Tropical Climate Update

Another tropical cyclone likely for northern Australia

A weak monsoon trough, which currently sits across northern Australia, is forecast to re-strengthen in the coming days. Many of the favourable broadscale climate factors which supported the development of tropical cyclone Marcus are still prevalent in the region, maintaining an environment conducive to tropical cyclone formation. There remains a significant cross-equatorial wind-flow into northern Australia which is interacting with a deep southeasterly wind-flow. This provides rotational energy for the formation and intensification of lows within the monsoon trough.

Another tropical low has recently been identified near the Torres Strait, and based on current weather models, this low is likely to undergo further intensification in the next few days. While the models agree the low will move west in the short-term, and strengthen over the Gulf of Carpentaria, it's too early to determine exactly which parts of the Gulf coast might be impacted by this system.

Tropical cyclone Marcus, which impacted the northwest of the Northern Territory and northern Western Australia, has moved offshore and is tracking westwards across the Indian Ocean. Marcus has intensified to a severe tropical cyclone (category 3 or greater) but is not expected to directly affect any additional populated regions before weakening to below tropical cyclone intensity.

Marcus generated widespread gusts of more than 100 km/h across parts of northwest Australia after reaching tropical cyclone intensity on the morning of 16 March. The tropical cyclone made a direct hit on Darwin at category 2 strength, generating sustained gale-force winds (greater than 62 km/h) for six hours. The peak gust recorded in Darwin was 130 km/h; the strongest wind gust from a tropical cyclone since severe tropical cyclone Tracy devastated Darwin in 1974. Event rainfall totals were relatively moderate, however Warruwi, on the Northern Territory's north coast, had a peak total of 275 mm over three days. The level of destruction from Marcus was much less severe than that from Tracy, however there was widespread infrastructure and vegetation damage across the city and nearly half of all Darwin properties lost power.

For up-to-date tropical cyclone information for the Australian region, including daily cyclone outlooks, please visit the Bureau's current tropical cyclones webpage.

Tropical wave activity remains in Australian region

A pulse of the Madden–Julian Oscillation (MJO) near the Maritime Continent remains weak, however some indicators suggest it is helping to provide a favourable atmospheric circulation for enhanced cloudiness and rainfall across northern Australia. Equatorial Rossby wave activity, which was likely the most significant tropical wave associated with tropical cyclone Marcus, remains present across northern Australia. In its current location, the Rossby wave, a westward moving tropical pulse of low pressure, is reinforcing cross-equatorial flow into Australian longitudes and provides favourable conditions for enhanced tropical convection and tropical cyclone formation in the region.

See the Bureau's current MJO monitoring for more information.

Pacific Ocean returns to neutral

La Niña has ended, as the El Niño-Southern Oscillation returned to a neutral state, with the tropical Pacific Ocean warming since late December. Waters beneath the surface have also warmed, and atmospheric indicators such as the Southern Oscillation Index (SOI) are neutral.

See the Bureau's current ENSO Wrap-Up for more information.