THE CLIMATE KELPIE BLOG: What’s predicted in June?

Posted by BCG on 4th June 2021

Australia’s main climate drivers, the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) remain neutral and will have little influence over Australia’s climate for the next few months. There is, however, large parts of the eastern Indian Ocean with ‘Above Average’ sea surface temperatures and ‘Below Average’ temperatures near the Horn of Africa which could see the formation of a negative IOD later in the year. A negative IOD typically increases the changes of ‘Above Average’ rainfall for southern Australia but with model accuracy improving over winter, forecasters will have a better idea of the likelihood of this occurring in the coming months.  

Our shorter-term climate driver the Southern Annular Mode (SAM) is currently negative and expected to remain this way for the first week of June before heading back up to neutral where it will have less of an influence on our climate. A negative SAM typically increases the rainfall over parts of Western Australia and south-eastern Australia but reduces rainfall for northeast New South Wales, southern Queensland and coastal parts of South Australia.   

The Madden-Julian Oscillation (MJO) is now over the Maritime Continent and is expected to move to the western Pacific region during June. In this position, the MJO can contribute to ‘Below Average’ rainfall across Australia’s north east.

The overall outlook for June to August is for rainfall to be ‘Above Average’ for much of northern, central and eastern Australia, however parts of western Australia are likely to be ‘Below Average’. In terms of temperatures, minimums are likely to be ‘Above Average’ across much of Australia except for the western coastline of Australia where equal chances of ‘Above’ or ‘Below Average’ minimum temperatures are likely. Maximums are likely to be ‘Above Average’ for northern and eastern Australia as well as the far south west of Western Australia however, central Australia has equal chances of maximum temperatures being ‘Above’ or ‘Below Average’ and central Western Australia has an increased chance of ‘Below Average’ maximum temperatures.

Rainfall Roundup

In May, rainfall was ‘Below Average’ for much of Australia except for western parts of Western Australia, south east Queensland, along the coast of southern New South Wales and into Victoria, where rainfall was ‘Above Average’ (Fig. 1). Despite this, rainfall totals over the last 3 months have been ‘Above Average’ for much of New South Wales, central Australia, western and northern parts of Western Australia as well as pockets of Queensland, the Northern Territory and south east Victoria. Unfortunately, some regions are yet to receive decent rain notably north west Victoria, south west New South Wales and south east South Australia where rainfall for the last 3 months has been ‘Below Average’ to ‘Very Much Below Average’ (Fig. 2).

Figure 1. Rainfall deciles for May 2021.
Figure 2. Rainfall deciles for March 2021 to May 2021.

Rainfall Forecast

The BoM’s ACCESS model predicts that rainfall in June is likely to be ‘Above Average’ for much of northern, central and eastern Australia, however ‘Below Average’ rainfall is likely along the west coast of Western Australia, southern Tasmania, and a small pocket in south east Victoria (Fig. 3). For the three-month forecast, June to August, the rainfall forecast closely resembles the outlook for June (Fig. 3). At this time of year accuracy for the three-month forecast is moderate to high for most of Australia except for parts of northern Australia, the far south west of Western Australia and much of the south eastern parts of Australia (Fig. 3). 

Figure 3. Australian rainfall outlook for June to August 2021.

Temperature Roundup

Maximum temperatures in May were ‘Average’ to ‘Above Average’ nationwide (Fig. 4).  Minimum temperatures on the other hand were mainly ‘Above Average’ across much of Western Australia will a few small pockets in the other states and territories (Fig. 5). The rest of Australia was mostly ‘Average’ except for some areas where minimum temperatures were ‘Below Average’, notably through northern Western Australia and the Northern Territory as well as western New South Wales (Fig. 5).

Figure 4. Maximum temperature deciles for May 2021.
Figure 5. Minimum temperature deciles for May 2021.

Temperature Forecast

The BoM’s ACCESS model forecast suggests that over the next three months maximum temperatures are likely to be ‘Above Average’ for northern Australia as well as the south east and far south west of the continent (Fig. 6). For central Australia, there are increased chances of ‘Below Average’ maximum temperatures and this propagates to the central west of Western Australia where ‘Below Average’ maximum temperatures are also likely (Fig. 6).

For minimum temperatures, much of Australia is likely to be ‘Above Average’ for the next three months apart for the far west coast of Australia where there are equal chances of minimum temperatures being ‘Above’ or ‘Below Average’ (Fig. 7).

At this time of year accuracy for the three-month maximum temperature forecast is moderate to high for much of Australia, except for a strip through the Northern Territory, central Queensland and down into the New South Wales north coast where accuracy is low (Fig. 6). For minimum temperatures, accuracy is high for much of Australia unless you are in the south west of Western Australia or select regions of south east Australia where accuracy is low (Fig. 7). 

Figure 6. June to August 2021 maximum temperature outlook.
Figure 7. June to August 2021 minimum temperature outlook.

Climate and Water Outlook Videos

The Bureau of Meteorology releases regular outlook videos, covering all this information. Watch the most recent video below.

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