Model Output Discussion - Christmas week and beyond

[CoventryWeather]

9 minutes ago, northwestsnow said:

Does it get any worse ?

Can't see what the problem is with that chart. Clearly the trough in the Atlantic is weakening and moving South - heights heading towards Scandi and weakish heights heading out of Canada and NA. 

To me, that's a better pattern for day 10, with a short lived cold snap on offer if it went out further.

[supernova]

Time to get properly stuck into the egg nog and crack open the Quality Street based on that rather uninspiring output - cool and windy zonal is being kind! Not much in the way of straws to clutch at other than the merest hint of height rises towards Scandi as we get further into January but hoping we see more robust indications of this over coming days to at least give us a bit of festive cheer and interest. One thing we can definitely rely upon with the UK weather is that it can all change very quickly. Merry Christmas all.

PS Whilst it's quiet, can I just thank the regular NW contributors and mods who give their time and knowledge so generously -  I've been reading and learning on here for more than ten years and it's become a welcome staple of my winter season. Cheers. Jim

 

Edited December 22, 2022 by supernova

[Kasim Awan]

Does seem to be a strong signal to push the jet south day 8 onwards.

[Cold Winter Night]

10 minutes ago, Drifter said:

Cold high over the pole, vortex split all over the shop, jet stream looking more amplified etc. 

Id expect the high to ridge over us towards Iceland on the next frame

 

Trust me, my Spidey senses are tingling for this.

I would agree, although, timing wise, a slight delay in the drop of that second trough would perhaps give a bit more confidence?

The continued absence of a powerful TPV in its usual location remains the most interesting thing going forward.
This leaves opportunities for a more meridional flow, with troughs digging South.

No typical +NAO setting in, even if that doesn't directly mean "Cold IMBY." It could even bring very mild temperatures our way, but in the long run that can flip.

[Derecho]

Uninspiring output at the moment, typical westerly fare...

European variant of the NAO shows good support for it to remain positive in the GFS ens...

[Stuie]

16 minutes ago, Quicksilver1989 said:

Uninspiring output at the moment, typical westerly fare...

European variant of the NAO shows good support for it to remain positive in the GFS ens...

This is somewhat true but a hell of a lot of scatter. Image 1 from a couple of days ago.

 

 

Edit: Just seen your locations, would be good to see those.

Edited December 22, 2022 by Stuie W

[Lukesluckybunch]

Another boring uninspiring ECM run..remains changeable next couple of weeks with no real weather pattern dominating

[Gowon]

 JMA develops a nice little wedge to our NE - something's brewing I think

 

[MATTWOLVES 3]

A few runs appearing up North pushing that -10 line..and further South more of a colder cluster than what we have seen the last couple of days.

Give it another couple of days and I feel we may start to see a colder trend emerge.

A very positive evening to you all.

Edited December 22, 2022 by MATTWOLVES

[Battleground Snow]

ECM46  still looks interesting in the later weeks, but can we give it any weight?

[northwestsnow]

4 minutes ago, Gowon said:

 JMA develops a nice little wedge to our NE - something's brewing I think

 

That's a damn sight better than EC

[Gowon]

2 minutes ago, northwestsnow said:

That's a damn sight better than EC

It's the best chart we've seen in a while for sure.

The ECM has potential at day 10 to go on develop something along the same lines. 

[sebastiaan1973]

Sorry to say. No signal for SSW or significant weakening of the stratospheric vortex.  Above 40 m/s is considered strong. 

[KTtom]

19 minutes ago, Battleground Snow said:

ECM46  still looks interesting in the later weeks, but can we give it any weight?

I guess its how you interoperate them, to me week 3 isnt that far off week 1 for our neck of the woods,  nothing to get my interest up there.

[SqueakheartLW]

3 minutes ago, sebastiaan1973 said:

Sorry to say. No signal for SSW or significant weakening of the stratospheric vortex.  Above 40 m/s is considered strong. 

The disconnect is still there going by this chart. Raging up top but nothing too far above average at the most lower down and most of the time a little below average

[LRD]

10 minutes ago, KTtom said:

I guess its how you interoperate them, to me week 3 isnt that far off week 1 for our neck of the woods,  nothing to get my interest up there.

4, 5 and 6 look good

Still noise at this point of, course, but the 2nd half of the EC46 still looks good

[Eskimo]

My only crumb of comfort for everyone in here is that less than 1% of people across the European continent will see falling snow on Xmas day with the vast majority of countries seeing milder than average conditions - laying snow exclusive to mountains.

That remains the case for at least 10 days after if we take the models as gospel. Isn't restricted to our green and pleasant pastures. 

[Cheshire Freeze]

CFS seeing a strong Euro high anomaly for January- yuk!

[feb1991blizzard]

30 minutes ago, sebastiaan1973 said:

Sorry to say. No signal for SSW or significant weakening of the stratospheric vortex.  Above 40 m/s is considered strong. 

There is a decent clustering going sig below long term average in Jan (albeit briefly and the ens mean only very briefly)

[Hotspur62]

7 minutes ago, CreweCold said:

CFS seeing a strong Euro high anomaly for January- yuk!

Just as well it’s the cfs then!!

[MJB]

58 minutes ago, Battleground Snow said:

ECM46  still looks interesting in the later weeks, but can we give it any weight?

Pfffffffttttttt  enough said I think 

[bluearmy]

52 minutes ago, Battleground Snow said:

ECM46  still looks interesting in the later weeks, but can we give it any weight?

First week Jan looks to be split sceuro ridge or flat cool zonal    Second week similar 
                                                     
 

Third week Jan splits the option with a nw euro high aswell 

32 minutes ago, sebastiaan1973 said:

Sorry to say. No signal for SSW or significant weakening of the stratospheric vortex.  Above 40 m/s is considered strong. 

Good to see the rampant upper vortex dropping back, possibly below average before it recovers to be reasonably strong though nothing like it is in a weeks time 

[Mike Poole]

4 minutes ago, feb1991blizzard said:

There is a decent clustering going sig below long term average in Jan (albeit briefly and the ens mean only very briefly)

I’d not take that as necessarily a good thing, one thing that will slow the strat vortex down from a fast speed as I understand it, is coupling to the trop.  I personally think that those who have claimed that is already happening have jumped the gun, but middle third of January such a coupling could be quite likely, other things being equal.  

I think we need to see the trop pattern develop into something primed for cold before then, which gives us a window, but not a huge one.

[Uncertainty]

The January blocking signal on the ec46 is consistent now. @northwestsnow in answer to your questioning its  worth.. what else should one use ? Gfs extended? JMA weeklies? The cfs? Or should we simply abandon sub seasonal forecasting altogether? It may be the final frontier but it is my area of interest. IMHO The 46 is the best we have and right now it holds significant  interest for coldies into January. 
 

Notably, it weakens the zonal winds at 10hpa slightly below average in the first half of Jan. The GEFS are similar and we also have consistency from its previous run. Seen as the upcoming quasi zonal spell is likely trop driven anyway there remains no convincing evidence that a pv of doom is on the horizon nor a consistent signal for coupling. @jules216 you’re right it doesn’t show an ssw but it wouldn’t yet and the trop patterns it advertises, especially late Jan with a decent Ural block, could perhaps set something significant off into February. (It does look like that’s when one might occur now).

 

We can therefore examine any blocking forecast with less scepticism than would be the case under a strong, coupled strat regime.

The precip charts for weeks 3 - 6 show the unsettled weather favouring a southerly track

W3

W4

W5

W6

 

The MJO passing through 7-8-1 would also support a more blocked pattern. This is indeed what is advertised.

 

The JMA weeklies hint at an MAR for the latter half of Jan

@CreweCold You’re very downbeat at present mate (you don’t need to explain why to me ) but are you backing the cfs over the eps for the 2nd half of Jan?

So it’s a case of continued intrigue into January, though a 15+ day of westerly winds does look likely in the interim. My punt is that cold chances resume around mid month.  Another westerly spell in early Feb followed by an ssw. If it’s an absorptive event then an epic late Feb / Early March could follow. 
 

[bluearmy]

13 minutes ago, Mike Poole said:

I’d not take that as necessarily a good thing, one thing that will slow the strat vortex down from a fast speed as I understand it, is coupling to the trop.  I personally think that those who have claimed that is already happening have jumped the gun, but middle third of January such a coupling could be quite likely, other things being equal.  

I think we need to see the trop pattern develop into something primed for cold before then, which gives us a window, but not a huge one.

looks like that week sees pressure from a strat Aleutian ridge is responsible for the drop off in zonal flow Mike and the v strong week coincides with the spv right over the pole  

the month in general sees the spv at 10hpa hanging around svaalbard 
 

l

Edited December 22, 2022 by bluearmy