Model output discussion - into the start of Winter

[sheikhy]

Icon massive difference compared to 12z run!!more amplified and drops a trough to the south eat of us at 120 hours!!

[sheikhy]

Just now, nick sussex said:

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

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

Good timing mate just posted the same thing!!!!a move towards the ecm from icon!

[SMU]

Just now, nick sussex said:

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

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

The ol ' horseshoe jet in Action..

@booferking wont be happy!

[Griff]

1 minute ago, nick sussex said:

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 .

 

1 minute ago, sheikhy said:

Icon massive difference compared to 12z run!!more amplified and drops a trough to the south eat of us at 120 hours!!

Get a room you two.... But thanks! 

[nick sussex]

Just now, sheikhy said:

Good timing mate just posted the same thing!!!!a move towards the ecm from icon!

We want the less progressive option but without the low blowing up over the UK .

And we certainly want rid of the UKMO output. The ICON given the upstream pattern expected evolution looks a nailed on easterly . If there’s a stronger Scandinavia ridge in place then more chance it can add more pressure on the upstream low to disrupt more favourably .

 

[sheikhy]

Just now, nick sussex said:

We want the less progressive option but without the low blowing up over the UK .

And we certainly want rid of the UKMO output. The ICON given the upstream pattern expected evolution looks a nailed on easterly . If there’s a stronger Scandinavia ridge in place then more chance it can add more pressure on the upstream low to disrupt more favourably .

 

Yes mate for defo!!!maybe 18z gfs can provide us with what we want to see!!!here goes.....

[booferking]

Just now, Steve Murr said:

The ol ' horseshoe jet in Action..

@booferking wont be happy!

Have you took over the controls of ICON toI'm all for it if it keeps it up spilit that low earlier and hopefully produce an easterly before it just sinks and blows up over us.

[kold weather]

18 minutes ago, Steve Murr said:

 

One of the best easterlies I have ever seen !!

Seriously the evolution is just pure filth! Its almost as good as it gets in terms of the upper high over Scandinavia and into much of the Eurasian portion of the Arctic.

Whilst I doubt we go anywhere near that extreme, there is some tendencies already being seen towards the Azores high trying to ridge up and over the top towards Scandinavia. With a bit of luck we will get one in the near future that has some decent deep cold to tap into. This combined with more than a few hints that the zonal wind speeds are due to drop, perhaps markedly, and its perhaps not a totally outlandish prospect down the line.

[legritter]

Hi gang ,i have been about lurking in the shadows and reading your posts and great that you are all happy at the moment .I'm certainly happy looking at the Northern hemisphere charts will some meaty tantalising possibilities lurking in the mist and winter about 4 days away .time to get ready for some curtain twitching, and behind the sofa chart watching .So some calm anticyclonic weather to come to take us into December, then a messy picture out to about the 4th of December, then its very uncertain which way the charts will take us ,what is almost certain is Tomorrow it will change and 10day charts will put a smile on your face one day and put you on PROZACK the next .So currently the Ecm looks promissing out to 192 hrs ,and some possibilities on the Gfs ,some tantalisingly 850s about come 10days from now .So gang get ready for approximately 182 Ecm runs  ,and 364 Gfs runs this Meteorological winter .but be warned ,they are all programmed to fool you ,tease you, make you happy ,make you sad , they are also capable of causing Meltdown  on our wonderfull Forum ,and occasionally they can be right. All eyes now on tonights Gfs run ,is there a 528 Dam line lurking out past next weekend thats weekend 5/6th or Azores mushy monster .I love this forum ,i wish you all well over this coming crisis ,keep safe ,I eat healthy tonight 2 sausage  baps !! Brown sauce,  its my treat once a week ,take care all ,cheers ,legritter. 

 

[northwestsnow]

 

EC control is very nice tonight !!

I'm getting quite excited for Decembers prospects !

Let's keep those low  heights across Europe please weather Gods ...

[Mike Poole]

Just before the pub run (with pie and chips every pint of course) does anyone know exactly what has driven this very obvious shift of the developing trop vortex away from Greenland and Canada?  It isn’t the strat, I’m sure.  Look’s like it is in a hurry too, can’t run fast enough to get away (GFS 12z T192):

Is this just random chance, because it sure looks unusual to me, not complaining mind you!!

[SMU]

The pubs run & GFS is struggling with resolving the jet & its returning SW element through Scandi - as a result another 24 hours of catch up ....

 

[Scott Ingham]

1 minute ago, Mike Poole said:

Just before the pub run (with pie and chips every pint of course) does anyone know exactly what has driven this very obvious shift of the developing trop vortex away from Greenland and Canada?  It isn’t the strat, I’m sure.  Look’s like it is in a hurry too, can’t run fast enough to get away (GFS 12z T192):

Is this just random chance, because it sure looks unusual to me, not complaining mind you!!

Its the second layer of angular momentum that drives dense cold away from an increase in easterly trade winds also driven by a higher gwo orbit. Its the first stage of 3 ssw precursors. Something studied by nasa currently not know by many in British meteorology but will all be made available soon. From the model I have been lucky to see there is a 45% chance of a ssw between the 19th and 29th of December 

[bluearmy]

3 minutes ago, Mike Poole said:

Just before the pub run (with pie and chips every pint of course) does anyone know exactly what has driven this very obvious shift of the developing trop vortex away from Greenland and Canada?  It isn’t the strat, I’m sure.  Look’s like it is in a hurry too, can’t run fast enough to get away (GFS 12z T192):

Is this just random chance, because it sure looks unusual to me, not complaining mind you!!

It’s not that unusual for the vortex to head from Canada to Asia but it is unusual for it to stay there. It would normally head back fairly swiftly and bring an increased Atlantic jet each time it makes the journey 

 

[kold weather]

11 minutes ago, northwestsnow said:

 

EC control is very nice tonight !!

I'm getting quite excited for Decembers prospects !

Let's keep those low  heights across Europe please weather Gods ...

Its another one of those 'shower' mind you. It looks synoptically fantastic, then look at the actual flow and its a little bit, well, meh temperature wise.

The big problem with alot of the set-ups we are seeing, and I will keep banging on about this, is we just don't have any decent level of cold across Europe. Thats not to say it won't get colder than normal, it will. However without a strong surface cold pool to draw upon any sliders are going to high a high chance of introducing air just that little bit too warm. Given we are in early December the uppers don't look quite there from any easterly flow either (-5c with SST's above average in early December won't cut it for much in the way of snow from the north sea)

Of course the thing I will say is keep getting LPs sliding across is no bad thing and we may get there anyway in the end, I just would prefer getting even a short lived northerly first, or a strong undercut Scandi high type situation to pull air in from the far NE.

At the moment the diving LP's are just circulating recycled Atlantic air via Europe, and its simply IMO not quite at the level of cold we really need to make things properly interesting...

Yet...

 

Edited November 26, 2020 by kold weather

[Scott Ingham]

7 minutes ago, Scott Ingham said:

Its the second layer of angular momentum that drives dense cold away from an increase in easterly trade winds also driven by a higher gwo orbit. Its the first stage of 3 ssw precursors. Something studied by nasa currently not know by many in British meteorology but will all be made available soon. From the model I have been lucky to see there is a 45% chance of a ssw between the 19th and 29th of December 

2010 had a huge eamt event that did a similar thing. But it was a bigger event than what is seen this year. The difference this year is we already have a huge Russian HP moving west. The torque event will drive the Greenland pressure rises the resultant trough dropping into western Europe against an advancing russian/Scandinavian block and Aleutian low is the second stage of the 3 stage process. We didn't have such a huge pressure rise to the east in 2010 to give us a ssw chance. This set up has the potential to deliver a long period of below average temperatures if we follow December with high pressure over the uk then the results of the ssw kicks in

[sheikhy]

Low struggling to get past ireland on the 18z at 180 hours!!scandi high out in full force!!!

[SMU]

This is why I love continental flows - a rarity in the Uk a developing upper air cold pool situ with uppers going from +2 to -6 & showers turning to snow

[Daniel*]

13 minutes ago, Scott Ingham said:

Its the second layer of angular momentum that drives dense cold away from an increase in easterly trade winds also driven by a higher gwo orbit. Its the first stage of 3 ssw precursors. Something studied by nasa currently not know by many in British meteorology but will all be made available soon. From the model I have been lucky to see there is a 45% chance of a ssw between the 19th and 29th of December 

It sounds like mumbo jumbo to me. The movement of trop PV is mostly down to big +PNA event the big ridging in western North America gives a big shove to Eurasia.  

[Scott Ingham]

2 minutes ago, Daniel* said:

It sounds like mumbo jumbo to me. The movement of trop PV is mostly down to big +PNA event the big ridging in western North America gives a big shove to Eurasia.  

Ans its angular momentum that creates this amplification. It doesn't just happen randomly its all part of an angular momentum budget so excuse me its not mumbo jumbo. Tamara I'm sure would explain as I dont have the time to get into it. But it's not "mumbo jumbo"

[nick sussex]

The GFS quite messy later on but certainly not without interest .

Its amazing how that angry looking low to the nw you’d normally expect to barrel its  way eastwards just grinds to a halt and starts pivoting .

Still a lot to be resolved in terms of detail but the pattern is quite unusual for this time of year and at least has some decent potential moving forward.

 

[Met4Cast]

12 minutes ago, Scott Ingham said:

2010 had a huge eamt event that did a similar thing. But it was a bigger event than what is seen this year. The difference this year is we already have a huge Russian HP moving west. The torque event will drive the Greenland pressure rises the resultant trough dropping into western Europe against an advancing russian/Scandinavian block and Aleutian low is the second stage of the 3 stage process. We didn't have such a huge pressure rise to the east in 2010 to give us a ssw chance. This set up has the potential to deliver a long period of below average temperatures if we follow December with high pressure over the uk then the results of the ssw kicks in

Do you have access to the AAM/GWO charts? Seems like you know what you're talking about! Seeing them would be a huge help

[Premiere Neige]

1 hour ago, virtualsphere said:

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:

 

Looks quite similar to 2009 I would say...

[Scott Ingham]

3 minutes ago, Met4Cast said:

Do you have access to the AAM/GWO charts? Seems like you know what you're talking about! Seeing them would be a huge help

Yes and so do you MET4cast as ive seen you post them. Im not here to have my views picked apart. I don't post often as I work researching future meteorology. Comments like that patronizing are what put me off commentating in the first place. Get a grip and some respect 

[Daniel*]

7 minutes ago, Steve Murr said:

This is why I love continental flows - a rarity in the Uk a developing upper air cold pool situ with uppers going from +2 to -6 & showers turning to snow

It is something I’ve observed frequently over years the uppers trend colder closer to time. All you need is lower pressure, lighter winds and it will just get increasingly colder not just surface, this time of year it’s best for it... nights are long! There does look to be some potential around 5th for some wintriness, hills only at this stage. Hopefully we can squeeze out more.