Welcome to the Climate and Water Outlook for autumn 2016.
El Niño and the warm Indian Ocean continue to dominate our climate.
Northern Australia has had a poor wet season so far, and unfortunately the outlook is continuing
dry.
In the south, odds have risen for above-average autumn rainfall.
First, let's look at recent conditions.
Summer has seen mixed rainfall across the country.
In the north, a short-lived monsoonal burst arrived in mid-December.
In January, the monsoon switched off, while southern Australia received most of its summer
rainfall.
However, February has been unusually dry for most of the country, with the northern monsoon
yet to return.
While some of the driest areas in Queensland received welcome rains over summer, this hasn’t
broken the drought.
Severe deficiencies persist in parts of Queensland and all southeastern States.
For example, Longreach has now missed out on nearly 18 months of normal rainfall in
the past three years.
Australia’s first cyclone this season—tropical cyclone Stan—crossed the WA coast on the
last day of January.
This was the second-latest start to our cyclone season in nearly 50 years of records.
Severe tropical cyclone Winston in Fiji—one of the strongest cyclones ever in the southern
hemisphere—is a reminder that we’re still in cyclone season.
Keep an eye on our website for the latest cyclone forecasts and warnings.
Turning to temperature, summer has again been warmer than average.
Southern Australia has experienced several short, sharp heat events.
Western Australia suffered through a prolonged heatwave in early February, including four
days in a row over 40 degrees in Perth, equalling the record set in 1933.
In fact, on 11 February, nine of the top ten hottest spots in the world were all in Western
Australia.
Because of the hot summer and low rainfall since late winter, streamflows have been lower
than usual.
For instance, the iconic Darling River has stopped flowing at Wilcannia and places further
north.
Water storages in the Murray–Darling Basin are now only 39 per cent full—their lowest
since the end of the Millennium drought in 2010.
Many other storages have declined for several months, and are now at lower levels than at
this time last year.
Lower-layer soil moisture also remains below average in parts of southeastern Australia.
Our new Landscape Water Balance website provides detailed soil moisture information for your
location.
So what's driving Australia’s climate right now?
The southern Indian Ocean is still at record-warm levels, and sea surface temperatures to our
north have flipped from cooler to warmer than normal.
These two factors help to feed moist tropical air across southern Australia.
While El Niño is still a drying influence, the good news is that it's declining in the
Pacific Ocean.
For instance, the trade winds—which typically become light during El Niño—have recently
been their strongest in nearly two years.
Looking ahead, all eight of the climate models we survey predict that El Niño will end in
the second quarter of this year.
So what’s the outlook for autumn 2016?
Odds favour above-average rainfall for much of southern Australia, consistent with a typical
El Niño breakdown.
However, the northern wet season is likely to finish below average.
Our rainfall outlook has low to moderate accuracy at this time of year.
Turning to the streamflow forecast for February to April:
Low flows are more likely at 52 locations.
Thirty-two sites have near-median flows forecast, with high flows at 21.
Accuracy for these streamflow forecasts at this time of year is high.
Temperature outlooks show warmer-than-average days and nights for much of Australia.
Accuracy for this outlook is moderate at this time of year.
In summary:
El Niño is slowly declining.
Odds favour above-average rainfall for southern Australia, but a drier and warmer finish to
the northern wet season.
Streamflows are expected to remain low in many areas.
For more details, head to our website at bom.gov.au/climate/ahead.
You can also follow us on Facebook and Twitter.
Our next video will be released on Thursday 24 March.
For the Bureau of Meteorology, I’m Andrew Watkins.