Weekly Tropical Climate Note

Monsoon break in the north as rainfall moves inland

With the recent dissipation of the monsoon trough over northern Australia, much of the region has experienced an inactive period in the monsoon this week, with many locations receiving only minimal rainfall from isolated showers and storms. Instead, an active trough has persisted further south for much of the week, focusing rainfall over parts of northern Western Australia, central Northern Territory, and Far North Queensland.  Rainfall over these regions has been well above average, including isolated daily totals in excess of 100 mm. In particular, Tennant Creek (Northern Territory) experienced a 1-in-50 year rainfall event when 70 mm fell in just over an hour, resulting in flash flooding. A low which developed over northwest Queensland during the weekend is expected to continue to move west over the coming days, bringing with it the possibility of further heavy falls and flooding to already saturated parts of the central NT and northern WA. Reduced rainfall conditions in the far north are expected to persist for the next few days, before a possible increase in more monsoonal-like activity early next week.

Madden-Julian Oscillation currently weak, may strengthen

Heavy rainfall observed over parts of inland northern Australia this week is not related to the Madden-Julian Oscillation (MJO), which has remained weak or indiscernible over recent weeks. There is a strong consensus between climate models that the MJO will strengthen over the western hemisphere in the next few days. When the MJO is in the western hemisphere at this time of year, the focus of tropical convection is shifted to Africa and the Indian Ocean, while the northern Australian and Maritime Continent regions typically experience decreased cloudiness and rainfall.

Australia’s tropical cyclone season has been relatively quiet so far, with only one named system in late December (Tropical Cyclone Yvette). Some models predict the MJO will progress eastward reaching Australian longitudes by the end of the month. As the MJO moves eastward the risk of tropical cyclone development in the Australian region will increase. For more information on tropical cyclones affecting the Australian region, please check the Bureau’s tropical cyclone webpage.

For more information see the Bureau's current MJO monitoring information.

ENSO-neutral conditions to continue

The El Niño-Southern Oscillation (ENSO) in the tropical Pacific Ocean remains neutral, and most climate models predict it will remain so throughout the Australian summer and autumn. Most ocean temperatures and atmospheric indicators of ENSO remain within the neutral range.

See the Bureau’s ENSO Wrap-Up for official El Niño, La Niña and Indian Ocean Dipole information.

Product code: IDCKGEW000

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