A GEELONG weatherman has turned up the heat on official forecasts of a dry, warm winter across the region.
Geelong Weather Services director Lindsay Smail doubted the Bureau of Meteorology (BoM) predictions “because of the poor results of such outlooks in the past”.
He said the bureau itself “admitted a very low accuracy level” for Geelong winter rain predictions and its forecast for totals below long-term averages this year had “several problems”.
An El Nino event, predicted for 2015, was never a guarantee of a dry winter in Geelong, Mr Smail said, while warm Indian Ocean temperatures could produce “good falls” over southern Victoria any time of year.
He also questioned the bureau’s choice of historical data, saying the trend in Geelong was toward wetter winters.
“In 1990 the 30-year figure was 132mm and decreasing, by 2014 for the previous 30-years it was 137 mm and rising.
“The point is that no good scientific conclusion can be made on the basis of questionable data.”
Mr Smail also had “misgivings” about the bureau’s prediction of a 65 to 75 per cent chance of above-average winter temperatures.
“The bureau admits moderate historical accuracy for this outlook, hardly confidence-inspiring.”
Mr Smail said the bureau “conveniently ignored” how temperatures readings changed after it moved Geelong’s automatic weather station from a rural setting near Grovedale to urban Breakwater.
“Since 2011, when this move took place, many minimum temperatures have increased over the earlier figures.”
The weather station was now subject to an “urban heat-island effect” from surrounding infrastructure, which produced higher minimum temperatures, Mr Smail said.
Mr Smail writes a monthly weather summary for the Geelong Independent.
