Weekly Tropical Climate Note

Madden–Julian Oscillation currently weak

The Madden–Julian Oscillation (MJO) and other intraseasonal atmospheric waves across the tropics are currently having no significant influence on weather across northern Australia. Climate models indicate the MJO will likely strengthen near Africa or the western Indian Ocean in the coming week, and then track slowly eastwards. In this scenario, the only influence on northern Australia may be an increase in onshore flow across the north Queensland east coast, potentially leading to isolated areas of above-average rainfall.

Further north, the influence of an MJO pulse over the Indian Ocean at this time of the year is typically confined to the Indian subcontinent and parts of South-East Asia.

Read more about the Madden–Julian Oscialltion

Easterly winds influencing Australian tropics

The primary climate influence across northern Australia and the broader tropics close to Australian longitudes is a widespread easterly wind flow. This has been a feature for the last month or so, and climate models generally indicate this wind regime will continue for at least the next month. This appears to be related to higher than normal surface pressure around Australian longitudes in the mid-latitudes in both hemispheres, leading to enhanced trade winds in the southern and northern hemisphere.

As a result of the increased easterly flow, east-facing coasts of tropical Australia have recently observed average to above-average rainfall, whereas inland regions and west-facing coastal zones have had below-average rain.

Widespread above-average rainfall across Asia

Monsoonal conditions continue across the Indian subcontinent and further east into parts of Asia. Across India, cumulative rainfall since 1 June is about 20% above average. Further east, many southern and eastern regions of China have seen very heavy rainfall, leading to widespread flooding.

Product code: IDCKGEW000

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