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ENSO and IOD likely to remain neutral through southern winter, says Bom

La Niña El Niño Enso

MELBOURNE, Australia – Australia’s major climate drivers—the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD)—are likely to remain neutral through the southern winter, reports the Bureau of Meteorology of the Australian Governement (BOM).

Indicators of ENSO including the Southern Oscillation Index (SOI), trade winds, cloudiness near the Date Line, and sea surface and sub-surface temperatures in the tropical Pacific Ocean are all at neutral levels.

Warmer than average ocean temperatures in the Pacific, near to and west of the Date Line, have enhanced cloudiness in the region. This pattern would typically reduce rainfall over northeast Australia. However, waters are also warmer than average around northern Australia and in the eastern Indian Ocean, which would typically increase rainfall over large parts of Australia.

Six of the eight climate models surveyed by the Bureau indicate that ENSO is likely to stay neutral through the southern hemisphere winter, meaning it will have limited influence on Australian and global climate in the coming months.

The remaining two models suggest La Niña conditions may develop during winter. ENSO predictions made during autumn tend to have lower accuracy than predictions made at other times of the year. This means that current ENSO forecasts beyond May should be used with some caution.

The Indian Ocean Dipole (IOD) is neutral. The IOD typically has little influence on Australian climate from December to April. Most climate models surveyed indicate the IOD will remain neutral through the southern hemisphere winter.

The Madden–Julian Oscillation (MJO) is forecast to strengthen and increase the chance of drier than average conditions across northern Australia for the remainder of March. The Southern Annular Mode (SAM) is currently neutral and is forecast to remain neutral for the next three weeks. The SAM has little influence upon Australian rainfall in autumn.