Rainfall deficiencies ease in Queensland but persist in other areas
Rainfall for March was very much above average across much of northern and eastern Queensland into southern parts of the Northern Territory, as well as much of Tasmania. A small area centred on the Mid North Coast of New South Wales also saw above average rainfall. Below average rainfall was recorded across much of the rest of southern Australia, with some areas of very much below average, decile 1 (lowest 10%), rainfall.
Compared to the previous Drought Statement, deficiencies have decreased in inland and western Queensland, and slightly decreased on the east coast of New South Wales between the Manning and Illawarra districts.
Much of the rain in Queensland was from a low at the start of the month, or tropical cyclone Nora toward the end of the month. These both brought heavy rainfall and caused flooding, but did help to ease longer-term rainfall deficiencies. The Weekly Rainfall Update provides commentary on the effect of recent rainfall on rainfall deficiencies each week.
Recent rainfall in Queensland has also decreased rainfall deficiencies in western Queensland that were reported in the previous Drought Statement for the 9 months starting in June 2017. Deficiencies for that period now largely resemble those for the 12 months starting in April 2017. There has been some expansion of deficiencies in South Australia due to the dry start to the year across the region, and this will now be monitored closely at shorter timescales as the southern wet season begins.
It has been a very dry start to the year across much of mainland southeastern Australia. The January to March period was the driest first quarter of the year for New South Wales as a whole since 1986. Areas of rainfall deficiency are present at this 3-month period across large areas of northwestern Victoria into southeastern South Australia and some central and western parts of New South Wales, with some areas having less than 25 mm of rainfall over the last three months. Whilst these deficiencies are at a climatologically drier time of the year for this region, the Bureau of Meteorology will monitor the situation closely for any further deficiencies as the southern cropping season begins.
12-month rainfall deficiencies
Above average March rainfall decreased rainfall deficiencies in inland and western Queensland, and slightly decreased rainfall deficiencies on the east coast of New South Wales between the Manning and Illawarra districts.
Serious to severe rainfall deficiencies remain across large areas of western to central and southern Queensland; in an area of eastern New South Wales affecting the Illawarra, Central Tablelands, Sydney, and Hunter regions; and in scattered pockets of northern and western New South Wales. Serious or severe deficiencies are also observed across the Flinders Ranges in South Australia, and a small area in eastern Victoria. Rainfall deficiencies remain generally similar along the west coast of Western Australia, but continue to develop along the coast of the South West Land Division with serious rainfall deficiencies in small scattered areas across the southwest.
Soil moisture in the lower layer (from 10 cm to 100 cm deep) for March increased over much of Queensland and Tasmania, and decreased over inland New South Wales and northwestern Victoria.
Soil moisture was above average across much of Western Australia, excluding western coastal areas, areas of the east and north of the Northern Territory, and much of Queensland, especially in the north.
Lower-layer soil moisture was below average for most of most of New South Wales (especially central and western regions), Victoria (especially in the northwest and most of Gippsland), southeastern South Australia, and western coastal areas of Western Australia.
- March rainfall was below average for large areas of southern mainland Australia
- Rainfall was above average for large parts of Queensland (particularly in the north), and much of Tasmania
- Rainfall deficiencies have decreased across western Queensland at the 12-month timescale, due to above average March rainfall
- Deficiencies persist with little change along the west coast of Western Australia and in eastern New South Wales at the 12-month timescale
- A very dry start to the year across much of mainland southeastern Australia
- Lower-layer soil moisture was below average for March across much of southeastern Australia
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 24 April 2018, rainfall was recorded in the northern Top End of the Northern Territory, along the east coast and across southern and southeastern Queensland, northeastern to central coast New South Wales, and southwest Western Australia.
At the beginning of the week, a moist onshore flow brought showers to the east coast of Queensland and northeastern New South Wales. Showers and isolated storms were triggered along a surface trough extending from the base of the Top End, across to the Gulf Country, and through inland to southeastern Queensland. Thunderstorms developed about the Top End and produced moderate falls in the Darwin–Daly District.
In the middle of the week, the inland surface trough extended from central Queensland to central New South Wales while a surface trough developed off the coast of New South Wales. These systems produced widespread showers and storms with moderate falls recorded over inland southern Queensland, and from the northeastern to central coast New South Wales. Further showers and moderate falls were recorded over southeastern Queensland and northeastern New South Wales as the onshore showers continued for the remainder of the week.
At the end of the week, a northwesterly flow affected the southwest of Western Australia as a cold front tracked across the southern coast of the State. A cloudband extending through central and southern Western Australia produced moderate to locally heavy falls in the State's southwest.
Rainfall totals in excess of 50 mm were recorded in the Northern Rivers District on the New South Wales coast and parts of the coast in southeastern Queensland, and isolated locations in the Darwin–Daly District in the Northern Territory, and southwest Western Australia.
Rainfall totals between 15 mm to 50 mm were observed in in South West Western Australia; across central to northern coast and inland north of New South Wales; southern inland and southeastern Queensland; and in the northern Top End of the Northern Territory.
Weekly totals of up to 10 mm were also recorded in part of southeastern New South Wales, western Tasmania, and about the coast of South Australia and the southern Gulf Coast in the Northern Territory.
Little or no rainfall was recorded in Western Australia away from the southwest, most of South Australia, Victoria and Tasmania, western and most of southern New South Wales, western and northern Queensland, and the Northern Territory excluding the northern Top End.
Impact of recent rainfall on deficits
The Drought Statement, issued on 5 April 2018, discusses rainfall deficits over Australia for the 12-month (April 2017–March 2018) period. Rainfall deficit maps are available for these periods as well as for standard periods.
The maps below show the percentage of mean rainfall that has been received for the rainfall deficit period for the 12-month periods ending 23 April 2018.
Rainfall for the period 1 April to 23 April 2018
Serious to severe deficiencies for the 12-month period affect areas of western, southern inland and central Queensland; an area of eastern New South Wales affecting the Illawarra, Central Tablelands, Sydney and Hunter regions; and in scattered pockets of northern and western New South Wales. Serious to severe deficiencies are present across the Flinders Ranges in South Australia, and a small area of coastal eastern Victoria. Deficiencies also persist along the west coast of Western Australia.
Rainfall in the last week made little difference to deficiencies in affected areas. Affected areas of Queensland and New South Wales have received between 30% to 60% of average rainfall for the period. Affected areas in Western Australia have received less than 40% of average, with some areas receiving less than 20% of average for the period.
Product code: IDCKGRWAR0