Tropical Climate Update

Australian region

Recent conditions

For the week ending 12 January, a monsoon trough and low pressure areas generated showers, thunderstorms and rain with locally heavy falls in parts of the tropical north, while Tropical Cyclone Koji brought widespread rainfall and thunderstorms to much of eastern Queensland (see section below for details on Tropical Cyclone Koji). Weekly rainfall totals of 50 to 300 mm, locally higher, were recorded across parts of eastern and tropical Queensland, the Top End of the Northern Territory and areas in the north of Western Australia. The highest weekly total (at a Bureau gauge) was 395.0 mm at Mt Jukes in Queensland, which included the highest daily total of 251.0 mm in the 24 hours to 9 am on 12 January.

During the week, low-intensity to severe heatwave conditions developed across southern parts of the Northern Territory extending into Western Australia, which were part of the broader severe to extreme heatwaves further south.

Maximum temperatures were below average in parts of northern Australia on most days during the week. Daily maximum temperature anomalies were up to 4 °C below average in parts of the tropics, with areas in Queensland more than 8 °C below average on some days.

Fortnightly forecast

The forecast for the fortnight of 17 to 30 January, issued on 12 January, shows rainfall is likely to be below average for tropical Western Australia, the Northern Territory and parts of western Queensland. For northern and eastern Queensland, the forecast signal is weak meaning roughly equal chances of a wetter or drier fortnight.

Maximum temperatures are likely to be below average for parts of eastern Queensland and above average across Western Australia and the Northern Territory extending into western Queensland. Minimum temperatures are likely to be below average for central and western Queensland extending into eastern parts of the Northern Territory and above average for much of remaining tropical north.

Madden–Julian Oscillation

As of 10 January, the Madden–Julian Oscillation (MJO) has strengthened in the Western Pacific, though it remains relatively weak. Most forecast from surveyed models suggest that over the coming week the MJO is likely to strengthen further in the Western Pacific region and progress eastwards across the Western Pacific. At this time of year, the MJO in the Western Pacific is typically associated with enhanced rainfall and westerly wind anomalies in parts of Australia's tropical north.

Severe Tropical Cyclone Jenna

Tropical low 11U developed on 4 January in the Indian Ocean, north-west of the Cocos (Keeling) Islands. It initially moved to the south-east before reaching tropical cyclone intensity on 5 January and was named Jenna. Tropical Cyclone (TC) Jenna passed close to the Cocos (Keeling) Islands as a Category 1 system as it tracked southwards, before turning to the south-west and intensifying. It briefly reached its peak intensity as Category 3 system (Severe TC) on 7 January, with sustained winds of 150 km/h and central pressure of 967 hPa. On 8 December, it weakened below tropical cyclone strength just prior to exiting the Australian area of responsibility (AOR). Jenna was the sixth TC in the Australian AOR this season,

Cocos (Keeling)Islands experienced a period of strong winds and heavy rainfall on 5 January as Tropical Ciclone Jenna passed close by. It is the first time since reliable observations began in 1970 that the Cocos (Keeling) Islands were impacted by two tropical cyclones in one season (Tropical Cyclones Grant and Jenna).

Tropical Cyclone Koji

Tropical low 12U developed in the Coral Sea north of Willis Island on 8 January. Moving south-westwards towards Queensland's north-east coast it rapidly intensified, reached tropical cyclone strength on 10 January and was named Koji. It was the seventh tropical cyclone in the Australian AOR this season. Tropical Cyclone (TC) Koji reached its peak intensity early on 11 January as Category 2 system with sustained winds of 95 km/h and central pressure of 989 hPa. It quickly weakened before making landfall on the morning of 11 January as a Category 1 system. TC Koji made landfall between Ayr and Bowen, bringing heavy rainfall and strong winds with gusts exceeding 80 km/h to the area between Bowen and Mackay. After crossing the coast, it weakened below tropical cyclone intensity while moving to the south-west continuing to bring heavy rainfall to areas along its track, including daily totals of over 200 mm in some areas. Further rainfall over mostly saturated soils contributed to flooding in some river catchments.  Ex-TC Koji is forecast to track westwards through the Gulf Country in the following days.

See the tropical cyclone 7-day forecast for the latest advice on systems in the Australian region.