A weak NiAo condition prevails. The sea surface The sea surface temperature, over the NiAo3.4 region crossed El NiAo thresholds during October through December 2018 and the coupling between ocean and atmosphere has commenced but is currently weak.
The warning trend of sea surface temperature decreased in January 2019 compared with December 2018 (See Figure 1).
Global ENSO forecasting centres indicate the likelihood of El NiAo development during MarchMay2019.
Bureau of Meteorology (BOM), Australia, 19 February 2019: "The chance of El NiAo conditions is likely to be 50 per cent during the southern hemisphere autumn (MarMay 2019)."
Climate Prediction Center/National Centers for Environment Prediction (CPC/NCEP) and International Research Institute for Climate and Society (IRI) of Columbia University, 14 February 2019: "The probability of El NiAo conditions is likely to be 65 per cent during February to April 2019."
World Meteorological Organization (WMO), 26 February 2019: "The chance of an El NiAo event to occur during MarchMay 2019 is estimated to be about 5060%."
The "cyclical tendency" of ENSO allows us to predict its development, sometimes almost a year in advance. However, there are elements in the climate system that introduce randomness and hence reduce, its predictability. These elements seem to be at their peak during spring (MarchApril) in the northern hemisphere during which the ENSO forecast skill dropsoff dramatically than in any other time of the year. This is popularly known as the "Spring predictability barrier." Hence ENSO forecasts should be used with great caution for the period beyond May 2019.
Source: UN Development Programme