Tropical Climate Update

Monsoonal conditions to strengthen across northern Australia

After the first burst of monsoonal weather across Australia last week, a monsoon trough which formed off the northwest of Australia recently dissipated. Current atmospheric conditions are favourable for the redevelopment of a monsoon trough across northern Australia in the coming week.

The main focus of monsoonal conditions near the Australian region is currently well to the east of the country, associated with severe tropical cyclone Yasa, east of Vanuatu. While Yasa is not expected to move near Australia, it is likely that a monsoon trough in the vicinity of Yasa will extend westwards in the coming week, across the Gulf of Carpentaria and into the Timor Sea, to the north of Australia. This could lead to the establishment of a broad monsoon flow across northern Australia, and potentially the official onset of the Australian monsoon at Darwin.

Madden–Julian Oscillation remains active in Australian region

A pulse of the Madden–Julian Oscillation (MJO) which last week assisted the formation of a monsoon trough to Australia's northwest, moved eastwards during the past week, but remains in a location favourable for increased cloudiness and rainfall across Australia's tropics. At this time of the year, an MJO in its current location over the eastern Maritime Continent, is typically associated with above-average rainfall across virtually all of far northern Australia and the tropical zone to Australia's north.

Climate models predict the MJO pulse will slowly track further eastwards in the coming week, but it is likely to remain in a location that should sustain an environment favourable for increased rainfall and cloudiness across the Australian region. The MJO’s presence in the Australian region is favourable for active monsoonal conditions across the region.

Read more about the Madden–Julian Oscillation

Increased risk of tropical cyclone activity near Australia

With the likely return of a monsoon trough, there is an increased chance of tropical low and tropical cyclone formation in the Australian region. Current weather model guidance suggests a possible low-pressure centre developing within the monsoon trough that is expected to be near northern Australia in the coming week, although there is high uncertainty as to where a tropical low might form.

Meanwhile, severe tropical cyclone Yasa lies over the western South Pacific Ocean between Fiji and Vanuatu. Yasa is currently slow moving and expected to intensify in the coming days. It is expected to commence a south-eastwards track in the next day or two and move towards Fiji later this week. Forecasts out of the Nadi Tropical Cyclone Centre indicate Yasa could strengthen from its current category 3 intensity to a category 5 system, potentially making landfall at Fiji with sustained maximum winds in excess of 205 km/h.

Read more about Australian tropical cyclone outlooks and warnings