A strong Madden-Julian Oscillation (MJO) propagated eastwards over the Maritime Continent during the last week, entering the far western Pacific on the weekend. This event is forecast to remain strong as it moves further eastwards into the Pacific over the coming week and it is not expected to return to Australian longitudes until at least mid-to-late April.

Over the past week, the monsoon trough strengthened over the Timor and Arafura Seas before migrating southwards over land.  A deep low within the trough was responsible for monsoonal showers and storms that developed over the NT’s western Top End and the Kimberley region.  However, convection remained suppressed from the Solomon Islands to the Date Line, with the South Pacific Convergence Zone (SPCZ) shifting further west than normal.

With the MJO currently over the western Pacific Ocean and the Northern Australian Monsoon (NAM) over northern Australia, the risk for tropical cyclone formation and above average rainfall across northwestern Australia will  be low to moderate, with the focus shifting towards the northeast.  A tropical low just to the southeast of the Gulf of Carpentaria is expected to track southeast into central and (eventually) eastern Queensland over the next few days, bringing heavy rain across most of the region. The MJO is forecast to contribute to enhanced convection over the western Pacific in the next fortnight with moderate to high risk for topical cyclone formation and above average rainfall in the area.

Suppressed conditions of the NAM this week will lead to a decrease in precipitation across far northern Australia but with humidity levels remaining high in a westerly flow.  Over the weekend a gusty and cool southeasterly change will propagate north across central Australia as the trough migrates towards the north coast, contracting showers and storms northwards.

http://www.bom.gov.au/climate/tropnote/tropnote.shtml