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Gray-Wolf

E.N.S.O. Discussion

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15 hours ago, Gael_Force said:

AKA Nino killer...??

cdas-sflux_ssta_relative_global_1.png

 

Ha. Just in time for summer. 

Personally i see our current move to weak Nino as more residual due to the lack of Nina rather than ocean driven like 2015 so it is my belief that it's the type of event that could suddenly collapse were the sub-surface to move against us. That said, i don't see a threat right now and so would take those trade surges as intermittent. 

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59231796ce93f_CFSensoMay2017.png.e670de7CFS has all but abandoned Nino. 

Edited by summer blizzard

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A new paper looking at long period central Pacific ENSO trends.

Recent enhancement of central Pacific El Niño variability relative to last eight centuries.

https://www.nature.com/articles/ncomms15386

Discussion highlights.

Taken together, our results suggest that anthropogenic climate change has had a profound effect on SSTs in the CP, whereby anomalous warming over the last decades is accompanied by an increase in interannual variance. NIÑO4 SST values over the last two decades are likely higher than natural variations over the last 818 years, owing to a combination of relatively high CP ENSO activity and a late 20th century warming trend. In light of our results, it seems plausible that the dominance of CP ENSO extremes in the first two decades of the twenty-first century may continue, albeit with some important caveats. First, the global climate impacts of future CP ENSO extremes will critically depend on the evolution of the mean climate state in the tropical Pacific36,37, which itself is poorly constrained at present. Second, the new Taiwan tree δ18O record is the newest addition to growing archive of high-resolution paleo-data sets that can be used to probe the sensitivity of tropical Pacific climate to a variety of external climatic forcings over the recent past. One such example comes from the early- to mid-Holocene, when some models and data suggest that processional insolation forcing may have driven a shift towards greater CP ENSO activity and less East Pacific ENSO activity37. Should the dominance of CP ENSO extremes continue in the coming decades, investigations of the causes, and consequences, of any past shifts towards CP ENSO may provide some clues about future tropical Pacific climate trends and their global impacts.

ncomms15386-f2.jpg

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On 2017-5-29 at 18:18, summer blizzard said:

59231796ce93f_CFSensoMay2017.png.e670de7CFS has all but abandoned Nino. 

Wow so ENSO neutral looking likely again judging by that.

Surely we won't have a similar winter to the last one? Please no!

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On 2017-6-4 at 17:26, CreweCold said:

Wow so ENSO neutral looking likely again judging by that.

Surely we won't have a similar winter to the last one? Please no!

El Nino looks to have lost its way for now.  Hopefully we won't see a winter similar to last year but wouldn't be surprised if we experience another duffer unfortunately.

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With a very different QBO profile there should be notable differences to last winter even if ENSO is in a similar state, but there should in fact be less of a lingering La Nina tendency in the atmospheric circulations so that'll make for two notable differences. Being further away from the solar maximum should also help. 

Whether it will work out nicely for our little slice of the N. Hemisphere, well that's a matter beyond effective resolution at such long range.

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I'd not rule us out headed on the negative side of neutral given that there is no more PDO support. 

In terms of ENSO we've seen the trades finally let up which should feed through into modelling for the second half of June however they are forecast to return.

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Well, we can see below that a westerly surge no doubt contributed to the pressure build in the mid-lattitudes but the pattern since May has been pretty clear, one of fairly dominant easterlies over the Pacific which no doubt are kidding the atmosphere into a Nina like response. I don't see an end to this soon. 

DDFnCR0UAAAC594.jpg:large

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1 hour ago, summer blizzard said:

Well, we can see below that a westerly surge no doubt contributed to the pressure build in the mid-lattitudes but the pattern since May has been pretty clear, one of fairly dominant easterlies over the Pacific which no doubt are kidding the atmosphere into a Nina like response. I don't see an end to this soon. 

DDFnCR0UAAAC594.jpg:large

u.anom.30.5S-5N.gif

There's a little bit of difference between ECM and GFS with respect to those equatorial zonal winds with the latter more varied/less coherent with the easterlies, although admittedly the latter is only an operational run rather than full ensemble - not sure why Ventrice chooses the operational for such a projection but oh well.

The disagreement is small, but enough that I can see why GFS has given the Azores High a little more say across Europe than ECM over the past couple of runs.

That ECM has at least trended toward increased AH influence does give me a little hope but there's still a long way to climb out of the pit of concern.

 

Edited by Singularity

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 ....and 

2cat_20170601_sst_months24_global_deter_

Is there such a thing as a modiki Nina?

16 minutes ago, Singularity said:

not sure why Ventrice chooses the operational for such a projection but oh well.

The WSI image says ECMWF EPS ... surely that's the ensemble means.

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4 hours ago, Gael_Force said:

 ....and 

2cat_20170601_sst_months24_global_deter_

Is there such a thing as a modiki Nina?

The WSI image says ECMWF EPS ... surely that's the ensemble means.

Not heard of such a version of La Nina but looking through historical cases I can see that La Nina events do have a tendency to feature the peak anomalies further west than a classic El Nino is known to.

What we seem to be witnessing is a regional response to the anomalous easterlies which may in turn be reinforcing itself, but only within that area due to a lack of the other supportive mechanisms that are needed to generate a full-scale La Nina event (this being why the models are so hesitant to kick one off even after the recent negative trend).

This regional development is causing a lot of trouble when trying to figure out how the downstream patterns will respond, in particular for us the Atlantic-Euro pattern. Just how coherently can a La Nina-like state be forced when the forcing is coming from a narrower region than seen with La Nina events? If it's very coherently then we're going to struggle to get much of a summer back this side of late July (that being when the wave-guide tends to shift again), but if not then we should tend to see some interludes of, say, a week or two during which the Azores High builds northeast across the UK and Europe with greater strength again, before a week or two the other way again, making for a notably two-faced summer that lurches between fine, dry and very warm/hot and changeable/unsettled with near average/cool temperatures.

Currently we're sliding unpleasantly into the latter and it looks to make my planned hiking holiday in Wales from Friday onward rather precarious at times. The loss of the positive-neutral (as in, neutral but tending a little positive i.e. Nino at times) oceanic state was a tragic turn in the year of 2017 for those seeking a predominantly fine summer in which a break in the UK stood a great chance of being at least half-fine (as in half of the time).

 

Oh - and I was referring to the chart I posted which is from Mike Ventrice's site and shows the GFS operational in isolation.

Edited by Singularity
Remembered Second Question

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With regards to the La Nina wave hanging around it's probably worth saying that the lack of a PDO response was probably a factor in it struggling to get going last year in my opinion. It's probably worth saying that the west coast of the US at least is now looking much more normal. 

anomnight.6.22.2017.gif

 

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22 hours ago, summer blizzard said:

With regards to the La Nina wave hanging around it's probably worth saying that the lack of a PDO response was probably a factor in it struggling to get going last year in my opinion. It's probably worth saying that the west coast of the US at least is now looking much more normal. 

anomnight.6.22.2017.gif

 

pdo_warm_cool3.jpg

We have the section along the western U.S. coast in line with a negative PDO - notice that the negative anomalies are typically weak - but the stretch going west from there to the eastern coasts of Asia is more akin to a positive PDO setup. This is the more significant contributor to the index and as a result it continues to measure positive, albeit not very strongly. 

What's really interesting is that those cold anomalies along that belt are in (perhaps large) part a consequence of the anomalous snow cover across Siberia that built-up over the winter and lasted longer than usual through the spring, which is being linked by an increasing number of studies to the reducing Arctic sea ice and resulting increased moisture availability across the high latitudes of the Asian continent.

So we may be witnessing an early example of a feedback mechanism that threatens to push the PDO toward positive more often than would otherwise be the case. This could be why there is a loose consensus among climate models for El Nino events to become more frequent/longer lasting with climate change - it depends on how well those models are capturing the Arctic sea ice loss and it's impacts on atmospheric moisture levels.

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IMG_9005.thumb.GIF.438b655cbcd169101f4f0

Nino fail. 

Wonder how the analogues look for a -ENSO, -QBO, low solar activity winter. 2005 possibly rings a bell. 

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3 hours ago, summer blizzard said:

IMG_9005.thumb.GIF.438b655cbcd169101f4f0

Nino fail. 

Wonder how the analogues look for a -ENSO, -QBO, low solar activity winter. 2005 possibly rings a bell. 

2005-2006 was, at times, very close to seeing some special winter weather. The HP trying to build to our E was a common theme but it never managed to manifest enough to gain a proper foothold. There was an early March cold spell also IIRC.

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Looking at the Pacific pattern the GFS suggests no real change to that seen since ~20th June with a neutral/lightly negative pattern albeit it does forecast the Indian Monsoon to pick up (what that means for us i don't know, if anything). The Euro is a bit starker with a much more classic negative pattern. 

On the whole then i think it backs those models who want things to trend less positive in ENSO but it also suggests little change in our fortunes over the next 10-15 days. 

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On 6/25/2017 at 20:50, Singularity said:

qfa

Earlier today Tamara posted the MJO VP200 forecast showing stronger westerlies over Indonesia and an assertion that this MJO wave will increase our summer prospects (as you also talked about recently).

I'm just wondering in light of the persistent trades around the dateline (not really forecast to change much) why one is so optimistic that it will presumably have the amplitude to cross the Pacific to a better location for us intact. 

Can you also if possible enlighten us as to the effects on our weather here of an active MJO wave over Indonesia, the western Pacific and eastern Pacific (my basic understanding was only the eastern Pacific was really much good for us).  

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9 hours ago, summer blizzard said:

u.anom.30.5S-5N.gif

Feel free to elaborate about the significance of this.

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On 7/9/2017 at 18:14, summer blizzard said:

Earlier today Tamara posted the MJO VP200 forecast showing stronger westerlies over Indonesia and an assertion that this MJO wave will increase our summer prospects (as you also talked about recently).

I'm just wondering in light of the persistent trades around the dateline (not really forecast to change much) why one is so optimistic that it will presumably have the amplitude to cross the Pacific to a better location for us intact. 

Can you also if possible enlighten us as to the effects on our weather here of an active MJO wave over Indonesia, the western Pacific and eastern Pacific (my basic understanding was only the eastern Pacific was really much good for us).  

I'm not allowed to go into much detail for NDA reasons but broadly, the wave train that typically occurs in response to Indonesian MJO activity is almost the reverse of that for eastern Pacific activity across most of the Pacific Ocean, yet the wavelengths are also shorter and this happens to mean the downstream ridge/trough position over N. America is similar between the two MJO phases, and so on across the N. Atlantic and N. Europe.

This is as far I dare describe it and may not be entirely precise as a result, but what matters more is the response in the Atlanitc-Europe sector, the most significant of which for both MJO scenarios is a northward displacement of the Azores High which then tends to ridge east although not always persistently. We're seeing this feature in current model output, with the usual dramatics as smaller scale features play in - these being the reason for 'not always persistently' and, as it happens, many disgruntled faces on the MOD thread this morning :rolleyes:.

Edited by Singularity

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1 hour ago, Singularity said:

NDA

Please explain this-thanks

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2 hours ago, johnholmes said:

Please explain this-thanks

Non disclosure agreement.

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