Model Output Discussion - Staying cold into the new year

[topo]

ECM 850s ensemble mean rising towards mid January. 

ECMWF 14-day ensemble weather forecast for London

METEOLOGIX.COM

---

London, England, United Kingdom - The ideal weather forecast for the next 14 days. See the results of all 50 ensemble members of the ECMWF model in direct comparison for several parameters.

 

[reno]

Hi all, rarely post as have no technical knowledge however am avid reader of this forum for many many years,

Always a delight to read the intelligent interpretations of model predictions, let's not forget these models are predictive tools of events not yet occurred and not to blame if they go down another route..

For me things appear more exciting for avid coldies than since 2010/2013, posted in the regionals regarding Mondays 9cm fall followed by 6cm today (stoke) this is a rarity, normally wrong side of marginal time and again, this bodes well going into jan as Uk is nearly always marginal, oh and my kiss of death, 7-10 day charts have bit of a 62/63 look to them... with a ssw to come...

How many times have we heard that you say....

Patterns normally go against our desires but every now and then we hit gold, certainly have lots of the main pieces in play, let's hope they fall kindly.

Chart attached 30/12/62 note the Eastern European high that some are bemoaning now !!

Dave

[Froze were the Days]

1 hour ago, BLAST FROM THE PAST said:

 

haven’t seen that...what would that mean

errrmm!...we're piggy in the middle and it's hardly ever our turn?

[Methuselah]

9 minutes ago, Froze were the Days said:

Well you're right there! but also at the 850 uppers...but the times are changing. If I don't get any lying snow in the next few weeks I'm going to saw my leg off.

By the way latest CFS not a million miles away from ECM near day 10...perhaps lacking the Arctic blast and associated LP

 

No problems here, Froze... following such a good day's model-watching, I'm already legless!

[Duncan McAlister]

I like the consistency of the models at the moment, just reliably cold, seasonal weather in the heart of winter with the odd surprise snow flurry. Better that than a spectacular easterly at +240 that ends up letting you down (even if they come off - invariably too dry in this part of the world)

[Tim Bland]

5 minutes ago, topo said:

ECM 850s ensemble mean rising towards mid January. 

ECMWF 14-day ensemble weather forecast for London

METEOLOGIX.COM

---

London, England, United Kingdom - The ideal weather forecast for the next 14 days. See the results of all 50 ensemble members of the ECMWF model in direct comparison for several parameters.

 

As Blue said earlier: Massive split at the end. Everything from +10 to -10 850hpa. Not sure how these compare to last few runs? 

[Allseasons-Si]

Looking at the day ten mean 500mb,850's and height anomalies from both the ECM and gefs and i have got to say they are singing from the same hymn sheet with W Greenland heights and W Russia heights with some sort of trough coming down from a northerly quadrant with low height's underneath

these are stunning charts and a far cry from last winter

Edited December 29, 2020 by Allseasons-si
typo

[Man With Beard]

Looking at the ECM ensembles D11-D15, decent blocking is forecast in the Atlantic at D11, but the clusters show a large amount of scatter by D15. Nothing unusual to have such scatter by then, in fact, it's less usual to have a strong consensus. However, heights to the west seem the diet on all clusters, and cold with instability seems a common theme too. If we get to the end of this cold spell with no significant snowfall for most of the UK, I'd consider us to have been unlucky.

Edited December 29, 2020 by Man With Beard

[WINTRY WALES]

43 minutes ago, chionomaniac said:

It really depends on the trop and strat conditions and dynamics leading up to the SSW.  The more that I have learnt since the first strat thread is that there are many determining features between trop and strat. There are a few occasions in history where the pre SSW trop pattern was better than the post for us in the UK. And that shouldn’t be ignored.  If I was in the east USA I would be hoping that the SSW shakes the trop pattern up somewhat. I’m not. I want reinforcing of it. Risky at this point

Hi Chino...from a novice point of view and I’m sure that one that is shared a plenty on here today...the word “risky” wouldn’t have been used days prior to this...now the mood seems kinda risky and a worry...has your confidence dropped slightly ?This is to the other strat experts also

[Mike Poole]

32 minutes ago, Man With Beard said:

Looking at the ECM ensembles D11-D15, decent blocking is forecast in the Atlantic at D11, but the clusters show a large amount of scatter by D15. Nothing unusual to have such scatter by then, in fact, it's less usual to have a strong consensus. However, heights to the west seem the diet on all clusters.

Look at the borders.   Given the current setup we want red ones (Atlantic ridge) or green ones (-NAO).  Mostly OK, but some uncertainty as you’d expect.  I don’t think this pattern is going to go away prior to the SSW, though.  After, I’d be lying if I said i had any idea!  

Edited December 29, 2020 by Mike Poole

[That ECM]

9 minutes ago, WINTRY WALES said:

Hi Chino...from a novice point of view and I’m sure that one that is shared a plenty on here today...the word “risky” wouldn’t have been used days prior to this...now the mood seems kinda risky and a worry...has your confidence dropped slightly ?This is to the other strat experts also

Not a Strat expert but I believe that he is saying that nhp is good for us in terms of cold as we stand. A SSW could shuffle the nhp less favourably for cold for us. OR you could just read the post below. Not as in depth and detailed as mine but.......

Edited December 29, 2020 by That ECM

[Catacol]

49 minutes ago, feb1991blizzard said:

Agree without the split it will probably knacker us, but we cannot wish the SSW is not going to happen right now because it pretty much nailed on will, so we desperately need a split, also though if we had massively strong zonal westerlies up above all the way through winter, would this trop pattern have been allowed to persist, you have to think that in such a scenario, the trop would have responded at some point with a +NAO.

I’ve spent much of the day on and off thinking about this. A vortex split is not out of the question yet, but the direction of travel seems to be currently towards a signficant displacement and extended reversal. Lots of posts today musing over SSW impacts when it is a displacement - but I’m not convinced by the pattern matching on this. The sample size is very small, whether one goes with a top 5 wave 1 reversal, Masiello’s 4 year analog of SSWs in our current context (and he didn’t factor in QBO or MJO either) or any of the other discussions out there.

One long term risk is the possibility of a vortex recovery and a lock in to pacific Nina forcing that could flatten things back out in February. Back again to the post yesterday around a 2-3 week memorable spell or a 6-8 week historic one. I also wanted to see a split vortex because in that scenario I don’t think vortex recovery is an issue. With a displacement it is, and we are left looking for signs of what might happen.

Chio is right of course to focus on the now. We have a great pattern developing here which looks about as nailed on as it ever could be out to mid Jan at least. Why worry about what might happen in 21 days’ time? Quite right. But I can’t help musing, because the really deep cold uppers look to me to be a projection for the longer term, and that means wishing that the vortex stays broken. At least for me it does!

No answers or projections really at present bar the thought that very strong Greenland ridging might create a unique feel to a wave 1 displacement that we haven’t seen in previous events. The current warming is Ural driven rather than Pacific driven, and that means a different angle to the usual displacement that might cause ongoing vortex grief via North Atlantic blocking. We know that tropospheric impacts from a Greenland ridge are not of the same magnitude as per vertical wave breaking created in other places, but if vortex energy heads to Russia as currently is probably the best guess, then as Webb has said today the Greenland high may be in residence for a long long time. No westerly pressure to shift south, reinforced by ongoing pacific jet events, and possibly even supported by reverse flow back through Europe as the battered and unhappy vortex sets up shop over Russia for a while....always assuming downwelling reversal impacts.

All very complicated. I’d love to see the split modelled again and occur at short notice. It is still possible. If not, we ride Chio’s near time wave for 3 weeks or so and then watch with a degree of uncertainty as to what happens in the second half of winter.

Best keep this post on topic. Point of note for me today - EPS 240h shows perhaps the beginning of the end for the East European ridge that has pumped above average air into the mix. Good news. And note the Ural high anomaly is still present....so perhaps we are not yet done with kicking the vortex around this season.

Great data and model watching continues!

[Methuselah]

7 minutes ago, Allseasons-si said:

Looking at the day ten mean 500mb,850's and height anomalies from both the ECM and gefs and i have got to say they are singing from the same hymn sheet with W Greenland heights and W Russia heights with some sort of trough coming down from a northerly quadrant with low height's underneath

these are stunning charts and a far cry from last winter

It's all just there 'for the taking' Si... If I don't see any meaningful snow from this, I'll saw @Froze were the Days's other leg off!

[Tim Bland]

Does anyone know how good the extended GEFS are modelling the possible effects of the SSW? Not many cold ones by end of Jan so I’m hoping they are not factoring this in? 

[MATTWOLVES 3]

Firstly folks a quick look at tonight's UKMO at day 6,and the impressive Heights over Greenland..

And with all the talk of an SSW which appears to be taking place now as we speak...its exciting...I feel like it a couple of weeks from Xmas again and I'm gerrin excited over what presents I may have...sorry folks I'm a big kid at heart...its just the thought of what could be coming for you.

So also in this post I've included a graph showing the average temperature anomaly.0-30 days after a major warming event,with the main cooling over Eurasia and the Eastern States.

Also a graph illustrating increased snowfall in the same areas as above. There is also a graph that shows how a major SSW impacted the 84/85 winter. And how it played a major role in its development.

So even though there may be know guarantees in anything in life...I will sure as hell take those odds for increased wintryness..

 

 

[Tom Jarvis]

Erm this tweet says the SSW has actually started 

 

[Frosty.]

The ECM 12z op / mean are singing from the same hymn sheet..both about to pull the trigger for something even colder!..to me, cold looks locked in, can’t see anything mild, even those areas that have occasionally less cold uppers (850’s) would still be cold at the surface..I believe we are looking at entrenched cold with no milder mixing out!... this could be the winter coldies have been craving for a good number of years..fingers !

[snowice]

1 hour ago, chris55 said:

There is an old adage on the Netweather forums....

”you only know the train is coming, when you can actually see the train” this stems from times looking at weeks of zonality trying to spot the change to an easterly...

Right now, believe it or not, we have actually boarded the train. However, the train is one of the two carriage ones that’s a bit rickety, we are all on board but it’s not to everyone’s liking. Some are in the nice seats and some are standing only and this is causing a bit of bickering.  But we are on the train nonetheless.

No doubt we are heading to our destination, hopefully to be transferred to the new intercity where we can all relish and enjoy the journey. But alas, the ride will be littered with unexpected stops and the occasional break down along with some periods of smooth running. We might end up at our destination of Arctic bliss or we could be subject to a bus replacement service...I’m quietly expecting the the former..

And that is what makes this place so enjoyable  

Your on the right track there

[Flash bang flash bang etc]

3 minutes ago, snowice said:

Your on the right track there

I rail-y enjoyed this

[Allseasons-Si]

4 minutes ago, General Cluster said:

It's all just there 'for the taking' Si... If I don't see any meaningful snow from this, I'll saw @Froze were the Days's other leg off!

Then he will be doing handstands

anyway,the latest ICON has the heights a little further south than the 12z

18z 120 v's 12z 126

and looking at the latest snow chances the ICON pushes that low further south on Wednesday and also delays the band of PPN coming down from the north on Thursday but there is a faint band before it.

 

 

[ANYWEATHER]

Darling it's cold outside......!

[nick sussex]

Longer range ensembles are unreliable at the best of times . Throw in a SSW and you’d be better off reading the tea leaves .

 

[ICE COLD]

I’ve heard this model is held in high regard by the met . Nice chart tho . 

[sheikhy]

Expecting gfs to move towards ecm!!!!if it doesnt i be really surprised!!!!a ukmo run would be perfect!!

[Snowjokes92]

1 hour ago, Met4Cast said:

The background signals are solid. We have MJO potentially moving into a low amplitude phase 2 which is supportive of blocking around Greenland, this only serves to support the potential for blocking there, rather than "drive" it.

The GWO orbit is favourable and likely to remain favourable well into January for high-latitude blocking, as it swings around into phase three we could see a slight Atlantic push, but with a HLB in place this could bring snow potential.

An almost record breaking +EAMT event is currently underway and will serve to support further blocked conditions in the Atlantic/Greenland sector as we go into January. The insane blocked charts we're seeing are very much trop led at the moment and what we're seeing is very, very good. A protracted period of below average temperatures out to the 2nd week of January seems increasingly likely.

From there? Who knows, perhaps a slight pattern relaxation or perhaps the GFS is over-doing the lows and as we get closer to the 6th Jan they'll start trending southwards.

The extended EPS is very blocked, some clusters are too far west with the block & thus we'd likely see less cold conditions moving up into the UK, but overall I'm not too worried at this stage.

As for the SSW potentially scuppering the pattern, it's a possibility. But that's some three weeks away before any potential impacts from downwelling, and at least 2 weeks away before we're going to start having some idea. Heck, models still can't agree on exactly WHEN the SSW will take place. 

All good going forward. We're in a cold spell, it's likely to turn colder. I really can't understand the negativity. Ian Brown would be saying "wtf" at the current outputs.

 

Great post and very informative. What got me is the +EAMT event. Not totally clued up on it but aware its a big player in the coming days/weeks. I am presuming this is still to happen, have the models got the data in their runs to support it or is this due to start showing in the runs when it happens. If its not already been picked up on, then goodness could be some really juicy runs or maybe thats already behind some of the lovely runs for coldies?