Model Output Discussion - Winter arrives

[winterof79]

Seems to me there's a growing consensus for an easterly feed around the 5thDecember

[Griff]

13 minutes ago, Dennis said:

 

thats not often seen last years at a december start

Big to Dennis, he absolutely one of my favourite most enthusiastic and dedicated twitter accounts, always a go to for a hot tip and never disappointed when the chase goes off on one, which less face it is always more likely than not. 

Nice one, keep up the great work. 

Edited November 28, 2021 by Griff

[Dennis]

thoughts on MJO - i thnk higher 7 will be seen  on the charts from next weekend

 

 

[Griff]

6 minutes ago, Dennis said:

thoughts on MJO - i thnk higher 7 will be seen  on the charts from next weekend

 

 

And this is why I no longer have much to post on the twitter thread  

[Mike Poole]

15 minutes ago, Dennis said:

thoughts on MJO - i thnk higher 7 will be seen  on the charts from next weekend

 

 

That looks positive, but I’m still not convinced that the MJO is a driver for this setup - we have had a meridional pattern for nearly a year now, the MJO (at the best of times) can dictate terms for a month or two.  For sure, the phase 7 evolution will help, but something else is in the driving seat.  Hey ho!  Onto the pub run…

[Mike Poole]

ICON 18z T120, is that the feature that was shown on the UKMO:

If so we’re on the way to upgrade city!

[damianslaw]

GFS sticking firm with it's high over Scandi setting up and low pressure sinking SE into central Europe..  NW-SE aligned jet.. and then a fight off between the Atlantic and the high... either way cold air drains into the mid Atlantic and we are in slider low territory. Notably ECM is now aligned to GFS in the near reliable timeframe 144hrs.. look at the rise in heights on 5 Dec same place.. Atlantic trough negatively aligns . Will this trend continue.. there has been a marked shift in the models past 24 hours.. 

[Kentspur]

2 hours ago, Tim Bland said:

Shove that cold west a bit and slide / disrupt those lows a bit more and the ECM would be great from a Snow perspective 

Awww yes us Kentishmen love a good old Scandi high and Easterly we got naff all from the northerlies this week

[Kentspur]

1 hour ago, Mike Poole said:

Interesting day on the model watching front, for sure.

ECM and GEM edging towards UKMO and GFS who not just hold their line, but reinforce it.  Scandi high will be nailed on tomorrow 0z, I think.  So where does that leave us 3 days away from winter (it is actually snowing outside here right now!).  I have always been struck on the run into winter by the consistent meridional jet, as I have often posted, it has been here since last winter, right through summer, same thing happened in 2010.  

And here we are in the last week of November and it has just turned freezing cold.  History repeating? Too early to tell, I don’t think it will be quite like 2010, but if the high that calls the shots of a multi-blocking pattern* does set up, is over Scandi this time, it might be much snowier for the south than 2010 was.  How important that cold pool to our east might be this year!!

*2010 was a major, repeat major, Greenland high.  In the south it was freezing but snowless down south until I think the week before Christmas.

We are I think one or two suites of model runs off confirming the start of a cold spell proper, whether it will match or even surpass 2010 remains to be seen, but these patterns don’t come along often so enjoy it if it happens…

I disagree with the snowless bit we had heavy snow for 3 to 4 days constantly from this very date until about 1st December and had the most snow I've witnessed (far more than during the beast 17-18) discounting that event that single event alone has given us more snow than all the winters combined since Nov-early Dec 2010

[Mike Poole]

1 minute ago, Kentspur said:

I disagree with the snowless bit we had heavy snow for 3 to 4 days constantly from this very date until about 1st December and had the most snow I've witnessed (far more than during the beast 17-18) discounting that event that single event alone has given us more snow than all the winters combined since Nov-early Dec 2010

Yes, sorry, that would be the wishbone effect, you live near the east coast, I live 90 miles from any coast, which would explain the difference.  2010 affected people in different locations differently…it was bitingly cold though for all of us!  Anyway, let’s see what the pub run gives…

[Kentspur]

1 hour ago, topo said:

Probably some of the best runs I have seen since February 2018.

ECM mean is outstanding and the set ups that all the models suggest for the next 10 days are incredible for early December.

This is a classic set up for southern Norway that brings a lot of snow. I have seen similar set ups in late January, February or March but I can't remember something similar during early December

Glad to see Scandi cooling down nicely my brothers visiting Oslo tomorrow any recommendations?

Edited November 28, 2021 by Kentspur

[Catacol]

10 hours ago, Broadmayne blizzard said:

I am always more encouraged about possible  upcoming cold/snowy conditions when the models show a gradual building of an in situ cold pool over North West Europe rather than a sudden switch to 60mph easterlies at day ten. 

The current output ties in well with the meridional and quiet Atlantic conditions that have marked out much of the past few months. 

In some ways the current situation is not that dissimilar to the end of November beginning of December 1981. 

 Not saying we'll see a repeat of that but the quiet atlantic  and unexpected gradual build of heights to the north and scandi troughs helping to build an insitu cold pool are not a million miles away.

As ever we wait to see what unfolds.

 

Much truth here I think. We have indeed had a very quiet Atlantic, and we have a hemispheric pattern that is unusual compared to many of the last 10 years. Very cold air in Alaska as a trough digs in there, particularly deep cold over Scandinavia, and models suggesting Atlantic wave breaking in December when for years we have tended to endure dominant westerlies at times when momentum falls and the Azores High remains stubbornly fixed in place. I’m far from convinced we have the necessary spike in momentum to get a Scandy High in place at this early stage of the season…but it would be a great time to see it happen and shred my own December prediction.

The coming week SHOULD see the pattern gradually relax. Torques remain fairly static and I don’t see a tropospheric setup for a big increase in EAMT yet. Momentum has been fairly flat too in recent days, and lag effect one would think would encourage that more +NAO feel. The MJO is the one driver suggesting some support for amplification, but I wouldn’t say it was a very active signal. Moderate perhaps if one of the better ensemble members comes off. Take all this together and hard experience would suggest Atlantic inbound.

And then we get this 

 

not quite out the blue because the 2 previous runs showed some gentle disruption to the flow over Scandy but definitely not as strong as this tonight. The trend within the ENS is moving towards a more significant wave break than we might have the right to expect. And look at that low pressure signal embedded over SE Europe. 2 weeks ago this was the ECM prognosis for the period ahead

Complete transformation in the signal over Europe as our usual stagnant SE Euro block appears to be in retreat now. Jules must surely be doing cartwheels…!

If it comes off then a Scandy block will alter the wind direction for a day or three at least before probably fading East, but perhaps more importantly it will reinforce the sense that this winter is setup differently to most from the last 10 years or so. Note also wave 1 pressure is forecast to begin in the next week, and the NE pacific continues to cool while Nina continues to edge east. Usually we have to try hard to find signs that the westerly Atlantic pattern across the season might be disrupted. Not so this year! 

 

Edited November 28, 2021 by Catacol

[tight isobar]

Quick- and to the point regarding the ecm 12z run @great = if it’s going in the correct direction your looking  for... it has to start somewhere!!!

[Don]

1 hour ago, winterof79 said:

Seems to me there's a growing consensus for an easterly feed around the 5thDecember

Interestingly, that’s when the easterly arrived in December 1995.

[Uncertainty]

Not mine to post but the extended eps beyond 300 still has that low euro heights / Ural blocking / Aleutian Low combo. If it holds for the 0z then surely last weeks abominable EC46 won’t be repeated. Were such a pattern to establish for 2-3 weeks then it’ll be time to look high up for our mid winter destiny. 

 

Edited November 28, 2021 by Uncertainy

[Mike Poole]

2 minutes ago, Uncertainy said:

Not mine to post but the extended eps beyond 300 still has that low euro heights / Ural blocking / Aleutian Low combo. If it holds for the 0z then surely last weeks abominable EC46 won’t be repeated. Were such a pattern to establish for 2-3 weeks then it’ll be time to look high up for our mid winter destiny. 

 

Hey, I’m still trying to work out our early winter destiny!  But I know what you mean re strat precursors, however, there is still much mileage in early winter cold…as the pub run rolls…

[tight isobar]

Snow chances are there Wednesday/Thursday/Friday- and no surprises to get surprises! @ northerly #2 - my punt is still for perhaps more from this than the by then last we now await the 18z evolution for the easterly.

[Catacol]

6 minutes ago, Uncertainy said:

Not mine to post but the extended eps beyond 300 still has that low euro heights / Ural blocking / Aleutian Low combo. If it holds for the 0z then surely last weeks abominable EC46 won’t be repeated. Were such a pattern to establish for 2-3 weeks then it’ll be time to look high up for our mid winter destiny. 

 

I think we are definitely in the strat game any time from 1 month from now onwards. Low pressure over the north pacific does not want to loosen its hold, assisted probably by a -PDO....and while I think from memory the Ural High was a little stronger last year than this, we certainly have enough going on there to hope for some wave 2 pressure. As the calendar shifts to December the tropospheric patterns become key, and we could really do with a massive spike in EAMT around mid month. Watching brief on that. Meanwhile the MJO confounds me....and 100% not for the first time. The most hard to predict of all drivers and already looking like it is way off the timetable I had set in my mind for it....so we will see what we will see there - but secondary in any case to what happens aloft. 

[Catacol]

5 minutes ago, Mike Poole said:

Hey, I’m still trying to work out our early winter destiny!  But I know what you mean re strat precursors, however, there is still much mileage in early winter cold…as the pub run rolls…

Yes Mike - any move towards a Scandinavian High in 7 - 10 days will extend this early cold....or perhaps restart it after a few days of more average fare. I hope folk don't get too convinced it will land though - as per my long post above I'm scratching my head a bit and not quite able to believe that a break like that will actually come off when usually the atlantic is firing up. But who knows - maybe so.....!

[Mike Poole]

Pub run T132 vs 12z T138:

18z more like UKMO with the heights cut off rather than leaking.  I think this will be a better run than 12z.

[Battleground Snow]

2 minutes ago, Mike Poole said:

Pub run T132 vs 12z T138:

18z more like UKMO with the heights cut off rather than leaking.  I think this will be a better run than 12z.

Slightly stronger scandi heights, low pressure forced further south into Europe. Gets a big  from me

[Mike Poole]

3 minutes ago, Catacol said:

Yes Mike - any move towards a Scandinavian High in 7 - 10 days will extend this early cold....or perhaps restart it after a few days of more average fare. I hope folk don't get too convinced it will land though - as per my long post above I'm scratching my head a bit and not quite able to believe that a break like that will actually come off when usually the atlantic is firing up. But who knows - maybe so.....!

My point is that there is something inhibiting the Atlantic, don’t know what!,  has been for nearly a year, if it was ever going to fire up and beat it, it was late Autumn, it hasn’t…so all bets are off if we are comparing to recent years, 2010 the best analogue in my opinion.  

[pages]

3 minutes ago, Mike Poole said:

Pub run T132 vs 12z T138:

18z more like UKMO with the heights cut off rather than leaking.  I think this will be a better run than 12z.

This might even better than ukmo the core of the cold is further south. Might not get as much shortwave action off Norwegian coast on this one

[sheikhy]

Hmmm 18z!!!not like the ecm but not as good as 12z!!although heights look stronger across scandi!not sure where this will go...!

[Mike Poole]

Pub run T168 excellent, prediction, a pub run special FI on this one: