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Vorticity0123

Long range forecasting and teleconnections

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Good post on an area that I've been exploring myself.  

 

Regarding mountain torques I had a good exchange with Tamara on this subject - it's certainly a interesting topic.  The model thread often gets focused on the stratospheres impact on the troposphere particularly via warnings but of course it works two ways and the Rossby waves deflecting upwards are an important influence and driver of the warmings.

 

There's actually a nice wiki entry on the subject http://en.wikipedia.org/wiki/Rossby_wave

 

I still have plenty to learn on this subject but thought your post was a very tidy and clear summary.

Edited by Trom
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Great to see this thread up and running.

 

There is much to be gleaned in terms of longer range forecasting  through the teleconnections and  atmospheric drivers that the like of Tamara, Vorticity and the much missed GP tried to interpret on our behalf.

Edited by mcweather
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Great post Vorticity!

 

Im really looking forward to reading this new thread and I am going to learn much from it. Its very interesting to look at the whole picture and global drivers etc. Good stuff :good:

 

I cant wait for more posts to come from you and Tamara etc!

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A question for Vorticity.....

 

Why have you used the JFM rather than the FMA composites? As said on model thread, I don't know a lot about this subject so would be interested to know if there is a lag that indicates we should be back two months for the composite rather than use middle month (March) which is the one that the current mid term forecast goes into.

 

Both those composites have a tendency to Greenland blocking - as per IF, isn't that what the GloSea5 was showing for March?

 

UGPoyRQ.png

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Its worth interpreting the GWO phase composites in the same way as one might interpret agreement of the NOAA upper height anomalies and the variance in scope they still can offer for surface pressure features. As per these upper height anomaly forecasts, we should be equally careful in not taking GWO composite charts too literally at face value - but interpret them taking into account the large scale number of drivers operating at any given time within the hemisphere.

 

Activity within, and the overall state of, the stratospheric polar field also play a large part in how we interpret the GWO composites. Clearly within any amplified pattern context, the strength and orientation of the polar vortex will determine how much meridional forcing can be achieved within the boundary of the polar front jet. This especially applies to the dominant La Nina type -ve tendency AAM state that has existed throughout the winter, and looks set to continue for the foreseeable future

 

Why is this?

 

Much as regularly posted on the MOD thread, a Nina type atmospheric state in the winter season supports the development of sub tropical ridging into mid latitudes - and a prevailing +NAO. Easterly wind surges in the tropics pump up these ridges and the extra strength we have kept seeing in the Azores High has limited the extent of amplification potential along the PFJ.

 

It has only been when the stratospheric vortex was displaced our side of the pole at the turn of the month, that we have seen more sustained amplification along the PFJ. But its worth remembering that it is the same GWO cycle through -ve MT stage 8/1, which is the signal to retrogress the pattern upstream in the Pacific (withdraw the Azores ridge westwards in the Atlantic) that occurred in late January, prior to the sustained amplification into February, as we are seeing right now in the modelling. In fact the cycle was initiated in mid late December and occurred a second time in mid January before this.

 

Each time through the course of this winter has seen a different amplification strength and longevity - but the NH sequence of upstream retrogression has near enough identically been in accord with GWO winter month composites under GWO Phase 1/2 -ve AAM momentum. With the caveat that AAM showed signs of Nino breakthrough into GWO Phases 4/5 after mid Jan. This led to a +EAMT which gave some hopes towards a partial resurgence at least of the autumn Siberian High SIA/SCE -AO feedback loops which went AWOL into the start of winter

 

We saw this late January

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2015012900-0-6.png

 

Whilst the GWO orbit was headed right to where we are now. Compared to this

 

http://www.meteociel.com/modeles/ecmwf/runs/2015021812/ECH1-96.GIF?18-0

 

Overall similarities in terms of the westward retraction of the Azores High, and the more NW/SE axis of troughing in the Atlantic from the upper vortex which is the result of tanking -AAM in the atmosphere, with Pacific Rossby wave activity initiated through -ve MT occuring across the US as the GWO orbits into Phase 1

 

And we have a near replica copy of predicted GWO orbit imminently, as late January, through another fairly high amplitude orbit Phase 1/2 to reflect these synoptics

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

Look however at the quite different ways that the polar profile is modelled in each of those meteocil charts. This has implications for how the jet axis will behave in the Atlantic and impacts on our surface weather.

 

The difference this time is that we do not have that displaced vortex signal to sustain any upstream amplification signal feeding downstream as the Azores High retreats westwards. Also, we have more stubborn easterly trade winds underpinning the strength of the Azores High, and correspondingly greater westerly momentum transport at mid to higher latitudes.

 

This means that amplification along the PFJ is limited this time around and whilst we see a persistence of a NW-SE jet axis, with repeated PM incursions suggested, we do not expect to see the jet digging N-S and a pronounced amplified Atlantic ridge on a sustained basis such as we saw into early February with charts like this.

 

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2015020200-0-6.png

 

So, in summary, same GWO orbit cycle at very similar amplitude to previously- but different surface implications for the UK in terms of how much, and how sustained the jet amplification is that verifies.

 

Both instances however, fit perfectly within the GWO Phase 1/2 composite expectations for Jan/Feb

 

Shortening wave lengths into Spring, under the same negative tendency atmospheric patterns, start to have different implications for amplification behaviour and also surface positioning of the same Atlantic ridging profile of the winter.

 

But that is best discussed and illustrated if and when we come to it :)

 

Updated early March :  Phase 1/2/3 GWO orbit losing weak/moderate amplitude and heading back to no coherent phasing and little forcing on patterns. Much as was seen towards the end of the first week of February (following polar vortex displacement). This, in conjunction with continued +AO profile and MJO tropical signal supports return of mid latitude ridging as signalled by models.

 

Indicated lack of frictional and MT's highly reduce the chances of significant amplification in the meantime and will continue to support and strengthen mid latitude ridging. On this basis, expectations of the jet stream remaining to the north of these ridges in tandem with +AO mean that any attempted breakdown from the north is going to be hard to achieve into the medium term in many southern part of the UK.

 

Updated 5/3/15 : Interesting changes to the AAM budget which suggests a shift towards +ve tendency. This change quite likely ocean> atmosphere linked through the latest Kelvin wave in the Pacific and the implications for the ENSO regions in the Pacific (and the MJO).

 

The GWO is forecast to break through Phase 5 into low amplitude Phases 6 and 7. This signals a modest +EAMT, and albeit only low amplitude GWO forcing suggested at the moment, it should still be enough for some warming in the stratosphere this side of the pole as a consequence of the Asian MT wave breaking activity. In tandem with MJO phasing, it gives support for blocking towards Scandinavia which the models are picking up on.

 

The coming days may well increase this signal to a higher amplitude and further increase confidence for blocking

 

This was exactly what I was looking for a month or so back to provide a much more interesting finish to winter. 5 to 6 weeks later on, the potential for cold is clearly blunted and offset by much greater insolation. March 2013 was exceptional because the Siberian feedbacks were already evident in our weather patterns in the heart of winter - hence the very deep cold pooling which occurred.

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

Edited by Tamara
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Very good posts above, are any of you willing to make a prediction for next winter - on drivers and signs as I know models are not worth looking at.  Is America going to make it 3 in a row for exceptionally cold to the NE and are we going to have another winter with a lack of HLB or MLB....Prob way too early for this but would be nice to read your thoughts.

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Lots going on in the oscillation department at the moment!

 

The AO is tanking positive but maybe becoming to big for its boots?

 

post-2839-0-53057600-1425719955_thumb.gi post-2839-0-96060500-1425719318_thumb.gi

 

 

The MJO (gfs) looks to have been on the Red Bull,with MOGREPS heading the same way.

 

post-2839-0-32513500-1425719224_thumb.gipost-2839-0-03326800-1425719225_thumb.gi

 

 

Looks like a recipe for some major changes across the Northern Hemisphere this month.

 

 

Just to add that the GWO is going off the scale as well.

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

Edited by Cloud 10
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I'm not sure if this is the correct area for this post as the subject is not strictly a teleconnection. The Atlantic multidecadal overturning circulation (AMOC) has been in the news recently regarding possible regional climate change with several new papers suggesting a decline over the next few decades.

 

The website of the AMOC monitoring array has some very interesting articles and also the data collection updates. This article in the publications section caught my attention and may be of value in long range forecasting. Some of the coldest winters coincide with a drop in overturning speed - big question I have - is it cause or effect?

 

http://link.springer.com/article/10.1007/s00382-014-2274-6/fulltext.html

 

 

We construct a composite of the AMOC anomalies (Ψ′) from the five eddy permitting hindcasts that span the time period 1958-2001 by removing the linear trend from each ensemble member and then removing the seasonal cycle. The AMOC anomalies are then averaged to produce the ensemble mean (Fig. 2). This composite reveals several strongly negative events, some substantially in excess of 2 standard deviations from the mean. There is a strong negative event in 1962/63, one in 1980/81 and another in 1983/84. There is also a minimum in 1986/87 with a duration of 3–4 months. We can also identify two pairs of events, one pair in 1968/69 and 1969/70, and another pair in 1977/78 and 1978/79. One further example in the time series which may also be a weaker analogue of the 2009/10 event occurs during 1996/97 and 1997/98. The event in the winter of 1996/97 occurs slightly later (around March) than other events in the time series (typically January-February). It coincides with an anomalously strong northward Ekman transport anomaly in February, which we suggest is likely to have reduced the impact and altered the timing of the negative event.

 

Full menu here  http://www.rapid.ac.uk/rapidmoc/

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After a long period of silence, here is an update on the teleconnective field. Summer has become established across the Northern Hemisphere. Quite some things have changed in the teleconnective area, with the emergence of a full-fledged El Nino being the most important. Furthermore, we have seen a hyperactive end of June and start of July in terms of tropical cyclones, which can be nicely explained by the Madden-Julian oscillation (MJO). In this post I will explore the two aforementioned features, but I will not (yet) go over to forecasting. In short, this post is a review of a few remarkable features over the past months.

 

Significant El Nino event emerges

 

The most striking event over the past few months is the strengthening of an El Nino event. If one looks at the average sea surface temperature (SST) anomalies over the majority of June, the signature is clearly evident:

 

 

post-20885-0-48976200-1437248455_thumb.p

SST anomalies between June 10 and July 1 (Courtesy: NOAA).

 

Note the swath of above-average SSTS extending all the way from Peru towards the International Dateline and beyond (180 E/W). The atmosphere is responding to these anomalous SSTS by behaving as an El Nino, with more convection than average occurring in the Central Pacific near the Equator. Lots of other atmospheric occur due to this El Nino event, which can be found here: http://www.pmel.noaa.gov/tao/elnino/impacts.html#part1.

 

The atmospheric 'imprint' of the El Nino has materialized this year, unlike last winter where a La Nina atmospheric pattern coincided with a sea El Nino pattern (albeit a weak one). This difference can at least partially be attributed to the fact that current El Nino event is much more vigorous than last years' one, as discussed by Tamara in the above post.

 

Much more about the current state of the El Nino event, including forecasts, can be found in the links below:

 

http://www.elnino.noaa.gov/

 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html

 

http://www.pmel.noaa.gov/tao/elnino/impacts.html#part1

 

http://www.wunderground.com/news/el-nino-outlook-strong-possible-may2015

 

Hyperactive tropical cyclone activity and MJO

 

During the end of June and the start of July, we have seen a hyperactive period in terms of tropical cyclones. In fact, it has been an active first half of the year 2015 in terms of tropical cyclones in the North Pacific. Up to the end of June, 11 tropical cyclones developed in these waters. July has continued the anomalous activity, as a couple of cyclones developed in early July as well.

 

Can this activity be explained by ENSO (the current El Nino event)? The answer is only to some extent and only for the Eastern and Central Pacific. As can be seen in the SST anomalies image at the start of this post, SSTS are much above average over much over the Eastern and Central Pacific, thereby aiding in tropical cyclongenesis. But what about the West Pacific?

 

More importantly, the MJO has played a major role in the tropical activity over the past month or so. Take a look at the image below:

 

post-20885-0-24579500-1437250458_thumb.p

Hovmoller plot: OLR anomalies averaged between 5S and 5N across the globe. The development of a tropical cyclone is indicated by a red TC mark. Courtesy: CICS-NC

 

Negative OLR (outgoing longwave radiation) anomalies indicate more than average convection whereas positive OLR anomalies indicate less than average convection. The reasoning is that convective cloud tops are relatively cold, and therefore they emit little longwave radiation. On the other hand, under clear sky conditions, the OLR is emitted mainly by the sea and the atmosphere just above, which is comparatively much warmer. As a result, the OLR is much larger.

 

An MJO event usually shows up by negative OLR anomalies (so increased convective activity) ahead of an area of positive OLR anomalies (decreased convective activity).

 

What can be seen is at the end of June, a strong MJO event developed with its axis around 60E. This event moved slowly eastward towards the International Dateline about midway in July. Interestingly, almost all tropical cyclones that formed between Mid-June and Mid-July formed at or ahead of the axis of the MJO event, just behind the time when the convection was strongest. This relationship shows that the MJO has been a major player in tropical cyclone formation over the past month.

 

Currently, we only have two tropical cyclones left, being weakening TC Dolores in the Eastern Pacific and TD Halola (which has weakened far more than anticipated initially from typhoon strength).

 

Furthermore, a great link about the MJO containing lots of neat graphs (in Hovmoller format) can be found here:

 

http://monitor.cicsnc.org/mjo/v2/

 

Last but not least, a recent paper has advertised that for forecasting MJO events, heating near the surface may be playing a key role. More here: https://forum.netweather.tv/topic/83594-lower-level-atmospheric-heating-important-for-mjo-model-simulation/

 

Summary

 

Aside from a major El Nino event, we have had a significant MJO pulse as well, which has aided in tropical cyclone formation. Much questions are not addressed yet in this post, though. The only thing that can be safely said for now is that an El Nino event will persist in the forseeable future. But what is the effect of the highly active period in terms of tropical cyclones on our own weather? Lots of 'energy' has been pumped in the extratropics, which will undoubtedly have an impact on our weather, but in which way? Is the MJO itself going to develop and can we forecast it, probably by looking at the GWO? Very interesting to say the least, but time is running short, and my knowledge is not yet great enough to answer these questions.

 

Any contributions, or possible answers to the aforementioned questions are greatly appreciated! :smile:

 

Sources:

http://www.elnino.noaa.gov/

http://www.climate.gov/news-features/blogs/enso/july-2015-el-ni%C3%B1o-update-bruce-lee

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html

http://www.wunderground.com/news/el-nino-outlook-strong-possible-may2015

https://noaanhc.wordpress.com/

http://blog.metoffice.gov.uk/2015/07/09/multiple-tropical-cyclones-in-the-pacific/

http://www.atmos.albany.edu/student/carl/weather/index.html

http://mikeventrice.weebly.com/cckwmjo.html

http://monitor.cicsnc.org/mjo/v2/

Edited by Vorticity0123
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Winter is now well underway, though it is all feeling more like mid-Autumn. The UK has been soaked over and over again, sometimes by bands of moisture-loaded conveyor belts originating all the way from the tropics. For much of Europe, December has also been a record-shattering month. In the Netherlands, the average temperature record high was literally crushed by an astounding 2.3*C!

After this extremely warm and for the UK very wet December, hopes are up that probably the rest of the winter may deliver some  wintry weather, or at least some dry spells. Will this finally be bound to come? In this post we’ll go through a journey of teleconnections in search for signals for the weather to come in the near and far future. Off we go!

Blocked and stretched

Before diving into the teleconnections, we will first examine the broad picture on the Northern Half.

GFS_00.thumb.gif.060c08b3195fca4e1f17202

GFS analysis of 500 hPa heights (colours) and surface pressure (contours) as of 12Z 03-01

Here it is important to note that the main focus will lie at the 500 hPa heights, as these are less sensitive to surface disturbances and friction. The pattern is looking far from circular to say the least. Two strong blocking highs (indicated by the black arrows) are well visible on the scene. One is located over the western US, while the other one (also the stronger one) exists over central Siberia.

In between these ridges of high pressure, an elongated area of troughing is extending all the way from Japan down to Canada (black line and blue/purple colours). This troughing is ‘squeezed’ by these two ridges of high pressure. With some imagination one might call the area of troughing indicated by the black line as being the tropospheric polar vortex (or vortices).

The same pattern up high?

The pattern described above is also nicely represented in the lower stratosphere:

EC_aloft.thumb.jpg.4d6d6302f350ab02e2a77

ECMWF analysis of 100 hPa heights as of 12Z 03-01

Note that the orientation of the map is slightly different from the one before! Here we also see a highly elongated polar vortex stretched from Japan to Canada (indicated by the black line). The similarity to the 500 hPa pattern is quite striking. This is also the reason why I am mentioning the term ‘tropospheric polar vortex’ above, since the locations in the mid-troposphere and the lower stratosphere nearly overlap.

With a little bit of fantasy, the same ridges of high pressure can be found in the lower stratosphere as well (compared to the 500 hPa level, referred as the mid-troposphere). However, these ridges are notably less pronounced aloft.

Still cold in the Atlantic ocean – even record cold?

Time to go into the ‘deep’. As noted in the thread about the Atlantic Ocean, the ocean has been notably colder than average during the past year or so. In fact, according to Phil Klotzbach, northern parts of the North Atlantic have seen the coldest SSTS (sea surface temperatures) on record! That is quite impressive for a warming Earth to say the least.

Map.thumb.png.38cbb49db901294ad4157ec12f

Sea surface temperature anomalies over the past year over the Atlantic. Courtesy to Phil Klotzbach.

Unfortunately, coupling these anomalies to air pressure anomalies is hard to say the least. This has to do with the wealth of factors that affect the weather aside from the SSTS.

Very strong anomalies aloft coupled to the ocean

Still, let’s boldly see whether there is any kind of linkage. And I can say, there is quite a strong one!

Map_2.thumb.png.750ed8ed91ce73a6a1a7c88a

500 hPa height anomalies over the past year over the Atlantic.

Negative heights (so anomalous low pressure) has dominated during 2015 near Greenland and Iceland, while positive heights (anomalous high pressure) prevailed over the Atlantic subtropics. This is typical of a positive NAO pattern.

Is it possible to couple the record low sea surface temperatures in the North Atlantic to these strong height anomalies? Probably, but for me it would go too far to put a one to one relationship here.

Still, an explanation that is possible is that the record cold North Atlantic SSTS, coupled with the slightly warmer waters in the subtropical Atlantic, strengthened the temperature gradient between these areas in the atmosphere. This could have resulted in stronger and more frequent low pressure activity over the North Atlantic.

Currently, the same SST anomaly pattern is still there. Often SSTS do not change rapidly over time, so it is a reasonably safe assumption to say that this situation will remain the same for the coming winter.

El Nino has dominated – and will continue to dominate

About ENSO we can be very brief. A strong El Nino has developed, and this El Nino appears to continue for the rest of the winter at least.

ENSO.thumb.gif.6a80ec8c83f733a00505cbbbe

Sea surface temperature anomalies over the last week over the Eastern Pacific.

Though El Nino does not have many direct effects to our weather, it does have predictive value when looking at other subseasonal teleconnections like the MJO. So let’s take a look at these!

MJO on the run, but does it have any predictive value?

The MJO is currently rather active and located in Phase 6 or 7. The future of the MJO seems to be very uncertain yet, with the GFS and ECMWF being at two different paths so to speak.

MJO_ECMWF.thumb.gif.12d1bab4af3a809437a9MJO_GFS.thumb.gif.097f9ef1e0a2401c95f581

ECMWF (left) and GFS (right) MJO forecasts per 1 January.

So, where does this bring us? According to the GFS, the MJO will remain very active and progress from phase 7 to 8. The ECMWF is much more ‘progressive’, and takes the MJO through phase 8 and 1. It also weakens the MJO significantly.

Based on the ENSO, it is possible to make composites for each phase of the MJO based on past events. In this way it enables one to forecast future pressure patterns based on past and future MJO data. This could be quite a convenient way of forecasting.

It is important to remember that these composites do not act as a literal comparison, they cannot be taken at face value. Rather, they should be used as an indication. In the links below the 500 hPa anomaly composites for each relevant phase are given for January with an El Nino active.

Phase 7 (check with the current situation!)

Phase 8

Phase 1

Phase 2

The 500 hPa anomaly pattern of the current location of the MJO (phase 7) does by no means reflect the current pattern observed at 500 hPa (see the first image of this post as a reference). The only thing I can see which matches the current situation is the high pressure activity over Siberia. Phase 8 and 1 would indicate high pressure activity over Europe or later on, Scotland, but for now these signals are not being modelled.

GWO spiking upwards

One of the strongest signals so far is the Global Wind Oscillation. It has been showing very high angular momentum amounts during the past few weeks or so.

GWO.thumb.png.8626639e7bccb16438c44e56ad

GFS MJO forecast per 3 January.

The GWO trend is even ‘off the charts’ (rightward) today in Phase 5. Later on, the GWO is trending towards Phase 6 and 7, and probably 8 in the end. Apparently, the AAM (atmospheric angular momentum) budget is expected to remain very high over the next few days or so.

Admittedly, I am not yet skilful enough to interpret these GWO plots and translate them into something of value to the weather over Europe. For this I would refer to Glacier Point or Tamara, who are much more knowledgeable on this subject than I am

Upper stratospheric polar vortex remaining steady?

For now, it appears that the polar vortex in the upper stratosphere is not going to give way very quickly. Therefore, it does not seem to have much influence on the weather to expect in the near- and medium term. Read more here: https://forum.netweather.tv/topic/84231-stratosphere-temperature-watch-20152016/?page=21.

Blocking over the North Pole far ahead – reflecting the MJO?

In the long term, some interesting developments appear to be going to unfold.

NOAAANOMS.thumb.gif.c25018666161c0413a60

NOAA 8-14 day 500 hPa heights (green) and anomalies (red and blue contours).

Notice the very strong positive anomalies extending from California to the North Pole. A very strong block (denoted by the black arrow) appears to be going to set up shop there. Such a strong blockade would cause very cold air to flow out over the US in the long range. The troughing remains elongated from the right parts of the North Pole towards eastern Canada. Finally, some weak blocking can be seen over the Atlantic sector as well, but the signal appears to be weak at best.

Interestingly, this situation does show quite some similarity with phase 7 of the MJO given above, notably the blocking over western Canada and troughing to the southwest of Alaska. This would make sense if the GFS MJO forecast of a few days back would come to fruition. And in this way, the signal of Atlantic blocking is reflected in the MJO as well.

Closing the scene – mixed signals?

Now that we have seen all the confusing signals, it is good to summarize them and link them together. Here we go:

1)      The northern Atlantic Ocean continues to be cooler than average, and the subtropical Atlantic warmer than average. In 2015, this has been reflected by a strong positive NAO pattern (strong low pressure near Iceland, strong high pressure near the Azores). With the SST pattern to persist, one could argue that troughing will prevail near Iceland, giving unsettled weather as a consequence. However, this relationship does not have to be a cause-effect one.

2)      El Nino remains very active.

3)      The MJO is currently active in phase 7. While MJO composites do not seem to make much sense for the time being compared to the current pattern, they appear to be becoming more and more prevalent in the future if the MJO stays in phase 7 as the GFS forecasts. This would point to a block over the Northern Atlantic, destructively interfering with the first point.

4)      The AAM budget in the atmosphere is very high and forecast to stay high for the next few weeks.

5)      The upper stratospheric polar vortex does not show any signs of weakening rapidly as of yet.

Where does this all leave us? Based on persistence, one could argue that to some extent low pressure will continue to dominate the scene near Iceland. However, this signal is more of a background signal with little value in the short-term (as in a yearly average sub seasonal variations could still be very large).

Judging from model ensemble forecasts and the MJO, ridging above the northern Atlantic appears to be a more reasonable bet. My guess is that the Atlantic ridging scenario is the most likely outcome, though the signal is at odds with the background signal for trouhging to prevail in that region. Lso, the MJO forecast is rather uncertain as well. So all in all, the statement above is not a rock solid one to say the least. Nevertheless, it will be interesting to see whether the signals mentioned above will be reflected in a few days in the models as well!

Sources:

http://www.wetterzentrale.de/topkarten/fsavnnh.html (weather maps)

www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/ (stratospheric ECMWF weather maps)

http://www.nhc.noaa.gov/aboutsst.php (SSTS)

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl (Very convenient site to do own climate analysis)

http://www.atmos.albany.edu/student/nschiral/gwo.html (GWO forecasts)

http://www.americanwx.com/raleighwx/MJO/MJO.html (MJO composites)

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml (MJO forecasts)

Edited by Vorticity0123
Added sources
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I haven't had much of a chance to do this for the last couple of years but I wanted to do a very crude early look at some analogue years based upon current projections for teleconnections. The three I've looked at for now are QBO, ENSO and Solar cycle progression.

For all three there is hardly a scientific methodology behind it. For QBO I took the closest matching profiles I could at 50mb (with some attention paid to 30/70mb either side of this too) - the numbers outside of brackets are the closer years I could find, the ones in brackets possess similar-ish profiles but not quite as good as the other years. This gives us a bit more data to potentially play with though. For ENSO, pretty similar to above in terms of looking at the annual profile, but here the years in brackets are years in which we remained ENSO neutral, albeit slightly negatively, where as the years outside of brackets are winters which dipped down into weak-ish La Nina.

Finally, solar cycle progression is by far the crudest of the measures. I've taken the years in the declining phase of the solar cycle with an annual smoothed sunspot number of approximately 40-50 - really not entirely scientific but within the constraints of time it should give us some idea for now.

So here were the years I picked out for each:

QBO (Close but not exact profile matches)

1962,(1965),(1972),(1974),1976,(1979),1981,(1986),2000,2014

ENSO (remained neutral rather than weak La Nina)

1954,(1961),(1962),1967,(1978),(1981),1984,1995,(2001),(2005),2007,(2012)

Solar Cycle Stage

1952,1962,1974,1984,1994,2005

The years with at least 2 'matches' are:

1962, 1974, 1981, 2005

 

I am not going to be issuing any sort of forecast based upon this very crude measure, but hopefully it's something just to get a little bit of a conversation going as we head towards the business end of the weather year - if I can get a bit more time soon then I'll try and add in some composite plots.

 

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On ‎17‎/‎09‎/‎2017 at 12:57, snowking said:

I haven't had much of a chance to do this for the last couple of years but I wanted to do a very crude early look at some analogue years based upon current projections for teleconnections. The three I've looked at for now are QBO, ENSO and Solar cycle progression.

For all three there is hardly a scientific methodology behind it. For QBO I took the closest matching profiles I could at 50mb (with some attention paid to 30/70mb either side of this too) - the numbers outside of brackets are the closer years I could find, the ones in brackets possess similar-ish profiles but not quite as good as the other years. This gives us a bit more data to potentially play with though. For ENSO, pretty similar to above in terms of looking at the annual profile, but here the years in brackets are years in which we remained ENSO neutral, albeit slightly negatively, where as the years outside of brackets are winters which dipped down into weak-ish La Nina.

Finally, solar cycle progression is by far the crudest of the measures. I've taken the years in the declining phase of the solar cycle with an annual smoothed sunspot number of approximately 40-50 - really not entirely scientific but within the constraints of time it should give us some idea for now.

So here were the years I picked out for each:

QBO (Close but not exact profile matches)

1962,(1965),(1972),(1974),1976,(1979),1981,(1986),2000,2014

ENSO (remained neutral rather than weak La Nina)

1954,(1961),(1962),1967,(1978),(1981),1984,1995,(2001),(2005),2007,(2012)

Solar Cycle Stage

1952,1962,1974,1984,1994,2005

The years with at least 2 'matches' are:

1962, 1974, 1981, 2005

 

I am not going to be issuing any sort of forecast based upon this very crude measure, but hopefully it's something just to get a little bit of a conversation going as we head towards the business end of the weather year - if I can get a bit more time soon then I'll try and add in some composite plots.

 

1962!!!! YES!!!!

 

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