Rain marks a break, but not drought ending

Rain marks a break, but not drought ending


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Much of northern Victoria received more than 25mm last week, with the highest totals around the northeast.

Much of northern Victoria received more than 25mm last week, with the highest totals around the northeast.

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Much of northern Victoria received more than 25mm last week, with the highest totals around the northeast.

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Much of northern Victoria received more than 25mm last week, with the highest totals around the northeast. But rain gauges in far western parts of the state collected less than 5mm. So has the autumn break arrived? Is this the end of the drought?

Most of Victoria has now received its autumn break, but far western Victoria is still waiting on their first 25mm accumulation over three days. The timing of the break was close to average for many places.

But most people will be looking for follow up rains soon, as many areas did not have much stored soil moisture coming out of summer.

April root-zone soil moisture was well below average for a large area spanning from the central and north west of the state. However, with last week's rainfall, soil moisture across the north and parts of central western Victoria is now average to above average for this time of year.

But does the good rain mean the end of the drought?

Because people use water in different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of the amount of rainfall that has been missed. Agriculturalists rate the impact on crop or pasture growth, hydrologists look at stream and river flows, dams and ground water levels, while sociologists define it by social impacts - such as less money circulating in the towns and impacts on the mental health of the communities.

For the current dry, four month rainfall deficiencies are severe for most of western and southern Victoria, while 13-month rainfall deficiencies are severe for much of Gippsland.

Unfortunately, the outlook for May indicates widespread above average rainfall is unlikely. Chances of above average rainfall lie between 35 and 45 per cent for most of western Victoria. It wouldn't be a surprise if some sites do record near-average or even slightly above average monthly rainfall, but sadly the odds don't favour that occurring for everyone.

It's encouraging that the dry signal in the outlook doesn't extend beyond May. The three-month May to July outlook shows roughly equal chances of being drier or wetter than average. East Gippsland is the exception, where a drier three months is favoured in the east.

The chance of El Nino developing in 2019 is about 70pc, but climate models indicate any event is likely to be short lived. El Nino typically means below average rainfall for Victoria during winter-spring.

- Jonathan Pollock, BOM climatologist

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