Tropical Climate Update

Monsoon trough across northern Australia

The past two weeks have seen increased tropical activity across much of northern Australia. Monsoon onset was finally observed at Darwin on 7 February, the latest onset since records began in the 1957-58 wet season, surpassing the previous latest onset date of 25 January (during the 1972-73 wet season). While the onset of the monsoon was late to arrive in Darwin, the monsoon trough was established over Queensland from the end of January and also briefly in northern WA.

The establishment of the monsoon trough brought heavy rainfall and cooler conditions across the tropical north. Weekly rainfall totals (to 10 February) exceeding 100 mm were recorded in a large area  of Western Australia's Kimberley district, northern parts of the Northern Territory, and most of northern Queensland where large areas recorded weekly totals greater than 200 mm.

Multiple sites between Cairns and Mackay on Queensland's east coast observed weekly totals exceeding 500 mm, with the highest weekly total (at a Bureau gauge) of 776.0 mm at Cardwell Range. The highest daily rainfall total during the week ending 10 February was 322.2 mm at Queensland's Hamilton Island in the 24 hours to 9 am on 5 February.

For the fortnight beginning 15 February, rainfall is likely to very likely (60% to greater than 80% chance) to be below average across tropical Western Australia, the Northern Territory and western Queensland, with rainfall in the typical range for most of eastern Queensland. Maximum temperatures are likely to be above average for much of Western Australia, northern parts of the Northern Territory and parts of Queensland's Peninsula and Gulf Country districts as well as along the north-eastern coast, but below average for the Northern Territory' south-east and central and south-western Queensland. Minimum temperatures are likely to be above average for the coastal areas of Western Australia, the Top End in the Northern Territory and parts of northern and eastern Queensland, but below average for areas further south.

Tropical cyclones and Tropical Lows in Australian region

Tropical Cyclone (TC) Taliah developed to the north of Western Australia's Pilbara coast on 2 February and reached Category 3 intensity (Severe TC) on the morning of 4 February while tracking westwards, well south of Christmas Island. From 7 February, it started to weaken and on 10 February was downgraded to a Tropical Low. It quickly regained tropical cyclone intensity and continues to track westwards. TC Taliah did not impact the Australian mainland or any island communities. It is forecast to exit the Australian region on 12 February.

A weak tropical low (18U) formed near the north Kimberley coast (Western Australia) on 8 February. The low is forecast to move in a south-westward direction towards Western Australia's Pilbara coast and slowly strengthen, potentially reaching cyclone intensity from 12 February. It is forecast to make a landfall this week but there is a large uncertainty in the location of coastal crossing. The slow movement of the system as it approaches the coast may result in very high rainfall totals, wind and storm surge.

An active low pressure trough will persist across northern Queensland and the Coral Sea during the coming week. A tropical low (19U) may form in the eastern Coral Sea, well away from the Queensland coast. It is forecast to track eastwards, moving further away from the Queensland coast. Another tropical low (20U) may form in the western Coral Sea from 11 February and is forecast to move south-eastwards, also away from the Queensland coast.

For the latest details on tropical low and tropical cyclone development, check the Tropical cyclone 7 day cyclone forecast and the Fiji Meteorological Service Tropical Cyclone outlook.

Madden–Julian Oscillation approaching the Western Pacific

During the week ending 10 February, a moderate to strong pulse of the Madden-Jullian Oscillation (MJO) progressed across the Maritime Continent and entered the Western Pacific enhancing tropical activity over the region and triggering the monsoonal burst across northern Australia.

Forecasts for the MJO show a large spread in likely strength outcomes, but climate models generally suggest that over the next week, the MJO pulse may temporarily weaken while in the Western Pacific.