For more than 30 years, since March 1991, prolific weather forecaster Don White has been supplying The Land with a weekly column aimed at farmers who talk to neighbours about when it might happen to rain.
In those earlier days the forecast was manually calculated with a lot of emphasis on upper level wind and temperature patterns gleaned from dozens of weather balloons sent up constantly all across the Australian continent.
With the advent of space perspective satellite imagery in the 1980s forecasters began to use the visual cloud formations as observed from space. In the 1990s when high resolution imagery became freely available through Japanese satellites, the Australian Bureau of Meteorology came to rely more on that tool, than the old fashioned weather balloon - a decision Mr White says was not well considered considering their ability to detect temperature variations and slight changes in wind fields.
"I think it's a shame for the short-term forecaster," he said. "In a country as big as ours there are countless minor upper convergence zones, pools of cold air that forecasters can totally miss unless it occurs over Sydney, Williamtown or Nowra where they still release these balloons and yet each of these locations are almost on top of each other. It used to be that weather stations at Moree, Wagga Wagga and Coffs Harbour would do the same."
Mr White said a remaining station at Cobar was the last one before Giles on Warakurna Station near the WA and NT border, with a lot of space in between.
"Now forecasters might not know these convergence zones have developed until they hit moist air over the eastern states," he said.
Australian weather has always intrigued Mr White, who began recording rainfall where he lived and collected information as printed in the newspaper from the tender age of five. He continued this detailed collation for another 50 years and as a result Mr White became familiar with trends across a wide geographic area.
This interest in the big picture continues to drive his forecasting, which he says talks more about climate drivers and general patterns than specific potential outcomes.
Mr White got himself qualifications in atmospheric physics and plied his trade selling forecasts to film and television crew keen to know if the sun would be out during a future advertising shoot. Energy companies in Queensland were also clients of his business, interested to know how a belt of thunderstorms might play out so that they can get crew on the ground to the right locations. In between these regular gigs he began penning a rural newsletter for farmers.
Modern computing has enabled weather forecasting with a range of modelling available to those who can interpret them. These complex calculations built from data that extends from the bottom of the oceans to the top of the troposphere are processed by supercomputers the size of which would make a gamers' eyes water.
"These are multi-million dollar machines that make an analysis of trends using algorithms," Mr White explains. "There might be a few of the models that remain on track for a while, or not, and then after two to three months another set of models will take over."
The result is incredibly accurate: 90pc true day to day and three days ahead. Beyond four to five days the ability to predict the movement of atmosphere, like steam in a pressure cooker, drops rapidly away. That's because small changes result in very different outcomes.
"A 5-10pc rate of movement of weather can mean the difference by one full day when forecasting one week ahead," he said, noting that some private forecasts purporting to predict 28 days out are "totally useless" and general to the point of reading like an astrology future.
"Anything beyond seven days you might as well throw a dart whereas I tend to be very cautious."
Mr White prefers to write about climate indicators that are affecting our continent at the moment - things like the Madden Julian Oscillation, that can fire up tropical convergence as it sails around the equator, returning every six weeks or so. La Nina and MJO are a mighty combination.
In winter the role of Indian Ocean Dipole is crucial to inland SE Australian rain - but only when the Indian Ocean is warmer closer to the Pilbara coast, allowing for uplift of moisture which blows across the desert to water winter wheat in NSW. Of course there is the Southern Oscillation Index, which correlates well with changing sea surface temperatures patterns in the Pacific to deliver La Nina or El Nino. In the Southern Ocean there is Southern Annual Mode, which changes frequently, and allows storms to come close to Tasmania. Accuracy of SAM is the poorest of all the indicators.
Climate change is the most important long term forecasting challenge and a tricky one, although the boffins have been getting one aspect of it very right from the beginning: There will be more extreme weather in the years to come.
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