WINTER is likely to be wetter than average across most of Western Australia, except for the South West where there is no strong push towards wetter or drier than average conditions.
The latest prediction is from the Bureau of Meteorology's (BoM) 2020 winter outlook, with most of the country showing an increased likelihood of wetter than average conditions in the coming three months.
BoM manager of long-range forecasting Andrew Watkins said the outlook was being largely driven by warmer than average ocean temperatures off north west WA, as well as warm ocean temperatures in the western Pacific.
"Ocean temperatures in the eastern Indian Ocean are currently warmer than normal, and our models are predicting they will warm further throughout the winter months," Dr Watkins said.
"When warm sea surface temperatures occur closer to Australia, weather patterns shift towards us too, favouring more cloud and rainfall across the country.
"We last saw this happen in 2016, when a strong negative Indian Ocean Dipole formed to the west of Australia."
While the same results from 2016 aren't guaranteed, the warmer ocean temperatures surrounding the continent will push in the direction of better than average rainfall.
In WA, winter daytime temperatures are likely to be cooler than average across most of the State, but there will be warmer than average in parts of the north.
"Much of the State is looking at average to below average temperatures, particularly in those areas where we expect to see higher than average rainfall," Dr Watkins said.
"So the days are cooler than average, but nights are looking warmer for much of the State as we're expecting a bit more cloud cover over WA which should keep things warmer at night."
Autumn temperatures were above average over most areas and it is likely to be one of the top 10 warmest autumns on record for WA as a whole.
"For much of the State, autumn was drier than average, with the exception of the Pilbara which saw the remnants of a tropical cyclone bring some good rainfall," Dr Watkins said.
"In the South West we're still seeing weather systems which could bring a little more rain before the end of the season.
"In terms of temperatures it generally has been warmer than average for much of the State and we saw some very high temperatures earlier in the autumn, particularly in the North West."
