Rainfall deficiencies re-emerge in southeast Queensland
February rainfall was below average across much of Queensland (particularly south of a line between Boulia and Townsville), most of New South Wales (except the southeast), northeastern South Australia, and also across much of Tasmania away from the west. Rainfall for the month was above average for most of Western Australia, the Top End of the Northern Territory and the southern Gulf coast in Queensland, and also for areas along a line extending from the west coast of South Australia, through the eastern Eyre Peninsula, across the Murraylands and Adelaide region, and into northwest Victoria.
Rainfall has often been below average in areas along and east of the Great Dividing Range in the months since October 2016. The summer months have also been particularly warm for much of New South Wales and southern Queensland. A persistent upper-level pressure ridge remained over the continent for several weeks, positioned further south than is typical for the season and extending as far east as Lord Howe Island, which has also received below average rainfall. This ridge brought large-scale subsidence (sinking air) and reduced cloudiness during January and February, while a series of slow-moving high pressure systems over the Tasman Sea further contributed to conditions conducive to hot, dry weather in eastern Australia.
The latest Climate Outlook suggests that a drier than average autumn is likely for southern and central Australia.
4-month rainfall deficiencies
Areas of serious to severe rainfall deficiencies are present at the four-month timescale across greater southeastern Queensland (roughly southeast of a line between Rockhampton and Cunnamulla, with the area affected closer to the southern border becoming focused on the Darling Downs), while scattered localities around central eastern Queensland are also experiencing deficiencies.
Serious deficiencies extend into parts northern New South Wales in the Northwest Slopes and Plains district, and in a coastal pocket around Kempsey. A small area of deficiencies also exists in Gippsland in eastern Victoria, and adjacent far southeastern New South Wales.
Surrounding the regions experiencing serious rainfall deficiencies are large areas which are in decile 2 for November to February, meaning they have received rainfall in the lowest 20% of historical observations (serious rainfall deficiencies are analysed for areas with rainfall in decile 1, the lowest 10% of historical observations). Localities in decile 2 across central to eastern Queensland, northern New South Wales, and eastern Victoria to southeastern New South Wales will continue to be closely monitored for further developments.
Soil moisture in the lower layer (from 10 cm to 100 cm deep) decreased across much of the eastern mainland States from January into February. Soil moisture for February was below average for the eastern half of Queensland south of the Cape York Peninsula, the eastern half of New South Wales and the Riverina district, and parts of Gippsland in eastern Victoria.
Soil moisture increased across southwest Western Australia following very much above average rainfall during February. Soil moisture for the month was above average for Western Australia, the Northern Territory and South Australia; parts of Victoria in the northwest, southwest and central southern coast and in pockets of the northeast and central north; parts of the Gulf Country and around Birdsville in Queensland; and across most of Tasmania.
- February rainfall below average for much of Queensland, New South Wales, northeastern South Australia, and Tasmania
- Serious to severe rainfall deficiencies are present at the 4-month timescale in greater southeastern Queensland and northern New South Wales
- Soil moisture below average across much of the east of the eastern mainland States
Product code: IDCKGD0AR0
Soil moisture details are reported when there are periods of significant rainfall deficits.
Soil moisture data is from the Bureau's Australian Water Resources Assessment Landscape (AWRA-L) model, developed through the Water Information Research and Development Alliance between the Bureau and CSIRO.
See: Australian Landscape Water Balance.
What is drought?
Drought is a prolonged, abnormally dry period when the amount of available water is insufficient to meet our normal use. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of rainfall deficiencies. Agriculturalists rate the impact on primary industries, hydrologists compare ground water levels, and sociologists define it by social expectations and perceptions.
It is generally difficult to compare one drought to another, since each drought differs in the seasonality, location, spatial extent and duration of the associated rainfall deficiencies. Additionally, each drought is accompanied by varying temperatures and soil moisture deficits.
Rainfall averages, variability and trends
- Average rainfall: How much rain do you expect?
- Rainfall variability: How consistent is rainfall in your area?
- Rainfall history: Check tables, graphs and data from your local weather station.
- Rainfall trends: Has your rainfall changed?
Lowest on record - lowest since at least 1900 when the data analysed begin.
Severe deficiency - rainfalls in the lowest 5% of historical totals.
Serious deficiency - rainfalls in the lowest 10% of historical totals, but not in the lowest 5%.
Very much below average - rainfalls in the lowest 10% of historical totals.
Below average - rainfalls in the lowest 30% of historical totals, but not in the lowest 10%.
Average - rainfalls in the middle 40% of historical totals.
Above average - rainfalls in the highest 30% of historical totals, but not in the highest 10%.
Very much above average - rainfalls in the highest 10% of historical totals.
For the week to 28 March 2017 rainfall was recorded in northern, central and southern Western Australia, the northern half of the Northern Territory, northern and eastern Queensland, eastern and southern New South Wales, most of Victoria, and most of Tasmania.
At the beginning of the week an active monsoon trough extended across the far north of Australia, linking to a tropical low in the north Coral Sea. Meanwhile a tropical low off the northwest coast moved towards the Pilbara coast.
Troughs and broad areas of low pressure dominated much of the continent during the first part of the week. A coastal trough located off southeast Queensland produced moderate falls along the east coast and central interior of Queensland, with heavy falls reported about the Capricornia coast. A surface trough and a low pressure centre deepened and tracked eastwards over southeastern Australia, producing moderate falls in Victoria, southern and eastern New South Wales, and parts of Tasmania.
In the west a cloudband, associated with the tropical low, extended from the northwest to a low pressure centre near the south coast. Moderate to heavy falls were recorded in the Pilbara, the eastern Gascoyne, the Goldfields, and the South West Land Division. Moderate to locally heavy falls continued for several days from the Pilbara, through central Western Australia to the Eucla coast as the remnants of the tropical low progressed southward.
Another tropical low in the northern Coral Sea moved slowly west towards northern Queensland coast, intensifying to tropical cyclone strength by mid-week. Debbie was upgraded to severe tropical cyclone (category 4) before making landfall near Proserpine around midday on 28 March. Debbie brought heavy rainfall to a large area of central Queensland coastal areas during the day leading up to landfall.
During the week, an active monsoon trough across northern Australia also produced moderate falls in the Kimberley, parts of the Top End and the Cape York Peninsula.
The highest weekly total was 630 mm at Plane Creek Sugar Mill in the central coast of Queensland. Rainfall totals in excess of 200 mm were recorded along the east Queensland coast between Bowen and Gladstone, and around Port Hedland on the Pilbara coast of Western Australia.
Rainfall totals between 100 mm and 200 mm were recorded in the Pilbara and Goldfields districts in Western Australia, the Cape York Peninsula, between Ayr and to about Bundaberg on the east coast of Queensland, and some locations in central New South Wales.
Rainfall totals between 50 mm and 100 mm were recorded in parts of the Kimberley, in a broad area across the Pilbara, Gascoyne and Goldfields districts in Western Australia, and in isolated pockets of the southwest; parts of the Top End; across the Cape York Peninsula and along much of the east coast of Queensland; in northeastern and central New South Wales, and isolated pockets of Victoria
Rainfall totals between 10 mm and 50 mm were recorded in northern, central and southern Western Australia; the Top End and an area of the southern interior of the Northern Territory; northern and eastern Queensland; the eastern half and southern parts of New South Wales; southern, eastern and northern Victoria, and larges parts of Tasmania.
Little or no rainfall was recorded in remaining parts of Western Australia, all of South Australia, the southern half of the Northern Territory, western Queensland, and western and inland northern New South Wales.
Impact of recent rainfall on deficits
The Drought Statement, issued on 6 March 2017, discusses rainfall deficits over Australia for the 4-month period (November 2016–February 2017). The rainfall deficit map is 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 for the 4-month period ending 28 March 2017.
Rainfall for the period 1 November 2016 to 28 March 2017
Rainfall deficiencies for the 4-month period (November 2016–February 2017) emerged in southeastern Queensland, extending into Capricornia and the Central Highlands and Maranoa regions; parts of New South Wales in the central north and an area around Kempsey on the northern coast; and a small area of Gippsland in eastern Victoria.
Rainfall across most of the affected areas for the period to 28 March has been 60% to 80% of average.
Rainfall recorded in the past week eased deficiencies in affected areas of southern Queensland and New South Wales.
Product code: IDCKGRWAR0