Weather News

Indian Ocean Dipole breaks down

Ben Domensino, Tuesday December 31, 2019 - 15:35 EDT

The positive Indian Ocean Dipole that has underpinned one of Australia's warmest and driest years on record has finally broken down.

The Indian Ocean Dipole refers to an index that measures sea surface temperatures in the tropical Indian Ocean. When the index is positive, the pattern of sea surface temperatures across the Indian Ocean restricts the amount of moisture in the atmosphere over Australia. This typically causes below average rain and above average temperatures in large parts of the country.

The Indian Ocean Dipole adopted a positive pattern in late May and persisted in this phase until late December, reaching a strong peak in October. 

Image: Indian Ocean Dipole index showing a prolonged positive phase between May and December in 2019. Source: Bureau of Meteorology.

This prolonged and strongly positive Indian Ocean Dipole helped cause unusually warm and dry weather in Australia between winter and early summer, exacerbating the drought and helping bushfires burn across eastern Australia.

While Indian Ocean Dipole events usually dissipate in late spring, the strength of this episode allowed it to persist well into summer. However, the latest weekly index value has dropped to neutral territory for the first time in months. 

While this doesn't mean the weather in Australia will change abruptly, it does take this dominant climate driver out of the equation as we head into the new year.

More breaking news

Sydney Morning Herald
ABC News
9News
News Limited

Display Your Local Weather

Weather News

Atmospheric rivers form in both the Indian and Pacific Oceans, bringing rain from the tropics to the south

07:27 EST

A rare pair of atmospheric rivers have formed off Australia this week, channelling tropical moisture to both sides of the nation.

Sydney surfer dies after slamming into storm water drain, wild weather forces evacuations on NSW South Coast

17:22 EST

A surfer has died after being slammed into a storm water drain at Collaroy on Sydney's northern beaches.