Tropical Climate Update

Record breaking rainfall across northern Australia

This past week saw the Madden–Julian Oscillation (MJO) maintain moderate strength as it moved over Australian longitudes, contributing to strengthening westerly winds in the area and subsequent reinvigoration of the north Australian monsoon over the weekend.

High rainfall was recorded throughout tropical Australia, with the highest totals seen around the northwest Top End. Rainfall totals over the last three days in the region have been in the order of 250 to 400 mm, with several locations setting new records for February daily rainfall. The highest daily rainfall was 290.0 mm at Shoal Bay on Sunday. Darwin Airport recorded 201.8 mm - the highest daily total since February 2011, and the eleventh highest daily rainfall since records began at Darwin Airport in 1941.

The MJO is forecast to maintain moderate intensity this coming week as it moves over the western tropical Pacific. Typically there is still some enhancement to north Australian weather when the MJO is over this region, though this effect diminishes as the signal moves further away from Australian longitudes.

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

An increase in tropical activity in the southern hemisphere

The 2016/17 southern hemisphere tropical cyclone season has so far been very quiet. To date, no systems have reached severe tropical cyclone strength, the longest period of a system not reaching this intensity in the southern hemisphere on record.

Tropical storm Carlos, in the western Indian Ocean, is only the second system in the southern hemisphere to reach tropical cyclone intensity this season. The system is forecast to intensify over coming days as it moves southwest, close to Mauritius and La Réunion.

There is also the possibility of another southern hemisphere system reaching tropical cyclone intensity in the coming week. A low over water just north of the Kimberley region of Western Australia currently has a  moderate (20 to 50%) chance of developing into a tropical cyclone on Wednesday, as it tracks southwest over water. There is also potential for tropical low development over other parts of northern Australia, with a strong monsoon trough over the area. There is a moderate chance of a low in the Gulf of Carpentaria reaching tropical cyclone strength on Thursday.

For more information, see the Bureau's current tropical cyclone information.

El Niño–Southern Oscillation remains neutral

The El Niño–Southern Oscillation (ENSO) remains neutral.

Climate models indicate the tropical Pacific Ocean is likely to remain ENSO-neutral through the southern summer and autumn. Most models surveyed expect the tropical Pacific Ocean to warm during this period, meaning La Niña is the least likely scenario for winter/spring 2017. It should be noted that model outlooks that span the southern autumn period tend to have lower accuracy than outlooks issued at other times of the year. This means outlooks beyond May should be used with some caution.

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