According to the Bureau of Meteorology latest ENSO Outlook, the current neutral El Niño–Southern Oscillation (ENSO) has been raised to an El Niño ALERT. The chance of El Niño developing in 2019 has increased to approximately 70%, around triple the normal likelihood.
The latest WMO Climate Applications and Services El Niño/La Niña Update says, "the Sea surface temperatures in the east-central tropical Pacific were at or slightly below El Niño thresholds in January and February 2019, after maintaining weak El Niño levels during the last quarter of 2018. However, very few atmospheric indicators responded to the warmer than average sea surface temperatures until late January and February, when some finally reached weak El Niño levels in the central Pacific. Around two thirds of the models from WMO Global Producing Centres of Long Range Forecasts predict ocean temperatures to again reach weak El Niño levels during the second quarter of 2019. Given current conditions and model outlooks, the chance of an El Niño event to occur during March–May 2019 is estimated to be about 50–60%. The chance for a strong El Niño is low. The outlook for the second half of 2019 is currently uncertain. National Meteorological and Hydrological Services will continue to closely monitor changes in the state of ENSO over the coming months."
In Australia, El Niño typically cause reduced rainfall, warmer temperatures and shift on the extremes, reduced tropical cyclones and delay on monsoon onset.
For more information on the BoM ENSO Wrap-Up: http://www.bom.gov.au/climate/enso/