Will likely be followed by an at least moderate La Niña in 2019/20.
Not if we are now moving into a new regime of semi-perpetual El Nino/Neutral conditions.
I predicted an El Nino this year when the La Nina did not occur after 2015/2016. This was based on recent science looking at South East Asian Aerosol impacts on surface wind patterns in Nino 3/4 regions. I observed the rapid reduction in coal consumption in China that year and thought that it was due to an aggressive shift toward reducing air pollution.
In reality, the reduction in coal reports came from an increase in the washing of coal, a way to increase energy efficiency of processes, with no real net change in total consumption (just less reported deliveries with better combustion of the total mass delivered to sites).
While China is working to reduce air pollution, they are not working on it as aggressively as I had thought. They will continue but won't achieve significant (35% or better) SO2 emissions reductions for another 5-6 years, unless we have another global economic shock.
The fact that we are seeing these impacts toward a shift to perpetual El Nino/Neutral conditions already shows that the impacts of SO2 in Asia on ENSO is much greater than even the most recent published science (based on models and some early - circa 2014-2016 observations are showing).