Model output discussion - into the start of Winter

[blizzard81]

22 minutes ago, Bricriu said:

That is a Significant amount of blocking. Whatever about it getting cold enough for snow, surely there would be no swift return to zonality from that.

That chart led on to one of the mildest winters I can remember. And that's saying something. 

[SMU]

39 minutes ago, topo said:

Something like this please 

Whats that from - Awsome Easterly for crimbo period

[Bricriu]

3 minutes ago, blizzard81 said:

That chart led on to one of the mildest winters I can remember. And that's saying something. 

Oh. Which winter was this?

[stodge]

Evening all

Interesting model output has naturally produced a surge in comments and there's little point repeating what others have said (though that's not stopped me before). My perception is the models have struggled with the forthcoming evolution to some degree. That happens when conflicting signals are at play and naturally at this time of year we always hope the dice will fall kindly in terms of cold and, dare one say it, snow for the UK.

Needless to say, GEM 12Z has provoked plenty of comment. The LP disrupts just to the south of the British Isles leaving us on the cold side and while the 850s aren't too exciting, it's still the kind of chart we want to be seeing and the key point is the Atlantic is moribund.

ECM doesn't quite play the same game. The LP disrupts but then splits to the east of the British Isles - with one segment heading north and the other south leaving us in a chilly col:

Over to GFS 12Z OP:

That works out pretty well for the British Isles as the trough heads SE and pressure builds behind it leading to several days of cool, if not cold weather with a NE'ly flow setting up for southern and eastern areas. It's not as wonderful as this morning's 00Z pre-Parallel GFS which is a thing of beauty for fans of cold and snow. The main thing into FI is the PV remains over northern Siberia.

I'm not sure where this is going - some form of disruption of the Icelandic LP SE into the British Isles looks certain but where and how that disruption occurs and where that leaves us is far from resolved. The likelihood is pressure will build from either the NE or NW but whether that lasts or we see a reset to a more traditional synoptic pattern I don't know. 

[Chesil View]

Quite a bit of negativity around this evening, everyone seemingly wanting jam today.

Personally I think the models hold a lot of promise but from slow burner point of view. At the moment we are still on the journey to the point where the PV get shoved over to Siberia. This has massive implications down the line for the mid December period in my opinion. The implication being that the presence of the vortex in the Siberian domain can push the russian high westwards via Scandi. The other implication is that while the vortex is absent from the pole High pressure can grow in the  Greenland region more easily as well. Add to this a weak and southerly trending jet and that makes for interesting developments in my humble opinion.

Synoptically we are entering December when one would normally expect to be seeing considerable  zonality picking up and a lot more west to east energy. again the forecasting shows that to be the one thing that won't be happening in the coming days.

So my advice would be to hang on in there because there's a lot that's good from a coldies point of view going on. It might not be in the immediate term but I for one am rather excited to be entering December with the current set up in place.

 

[daz_4]

9 minutes ago, Daniel* said:

Well best we don’t look too far ahead. Looking quite wintry for you in near term in Central Europe even perhaps significant snowfall middle of next week, not a terrible way to start winter? 

Oh sure, at least it feels seasonal. Should get some snowfall over weekend in my neck of the woods. Let's see what the next few days will bring.

Anyway, P10 for me please though not sure you guys in UK would agree

Edited November 26, 2020 by daz_4

[blizzard81]

4 minutes ago, Bricriu said:

Oh. Which winter was this?

Top left hand corner of the chart gives the answer. Winter of 89/90.

[bluearmy]

13 minutes ago, Steve Murr said:

Whats that from - Awsome Easterly for crimbo period

Gefs monthly control 

[Frosty.]

I like the ECM 12z operational, it turns more unsettled but also colder from the second half of next week and would surely become cold enough for snow on high ground? especially further north?...perhaps some of us will get to see snow sooner than we think?    ..better than the 0z anyway!

Edited November 26, 2020 by Jon Snow

[Matt H]

A fairly chilly day 10 mean on the ECM. Good to see the vortex still moving away from Greenland on this run as well. Just hoping that the 00z run tomorrow doesn’t blow up the low again.

[Met4Cast]

There are 3 clusters in the 8-10 day EPS timeframe. The det run is in the biggest cluster with low pressure sat across the UK for that time period, though worth noting the other two clusters which do clear the low to the south of the UK.

Not worth looking beyond the 8-10 day range at the moment, until the trough disruption/upstream pattern is resolved we wont have a clear way forward. 

Quite a shift from members towards an increasingly colder upper air pattern too compared with the 00z run. 

Edited November 26, 2020 by Met4Cast

[Mike Poole]

23 minutes ago, Frosty Winter said:

A fairly chilly day 10 mean on the ECM. Good to see the vortex still moving away from Greenland on this run as well. Just hoping that the 00z run tomorrow doesn’t blow up the low again.

Hi @Frosty Winter, welcome to netweather and the madness of the winter model thread.  As you say the position of the vortex on the ECM mean is consistent yet again and gives hope for a reasonable amount of time where blocking scenarios can happen, even if they don’t land it for us first time, we should be thinking next 3 weeks to land something.  I’m not too worried about the day 8 low, looks overblown, I reckon at least it will become shallower and more elongated as it draws closer in time.  

[SMU]

45 minutes ago, bluearmy said:

Gefs monthly control 

Can you link it - I cant see it on WZ - I havent been on there in years!

[Daniel*]

Improved EPS in cuckoo land the Euro trough a long term feature, recent winters the Euro high has been omnipresent I know its very early but perhaps a sign this winter will be different. The Ski resorts will be very happy, we should be able to generate our own cold in Europe, might not be extraordinary, but perhaps cold enough for snow at low levels at times? I think it's fairly evident now the first half to December will be chilly. Most years we are in a much worse position than this.

[feb1991blizzard]

3 minutes ago, Steve Murr said:

Can you link it - I cant see it on WZ - I havent been on there in years!

Wetterzentrale - Top Karten - GFS Europe 99Z

WWW.WETTERZENTRALE.DE

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Wetterkarten GFS Europe 99Z

 

[Met4Cast]

A few members from the latest EC46 Zonal forecast going for a major SSW in late Dec/early Jan.. 

[virtualsphere]

As others have pointed out, worth remembering that where we are going into December doesn't always represent how the winter turns out overall:

     

However the trough dropping through / close to the UK that's currently being modelled is a positive sign looking at precursors to some recent cold spells:

     

The big difference in the first three charts from 1988, 1989 and Dec 2013 is the angry secondary lobe of the vortex building over NE America.  In the last three charts this isn't present, or is further west over North America with a smaller main vortex.  The positive thing about the current modelling to me is that upstream the vortex looks more like the latter examples:

 

[Mike Poole]

8 minutes ago, Met4Cast said:

A few members from the latest EC46 Zonal forecast going for a major SSW in late Dec/early Jan.. 

And the earliest of them not far out of range of the GFS, so we might see something showing up at the end of GFS runs quite soon, particularly if the Aleutian low, Russian high combo continues to be a feature in the current output, as per GFS 12z T270, and the strat at the end of the run:

Although at the moment the interest is in trop led scenarios, in winter it is best to be prepared for other scenarios too, and this one looks to be gaining in traction...we will see...

 

Edited November 26, 2020 by Mike Poole

[Met4Cast]

8 minutes ago, Mike Poole said:

And the earliest of them not far out of range of the GFS, so we might see something showing up at the end of GFS runs quite soon, particularly if the Aleutian low, Russian high combo continues to be a feature in the current output, as per GFS 12z T270, and the strat at the end of the run:

Although at the moment the interest is in trop led scenarios, in winter it is best to be prepared for other scenarios too, and this one looks to be gaining in traction...we will see...

 

Definitely *feels* like something is potentially brewing now, compared with all the previous blocked looking outputs we saw throughout November that never amounted to anything. 

The EC46 is an interesting update in that by week 3, there's no clear signal for any particular weather type, rare for the model to lose a signal that quickly. There seems to be a "tipping point" around December 15th with the Stat forecasts/extended outlooks that models seem to be struggling with, Simon Lee pointed the same thing out on Twitter too. 

Can't really remember the last time we were in a situation where anything beyond week 2 was a complete question mark, we usually have enough data to take a rough guess, even MOGREPS isn't giving a clear signal either way into December.

[Zak M]

1 hour ago, stodge said:

That happens when conflicting signals are at play and naturally at this time of year we always hope the dice will fall kindly in terms of cold and, dare one say it, snow for the UK.

Snow? What's this 'snow' you speak of?

Anyway, back to the models. P29 is a stonker...

   

[SMU]

24 minutes ago, feb1991blizzard said:

Wetterzentrale - Top Karten - GFS Europe 99Z

WWW.WETTERZENTRALE.DE

---

Wetterkarten GFS Europe 99Z

 

 

One of the best easterlies I have ever seen !!

[feb1991blizzard]

2 minutes ago, Steve Murr said:

 

One of the best easterlies I have ever seen !!

Yes - -15c not far away from you with the -20c not far into the near continent lurking behind it, shame it had to end there.

I have seen lower 850's but this run looks sustainable as well, thats the striking thing, it could end up a more prolonged 87 if it went further.

Edited November 26, 2020 by feb1991blizzard

[Uncertainty]

Good evening everyone.

The middle weeks of December have shown potential for interesting and atypical UK winter weather and today’s model trends do little to dispel that hypothesis.

First of all the latest EC46 is a significant upgrade certainly on last weeks nadir but also on Monday’s iteration.

Week 2 presents a strong Euro low anomaly not far off a centre in the favourable Genoa region. Anomalous heights are present in the mid Atlantic, but not quite a Greenland high.

The corresponding surface temps are cold, but they don’t scream snow.

I think given the op runs shown today we’d be fortunate to get a nationwide lowland snow event next week but clearly, given the anomaly above, its within the envelope of possibilities.

Week 3 shows a similar pattern with weaker anomalies 

I have posted the charts for the same time last year in a previous post, suffice to say these are much, much better. 
 

Week 4, which includes the Christmas period, also shows some interest, better illustrated  using 500mb heights

 

Heights over Scandi and perhaps into Greenland, hints of low pressure heading towards Iberia? Certainly one for the

The very silly range CFS has been like a dog with a bone for a cold Xmas week and it has to be right one day. 

And here’s the global view for week 5, taking us out of this dreadful year.

More northern blocking. 
 

The far reaches of the GEFS and GEM ensembles are interesting too

 

Crucially, they fit the narrative shown by the ECM above. Surprising consistency at that range it must be said.

 

I’m not sure about you guys but this feels a bit more than a pipe dream from the models for this period. These charts are unusual for December but we do have some teleconnections on side:

- Toned down moderate La Niña, showing a mixed profile perhaps not as central based as first feared.

- A potentially favourable pattern to perturb the stratosphere with persistent Ural heights. The latest EC46 has a minority cluster which go for a reversal, plenty of strong ones too mind showing it’s all to play for, mean below average. @Met4Casthas posted the chart above.

-Evidence for the MJO to traverse the maritimes towards the Western Pacific, is this more favourable in a WQBO? 
 

compared with last week

GEFS similar, though a little less bullish than recent days 

 

Overall an Atmospheric set up that was conspicuous by its absence last year. The dream of an early winter cold shot with the main course of a favourable mid winter SSW is indeed possible this year and thus the hunt, as it were, is well and truly on.

 

 

Edited November 26, 2020 by Uncertainy

[bluearmy]

5 minutes ago, Steve Murr said:

 

One of the best easterlies I have ever seen !!

The ec 46 control also finds an easterly for Xmas with a channel runner thrown in for good measure ....

[nick sussex]

The ICON 18hrs run is less progressive than the 12hrs run at T120hrs.

Notable change in the trigger shortwave now further sw with a stronger ridge over Scandinavia .

Edited November 26, 2020 by nick sussex