Summary
The progress towards an El Niño event this year has slowed over the past two months, as a consistent pattern of Pacific wind and cloud signatures has failed to materialise, and the Southern Oscillation Index (SOI) is only weakly negative. Furthermore, there is no example in the historical record of an El Niño developing this late in the year, and even if one did, summer is the time of year when El Niño-related impacts on Australian rainfall begin to break down. However, central Pacific surface temperatures are persisting at levels characteristic of El Niño, and the situation will continue to be monitored closely.
Surface temperatures in the western to central Pacific have hovered near El Niño thresholds for about three months now, but subsurface temperatures are below the levels normally associated with El Niño. Over the past two months warm subsurface waters in the far east have caused about a 1 to 1.5 degree rise in far eastern Pacific surface temperatures.
The Trade Winds continue to fluctuate across the tropical Pacific, although they have generally been weaker than average over the central to eastern Pacific during November. However, the response in surface temperatures has been negligible with virtually no change in the NINO3, 3.4 or 4 indices since late October. The past four to six months has seen a sequence of westerly wind bursts (WWB), each one of which has resulted in a temporary decline in the strength of the Trades. There has been no persistent and significant decline in the Trade Winds as normally occurs during an El Niño event.
Cloudiness in the central Pacific has oscillated between above and below average values since May, mostly as a result of the sequence of WWBs. This indicates that the atmosphere is yet to respond in a consistent fashion to the above average sea surface temperatures in this region. A sustained period of above average cloudiness would be expected during an El Niño. Cloudiness near the dateline was close to average during the past week.
It seems like the weak el nino has peaked or getting pretty close and not go more stronger as the recent update and data shows where the +1.5 C temp at el nino 3-4 area has stabilized for the past 3 weeks.Meanwhile 0.0C temps and -0.5 C are at el nino 1-2 area.
