Tropical Climate Update

Dry season weather pattern developing across northern Australia

As the official start date of the dry season approaches (1 May), broadscale weather patterns across the tropics are transitioning to a more typical dry-season pattern. South-easterly trade winds currently dominate the Australian region, as seen in the latest streamline chart, while the pressure charts show the belt of high pressure across southern Australia has recently moved further north and strengthened. This pattern will become further established in the coming weeks and months, resulting in sustained periods of dry south-easterly winds and stable conditions across much of northern Australia. These winds typically have low humidity after traversing the dry continental landmass of Australia, although the east coast of Queensland experiences an onshore flow in this wind regime. As rainfall average maps show, coastal north-east Queensland is one of the few regions across northern Australia to observe significant rainfall totals during the dry-season months.

Strong Madden–Julian Oscillation in Indian Ocean

A strong pulse of the Madden–Julian Oscillation (MJO) continues to track eastwards across the Indian Ocean. In recent days this pulse moved into the eastern Indian Ocean and is approaching the western Maritime Continent (MC). Most international climate models predict this pulse will weaken as it moves into the MC. However, some models indicate the MJO will persist at moderate strength as it tracks across the western MC. The MJO's influence on rainfall across northern Australia is relatively weak at this time of the year. However, if the pulse does remain moderately strong over the MC, humidity, cloudiness, and potentially rainfall, could increase over parts of far northern Australia and Queensland in the coming fortnight. Given monsoonal activity is shifting away from Australia, it is more likely that there would be a stronger influence on cloudiness and rainfall to the north of Australia, in places such as Papua New Guinea and parts of Indonesia.

Read more about the Madden–Julian Oscillation