Rainfall Update

For the week to 12 January 2021, rainfall was recorded in the northern inland Gascoyne, Pilbara and Kimberley in Western Australia, much of the northern third of the Northern Territory, most of Queensland except the south-west, eastern and northern inland New South Wales, and eastern Victoria.

At the start of the week, a surface trough extended from the Kimberley in Western Australia, across the base of the Top End in the Northern Territory, to the remnants of ex-tropical cyclone Imogen, located over the north tropical coast of Queensland. Another surface trough extended from the Gulf Country through western Queensland and inland New South Wales. Widespread showers and thunderstorms developed across parts of the Gascoyne and Pilbara, and northern Kimberley; also through central and northern parts of the Northern Territory, and across large areas of northern and eastern Queensland. Thunderstorms and showers also developed in northern inland and eastern parts of New South Wales, and eastern Victoria.

The remnants of ex-tropical cyclone Imogen lingered near the north tropical coast of Queensland for several days. Moderate to locally heavy falls were reported in the north tropical coast, and the Herbert and Burdekin districts. The trough through inland Queensland and the coastal trough, combined to generate persistent showers and thunderstorms and widespread moderate falls across the north tropical coast, and central to southern inland Queensland. Heavier falls were reported about the north tropical, Burdekin and Herbert coasts in Queensland, with major flooding on the Herbert and Upper Burdekin rivers.

From the middle of the week, thunderstorms continued over parts of the Pilbara in Western Australia, and the Top End in the Northern Territory and in western Queensland. The trough remained near-stationary along the north-east coast of Queensland until the end of the week, with another trough still located further inland. Combined with an upper-level disturbance, the systems produced widespread moderate falls across the Cape York Peninsula, north tropical to central coasts, Central Highlands and south-east of Queensland.

At the end of the week, a cold front and pre-frontal trough tracked across south-east Australia, and produced moderate falls in western Tasmania.

Rainfall totals in excess of 200 mm were recorded from the north tropical to central coasts of Queensland, including the highest weekly total of 502 mm at Gairloch in Herbert North Coast in Queensland.

Rainfall totals in excess of 100 mm were recorded in areas of the Pilbara and Kimberley in Western Australia, coastal parts of the north-west Top End in the Northern Territory, and along the north-east coast of Queensland from Cooktown to St Lawrence, as well as isolated areas in the Central Highlands.

Rainfall totals between 10 mm and 50 mm were recorded in the northern inland Gascoyne, Pilbara and Kimberley in Western Australia, most of the northern third of the Northern Territory, and remaining parts of Queensland away from the south-west, northern inland and most of the east coast of New South Wales, eastern Victoria, and western Tasmania.

Impact of recent rainfall on deficits

Rainfall deficits over Australia for the 9-month (April 2020–January 2021) period is discussed in the Drought Statement, which was issued on 8 January 2021. 

Rainfall deficit maps are available for this period as well as for standard periods. The map below shows the percentage of mean rainfall that has been received for the rainfall deficit period starting April 2020 and extended to the week ending 12 January 2021.

Rainfall for the period 1 April 2020 to 12 January 2021

Serious or severe rainfall deficiencies for the period starting 1 April 2020 are in place in Western Australia across large parts of the southern half of the State, excluding the western Gascoyne and southern parts of the South West Land Division (SWLD). Serious rainfall deficiencies are also affecting greater south-east Queensland.

Some inland areas of Western Australia have generally received less than 20% their average for the period, while areas in the northern SWLD have generally received less than 70% of their average for the period. Remaining areas in Western Australia have and areas in south-east Queensland and have generally received less than 60% of their average for the period.