Issue Notes

ENSO status: Weak La Niña-like conditions.
IOD status: Neutral.
SAM status: Neutral.

The El Niño Southern Oscillation (ENSO) is in a weak La Niña-like pattern. The US declared a La Niña event this summer, but this event has not met the BoM definition, and will likely end in the coming weeks. A La Niña typically increases rainfall over northern and eastern Australia, while reducing rainfall over southern coastal Australia and western Tas.

The Indian Ocean Dipole (IOD) is in a neutral phase and does not play a part in Australia's climate during this time of year.

The Southern Annular Mode (SAM) is in a neutral phase. Forecasts show a tendency towards the positive phase in autumn, with the long-wave pattern indicating that cold fronts are a bit less likely for Australia's longitudes over the next few months. During autumn, a positive SAM increases rainfall over most of eastern Australia, and decreases rainfall for SA, Vic and western Tas.

Rainfall outlooks are showing above average rainfall across much of northern Australia in April due to lingering monsoon activity. Above average rainfall is expected for the NSW coast through autumn, with wetter conditions also developing over western WA from late autumn. SA, Vic and Tas are expected to be average to slightly below average, with average conditions elsewhere.