Model Output Discussion - Into Winter

[blizzard81]

My advice, yet again, is to pay little attention to the notoriously unreliable GFS 06z and concentrate on the 12z runs later. 

[BLAST FROM THE PAST]

6 minutes ago, Lukesluckybunch said:

Exactly my point..say it how it is.. the last gfs 6z showed nothing exciting in the period 144-168 ..and we were left with a uk high which struggled to progress north

Only getting pushed back if you are expecting frigid uppers by 7/8th. Though  It’ll feel pretty cold by then.  There is a lot happening, expect more model dramas ahead

 

BFTP

[Weather-history]

1 minute ago, LetItSnow! said:

 No 1947 repeat in the forseeable future but with promising telecommunications and cold charts actually coming into a reliable timeframe, I 

How about January 1940 instead?  

 

 

[Lukesluckybunch]

1 minute ago, blizzard81 said:

My advice, yet again, is to pay little attention to the notoriously unreliable GFS 06z and concentrate on the 12z runs later. 

Many do say this..why is that blizzard?does it hold more information..

1 minute ago, BLAST FROM THE PAST said:

Only getting pushed back if you are expecting frigid uppers by 7/8th. Though  It’ll feel pretty cold by then.  There is a lot happening, expect more model dramas ahead

 

BFTP

I suppose so..next weekend is when the Action is due to start..that's still a long way off!

[blizzard81]

Just now, Lukesluckybunch said:

Many do say this..why is that blizzard?does it hold more information..

Just 2 decades of me looking at it and thinking what a pile of tosh

[bluearmy]

Going to be an interesting cross sectional to look at from that gfs run 

is that monster Arctic high a straight downwell of the reversal or does it come from trop influence ?

[Harsh Climate]

6 minutes ago, Lukesluckybunch said:

Mean not so good at 174..it has UK high written all over it

At 222h looks excellent to me?

[Lukesluckybunch]

2 minutes ago, Harsh Climate said:

At 222h looks excellent to me?

I'm not so sure..but fair enough,pert 13 looks excellent!

[Ali1977]

2 minutes ago, Lukesluckybunch said:

I'm not so sure..but fair enough,pert 13 looks excellent!

At least 50 percent of the ens look snowy at day 9

Edited December 31, 2023 by Ali1977

[Harsh Climate]

Some absolute peaches in the assembles 

  

 

[Lukesluckybunch]

Just now, Ali1977 said:

At least 50 percent of the ens look snowy at day 9

Yet again the op out on its own...why does this keep happening!?

[Ali1977]

Just now, Lukesluckybunch said:

Yet again the op out on its own...why does this keep happening!?

Not sure, actually probably only 30/40 percent look snowy, but others still look cold 

[Lukesluckybunch]

2 minutes ago, Harsh Climate said:

At 222h looks excellent to me?

I'm not so sure..but fair enough,pert 13 looks excellent!

[Johnp]

31 minutes ago, Howie said:

Of course another UK high. For God's sake...

Another? I can’t even remember the last decent uk high. 

[booferking]

8 minutes ago, blizzard81 said:

The ECM hasn't pushed the cold back though. Nor has the ukmo. 

Get the snow shovels out for ukmo and the Ec is flipping about like an old fart the form horse is uk high then to sink in my eyes currently been here all to often if it changes so will my optimism but i see a trend to keep pushing back anything that will deliver snow to my front door and after all that is what many of us is here for.

[northwestsnow]

Always worth remembering cold spells here are often preceeded by a UK high..

This has all the hallmarks of a slow burner from where I'm sitting..

[warrenb]

Just now, northwestsnow said:

Always worth remembering cold spells here are often preceeded by a UK high..

This has all the hallmarks of a slow burner from where I'm sitting..

Agreed, got all the hallmarks of a double dipper.

 

To many people wanting silver today, rather than gold tomorrow

[booferking]

Just now, warrenb said:

Agreed, got all the hallmarks of a double dipper.

 

To many people wanting silver today, rather than gold tomorrow

I wouldn't mind either but ideally this winter not next winter

[Jason M]

JFF, at 252 hours across the GEFS (including control) there are 11 UK Highs out of 31 runs. In addition there are another 4 or 5 which have heights south of UK. 

There are some very cold charts amongst the remaining runs. So basically its around a 50/50 split. The colder runs though are split between northerlies and easterlies so whilst they show cold spells they are not showing the same set up.

So, UK high remains most coherent signal IMHO but its a long way away and may well change for better or worse.

 

 

[KyleHenry]

3 minutes ago, bluearmy said:

Going to be an interesting cross sectional to look at from that gfs run 

is that monster Arctic high a straight downwell of the reversal or does it come from trop influence ?

Both but by a different mechanism,the PV displacement (SSW or close to reversal) permits the Arctic high to form by moving the PV off the default position.  The Aleutian low creates the brake for the WAA from the Pacific into the Arctic circle. Then the Arctic High is allowed to fill the vacant space. PV needs to reverse for the Trop AH to gain height in the target zone.

[sebastiaan1973]

Excellent development, a British anticyclone. Blocking in that area. 

Abstract

Sudden stratospheric warming (SSW) events can significantly impact tropospheric weather for a period of several weeks, in particular in the North Atlantic–European (NAE) region. While the stratospheric forcing often projects onto the North Atlantic Oscillation (NAO), the tropospheric response to SSW events, if any, is highly variable, and what determines the existence, location, timing, and strength of the downward impact remains an open question. We here explore how the variable tropospheric response to SSW events in the NAE region can be characterized in terms of a refined set of seven weather regimes and if the tropospheric flow in the North Atlantic region around the onset of SSW events is an indicator of the subsequent downward impact. The weather regime analysis reveals the Greenland blocking (GL) and Atlantic trough (AT) regimes as the most frequent large-scale patterns in the weeks following an SSW. While the GL regime is dominated by high pressure over Greenland, AT is dominated by a southeastward-shifted storm track in the North Atlantic. The flow evolution associated with GL and the associated cold conditions over Europe in the weeks following an SSW occur most frequently if a blocking situation over western Europe and the North Sea (European blocking) prevailed around the SSW onset. In contrast, an AT regime associated with mild conditions over Europe is more likely following the SSW event if GL occurs already around SSW onset. For the remaining tropospheric flow regimes during SSW onset we cannot identify a dominant flow evolution. Although it remains unclear what causes these relationships, the results suggest that specific tropospheric states in the days around the onset of the SSW are an indicator of the subsequent tropospheric flow evolution in the aftermath of an SSW, which could provide crucial guidance for subseasonal prediction.

How to cite. 

Domeisen, D. I. V., Grams, C. M., and Papritz, L.: The role of North Atlantic–European weather regimes in the surface impact of sudden stratospheric warming events, Weather Clim. Dynam., 1, 373–388, https://doi.org/10.5194/wcd-1-373-2020, 2020.

[FetchCB]

30 minutes ago, Weather-history said:

How about January 1940 instead?  

 

 

As you had already analysed 

 

[Harsh Climate]

12 minutes ago, northwestsnow said:

Always worth remembering cold spells here are often preceeded by a UK high..

This has all the hallmarks of a slow burner from where I'm sitting..

Considering the chase started around 22nd December, this could be the longest chase in the history of Netweather. 

Plenty of toys to be thrown out of prams and that's before any snow potential where there will be winners and losers right down to <T12  

[Met4Cast]

GFS det on the milder end of the back in the medium range, interestingly a few very cold members beginning to appear more consistently now.

As said earlier, still a lot to be resolved & we are likely to see further changes in the broad scale pattern. 

What is clear is January is not looking likely to be a zonal/Atlantic driven month, that in itself is quite notable. 

[Summer8906]

19 minutes ago, Johnp said:

Another? I can’t even remember the last decent uk high. 

June.