Tropical Climate Update

Heavy rainfall and major flooding in Far North Queensland

Significant rainfall accompanied tropical cyclone Jasper as it made landfall as a category 2 system on Queensland's north tropical coast on the evening of 13 December. Jasper then moved inland and rapidly weakened to below tropical cyclone strength, stalling over Cape York Peninsula.

A surface trough then developed over the weekend of 16–17 December, extending from ex-tropical cyclone Jasper eastward across the north tropical coast into the Coral Sea. Moist north-easterly winds from the Coral Sea converged along this near-stationary trough with easterly winds strengthened by a building ridge in the Tasman Sea. This resulted in heavy to intense rainfall over the north tropical coast and inland areas, which was intensified by conditions in the upper atmosphere and winds rising over the Great Dividing Range. Major flooding in Cairns was brought about by this heavy rainfall in already wet river catchments, due to earlier rainfall associated with ex-tropical cyclone Jasper's landfall.

For the 7 days to 9 am on Tuesday 19 December, the highest rainfall totals at Far North Queensland Bureau rain gauges were: 2252.0 mm at Bairds near the Daintree River; 2199.0 mm at Black Mountain; and 2102.0 mm at Whyanbeel Creek. A number of other gauges also recorded over 2000mm.

Flood warnings are still current, as of 12pm AEST 19 December, for the Tully, Murray, Herbert, Daintree and Mossman rivers in northern Queensland, and a flood watch is also current for parts of the Cape York Peninsula. For more information on the current warnings, see the Bureau's Warning Services.

Rainfall across the impacted region is currently easing, with no significant rainfall forecast for the next few days. Showers may be expected in some areas but are unlikely to contribute to increased flooding.

The system that was tropical cyclone Jasper is forecast to remain as a tropical low, moving north through the Gulf of Carpentaria, then to the north-east and potentially to the north of the Cape York Peninsula over the coming weekend.

For further, up to date information on this system, visit the Bureau's tropical cyclone forecast webpage.

Heatwave conditions to return to northern Australia

For the three days following 19 December 2023, heatwave conditions are due to return to northern Australia. Extreme heatwave conditions are forecast for parts of the Kimberley and eastern Pilbara of Western Australia and severe to low intensity heatwave conditions are forecast for much of the rest of northern Western Australia, and parts of western and northern Northern Territory, including Darwin. Low intensity heatwave conditions are forecast for much of central and northern Northern Territory, including Darwin, isolated pockets of north-west Queensland, and a band extending from the northern interior of Western Australia to the west coast, north of Perth.

This heatwave event is likely to continue as the weekend approaches, with severe heatwave conditions, with pockets of extreme heatwave conditions, forecast for the three days following Friday 22 December for parts of the Kimberley in Western Australia and northern Northern Territory, including Darwin. Severe to low intensity heatwave conditions are forecast for the remainder of central Northern Territory, northern Western Australia and north-west Queensland. Low intensity heatwave conditions are forecast for western Northern Territory, much of the remainder of the interior of Western Australia, and parts of northern and western Queensland. 

For further information on the heat wave warnings, see the Bureau's Heatwave Service for Australia.

Madden–Julian Oscillation over the western Pacific

The Madden–Julian Oscillation (MJO) is currently over the western Pacific. International climate models suggest it will move eastwards across the western Pacific over the coming days and weaken, potentially re-strengthening over the Western Hemisphere and Africa after a week.

While the MJO maintains its strength over the western Pacific, it increases the chance of above average rainfall over northern Australia. However, in the western hemisphere and Africa region, the MJO typically decreases the chance of above average rainfall.

Merry Christmas from the Bureau

Season's greetings from the Bureau. This is the final publication of the Tropical Climate Update for 2023 and the next publication will be on 9 January 2024.