast to reach levels above the warmest observed since reliable records began in 1950, with the majority of models indicating a peak value above 3 degrees Celsius. 

The Indian Ocean Dipole (IOD) is still neutral after exceeding a positive threshold for three weeks. 

“A positive IOD is likely to develop during the southern hemisphere spring and persist into early summer, although model guidance indicates some uncertainty in the strength and duration of the event,” the bureau says. 

An El Nino and positive IOD occurring together can bring a stronger and more widespread drying impact for Australia. 

The October to December outlook released on Thursday says below average rainfall is likely for much of southern and eastern Victoria, Tasmania, and northern parts of the NT Top End and Cape York Peninsula in Queensland. 

But for much of eastern Australia and parts of the north there are roughly equal chances of above or below average rainfall, and there’s an increased chance of unusually high rainfall across much of southern and central WA and some southern parts of the NT.