Welcome to the Climate and Water Outlook for Autumn 2017.
Summer has seen record-breaking heat in eastern Australia, but also record-breaking rainfall
in the north and the southwest.
Above-average temperatures are likely to continue in autumn; and the start of the southern cropping
season is likely to be drier than average.
But first, let's look at recent conditions.
Tropical lows and monsoon bursts have brought widespread rainfall and floods to western
and central Australia.
Southwest Western Australia had its second wettest February on record, with most of that
rain falling in the first two weeks.
While parts of southern WA had a cool start to the year, eastern Australia was very hot,
particularly in New South Wales and southern Queensland.
Moree and Mungindi have had more than 50 days in a row above 35°C.
The second week of February saw eastern Australia’s most severe heatwave since 2009.
On the 11th, the average temperature across all of New South Wales was 44°C. Even coastal
towns didn’t escape the extreme heat.
Fire danger levels during the heatwave were the highest on record in some parts of New
South Wales, with several severe bushfires affecting the State.
Soil moisture has been above average in areas receiving tropical summer rains.
However, in southeast Queensland and northeast New South Wales, there’s been little rain since September.
Combined with very high temperatures, soils have rapidly become drier than average in these regions.
Low rainfall and high temperatures in the eastern States have led to a recent drop in
water storages, but they are still far higher than this time last year.
So what's driving Australia’s climate right now?
In recent weeks, the central and eastern tropical Pacific Ocean has warmed, and climate models
suggest this warming is likely to continue during autumn.
This is in contrast to this time last year, when the Pacific was starting to cool.
Although it’s early days, we can almost certainly rule out a La Niña for 2017.
While our ENSO dial is at inactive, we’ll be watching the Pacific Ocean and the climate
models closely for any further warming.
The rainfall outlook for March–May indicates below-average rainfall is likely over much of Australia.
Several international models we survey also show dry outlooks.
Outlook accuracy is moderate at this time of year.
What does this mean for the 2017 Autumn Break?
Early indications are that these rains could be late.
Turning to the streamflow forecast for February–April 2017.
Median to high streamflows are most likely at 98 locations.
Low flows are likely at 28 locations, mainly in southern Australia.
Accuracy for our streamflow forecasts is moderate to high at this time of year.
In terms of temperatures: Days and nights are likely to be cooler than average in parts
of the far north, but warmer than average over the rest of Australia.
Further heatwaves are possible.
Temperature outlook accuracy is low to moderate at this time of year.
So in summary: Rainfall is likely to be below average for much of Australia; near-median
to high streamflows are likely in most places; temperatures are expected to be warmer than
average; and heatwave and bushfire risks are raised in many areas.
Our next video will be released on Thursday 30 March.
For the Bureau of Meteorology, I’m Robyn Duell.