There are growing signs that western NSW could see above average rain in the coming months, with a negative Indian Ocean Dipole pattern gaining strength to the north west of Australia.
In the near term, NSW will experience settled weather during the next few days and nights as a large high pressure system drifts across the state.
This high will cause sunny days and cold, frosty nights, before a weak cold front brings some cloud and brief rain to the state's southern and central inland on Sunday and Monday.
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There are also signs that another front could deliver further showers in southern and possibly central NSW towards the end of next week. However, there is still some uncertainty with next week's weather.
Looking further ahead, most long-range forecast models are tipping above average rain over much of NSW during the rest of winter and spring. This wet outlook is mostly being driven by a developing negative Indian Ocean Dipole (IOD) and the possibility of another La Nina.
The IOD is an index that measures the contrast in sea surface temperatures across the tropical Indian Ocean. This oceanic temperature contrast is important for Australia because it can influence our weather during winter and spring.
A negative IOD occurs when warmer than average sea surface temperatures develop on the eastern side of the tropical Indian Ocean, near Indonesia, while abnormally cool water develops on the western side of the tropical Indian Ocean, near Africa.
This negative IOD pattern causes more moisture to flow towards Australia from the north west, which usually enhances winter-spring rainfall over the nation's south and south east inland.
The IOD has been gradually entering a negative phase during the past couple of months and this trend is likely to persist into spring.
As a result, there is an increased likelihood of above average rainfall in NSW during the rest of winter and spring, especially on and west of the Great Dividing Range.
This developing negative IOD may also enhance the influence of La Nina if this Pacific Ocean climate driver re-emerges later in the year.
According to the Bureau of Meteorology, there is a 50 per cent chance of La Nina during the second half of 2022.
