Summer is just days away and the Bureau of Meteorology’s (BOM) official outlook suggests it’s set to be a summer of contrast. Dry in the west and wet in the east.
“Eastern Australia is tending to still look at above average rainfall unfortunately, for the eastern half of Queensland, New South Wales, much of Victoria and eastern Tasmania as well,” according to Andrew Watkins, head of long range forecasting at the BOM.
“But across in the west, we’re actually looking at an increased chance of below average rainfall across a number of areas.
“Remembering though in southern WA, it’s quite a dry time of the year.”
When it comes to temperatures, they are set to mirror the rain.
“Where we’re expecting it to be reasonably wet and cloudy it’s looking like it’ll be cooler than normal,” he said.
New South Wales, Victoria, parts of Queensland and south-eastern Western Australia are likely to have below average daytime temperatures while the rest of the country is relatively warm.
But cloudy skies are expected to keep overnight temperatures warmer than average for most locations, with the exception of parts of New South Wales and the Nullarbor.
IOD on the way out but La Niña hanging on
The negative Indian Ocean Dipole (IOD), which has been supplying moisture from the north-east over the past few months, is currently in the process of exiting stage left on cue as the monsoon moves down.
But that doesn’t mean the tap is turning off overnight.
“It would be lovely if the oceans changed and immediately the atmosphere changed as well,” Dr Watkins said.
“But look, unfortunately, you do tend to get some lingering effects at the end of an IOD or at the end of La Niña as well.”
The La Niña is currently expected to hang around until early 2023.
“Typically a La Niña would break down in the autumn. This one could break down a little earlier than that, which would be a bit of a relief after three La Niña summers in a row,” he said.
Raised flood risk going into summer
According to Dr Watkins, the current outlooks are suggesting higher odds of above average rainfall during December with the odds easing back a little as we get further into summer.
“To some degree that’s related to the IOD easing, and also the possibility of the La Niña easing a little later in the summer, as well,” he said.
“But unfortunately, the odds aren’t going back to dry conditions. We’re still on the wet side, even though the odds are reducing.”
On top of already saturated conditions.
“As soon as you’ve got wet soils, full rivers and dams that flood risk is going to remain high, regardless of the rainfall patterns.
“We’ve got a landscape set up now to not handle a lot more water. So we just need to be careful with any rain we get.”
Cyclones can also bring their own flood risk.
The overall trend has been towards a reduced number of tropical cyclones in recent decades but La Niña ups the risk.
This season there is a 73 per cent chance of an above average number of tropical cyclones.
Heatwaves, fires and cyclones
With all the recent flooding the focus may be on the rain but it is important to note that it does not mean we are off the hook for heatwaves and fires this year.
There is expected to be less extreme heat days than usual but La Niña’s actually encourages heatwaves with high overnight temperatures and humid conditions.
Likewise, the abundant growth over recent years ups the grassfire risk, especially if we get a stretch of hot dry conditions at the end of summer.
And of course, it has not been nearly as sodden in the west. The official summer bushfire outlook is expected to be out next Tuesday.
Wet out in the paddocks
A potentially wet start to summer is not good news for farmers trying to get a crop off this summer.
Kellie Penfold is a partner in a mixed farming operation at Henty in southern New South Wales.
“It’s probably been one of the most challenging years we’ve had in our 30 years of farming together, my husband and I,” she said.
The relentless rain, cold and storms mean she hasn’t got a break.
“You never should wish for no more rain, but probably no more rain would be quite good for a while, just to let it dry out,” she said.
Her harvest has been delayed but she is still hoping it will go as smoothly, without too much more rain or storms to slow them down.
“It’s going be a challenging harvest regardless just because of the wet paddocks and not being able to get grain trucks out into paddocks because it’s just too boggy,” she said.
Over in the Wimmera, Victoria, Susan Findlay Tickner was hoping for rain heading into spring but she got more than she bargained for.
“It started raining in September, October and November, and it didn’t stop. We’re tracking in about 100 millimetres above our average rainfall,” she said.
She said it has been variable in the Wimmera, with storms and hail decimating some crops but missing the next farm just down the road.
“We’ve lost about 50 per cent of our lentils because they did get wet feet and didn’t do very well,” she said.
“We did abandon our hay because we weren’t seeing a window where it would stop raining for long enough for us to get it bailed.”
But she is still optimistic about her canola.
“Of course, our biggest challenge is not just getting machinery across the paddock, it’s also getting the grain to the silos along on our local road network because our roads have been so badly damaged by the rain.”
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Lovely to see predictions for most of Australia. What happened to the forgotten states, South Australia and Northern Territory. I know we don’t count but it would be nice to be included sometimes.