ENSO 2017/18

If you're wondering what are the effects of La Nina on the globe? Here's the chart for the Summer months showing a typical La Nina's global weather/climate impacts but remember that no ENSO event, including El Ninos, is the same.

SST anomalies in the ENSO region have ever so slightly warmed up a bit within the past week but not a huge rise in temperatures. However, what I can notice going by the anomalies here on this chart is that the coldest of the anomalies are going more towards the central part of the ENSO region rather than just off the Peruvian coast. This would foreshadow the signs of a central based La Nina, or La Nina Modoki. There hasn't been as much research done on La Nina Modoki events as there has been done on El Nino Modoki events (such as 2009/10). El Nino Modoki is basically the same as La Nina Modoki by the way, just that the anomalies are warm than cold. This is the only source I can really find information on for La Nina Modoki: https://www.graincentral.com/weather/are-we-heading-for-a-la-nina-modoki/

The source does not show much for us here in Ireland as ENSO's influence on Ireland and Europe is very variable and has plenty of different situations, depending on the event and the strength of it. Going by a reanalysis I did previously which showcased Weak La Nina Winters that were preceded by Weak La Nina Winters, a Weak La Nina is very good for 2017/18 but my question this week is, going by the current SST anomalies, what does La Nina Modoki hold for us? Is it good for cold Winters as much as El Nino Modoki? We'll have to see.



The CFSv2 continues to show a Weak La Nina event for 2017/18 but it has totally gotten rid of the chances of a Moderate La Nina taking place.


The JAMSTEC meanwhile is going for a borderline ENSO neutral to Weak La Nina.

http://www.jamstec.go.jp/frcgc/research/d1/iod/2007/forecast/ssta.nino3.4.fcst.1oct2017.gif

NOAA has officially said La Nina conditions for 2017/18.

EDIT: Sorry for the confusion.

https://twitter.com/ClimateRealists/status/932581492789862400

No change in the Pacific in the past two weeks. La Nina is still firmly in charge.

Small update, the Pacific is still well and truly in a La Nina setup for its SST anomalies. I'd also like to pin point, though this is an ENSO thread, the cold SSTs around the Gulf of Mexico.

nacho libre wrote: »

I have read the nina forcing will stop the MJO going to phase 8- which is apparently the ideal state for a high latitude block to occur
However, M.T Cranium's good friend Joe Bastardi has suggested it will go to phase 8 and as a consequence he envisions a cold outbreak over Europe. A lot of the teleconnection experts dismiss this and they deride Bastardi as a biased cold ramper.

Although, some of the later frames of the GFS output are starting to show the continent going cold. So perhaps Joe Bastardi might be on the right track.

I have no clue on the MJO but here's what I've found regarding it in the next few weeks.

MJO is heading/with speed towards east towards WESTERN PACIFIC phase 7 with off the chart amplitude , strong active amplitude. Dynamical/statistical models strongly support continued MJO activity, with enhanced phase propagating from Maritime Continent to West Pacific.
February.

This will for sure interfere in La Nina state bases , interfere + will have great impacts also for Northern Hemisphere continents sensible weather patterns !

I read somewhere - I think it was from somebody like Joe Bastardi or Michael Ventrice - that La Nina has reached its peak now and it will weaken significantly through February.

The cold SSTs that was down towards Chile and Antarctica seem to have ascended further northwards in the Pacific to form quite a cold blob in the ENSO regions.

The ENSO figure for November-December-January was -1.0 which is the third tri-monthly period that the region has successfully reached the La Nina threshold. Two more tri-monthly periods at or below -0.5c and an official La Nina is designated.

It seems the high ridging into the eastern seaboard is evident of La Ninas for the month of February.

https://twitter.com/weatherchannel/status/963183322913476609

A pool of warm water has formed to the east of the equatorial Pacific which will put a damper on the weak La Nina. The latest ENSO 3.4 anomaly is -1.1c below average which shows the Pacific is still within the La Nina signature or threshold. Increasing chances of ENSO neutral forming during Spring 2018 but still quite low at this stage, around 50-60% likely. It seems Dec-Jan-Feb's ENSO 3.4 anomaly will be within the La Nina threshold which means that we need one more tri-monthly period of equatorial Pacific SSTs to be at least -0.5c below average for a weak La Nina to be officially designated. In my opinion, this is a highly likely occurrence.



http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Latest El Nino 3.4 anomaly is -0.7 which is within the weak La Nina threshold and I think we can say for certain now that 2017-18 was an official weak La Nina. We only have one week to go and it would take over a +2.0 anomaly to make it not a La Nina approximately, we all know that's impossible to do within over the space of a week. To think how it looked like we were going into an El Nino back in June 2017 was crazy then it completely flipped around in July. This is one of the latest developed ENSO events I've seen on record, even the incredibly weak La Nina of 2016-17 had developed in the Summer season and it ended on the last tri-monthly period (Oct-Nov-Dec) of 2016.

The latest NOAA SST chart on the 22nd March shows the ENSO region still firmly in a weak La Nina setup with the warm pool of SSTs that had been developing over to the eastern side of the equatorial Pacific in February continues to be an absence since the last update I gave here in the thread above.



However, if we look at the subsurface temperature anomalies, we can see quite an extensive and extreme warm pool developing just over to the western side of the equatorial Pacific. But if you look at the sea surface temperature anomaly chart above, that's where the coldest temperature anomalies are tending to be, they're like opposites of each other here. Usually, it takes a few weeks for the subsurface temperature anomalies to have an impact on the sea surface temperature anomalies so we should be seeing some warming of the equatorial Pacific soon.

Just remember one thng though that we're in the Spring unpredictability barrier which means it is literally impossible to say where ENSO will go in 2018-19. As we've seen from 2017, this barrier can sometimes carry on into the Summer too.



http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Just for what it's worth, here's what the CFSv2 is showing though it's only just predicting this given the current situation in the equatorial Pacific. If you cast your mind back to this time last year, many of its ensemble members were going towards a strong or perhaps even very strong El Nino. The model sees us gradually going towards ENSO neutral in Autumn 2018.

The Jan-Feb-Mar ENSO figure is now in and NOAA has officially designated the weak La Nina for 2017/18. I'd like to note the similarities to 1995/96 which also had a weak La Nina, a mild January, a cold February, a delayed Spring including a cold and wet March and the coldest May on record. Not to mention, 1995/96 was part of the Winter 2017/18 analogues! Very intriguing, I will discuss this more in the Summer thread since this is the ENSO thread.