Model output discussion - 5th December 2016 - Into Winter we go

[karlos1983]

GFS(p) not much kop on the 12z either. The slug needs salting !!

 

[weirpig]

Oh well desperate times perb1 brings the-8s into England by early next week

[Nick F]

15 minutes ago, Nouska said:

 

It is remarkable how two sites can present the precipitation anomaly for the 336 to 504 timeframe so differently.

   

 

The chart you posted on the left is up to 336hrs (week 2) and the right after 336hrs (week 3) though? Nevertheless week 3 does hint at a southerly tracking jet I guess ...

[weirpig]

Maybe I'm chasing the pot of gold at the end of a very long rainbow. But some of the ensembles paint quite a nice picture. Height rises do seem the theme some to the north east and a few to the northwest  still mileage in this yet 

Edited December 5, 2016 by weirpig

[damianslaw]

Going to take a break from model watching and this thread until Friday, I suspect by then we will see the longer range outputs moving away from the current perpetual atlantic onslaught as the signal for anticyclonic conditions begins to firm up once we hit mid December, and with it perhaps a bit less pessimism in this thread. Rarely does any model get it spot on past the 144hr timeframe anyway, nevermind 240 hr timeframe. I've seen many what might appear zonal charts to quickly do a u-turn thanks to sudden developments in the 96-120hr timeframe, shortwave features often the cuplrit.

The polar profile is still conducive to a weak atlantic assault as it has been since September, its just at this time of year, it tends to naturally have more fire about it, but is ripe for dampening..

[Nouska]

8 minutes ago, Nick F said:

The chart you posted on the left is up to 336hrs (week 2) and the right after 336hrs (week 3) though? Nevertheless week 3 does hint at a southerly tracking jet I guess ...

They both said +336 - my apologies. That would make more sense and better too as more ppn signal in the Med.

[Cheshire Freeze]

27 minutes ago, Carl46Wrexham said:

Scary thought. Get stuck in a real mild gunk rut and before you know it its mid January and suddenly...very quietly you start to hear the clock ticking.....

Yep..

However for me this winter is already looking like 2012/2013 over again. The GLOSEA5 update last month had me saying '2013' and the CFS is seemingly consistently going for January and March blocking. 

As I've said before, at no point has this winter looked like being front loaded to me.

Mean little in isolation but current CFS anomalies for Jan & Mar

A consistent theme has been for February to be more mobile. I reckon this is due to a downwelling of strong upper strat by that juncture. The March blocking signal I reckon to be due to a strong SSW/final warming.

I'll take an educated punt here and say that the new year period will see a period of cold/snow, give or take a few days either way. How far into January this potential lasts is open to debate...

Edited December 6, 2016 by CreweCold

[bobbydog]

The Outer Limits....

PARAnormal  maybe......

Edited December 6, 2016 by bobbydog

[Guest]

MY SECOND “WINTER 2016/17” FULL REPORT WITH DECEMBER 5TH INPUT

Please note that most of the charts that I refer to in this post are through “live” links which update periodically. So, if you are reading this a few days or even hours after publication (on Tuesday, December 6th at 0200), some of the charts may already have updated. My comments relate to what the charts showed at the time of this posting.

Despite severe time pressures, I have decided to try and provide weekly rather than fortnightly updates for the next few weeks as the Winter prospects seem to be on a knife edge with everything very much to play for. As usual, I am timing this report to include Dr Judah Cohen’s latest Arctic Oscillation report (just out 2 hours ago).

The Model Uncertainties Are Greater Than Ever:

What a week of ups and downs! Although the models came into general agreement and alignment, as one would expect, regarding this week’s forthcoming mild spell, there has been and still is considerable disagreement beyond D6 to D8. Extended ensembles have also been yoyoing and long range forecasts have been published with cautionary notes. This is hardly surprising with so much shorter term uncertainty and hugely conflicting background signals. Most of us were hoping that things might be largely resolved before mid-December but, if anything, the outlook for the second half of December (let alone the rest of this Winter) seems more difficult to predict now than it did two weeks ago! One thing is for certain, we have entered a brilliant period for model watching. 

At times like these, I feel it is important to take stock, step back and try to take an unemotional approach. There is absolutely no point in overreacting and being overly pessimistic or overly optimistic. We can continue to expect to see a huge range of medium term outcomes (perhaps for the D6 to D15 period and certainly beyond that). So many things need to be resolved and some of the regular posters have alluded to this while others seem to have given up far too easily!. Here are just some of outcomes to be resolved:

1. Polar Vortex - Just how strong and for how long will we see a recovery in the polar vortex? Will it still be split and where will the lobe(s) end up? Could it weaken again? Have some of the models (like the GFS) overstated the strength of this recovery? Surely the extent of this recovery is absolutely critical?

2. Jet Stream - Will the jet stream, which is strengthening right now remain strong for a prolonged period, take a direct zonal path, could it split and/or could it be forced or diverted  and meander well away from the our shores. A southerly jet pushing through the Med or even North Africa has been mooted as a possibility as has a northern arm extending way into Greenland before returning south. Which arm will have the greater impact? Will the first proper Winter cold in the USA be sustained for long enough to really fire up the Jet quickly or will the cold subside again (or be more restricted to the western and central states) with the Jet weakening again just as quickly?

3. Stratospheric Warming - Will the stratospheric warming that we have seen for a while propagate fully to the surface? Will other forces disrupt or encourage this. Might we see multiple warming events or at least one new major SSW later this Winter?

4. MJO - Will the MJO come to life again soon and, in time, move to the 7, 8 or 1 phases favouring high latitude blocking? Might this coincide with other favourable synoptics?

5. Other Considerations - The effect of some of the other teleconnections are rather beyond my limited knowledge. I always read with interest, the excellent posts from the likes of Tamara, Glacial Point, and Singularity (+ many others) but I do not claim to fully understand things like the QBO and impacts from solar activity! I take what we are told by these experts at face value and trust in their explanations.

6 Timing issues – it seems that the timing and the order of particular events might be critical.. To a lesser or greater extent, all the teleconnections interplay with each other but which is the most dominant and impacts on the others directly? I thought that one of the overriding factors was the near neutral to marginally La Nina conditions. Was this partly responsible for the record weak polar vortex? I’m sure it’s much more complicated than that but could similar factors help to prevent a prolonged strengthening of the vortex and the jet stream?  

Despite what many posters have said in the last few days, I do see various opportunities for further blocking in some of the models. I strongly believe that the GFS has been far too bullish with its greatly increased mobility and return to zonality. I noted with great interest the discussions regarding the GFS Parallel, highlighted by “bobbydog” and with a very helpful post from “Nick F” showing the planned developments. Even if the “Parallel” is still partly experimental, it is intended to be a considerable improvement on the current GFS model. It should address some of the recurring faults such as overstating the speed and depths of depressions. I accept that it is 6 hours behind but I fully agree with bobbydog, in that we should all pay the same amount of attention to both GFS models. They have been quite different for the last 2 days. By using both models, we can start to draw our own comparisons on this site over an extended period to see which model verifies the best in particular circumstances.

Arctic Sea Ice News and Analysis:

The last full update was on November 2nd with the next one, due in early December, is now overdue. I will edit this section if the new update appears in the next 24 hours. The ice extent map, however, is updated daily. Here’s the link:

http://nsidc.org/arcticseaicenews/

This highlights the record low overall Arctic ice extent during October and the very slow recovery since then. There is still very little ice in the Baring Sea and Kara Sea on our side of the Arctic and ice build-up in all other parts of the Arctic is either below or well below average.

Dr Judah Cohen’s Latest Arctic Oscillation Report:

Judah Cohen has just updated his AO report at 2330 on December 5th. This Winter he is aiming to update his site every Monday. Here is the link:

http://www.aer.com/science-research/climate-weather/arctic-oscillation

I copy the first part of his latest “summary” and “impacts” below.  

“Summary

The Arctic Oscillation (AO) is currently neutral and is predicted to trend positive week one and then trend negative week two.  I continue to expect large model volatility in the near term due to challenges predicting downward propagation of circulation anomalies related to the ongoing weak polar vortex (PV) event.  Model forecast are highly uncertain for next week.

The neutral AO is reflective of mixed pressure/geopotential height anomalies in the Arctic and across the mid-latitudes. However with positive heights over Greenland and Iceland and negative heights in the eastern North Atlantic, the North Atlantic Oscillation (NAO) is currently negative.  However the NAO is predicted to trend positive this week similar to the AO.

I continue to believe that variability associated with the AO does not currently best explain anticipated weather across the Northern Hemisphere (NH).  Instead I believe that the circulation associated with the polar vortex (PV) best explains the large-scale weather patterns across the NH continents.

The main PV center is predicted to reside over northwest Siberia for the upcoming week with a second more minor center over the United States sliding west into the eastern North Pacific with a Canadian high-pressure center separating the two.

In the near term this favors cold temperatures across Northern Asia and for Arctic high pressure to build across Alaska and northwestern Canada, with pieces of the Arctic high predicted to slide into the Western US over the next two weeks.

We heavily rely on October Eurasian snow cover in producing our winter forecast.  Typically the peak hemispheric response to snow cover variability is mid-January to mid-February.  This winter I believe the peak response will be from early to late December, or six weeks early.  This introduces greater than normal uncertainty in our winter forecast based solely on snow cover.

Impacts

It is my opinion that for the past two months the hemispheric atmospheric circulation experienced a nearly textbook response to extensive Siberian snow cover as outlined in Cohen et al. (2007).  I hope to provide support for that claim shortly either in the blog our on twitter (@judah47).  But as I discussed previously, there can be too much of a good thing, at least pertaining to the forecast, and that the response to snow cover variability was so efficient that the cycle of atmospheric responses is greatly accelerated.  Typically the hemispheric lower tropospheric response to snow cover occurs in mid-January and peaks in the weeks from mid-January through mid-February.  However this winter, I would argue that the lower tropospheric atmospheric response initiated the first few days of December and will likely unfold through the end of the month.  I would argue that there is unlikely to be a direct dynamic atmospheric response to snow cover variability in the months of January and February, creating additional uncertainty to the winter forecast.

The best analog that I can think of is the winter of 2009/10, when also the atmospheric response to a rapid advance in Eurasian snow cover was accelerated and peaked in December  (for a diagnosis of that winter see Cohen et al. 2010).  In that winter, a second sudden stratospheric warming (SSW)/PV weakening event occurred in February that helped the forecast to verify.  There are two important differences this winter compared to that winter.  The first is that winter was an El Niño winter and this winter is La Niña.  That favors a northwestward shift of the coldest temperature anomalies from the Southeastern US to the Northern Plains and Central Canada, which can be seen in the different forecasts from winter 2010 and this winter.  A second difference between the two winters, in 2009/10 the quasi-biennial oscillation (QBO) was easterly and this winter it is westerly (though it’s behavior is highly anomalous).  An easterly QBO is thought to favor SSWs and a westerly QBO to inhibit SSWs.  Therefore it is possible that a second SSW is less likely this winter compared to 2010, though SSWs occur in both phases of the QBO.

In the short term, it does appear that the drawn out PV weakening peaked in late November.  With a relatively quiet period in upward Wave Activity Flux (WAFz)/poleward heat flux predicted in the near term, I expect that the circulation anomalies associated with the PV weakening to episodically descend to the lower troposphere throughout the month of December.  This should favor through the month a mean negative AO (though a classic -AO pattern is looking less likely and not suggested by the recent SSW) and cold temperatures widespread across the NH continents.  Based on the recent and predicted near term PV behavior, that includes Siberia and Western Canada and the Northwestern US.

In the near term, with the primary stratospheric PV center over Northwest Asia followed by northerly flow as the PV recovers closer to the Pole, favors cold temperatures across Siberia and Northwestern Asia.  High pressure over Northern Canada and a secondary stratospheric PV center over the US favor building Arctic high pressure across northwest Canada and colder temperatures across the Northern US.  As the stratospheric PV recovers closer to the Pole, predicted cross-polar flow into Western Canada supports persistent cold in Western Canada.

For East Asia northerly flow in the mid-troposphere, favors episodic outbreaks of cold air from Siberia.  For Europe, the recent wind direction around the main stratospheric PV center over northwest Asia has been northerly resulting in the recent period of cold temperatures.  However as the PV center recovers towards the Pole, the wind direction is predicted to turn more westerly, which is a milder wind direction for Europe.  For next week positive geopotential height anomalies centered directly over Europe is predicted, which effectively blocks mild maritime air from reaching Western Asia but not Western and Central Europe and therefore milder temperatures are predicted for Europe.  However the center of positive geopotential height anomalies is predicted to migrate north of Europe after mid-month, which is a more favorable position for the eventual return of colder temperatures….”

His report goes on to assess the outlook over the next few weeks and beyond. Judah has back-tracked slightly highlighting  the current uncertainties in the models but still favours an eventual return to colder conditions in Europe once height rises re-establish to the north of Europe after mid-month. .

Arctic Oscillation (AO) Ensemble Charts: 

Right, now on to my usual indicators to see if there is any clue as to how things might pan out in the next few weeks. The Arctic Oscillation, which has been negative, is currently neutral.  During the next 7 days it trends slightly positive but then, just over half of the ensemble members go back into negative territory, some more strongly negative. This continues to demonstrate the current uncertainties which is evident across all the models. A negative AO would reflect greater high latitude blocking and there remains some evidence of this in the 7 to 14 day period. Here’s the link.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml

North Atlantic Oscillation (NAO) Ensemble Charts:

This is interesting. As with the AO, the NAO has been negative and is currently close to neutral. Some of the ensemble members go positive and stay there (but not strongly so) with several going negative again within 5 to 7 days and some members remain in negative territory throughout and several go strongly negative. This is certainly does not match GFS’s ever deepening low pressure, mobile scenario and much more demonstrates a faster return to higher pressure which is more in line with some of GEFS and GFS Parallel output. Here's the link:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

Please note that both the AO and NAO charts I show are based on GFS ensembles.

MJO Ensemble charts:

Here are today's MJO ensemble charts for the big 4 (all updated on December 5th). 

UKMO (7 day forecast):  

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml

ECM (14 day forecast): 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml

NCEP/GEFS (14 day forecast):

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml

JMA (9 day forecast):  

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml

Please note that last Winter I reported on Kyle MacRitchie’s specialist MJO predictions which seemed to always differ somewhat from the big 4. I have been in contact with Kyle during the summer and he feels that his charts are not adjusted frequently enough and should not be compared to the others. So, unless Kyle improves his updating standards, I shall discontinue reporting on his predictions for the time being.

COMMENT: All 4 start the MJO off in the circle of death (COD) but there are now some signs of renewed activity with an interesting divergence. The UKMO (shortest forecasting period) from tomorrow has it re-entering around the phase 2 to 3 boundary and steadily progressing to phase 4 during the next 5 days, all at quite low amplitude. The ECM attempts re-entry in the phase 1 to 2 boundary but largely remains in the COD although one stray member moves out into phase 7 and on into 8.. The NCEP/GEFS has a wider spread in phases 2,3 and 4 initially but quite a few members move into phases 7 and 8 with several at reasonable amplitude. The JMA remains large in the COD but several members to edge into phases 1 and 2. The overall mixed picture  underlines the current uncertainties but there is more than a hint of optimism and perhaps surprisingly, the GEFS is going for at least some high latitude blocking. Definitely one to watch..

Northern Hemisphere Snow Cover:

I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA).  When you go to their site you can change the date range and look at the Autumn and Winter seasons and set the date ranges. These are brilliant, very informative charts and great to play around with. I’ve set the links below to show the last 2 weeks from November 22nd to December 5th:

a) Animated Northern Hemisphere Snow Cover Changes (updated by NOAA December 5th):

https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/nh/20161122-20161205

b) Animated Europe and Asia Day Snow Cover  (updated by NOAA December 5th):

https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20161122-20161205

COMMENT: There is well above average snow cover over northern Asia and much of Scandinavia. The snow cover currently extends to eastern and northeastern Europe. The Arctic ice sheet has expanded quite quickly during the last few days but is still below the 2012 level (the record low year).

Current Arctic Regional Surface Temperatures:

GFS – Northern Hemisphere Current Temperatures:

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=9&carte=1

The link to this chart updates 6 hourly with each GFS run. At the time of writing it is showing a chart for 1900 GMT today (5thh December). As this is T0 to T6 hours, it should be pretty accurate. Here is a summary of the temperature readings that I will be following in future reports with comparisons for the previous reading on November 27th in brackets:

North Pole –  -28c to -32c (around -24c).

Barents Sea/High Arctic – -16c to -20c (around -8c to -12c).

Scandinavia – south +4 to -8; north -12c to -20c (mostly around -8c).

Northern Siberia - -32c to -40c (around -28c to -40c).

North West Russia - around -16c to -24c.(no change)

North-east Europe – -4c to -8c (around 0c  to -4c).

Please note:   At the time of posting this link it was showing 2000 BST on Monday, December 5th. I will always try to show the 2000 BST (1900 GMT) charts for a consistent comparison. The charts are automatically updated 4 times a day, so the temperatures shown will be different to those I just mentioned above. We can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/night time variations. So for like for like comparisons, for example the 2000 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 to 1700 or about 4 to 5 hours later. This also applies to some of the other charts I link to in this post.

Svalbard Daily “Maximum” Temperature Forecast for 10 Days:

Here are the links to the 3 Svalbard stations that I am monitoring.

Central/West Svalbard – Longyearbyen 28 m asl:   

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf

December 7th  -18c;    December 10th   -10c;    December 14th  -10c.

North-West Svalbard – Ny-Alesund:  

http://www.yr.no/place/Norway/Svalbard/Ny-Ålesund/forecast.pdf

December 7th  -18c;    December 10th   -15c;    December 14th  -14c.

Central South Svalbard – Sveagruva:   

http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf

December 7th  -22c;    December 10th   -17c;    December 14th  -16c.

The general trend is for the “maximum” temperatures (which have been above 0c for much of November) to remain well below freezing during the next few days, in fact these temperatures are generally lower than they were for almost all Winter 2015/16. This should aid some strong sea ice recovery but from such low levels, this is unlikely to have much of an impact on polar temperature contrasts with adjacent regions until later in the Winter.

These links will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at short range. 

To put the above figures into context, here is a link to the main Longyearbyen site:  

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html

COMMENT: This shows monthly means, and actual highest/lowest temperatures recorded during this winter and goes back further. Svalbard has been seeing “maximum” temperatures often running at 8c to 10c above their long term average throughout most of 2016. This has been the pattern for several years and is reflective of the warming Arctic and record low sea ice cover. The very latest trend is, however, more encouraging with temperatures falling to or even slightly below their long term averages. If this trend continues, then we should start to see new sea ice forming much more quickly in the coming weeks. In the meantime, it does mean that a northerly airstream from the high Arctic might have slightly more of an edge to it and could be the difference between rain and snow over lowland Britain given a marginal pattern. I still feel that we need to look to the east for any pronounced and more prolonged cold during late December and into January.

Final Comment:

Most of the models, indicators and forecasts continue in a very uncertain state. I still feel more optimistic than most and many of my indicators support this to a degree. Perhaps things will become clearer as the month progresses.

Next Update:

I’ll try and manage another full update to this report in a week’s’ time.

 

Edited December 6, 2016 by Guest
Correct typos and ensure all the links work

[Mucka]

Thank you for that BB62, very comprehensive coverage of where we are re teleconnections and what we might expect.

Must have taken a good deal of effort to writei it and like Tamara's posts they are a nice contrast to quickfire MO summaries in this thread.

S onto this mornings output.

UKMO has taken a step back but GFS a step forward as far as any potential blocking goes.

In that regard what a difference a little 24 hours can make with GFS today and yesterday comparisons below.

And day 10

Are we beginning to turn the corner or is this just a random variation never to be repeated?

Personally I will wait for some consistency and the ensembles and ECM to get on board but my gut tells me this is the start of some better output for blocking though it may take a while to find any consistency.

 

 

Edited December 6, 2016 by Mucka

[IDO]

47 minutes ago, Mucka said:

 

 

Are we beginning to turn the corner or is this just a random variation never to be repeated?

Personally I will wait for some consistency and the ensembles and ECM to get on board but my gut tells me this is the start of some better output for blocking though it may take a while to find any consistency.

 

 

I am certainly of the opinion that the pattern will be repeated as I see no changes in the NH drivers. So another UK HP for a week or so around D10 would tie in with that theory. Again where it sits and meanders will be the interesting stuff as we missed out on the cold recently and the GFS 0z run mimics that. Whether we can draw some of that cold west will be the issue. Again at the end of the run the Pacific Ridge falters and sinks again so no sustained WAA, as with the recent meridional pattern. The US/Canada again a direct hit as does East Euro/Russia.

Good support in the GEFS for a high close to the UK with no discernible locale for that high so cool to cold: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=0&ech=336

HP is certainly my preference at this time of year so a very good run which marries well with most current thinking (MET, etc).

[Johnp]

GEFS also strongly going for a build of high pressure, with signs of retrogression on many.

Could the Xmas miracle be unfolding?

[Captain Shortwave]

GEFs still holding out the promise of something drier from mid-month onwards

      

Any negative anomalies are very weak to our south so probably a decent mid-latitude ridge initially to the south east of the UK which will migrate to more of a UK based one later on. So if this is near the mark then increasing chance of widespread frost and fog as we approach the Christmas period. So seasonal but not overly wintry though again having a high in this location is a decent starting place to develop something much colder down the line.

[knocker]

Today

Roughly starting with Scotland and the north and east on the one hand and N. Ireland and the west on the other. The former starting very cold/cold and remaining on the cool side with sunny intervals whilst the latter cloudy and starting to feel the encroachment of the milder air from the south west. This will continue overnight to effect all.

The GFS this morning. Well to start no change with the upper pattern according to the GEFS anomalies. So a little more detail.

Some rain will effect Scotland overnight as a system tracks NE and the high pressure slips SE. The movement of the latter continues and by Friday more fronts have arrived from the west driven by the upper trough which then proceeds to deconstruct under renewed pressure from the Azores. A not unfamiliar story of late.

And as the trough deconstructs we again have the split jet scenario with a cut off low tracking SE and the other trough running around the north of Scotland and phasing with the eastern trough and dropping SE into Poland and bringing the cold air tantalizingly close once more. IMHO it's this sort of scenario that could introduce low pressure to the SE and isolate high pressure but it tends to flatter to deceive, so to speak

Thereafter we have a repeat performance. Strong ridging NE over the UK whilst the trough approaches from the west and deconstructs only this time energy transfer is pushed further north by the HP thus isolating two upper lows to the SW and SE. Essentially this all a variation on a theme of the interaction of the cold and warm air within the little changing upper pattern

So to continue with a little more surface and weather detail  After the weekend HP will generally be in charge as the Azores ridges NE and the moves east but restricting encroachment from the west to the north west whilst at the same time backing the airflow to the SE quadrant. So remaining basically dry with initially temps above average but cooling with change of wind direction.

EDIT

And funny enough the run finishes with the sceario I've been waffling on about lately/

Edited December 6, 2016 by knocker

[Iceberg]

Signs of a subtle shift in the models over night in the medium term. With less of a cross polar flow through the arctic and in turn a chance for pressure to migrate into Greenland. As shown by the longer range p gfs. It's a trend that's being picked up in the table gens view as well. It will invariably take longer than the models show but should occur in the 24/28 time frame imho. With a gradual pull back of the Atlantic showing the medium term onwards. 

A bit of unsettled, then drier, then colder. 

Edited December 6, 2016 by Iceberg

[Seasonality]

Morning weather fans. Something is brewing in the East. Much clearer drop and tighter clustering of lower temps in Central Europe than in recent runs and a clear cool down London too. And look where we end up on the 21st. Posted jokingly yesterday from CMA output but a solution reached for the same date by yesterday's 06z parallel. Euro slug has had salt poured on him and amplification is back. Well supported run by ensembles. Perhaps the model output change hinted at by GP is happening.

 

Edited December 6, 2016 by Seasonality

[Seasonality]

GFS and ECM comparable at 192h. No flat euro slug!

 

[Paul_1978]

Well well.....interesting GFS run. First time for a while we've not seen the HP get bulldozed out of the way. 6z awaited with interest!

[Ali1977]

4 minutes ago, Paul_1978 said:

Well well.....interesting GFS run. First time for a while we've not seen the HP get bulldozed out of the way. 6z awaited with interest!

ECM also interesting, no more Atlantic by day ten. Back to frosts, just need a few tweaks with the position of the high now.

More importantly, low pressure building in Italy and Greece.

Edited December 6, 2016 by Ali1977

[Iceberg]

Overnight change. 

Ecm yesterday and today at 240 and backed up by gfs p at 240 with the then Greenland high pull. 

High pressure migrates over the pole at t240 disrupting the cross polar flow previously seen. Atlantic strangled and then ghp migrated 

[SMU]

Morning all

day 16 on the GFS - right at the end we shape up with a decent elevated high -

Note the proper anomaly-

up until then not a great deal in the mix although post day 10 there could be enough amplitude to tug a chilly SE flow...

A long road to trudge but at least it could be a road..

Edited December 6, 2016 by Steve Murr

[Scandinavian High.]

Well it looks like over night we backtracked with the models the high pushing north out of Europe I'm not saying where going to get snow but this is much better output for sure is this a easterly trying to get going?

Edited December 6, 2016 by abbie123

[karlos1983]

Well I am pretty satisfied with the 00z, ukmo a bit meh but it's out of range to be fair.

now that expectations have been lowered / back in line, if we were to be in this position in 10 days time I'll be happy! 

 

Not without ensemble support either 

Edited December 6, 2016 by karlos1983

[Smiler1709]

Again the gfs throws out a little interest mid month, I'm sticking to my guns and saying mid month cold will return. Let's get the mild stuff out the way before xmas and let the party begin to really get us in the spirits.

[Seasonality]

20 minutes ago, Smiler1709 said:

Again the gfs throws out a little interest mid month, I'm sticking to my guns and saying mid month cold will return. Let's get the mild stuff out the way before xmas and let the party begin to really get us in the spirits.

The interest begins less than one week away, plenty of time for things to change but no longer in the far ranges of deepest FI. By the 12th the re-amplification is already apparent. Here at 162h.