Forecast

Issue Notes - Issued Feb 25

ENSO status: La Niña-like conditions. IOD status: Neutral. SAM status: Positive. Trending neutral. The El Niño Southern Oscillation (ENSO) is in a La Niña-like pattern. The US declaring a La Niña event has started, but this event has not met the BoM definition. 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 short positive phase. Recent forecasts no particular evidence towards a positive or negative phase in autumn, although the long-wave pattern indicates that cold fronts are a bit more likely for Australia's longitudes over the next few months. During summer and early autumn, a positive SAM increases rainfall over most of eastern Australia, and decreases rainfall for SA, Vic and western Tas. Rainfall outlooks are showing aboveaverage rainfall over large parts of northern Australia in March and early April (forecast late 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.