The Bureau of Meteorology’s (BoM) ENSO Outlook has been raised to La Niña ALERT. This is due to both renewed cooling in the tropical Pacific Ocean as well as climate models indicating La Niña is likely during the austral spring and early summer. Historically, when La Niña ALERT criteria have been met, La Niña has subsequently developed around 70% of the time; this is approximately triple the normal likelihood.
Four of seven climate models surveyed by the Bureau suggest La Niña could return by early-to-mid spring. The remaining three models maintain a neutral, though cooler than average, outlook for central Pacific sea surface temperatures for the remainder of 2022. If realised, it would be the first time on record there have been three consecutive La Niña events coinciding with back-toback negative Indian Ocean Dipole (IOD) years. All surveyed climate models indicate that negative IOD conditions are likely to continue into late spring. A negative IOD event is typically associated with above average winter–spring rainfall for much of Australia.