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Bring Back1962-63

​​​​​​​LEARNING ABOUT TELECONNECTION SCIENCE AND BACKGROUND SIGNALS

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The "Walker Circulation" (please refer to my entry on Gilbert Walker in my history post - the second post on this thread) is seen at the surface as easterly trade winds which move water and air westwards.

Regarding the history of this, and completely irrelevant, is a short post I made some years ago.

https://www.netweather.tv/forum/topic/64228-when-the-monsoon-failed/

 

Edited by knocker
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As above in Davids post regarding La Nina conditions and Higher sea surface temperatures, I Thought these GFS depictions of real time data really help visualise whats going on. You can easily see the La Nina state conditions in play forcing the warm waters back towards Australia / Indonesia.

5a611b19c7007_ScreenShot2018-01-18at22_08_09.thumb.png.a6aa715c353e0b811508a091d48981ad.png

Below are the Sea surface temperature anomaly 3D views, you can easily spot the Gulf Stream meandering from the Florida coast, my understanding is that this typically migrates all the way to the eastern side of Iceland before diving (thermocline) and working its way in a reverse motion. Is it typical to be so far south and east in the Atlantic at this time of year with low Angular momentum? If so the statements in your post above makes sence . "The Coriolis force moves fluids (and air flows) with poleward movements"  -   "Atmospheric circulation is the large-scale movement of air (in conjunction with ocean currents) is how thermal energy is redistributed on the surface of the Earth" 

5a611b2344d93_ScreenShot2018-01-18at22_08_57.thumb.png.c9ae6aa2426f75133688b330dbef7c75.png5a611f7c15b0e_ScreenShot2018-01-18at22_18_31.thumb.png.7f51141242c9e3baac0e81522671d802.png

It could also be that the amount of melting ice flowing into the North Atlantic from Greenland / the artic is playing havoc with the thermocline cycle, again depicted well on the anomaly 3D image above. This would cause the Gulf Stream to be held back further south and east of its original destination. From what I have read about this, colder UK winters will be experienced due to the latent warmth of the Gulf Stream no longer available to "tap" into. Sounds like a coldie's dream this climate change malarky :D

Another Question which I think I already know the answer to, is the Gulf Stream a true teleconnection and one which hasn't really been covered yet or regularly mentioned on netweather forums or is it simply a result of other teleconnections?

Edited by ghoneym
Clarity
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For what it's worth, IMHO, including subjects such as the Thermohaline Ocean Circulation under this thread heading is a leap too far, important though it is, and of courseit's not my call. But if anyone is interested:

The Thermohaline Ocean Circulation
A Brief Fact Sheet - by Stefan Rahmstorf

http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html

Edited by knocker
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Terrific posts above from @Tamara and @Bring Back1962-63. :)

David - may I agree that step 1 for us learners is to get to grip with what each teleconnection is and what is the impact on broader weather patterns (e.g. the MJO). Then as you say, step 2 is to move on to "how do they interact with each other, which ones assist or interfere with any of the others and which are the more (or most) dominant ones." You give a good example - La Nina impacting the amplitude of the MJO this winter. So this second step is obviously more complicated, but fascinating.

As an aside and on this point, I was reading the NOAA write-up on the Pacific/North America (PNA) teleconnection pattern yesterday and found myself wondering about the apparent conflict between the recent weather over the USA/Canada (warm west, frigid east) which aligns with this NOAA statement: 

The positive phase of the PNA pattern is associated with above-average temperatures over western Canada and the extreme western United States, and below-average temperatures across the south-central and southeastern U.S.  

But then further down the page it states that the positive phase of PNA is associated with El Nino?? I thought we've been in a La Nina this winter??

The positive phase of the PNA pattern tends to be associated with Pacific warm episodes (El Ni�o), and the negative phase tends to be associated with Pacific cold episodes (La Ni�a).

Anyway, not to worry - I'm sure as my understanding increases I'll better understand what's what! The above NOAA statements are here: http://www.cpc.ncep.noaa.gov/data/teledoc/pna.shtml

May I support David's request to our experts that it would be very useful in helping understanding if some annotated charts/diagrams were posted, explaining what they are showing. Forgive me showing an annotated Strat Chart as an example, but I did this one and posted it in that thread for confirmation of my interpretation (which Chiono kindly confirmed):

5a61b99f28ace_ZMZWLatHeightJMA13Novannotated.thumb.gif.7cd41e1a5b252327004d00a1bdb1b2da.gif

Right, I'm off to carry on reading through the GDSM paper provided by Tamara - but I'm finding I have to constantly stop and dive off to swot up on something it refers to! But great learning!

P.S. What a shame NOAA haven't replace the two retired scientists responsible for advancing understanding in this area. And sadly no more charts from NOAA.

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Apologies - I dropped a clanger this morning when tweeking my old annotated Strat Chart posted above. The area of westerly winds at 300 hPa 30N is the subtropical jet, not the trade winds!! :oops: My thanks to @Interitus for popping me a pm to kindly point this out.

For completeness, a revised chart: 5a62034de168e_ZMZWLatHeightJMA13Novannotated.thumb.gif.a34563d7bd6efa26996bbd182757ae6c.gif

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A very good needed thread this David. I’ll just watch from afar I don’t have any expertise but I’m eager to learn got some good starting points! Look forward to insightful mind-numbing future contributions. :) 

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A CHART CORRECTION TO MY LAST LONG POST AND THE UPDATED WEEKLY NOAA REPORT ON THE MJO

General Matters:

Just to prove that I'm capable of producing shorter posts, here's one (well, by my standards it is!). Just a couple of other matters to cover first. Thank you for your kind comments (@Blessed Weather). Malcolm. Re: your correction following that post - I find that one of the best ways to learn is by making a few mistakes along the way. Providing one is corrected in a polite and respectful manner, this can only lead to a positive outcome. I hope that some of the "silent readers" will feel confident enough to post on here and ask questions as well as getting involved in any debates and discussions - again another great way to learn. Unlike as we often see on the model thread, you should always be treated kindly over here. Almost all of us are learners, including the specialists in certain other areas of this vast science which has not been their main focus..On this subject, a big welcome to @Daniel* - please do feel free to participate.  

Malcolm, I often read some of the NOAA statements too and I know that @nick sussex (or a dark blue "N" now that NetWeather show the first name initial for those that do not provide a profile photograph - they'll quickly run out of background colours!) often posts some of their very useful reports on the MOD - always good to have some updated guidance from well respected sources. As you (Malcolm) now realise, it's so frustrating not being able to get the most up-to-date charts and plots on the latest direction of the atmospheric angular momentum tendency. The WDT site (referenced with a link in my last post) has updated several of their charts today up to January 16th (so a 4 to 5 day jump since yesterday) but most of the charts are still stuck on January 11th. There are some very marginal changes to the downward trend but far too little and far too early to get any coldies' hopes up. We'll need to exercise patience over this.

GWO Chart Correction (from my long post yesterday):

Yesterday, I posted a GWO forecast chart in my long post. It was up to January 18th. This morning it automatically updated itself to show January 19th which was a little different. It made my comments about that chart slightly inaccurate. I try to copy all the charts across in the same way which is: "save image in a new tab", then click on said tab, then "copy image address" and paste to my post in the pre-submit mode. On some sites like Meteoceil this generally works perfectly but on some sites (eg: these GWO charts and many of the NOAA charts) seem to have a life of their own and update automatically every day. I'm explaining this in detail in the hope that any computer buff or anyone else who's mastered these copying techniques can tell me if there's a better "fool-proof" approach to doing this. I'll try several ways now to see if it produces any better results - so please bear with me during this experiment!.

I'll start with the Nicholas Shiraldi "Albany" GWO charts using my standard approach (outlined above):

GWO 15 DAY FORECAST FROM 18.1.18gfsgwo_2.pngGWO 15 DAY FORECAST FROM 19.1.18 gfsgwo_1.pngSource: http://www.atmos.albany.edu/student/nschiral/gwo.html   

Next I'll "copy" and paste the same charts to a word document and copy and paste them back on here (this will mean that the white arrows will not appear (for moving back and forth between the charts):

 GWO 15 DAY FORECAST FROM 18.1.18      image.thumb.png.34b16708cb93df9a7560fd864e9bdf1a.png      GWO 15 DAY FORECAST FROM 19.1.18   image.thumb.png.14512678a0d0d5f51a67d4e138a1c543.png

Next I'll simply copy and paste directly from the site to here:

GWO 15 DAY FORECAST FROM 18.1.18        gfsgwo_2.png    GWO 15 DAY FORECAST FROM 19.1.18    Not Complete Yet

Finally, in a similar way to the first method but instead of "copying image to new tab", I'll "copy link to a new tab" before "copy image address":

GWO 15 DAY FORECAST FROM 18.1.18      gfsgwo_2.png        GWO 15 DAY FORECAST FROM 19.1.18     gfsgwo_1.png

Sorry for the duplications - it drove me half crazy too! Will any method work differently? We'll see tomorrow. Having got everyone suffering from a GWO overdose, I had better jolly well make a sensible comment on the changes. Yesterday the chart showed the AAM ending back well into phase 2. Today we see that it barely makes it back to phase 2 and mostly remains in phase 3. The AAM tendency is still negative but less strongly than recently. it is heading towards the centre which on these charts means the area where there is a weak GWO with no or little signal (no global position)  - not that different to the "Circle of Death" on an MJO plot. Where the AAm goes from there is still very uncertain. Please refer to my post for the annotated GWO chart as well as to comments in several earlier posts (like from @Snowy Hibbo who helped me with this bit - thank you).

MJO Update Reports from NOAA:

Now for something more useful (for some). NOAA produce a detailed weekly report on the MJO. The last one, up to January 15th, was published yesterday. To read the full report, here's the link:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

I shall just copy the summary below:

Overview

 The enhanced convective phase of the MJO has moved over the Maritime Continent through the last week.

 Dynamical models show eastward propagation of the MJO signal, with enhanced convection over the Maritime Continent for Week-1 and expanding over parts of the western Pacific for Week-2. Dynamical and statistical tools forecast a rapid decay in the signal during Week-1 and Week-2, with the signal rebounding at the end of Week-2. This is likely due to expected Rossby wave activity over the Pacific.

 Based on dynamical and statistical model guidance, the suppressed envelope of the MJO is likely to continue to constructively interfere with the base state of La Niña. Enhanced convection is expected over the Maritime Continent, as well as parts of the western Pacific for Week-2.

 An active MJO over the Maritime Continent in boreal winter yields a fairly strong teleconnection response in the Northern Hemisphere, though significance for parts of the continental US are low. Typical lagged extratropical circulation responses favor a period of persistent ridging building over the lower-48, especially over the eastern seaboard.

I now realise that the MJO forecast chart that I copied from NOAA into my post last night has also updated automatically! Is it just me or does anyone else suffer from this "copying images" problem? I copy many charts into my posts and just do not understand the inconsistency. With these NOAA charts there are less copying options available in the first place. I fully expect the chart below to update tomorrow afternoon from Jan 19th to Jan 20th! It seems that we wait patiently for some charts to update and others do it when we don't want them to (I won't try 4 different copying methods with this one):

 MJO - NCEP/GEFS  15 DAY FORECAST  19.1.18 TO 2.2.18 ensplume_full.gifSource: NOAA/NWS/CPC:  http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml 

The slight overnight change is that the MJO is now forecast to reach phase 6 by day 15. It still looks set to lose amplification  with many members showing it moving close to or into the "Circle of Death" or an inactivity period just when it might reach the phases 7, 8 and 1 (which favour HLB). The reasons for this have been stated by several posters on here and also in the NOAA statement. The La Nina induced easterlies may prevent any higher amplification (or increased activity) when it enters the western Pacific phases. I'm still learning about this fascinating relationship and I'll read up on it more (several useful links have been posts on this thread already).

That's enough messing around from me. I'm sorry that part of my presentation has been compromised - normal will be resumed soon (I hope!).. 

 

Edited by Bring Back1962-63
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@Bring Back1962-63
Hi David - one way of by-passing the problem of chart links that 'auto update' every day is to save a permanent copy of the image to a folder in your laptop and then use the 'choose files' option when drafting your post (which allows you to browse your laptop and pick the file) to add it into your post. So when you're on a website looking at the relevant image, just right-click on it and 'save as' to whatever file name you fancy.

While I'm on here this evening, may I ask if someone in the know could make a quick comment on the implications of the 'stronger atmospheric response to La Nina' that Michael Ventrice talks about today? Many thanks.

 

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FURTHER CHARTS UPDATE

Firstly, a big thank you to @Blessed Weather (see Malcolm's post just below my last post) and @ghoneym (who PM'd me last night) as well as @ArHu3 (who answered a similar query several weeks ago) for all assisting me with my "copying" images problem to prevent future auto chart updating once posted. You all suggested saving the image to a word document and copying back from there. Out of the four methods that I tried in my experiment above, method 2 was closely in line to this solution. Well, looking back at all those charts, I'm delighted to see that it has worked. Only the method 2 charts have remained stuck on the intended dates (Jan 19th and Jan 20th) while the other methods (1, 3 & 4) have all moved on an extra day this morning. For me, this is a major relief. I shall now post those two charts below and show today's chart as well with renewed confidence that my comments that follow will permanently relate to actual charts that I'm referring to:

   GWO 15 DAY FORECAST FROM 18.1.18           GWO 15 DAY FORECAST FROM 19.1.18        GWO 15 DAY FORECAST FROM 20.1.18     

  image.thumb.png.4904a647a3741470ead264d20e16ffcb.png               image.thumb.png.dc057a7583e85156854fc7d5380690db.png            gfsgwo20.thumb.png.a7835767aca9d1817f78faf1cbf106e3.png 

    Source: Nicholas Shiraldi "Albany" GWO charts http://www.atmos.albany.edu/student/nschiral/gwo.html   

As you can see, the latest GWO chart shows the AAM tendency continuing to rise very slowly but it is still forecast to be negative at day 15. The GWO is between phases 2 and 3 but is very weak with little or no signal. I will NOT post these charts every day unless there are significant changes to report. I just wanted to ensure that the correct charts are showing in relation to my long post further up this page.

Finally, as the final part of last night's experiment. I just want to re-insert yesterday's NOAA GEFS MJO chart using the new method as the one above will almost certainly auto update later today:

 

MJO - NCEP/GEFS  15 DAY FORECAST  19.1.18 TO 2.2.18           ensplume_small.thumb.gif.e7893d747dcb02c11741dd5c7ec227ab.gif

 

Source: NOAA/NWS/CPC:  http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml 

I hope for the sake of everyone that this is a successful end o my chart copying experiment.

  

Edited by Bring Back1962-63
Correct typos and check charts
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AAM UPDATE TO YESTERDAY

Just one more quick one from me today, a new chart also from the Albany website (as per the GWO charts):

                                                                                         

   RELATIVE AAM FROM 21.10.17 TO 19.1.18        prev60.thumb.png.21736be441a7eff911ed62b97feb11c9.png    Source: Nicholas Shiraldi "Albany" AAM charts - http://www.atmos.albany.edu/student/nschiral/gwo.html   

This confirms that the AAM remains negative but is flat lining with just a hint of an uptick right now. As I said before, we will need other conditions to change to see AAM trending positive which may not be for quite a while but one to keep a close eye on.

  

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My apologies that this is not a contribution to the thread, but may I say this is a really excellent part of Netweather, and is so helpful to those of us who have been piecing together in our minds the background signals/teleconnections learning so ably posted by GP, Tamara and Bringback1962-3  (to name but a few) over the years. It is also a great gathering place, from my observation, for those of us with an interest and who need a focal point of information without having to wade through the MOD. So thank you very much; my pen and A4 piece of paper are twitching as I feel the need to start writing things down and putting arrows between it all!

Edited by Reefseeker
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Hope this is right place to post this, if not then move,

I was wondering, have there been any past winters, where there has been a La Nina, let's say moderate strength or below, and there has been a 'proper' cold spell in later winter i.e. from around this date onwards?

Thanks

Brug. 

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19 minutes ago, Bruegelian said:

Hope this is right place to post this, if not then move,

I was wondering, have there been any past winters, where there has been a La Nina, let's say moderate strength or below, and there has been a 'proper' cold spell in later winter i.e. from around this date onwards?

Thanks

Brug. 

I’m sure 1995/96 was close to moderate La Niña and that was one of the coldest winters of the 20th century 

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43 minutes ago, Matthew. said:

I’m sure 1995/96 was close to moderate La Niña and that was one of the coldest winters of the 20th century 

If anybody wants to research, there's an extended record of ENSO here.

https://www.esrl.noaa.gov/psd/enso/mei.ext/

ext.ts.jpg  lanina.ext.jpg

Just off the top of my head, there seems to have been a very strong Nina episode during one of the coldest European winters of the last century .... 1917.

PS .... seeing it in graphical format shows a big step change after the strong one in the mid 70's. What caused that might help explain why weather patterns seem to have shifted since then.

 

Edited by Gael_Force
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1 hour ago, Matthew. said:

I’m sure 1995/96 was close to moderate La Niña and that was one of the coldest winters of the 20th century 

Here’s why I thought so; highlighted in green

0D58CDC8-6861-4BCE-B709-6977C5850560.jpeg

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Thx for the replies, yes I remember cold and lots of snow in Feb 1996. Also I think there are a few others such as 1956, 1985.

I have been talking to Tamara on here, and she says that most of the winters that had a La Nina designated, and featured significant UK cold weather, had some kind of atypical La Nina circulation going on, of course every La Nina is different. She says that 95-96 and 55-56 are in this category. 

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See paper in the link

 

Edited by knocker

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Folks - apologies for not contributing more in here at the moment. I'm seriously busy at work and struggling for energy....

One area for discussion I'd like to float is the oceanic-atmospheric coupling that we see occur and discusssed. I know what it looks like, and I know what it looks like when coupling is destructively interfered with  - but can anyone begin to explain to me what affects the strength of the coupling? The GWO is a measurement of global winds that, in essence, are a a reflection of the closeness of the coupling - but I am at a loss to understand why, for example, the coupling this season has been so strong when Nina itself has been comparatively weak. I was very interested early season in the easterly nature of the Nina pattern, and wondered (and read from others more qualified than me) that the warm waters around the maritime continent might serve to overwhelm the Nina signal as convection moved into the pacific. It hasnt happened.

So - why has the coupling been so strong... and why, in some years, do we see a-typical responses that can create a pattern like Feb 96 that I see mentioned earlier today? There are a couple of interesting posts over on the strat thread regarding geomagnetism and solar forcing. This is going to be an area of focus for me through the summer as I try and fight my hatred of hot, sunny days with associated burn, sweat and lethargy... but does anyone have a theory worth putting out in public now? 

(One thought - we spend hours and days talking about the pacific, but rarely about the atlantic. Are we guilty of paying too little attention to atlantic influence?)

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Last winter I wanted to take a look at teleconnections, luckily I still have some of the images I used saved on my computer. My approach was to look at the Outgoing Longwave Radiation (OLR) charts provided by the Earth System Research Laboratory (ESRL). Specifically I used the OLR anomaly charts in the hope that they would show where any areas of deep tropical convection were. See here https://www.esrl.noaa.gov/psd/map/clim/olr.shtml

The OLR anomaly charts show the difference from normal in the amount of infrared radiation (heat) being emitted to space from any particular location on earth.  Here is the chart for 12 December 2016 through 10 January 2017.

 

olr_anom_30dayjan.thumb.gif.ca84b9581ed7c210b0cbca4f2341021c.gif

The blue and red show where there is less radiation than normal leaving the earth, probably due to the radiation being emitted from high cloud tops, this is where I assume that tropical convection had been more frequent than normal. The brown and black areas show where more radiation than normal was leaving the earth, probably due the sky being cloudless and the radiation being emitted from the surface. You could possibly conclude that the chart shows bands of different shading (blue or brown) moving to the right and poleward emanating from the areas of convection.

 The following chart shows the anomaly in convective rainfall for the same period.

precip.thumb.gif.dd4384ec3d2cf210c074345539dc4d36.gif

The yellow and green colours show where there was more rainfall than normal. I think it matches fairly well with the OLR charts.

 

 

Here are the 500hpa anomaly charts for the same period.

 

500hpaanom.thumb.gif.532a289addcbef20c3b319882432da9a.gif

This is perhaps pattern matching rather than science, but for what it’s worth I feel from looking at this particular thirty day period there may well have been a connection between tropical convection and the actual weather patterns. If I recall correctly the MJO was in fairly low amplitude in the Indian ocean/Maritime continent. I find it curious that there was quite a lot of convection in the south Atlantic and a corresponding area of high pressure to the right and poleward, which just happens to be our neck of the woods. 

I hope my wittering has not cluttered up the thread, feel free to delete if it is

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Hello @nad, welcome to our new thread and an excellent first post. You have thrown up some interesting points. I'm still very much a learner myself  but I wonder if your analogy goes even deeper - I'll have a go and this may generate some response from one or more of our specialists (who should fell free to correct me). The ENSO state and the tropical forcing response with +/- atmospheric angular momentum (AAM) which are primary drivers and can assist or interfere with the MJO. The "current" east based Pacific La Nina has strengthened the north-east trade winds and the AAM has been quite strongly negative for a few weeks now. There is greater than average tropical convection in the central and particularly the western Pacific (and an active Tropical Storm/Typhoon season. The GWO (global wind oscillation) has been in phases 2 and 3. From what I understand, this assists the MJO in its maritime phase with decent amplitude as now but is much more like to suppress the MJO signal and interfere as it progresses into the western Pacific phases. Now, what I do know is whether the lack of northward and eastward forcing (more lateral expansion) may mean that there needs to be more vertical motion with a transference of heat from the surface. This is really a guess and I may be barking up the wrong tree but it might stimulate a better response than mine. It would be useful to compare those two charts with the current ones to see if there is any match with the conditions present now. We can also look back to last year and make a fuller analysis too

Please keep contributing whenever you wish to.  David 

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Hello David, thank you for your kind reply, suitably encouraged I will have a go at this year.

The OLR anomalies for this month show.

 

2018-olr.thumb.gif.4a9662fdf984a9e4a65d1af72edd4fb0.gif

 

Even though most of the tropical convection in the Pacific is in similar areas to last year, we can see the cooler water east of the dateline having an effect. In my opinion the basics are the same, with waves heading east and poleward, but perhaps not as clear cut as last year.

The convective precipitation chart for the same time shows:

5a6616cfc67c9_precipmonth.thumb.gif.d0fdcd10bb669f8a7485d6bbd9df95c9.gif

 

Intuitively one would think that the most convective activity would take place over the warmest water. Here are the Sea Surface Temperatures for the period.

 

sst_month.thumb.gif.f8ae385147bec71766b4acd9280e4e3e.gif

 

You could make the case that the precipitation has indeed taken place over the warmest water which is just west of the dateline. The MJO seems to have been pegged to the Maritimes and Indian Ocean, I’m not sure why this has been the case, could it be that once established the outflow from this convection suppresses storm formation further east? The idea of “my thunderstorms are bigger than yours” coupled with the strong trade winds might have been responsible.

Much of the documentation that I have seen regarding the MJO has a bias towards the North American continent, and with such a large ocean to the east, rightly so. I would think that any standing wave set up by persistent sea surface temperatures will be modified by any large area of deep tropical convection, and that the nearer to home that convection is the larger the effect.  You may have noticed from the precipitation charts that this year there has been enhanced convection in the South Atlantic and the Caribbean.

What effect has this had on the weather, below is the 500mb anomaly chart for the same time.

 

 

5a661762bc458_H500anom.thumb.gif.4478f6d6c6ae7e2d16d2ba075504b3ab.gif

 

There looks to be enhanced subtropical ridges around the globe, perhaps showing what the GWO advertises for low AAM in phase 3?  The Azores and Bermuda highs look noticeably pumped up.

From a parochial point of view I think that a closer look at what is happening in the tropics of the South Atlantic, Caribbean and possibly tropical South America may help our understanding.

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Thank you everyone for your posts in this interesting thread about teleconnection science and background signals.

If I understand it correctly, the current negative AAM is responsible for the enhancement of the effect of the La Nina (please correct me if I am wrong). I have some remarks on this issue.

I performed a quick study of the effect of a La Nina on the winter pattern, since 1950. I considered the 20 strongest La Nina’s, according to the ranking of the NOAA (https://www.esrl.noaa.gov/psd/enso/mei/rank.html), for January and February combined.

T79tQnF.png

We see that overall the effect in the Atlantic on the 500 hPa is neutral. Only very strong La Nina’s show an enhanced zonality (ranking 1-4).

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December had a ranking 20, in January the La Nina seems to be fading a bit. I have my doubts weather the current AAM (still) is enough to account for the lacking of blocking in the Atlantic and over Greenland, so far. 

Furthermore: the type of La Nina also plays a role in the teleconnection. This winter we have a EP La Nina. This should a least have some weakening effect on the zonality, in the Atlantic (https://www.researchgate.net/publication/271737956_Impacts_of_two_types_of_La_Nina_on_the_NAO_during_boreal_winter)

Finallly can anyone show me where to find the NOAA link where I can create composites using daily data, instead of monthly? I would like to check the 500 hPa anomalies for the first weeks of January.

Perhaps there are daily records of the ENSO, a possible weakening of the La Nina may be verified.

 

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