The Bureau of Meteorology (BOM) has released its Winter Outlook for 2018, predicting warmer and drier than normal conditions for large parts of Australia.
In its 2018 Winter Outlook, the Bureau said its forecast followed one of Australia’s warmest autumns on record and the nation’s second-warmest summer on record.
“Southern mainland Australia has also had one of its driest autumns on record,” the Bureau said.
It said winter rainfall was likely to be below average for NSW, South Australia, northern Victoria and western parts of Western Australia.
Climatologist at the Bureau, Jonathan Pollock said the shift towards drier conditions was particularly strong for areas in the Murray–Darling Basin and eastern NSW, which had a 70–80 per cent chance of below average rainfall.
“Elsewhere around the country, the chances of exceeding average rainfall are roughly 50 per cent,” Mr Pollock said.
“Daytime temperatures across much of the country are likely to be warmer than average, with the greatest chance [more than 80 per cent] in NSW, Victoria and Tasmania.”
He said overnight temperatures were also expected to be above average across the country, except for parts of the tropical north.
Mr Pollock said Australia’s main climate drivers, the El Nino–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) were currently in a neutral phase, meaning there was no strong shift in the outlook towards widespread wetter or drier conditions.
“When ENSO and IOD are neutral, other climate drivers have a greater influence,” he said.
“We’re expecting warmer than normal temperatures in the Tasman Sea this winter and associated lower-than-normal air pressure.”
Mr Pollock said this would mean a weakening of westerly winds over southern Australia that normally drew cold fronts up from the Southern Ocean.
He said snowfall was difficult to predict over long time frames but the dry outlook for June suggested a later than normal start to the snow season.
“However, when ENSO and IOD are neutral, we have historically seen deeper-than-average snow cover by mid-season,” Mr Pollock said.
The Bureau’s winter outlook can be accessed at this PS News link.
