Paul at Vencore Weather notes the ENSO forecast models and the data seem to be in alignment
Overview
Earlier this year, there were signs that a weak El Nino in the tropical Pacific Ocean could continue through the fall and even into the upcoming winter season, but there is now substantial agreement amongst numerous computer forecast models that La Nina conditions are likely to become established over the next couple of months and current observations back this notion. La Nina is a naturally occurring oceanic cycle that produces colder-than-normal sea surface temperatures (SSTs) in the equatorial Pacific Ocean whereas El Nino is associated with warmer-than-normal SSTs. The formation of La Nina in the tropical Pacific Ocean will likely have important ramifications around the world including significant impacts on the upcoming winter season, next summer’s tropical season, and global temperatures.
Computer model forecasts support the formation of La Nina
Numerous independently-made computer forecast models depict a change from the current near-neutral conditions in the tropical Pacific Ocean to La Nina conditions by the winter of 2017-2018. The plume of model El Nino Southern Oscillation (ENSO) model forecasts from mid-September indicate a transition to La Nina conditions are quite likely to take hold by later this fall. Indeed, some models are predicting a fairly strong La Nina by the middle of the upcoming winter season with sea surface temperatures as much as 1.5°C below-normal in the “Nino 3.4” region (central tropical Pacific).
Sea surface temperatures have indeed changed dramatically in the tropical Pacific Ocean between the spring and today with a “wavy” pattern of colder-than-normal water (bottom panel, blue region) now showing up in the same area that exhibited widespread warmer-than-normal SSTs back in April 2017 (top panel, yellow/orange region).
Read more here at Vencore Weather
As WUWT readers know, a large La Niña will likely bring global temperatures down, but it also suggests a dry water year for the west coast of the United States.
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I’d say there has been La Nina conditions since middle August. I don’t really care about NOAA’s arbitrary boxes and limits by which they define La Nina/El Nino conditions, I’m interested in the processes leading up to and during these events.
http://www.pmel.noaa.gov/tao/jsdisplay/plots/gif/sst_wind_anom_5day_jsd.gif
The tradewinds have on average been strong since the beginning of August, and at times very strong in the central and western Pacific, speeding up the equatorial undercurrent.
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/anim/wkxzteq_anm.gif
So now there is an impressive pool of cooler water in the EUC. This La Nina formation is little ahead of where it was last year at this time which developed into a weak La Nina.
Not a problem , thanks to the ‘heads you lose ,tail I win ‘nature of climate ‘doom’ cooling is also ‘proof ‘ that AGW is true .
A good La Nina indicator: Keep track of the price of mahi mahi filets in your local supermarket. Falling prices indicate the onset of La Nina conditions off the West coast of South America.
The Peruvian anchovies are showing healthy numbers and juvenile recruitment.
This indicates robust upwelling off Peru, evidence of La Nina like conditions.
https://www.undercurrentnews.com/2017/09/29/second-peruvian-anchovy-season-on-track-for-november-start/
A short and intense La Nina, while temporarily lowering SSTs, will have the end result of raising global temperatures since it is the power stroke of the ENSO pump, pushing warm equatorial water poleward, leading to potentially a global up-step in temperature such as occurred in 1999-2000.
By contrast, mild but prolonged La Nina like conditions can set the stage for globally static or declining temperatures, with a decrease in heat energy delivered both to atmosphere and high latitude oceans.
It also impacts upon cloudiness allowing solar insolation to recharge ocean temperatures.
In the BOM ENSO round-up skies have been quite blue recently (oddly in this graph below-line blue means more cloudy and above-line yellow means less cloud, blue sky:
http://www.bom.gov.au/climate/enso/wrap-up/archive/20170926.cloudiness.png
However those cloudless skies have not been warming the equatorial water that much:
http://www.bom.gov.au/climate/enso/wrap-up/archive/20170926.sub_surface_anom.png
Model projections should be taken with a pinch of salt.
I regularly look at the ENSO meter on the side bar. For the last couple of weeks, it has been close to the -0.5 anomaly, but recently it is back to very nearly neutral.
We will have to wait and see whether a La Nina develops. If it does develop late 2017/early 2018, due to lags, it is unlikely that this will be picked up by the satellite data set until April to June. The satellite is always less sensitive to La Nina than it is to El Nino, so unless the La Nina is very deep and/or unless it lingers for a long time, the pause is unlikely to reappear, at least not for some time.
The interesting question is whether La Nina conditions will impact before AR6 comes to be written. If it does, it will make the writing of AR6 difficult, if not, with the pause buster paper, AR6 will be a walk in the park due to the strong 2015/16 El Nino which very nearly turned out to be a double El Nino.
Richard
The range of ENSO model predictions in Anthony’s article above means that practically any outcome is covered!
I’ve argued since before the El Nino peaked, the volume of hot water seemed insufficient to sustain it for long. The El Nino itself was a peculiar one with fits and starts from 2015 and world temperatures were possibly as much warmed by the so called persistent “hot blobs” in the NH Pacific.
The LA Nina development has also been similarly peculiar with replacement of the hot blobs with cold ones. Instead of upwelling of cold water in the eastern equatorial Pacific being the main developer, cold water was slanting equatorward from the cold Blobs in both the NH and SH. This established a cold anomaly in the ENSO region before upwelling which is now getting underway. I didn’t seem to catch anyone’s interest with all this. I believe my analysis will eventually be formalized. It’s a mistake to not pick up on unexpected changes in patterns by experts.
I have accordingly been forecasting a very cold winter in the NH With La Nina and the cold Blobs and firm re-establishment and growth of the Pause period with declining temperatures. The settled science is about to experience some very unsettling developments.
Ps I also forecasted strong regrowth in ice extent and thickness at both poles. I believe this is a turnaround of major proportions. I suppose I’ll have to write this all again, though to catch someone’s interest
Gary
The recent “El Nino” was of the Mokodi variety meaning that it did not strongly engage the Bjerknes feedback, such that the mutual reinforcement of trade winds and Peruvian upwelling was not fully interrupted. The trades never really stopped, let alone reversed (as in 1997-1999, 1982-1983 etc.) and the Peruvian upwelling was not cut off – as shown by the persistent strength of the Peruvian anchovy fishery resisting all politically influenced warnings of a 1982-like crash. This difference between (politically influenced) doom forecasts and what actually happened was quite disruptive of the anchovy fishery and associated fishmeal global market leading to at least one company bankruptcy. CAGW distortion is spreading a baleful influence into more and more areas of economy and society.
Since it wasn’t a “real” el Nino, the following La Nina will also not be strong and full blown as in 1999-2000. This means no warming pulse of heated water being pushed poleward. Remember as Bob Tisdale often reminded us – a big La Nina spells warming in the long run.