Model Output Discussion - Christmas week and beyond

[Cold Winter Night]

I have not much to add to the model discussion above atm, but maybe it's good thing that the output isn't exciting as Christmas draws attention. More important things in the end!

So I too would like to wish you all a Merry Christmas!

[CoventryWeather]

Model output is uninspiring for the next 10 days or so. Hopefully some changes in the new year, but for now, a brief break over Christmas and New year celebrations. 

I wish everyone a safe and happy Christmas, and wish everyone a positive 2023.

[minus10]

Think it says everything when the long term average is slowly falling for most the 12z run while the mean is slowly rising!..

[Nick2373]

Going off the 06z looks like the Daffodils will be up Earlier this year. May save some turkey for Turkey skews on the Barbecue. 

[KTtom]

2 hours ago, mulzy said:

Mid latitude high is probably a decent bet in the 10-15 day period.  Whether the high can migrate to Scandinavia and advent much colder air remains to be seen.

Met Office seems to have dropped colder by mid January signal.

What draw me to your post whilst quickly scanning through the last few pages was the lack of 'likes'. Can see why now Just as models seemed to be buying into it, we may well be  back to the usual January straws of 'the vortex tends to weaken in February'.

[Nick2373]

1 minute ago, KTtom said:

What draw me to your post whilst quickly scanning through the last few pages was the lack of 'likes'. Can see why now Just as models seemed to be buying into it, we may well be  back to the usual January straws of 'the vortex tends to weaken in February'.

This is it so many hopes are pinned on a SSW, even yesterday I had two different quotes of cold is 67% and 70% the next page of cold to the uk from a SSW event. So by one page it had jumped 3% hey perhaps if we kept going by 10 pages it would have been 100%. 

[lorenzo]

Why wouldn't you be interested in an SSW when the vortex currently looks like this...

 

And, FTs are doing this...

Gonna be a fun slingshot out of this NAO+ pain..

[snefnug]

15 minutes ago, minus10 said:

Think it says everything when the long term average is slowly falling for most the 12z run while the mean is slowly rising!..

What does that mean please?  
 

[KTtom]

2 minutes ago, snefnug said:

What does that mean please?  
 

Above average upper air temps with the gap increasing. 

Edited December 24, 2022 by KTtom

[northwestsnow]

Think we will see an attempt at a Euro High northwards push by day 10 here..

[northwestsnow]

Day 9

I guess a lot depends on that low to our NW..

[lorenzo]

Oh go on then.. 

[mushymanrob]

SSWs dont always deliver, and those that do sometimes dont produce much in the way of lengthy cold or snow...

Just saying....

[mulzy]

Arctic high back at day 10 ECM.

 

[northwestsnow]

1 minute ago, mulzy said:

Arctic high back at day 10 ECM.

 

[mulzy]

2 minutes ago, northwestsnow said:

We need that arctic high to push towards the Atlantic sector.  Not sure how it does that but thats the end game we want. 

Edited December 24, 2022 by mulzy

[RJBingham]

28 minutes ago, mushymanrob said:

SSWs dont always deliver, and those that do sometimes dont produce much in the way of lengthy cold or snow...

Just saying....

I think the SSW that gave us 21c in February overdelivered. 

[bluearmy]

4 minutes ago, RJBingham said:

I think the SSW that gave us 21c in February overdelivered. 

Well if we were 21c then I’m sure it delivered somewhere …..

[RJBingham]

5 minutes ago, bluearmy said:

Well if we were 21c then I’m sure it delivered somewhere …..

Unforgettable

UK experiences hottest winter day ever as 21.2C is recorded in London | UK weather | The Guardian

WWW.THEGUARDIAN.COM

---

Parts of Britain exceed temperatures in Malibu, Athens and Crete

 

[Frosty.]

Merry Christmas all, not posting much, same disappointment as this time last year, total model implosion.. not much else to add really, the long term GEFS 12z mean sums things up pretty well and is par for the course for NW coldies!..anyway, I live in hope that Janvier will eventually bring something wintery to Blighty’s shores! …over and out!  

[Snowman.]

1 hour ago, feb1991blizzard said:

looking at the strat GFS ensembles, it does have the hallmarks of just running out of steam before a technical SSW so slight odds against, unless a secondary warming comes round the back soon after.

 

Lows becoming slow, heights randomly appears across the poles.

Defintely not the sign of a strong vortex, while we may have a zonal pattern here things change quickly.

[Formula_1_Fan]

I very rarely post because usually any questions I have are answered somewhere in the thread but whilst it's quiet.... 

 

Every Christmas we see someone mention the lack of data from fewer flights etc. Well I was wondering if this would apply with the current grounding of most flights from the weather in the states? I'm a little sceptical as to whether it makes a difference anyway but I thought I'd ask. 

 

Have a great Christmas and new year everybody, as ever its been great following the forum this year. 

[Eagle Eye]

19 minutes ago, lorenzo said:

Why wouldn't you be interested in an SSW when the vortex currently looks like this...

 

And, FTs are doing this...

Gonna be a fun slingshot out of this NAO+ pain..

Absolutely, vertical thermal Eddy's increasing in the reliable now putting large pressure on the Strat not to mention the GFS underdoing the strength of the AAM rebound. 

Caution

A lot of writing coming up...

As we go into the New Year Trop pattern,  the plausibility of an MJO driven signal also backed by the AAM is looking fairly reliable. I expect phase 6/7 to show by mid January (ish) in the NAO state as long as the AAM doesn't take a large downturn to a -VE state. Assuming horizontally and vertically stretched Eddy transfer in this 2D look at the Trop, especially the upper Trop then the transfer around the Earth of signals for blocking should be fairly good. The transfer of Poleward Eddy's relies on a holding of cn unstable inertia pattern preferably held by a fairly sustained +VE AAM signal that we might be entering now. This pattern combined with the MJO may support some form of Greenland blocking later especially if the East Asian jet retracts slightly and we can hold an amplified Rossby Wave pattern. Plenty to be cheerful about and it's Christmas time but it's still fairly far out and the strength of poleward Eddy's is yet to be determined really.  Whether the GFS is overdoing the MJO signal and therefore overdriving the poleward thermal transfer or not you can argue about. Personally, it's been underdoing the AAM and MJO signal for a long time and has tried to slow down the MJO signal for a while. So I think it may be overdoing the signal beyond the end of its output slightly in terms of Eddy's and that may show in a few days time. It could also be underdoing the signal by under amplifying the forecasts and hence we may be in better luck than we even think now.

Right now, I can't really tell and I won't know till after the event but looking long-term and I think a Greenland blocking signal could start showing itself in the output when we get into January. I won't go too much over the Trop pattern as of now but the AAM rebound bring stronger than initially forecast has given me hope that it can sustain itself for longer than forecast. If it can do that then we can look closer to home other than a potential SSW for colder prospects. Its a lot to ask from the AAM but I remain hopeful that it's festive cheer will keep up till my birthday on the 24th January.

Looking at the arguably more impressive Strat though and there's a lot less IF's.

The zonal wind is on its way down into the New Year, after the initial Vortex Intensification (VI), the Eddy's start to reach the Strat and the warmer air gets distributed away from the normal and Rossby Waves imparting easterly force and the zonal wind will weaken. Its as simple as that. 

Eddy's clearly strengthening into the New Year and the Wave-1 response is very clearly. This could potentially put a lot of pressure on the Strat.

Seeing as it's essentially the same as earlier today I'll quote myself quickly

" we should see some 'disconnect' between the two akin to thermal Eddy's slowly migrating up the Trop and into the Stratosphere because the upper Trop pattern response to the East Asian Jet Extension should be different to the Strat's reaction to the downstream energy scattering and Eddy vertical propagation simply because it is moving. Essentially what I'm saying here is that the Trop is getting moved earlier than the Strat and because the Earth is rotating the effects can look over exaggerated to what you would imagine. This is where the Earth's rotation helps us because it holds strong the unstable thermodynamics between the Trop and the Strat as energy cycles up the atmosphere and some cycles back down. This would distribute the Strat slower than the Trop and also mean that there is almost constant support for Wave-1 to at least keep it's strength slightly further beyond if/when the amount of Eddy flux starts 'drying up'. Eventually, this would lead to a radiative dampening of the Strat and the Strat and Trop connect up again so without a SSW or at least a large split, this could make the weeks worth of work and pressure on the Strat 'useless' so clearly we need to keep a large thermal gradient up as long as possible. Best things for that would be an extratropical 'wave train', an increase in AAM and/or MJO phases 6 and 7."

And the latest run still supporting my view (although still fairly far away of course but it's a well supported view) on how the 'disconnect' shows increased thermal Eddy vertical profiling.

Lots to be interested about going into the New Year and I'll keep updating everyone about it. Merry Christmas to this great forum and here's to a potential SSW in January (ish) if all goes well for us. Cheers.

[Daniel*]

There is growing support for the AO to lean negative among EC ens into early January.
 

Note I posted days before previously the control was going with idea… it is no longer alone or most commanding! This ain’t like last winter I seem to recall the AO was strongly positive pretty much throughout the entirety of the winter. It is cliche but others have said similar, something a little different about this winter.

Merry Christmas all btw  

[knocker]

9 minutes ago, Formula_1_Fan said:

I very rarely post because usually any questions I have are answered somewhere in the thread but whilst it's quiet.... 

 

Every Christmas we see someone mention the lack of data from fewer flights etc. Well I was wondering if this would apply with the current grounding of most flights from the weather in the states? I'm a little sceptical as to whether it makes a difference anyway but I thought I'd ask. 

 

Have a great Christmas and new year everybody, as ever its been great following the forum this year. 

Probably too short a time span but this may be of interest

https://www.ecmwf.int/en/about/media-centre/news/2020/drop-aircraft-observations-could-have-impact-weather-forecasts

Edited December 24, 2022 by knocker