I decided to look in more detail at Pacific SST in the four Niño ENSO areas and plot more a more detailed weekly graphs of SST and anomalies rather than rely on the monthly values as I’ve done till now. The weekly data is provided by NCEP, and extends back to January 1990. ENSO calculations are complicated and most countries that have an interest have different approaches for what constitutes an El Niño or a La Niña event. We are at the moment in a weakish El Niño event that started in September of 2018 and which at the moment looks like it’s about to falter.
According to the updated NCEP report of 20th May “El Niño is likely to continue through the Northern Hemisphere summer 2019 (70% chance) and fall (55-60% chance)“. They go on to say “Since early June 2018, near-to-above average SSTs have been present across most of the Pacific Ocean. During February 2019, positive SST anomalies strengthened across most of the equatorial Pacific. In the last month, positive SST anomalies weakened across the eastcentral Pacific Ocean”. The weakening that they mention is the cooling of SST in the Niño area 1+2, that’s the blue line in the graph below, which as you can see has fallen back steeply and is giving zero SST anomalies off the coast of Chile at the moment.