Tropical Climate Update

Low rainfall expected across northern Australia

The coming fortnight is likely to see below-average rainfall across much of northern Australia. This would continue a trend seen since early March, with intraseasonal climate drivers contributing to suppressed rainfall conditions across the Australian tropics.

Despite the generally suppressed environment across the broader Australian tropics, forecasts indicate 3 tropical lows of interest developing in the coming week. Two of these are expected over waters off the Western Australia coast, and the third closer to waters adjacent to the Northern Territory coast. Current forecast assessments indicate a low chance (less than 10%) of any of these systems intensifying to tropical cyclone strength. While northern Australia's wet season is slowly winding down, significant tropical weather is not unusual in late March and April. The official end date of both the northern wet season and the tropical cyclone season is 30 April.  

See current tropical cyclone outlooks

Madden–Julian Oscillation briefly weakens

A pulse of the Madden–Julian Oscillation (MJO) has rapidly weakened in recent days and is expected to become indiscernible this week. Most models indicate the MJO will re-strengthen over the Western Pacific region in the first week of April.

If the MJO strengthens over the tropical western Pacific, this could lead to an increased chance of above-average rainfall for parts of far northern Australia, particularly around Cape York Peninsula, Queensland, and the Top End of the Northern Territory. A larger chance of increased cloudiness and rainfall would typically be experienced across the Southwest Pacific region in this scenario, where the probability of tropical low and tropical cyclone development would also likely be enhanced.

At this time of the year, other atmospheric tropical waves (especially Kelvin waves and equatorial Rossby (ER) waves) can also influence rainfall patterns across northern Australia. Climate models indicate an enhanced phase of ER wave activity may move across northern Australia longitudes in the first fortnight of April. An ER wave could amplify the influence of the MJO and greatly increase the likelihood of above-average rainfall for several days across Australia's far north.

Read more about the Madden–Julian Oscillation and Climate Driver Update