Forecast

Issue Notes - Issued Jan 14

ENSO status: La Niña-like conditions. IOD status: Neutral. SAM status: Negative. Trending slightly negative. The El Niño Southern Oscillation (ENSO) is in a La Niña-like pattern. Recent conditions show some atmosphere-ocean coupling, resulting in the US declaring a La Niña event has started. 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 negative phase. Recent forecasts show negative SAM is more likely to dominate for the remainder of summer, due to the polar vortex taking an unusually long time to recover from the stratospheric warming event in winter 2024. During summer, a negative SAM decreases rainfall over most of southeastern Australia, and increases rainfall for far southwest WA and western Tas. Rainfall outlooks are showing above average rainfall over large parts of the country during summer, with closer to average conditions for the southwest corner of WA, southern SA and Vic, and central parts of Tas.