Model output discussion - 5th December 2016 - Into Winter we go

[fergieweather]

Just now, bluearmy said:

So with enso fairly neutral and the MJO in the COD, we should probably be at the mercy of the propagating strengthening strat zonal flow in conjunction with the west QBO.  That means charts like we are seeing on the 12z and 18z are unlikely.  

will be interesting to see if the 00z output is in the same ball park.

Well, we will see. There's no real support in 12z ECMWF EPS for anything so pronounced, albeit both it and the preceding 00z 15-d ENS do drop median TMax below avg (v model climatology) into early Jan. 

[snow mad]

both ecm and gfs coming up with broadly similar ideas at the 10 day range. 

[Cheshire Freeze]

CFS seems to be picking up on something for January now too. A few runs in succession which have shown a similar trend

[West is Best]

OMG the 18z. I mentioned earlier that c. 3 days ago UKMO was the first to suggest the mid-Atlantic ridge, then the ECM went with it on today's 12z and now this 18z GFS has gone to town. And how.

I expect it will all go pear shaped but I'd rather revel in the dream than the dross we've been enduring for days on end. Bring it on.

[Man With Beard]

The GEFS mean at T240 wouldn't discount some sort of northerly either

Not massively different to ECM mean at that time but not quite as much potential 

A reminder of how things can develop quickly.

 

 

[Allseasons-Si]

L@@k at pert 8,don't need to post charts but run it threw

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=192&code=8&mode=0&carte=1

pv on the Siberian side with a cross polar flow,i won't say no to that.

couldn't resist

Edited December 22, 2016 by Allseasons-si

[chris pawsey]

Dear all, some truly great charts for coldies this evening. Let's hope these trends continue, after all its the trends that count!

Let's hope that the start of 2017 brings the winter everyone craves. 

[bobbydog]

Pfffff....

 

Whatever...

Edited December 23, 2016 by bobbydog

[Paul_1978]

I'm erring on the side of caution for now. These charts might be a distant memory in the morning. Once bitten twice shy and all that 

:-(

[kumquat]

Couple of old stalwarts, first Iceberg then Teits and even Mr Crewecold (coming on board tonight) are seeing the potential. I can smell it in the air.

When those deep low heights get dragged over towards Siberia and we see a split down the middle through the Pole. Game on.

[joggs]

1 hour ago, CreweCold said:

CFS seems to be picking up on something for January now too. A few runs in succession which have shown a similar trend

Cmon Crewe the cfs.Up n down like fiddlers elbow.You know that.Yes it's what's showing but how many times in the last 4 months? 

Edited December 23, 2016 by joggs

[Daniel*]

I wonder if the GFS 18hrs was on the scotch...

Seen a lot worse. A tad more encouraged, looks like the control was off on one no real surprise. A fair few take a downwards path interesting prospects for early January..

Edited December 23, 2016 by Polar Maritime
To move discussion on.

[kumquat]

Still think things are looking good for coldies on the horizon into Jan. Plenty of charts showing retro to NW and cold pouring in down the NE side of the high into our shores.

[Cheshire Freeze]

36 minutes ago, joggs said:

Cmon Crewe the cfs.Up n down like fiddlers elbow.You know that.Yes it's what's showing but how many times in the last 4 months? 

I pay little attention to it...unless it churns out very similar output on consecutive runs...which it has done. 

Also it can't be that useless, it didn't back the potential for a colder Dec- unlike the others.

Edited December 23, 2016 by CreweCold

[chessfiend]

1 hour ago, Paul_1978 said:

I'm erring on the side of caution for now. These charts might be a distant memory in the morning. Once bitten twice shy and all that 

:-(

 

Yup, now in the parallel universe where the next ice age threatens every single winter to destroy NW Europe, charts like the northerly plunge, veering North easterly for 6 weeks, would be, err, yes par for the course. However, in this world of milder climates, let’s be realistic. Mild 9 times out of 10, normal is Bartlett High, occasional toppler – yay! So greetings of the season, take joy in the next sleety shower.

[Mucka]

Happy New Year!

From GFS

 

Our first taste of Winter, Is it finally on?

Atlantic ridge at day 9, can it make it into day 7 and nearer.

Or perhaps more pertinently, Can it make into the next run 

Edited December 23, 2016 by Mucka

[knocker]

The GFS is quite interesting this morning in as much it continues with renewed bout of amplification around the T180 mark. It appears to be facilitated by some interaction between the Siberian and Canadian vortex initiating a a deep cold trough swinging across N. America which produces some intense WAA around the n.east of same continent and some rapid height rises. Simultaneously a trough has shot west out of the Canadian vortex to be over Iceland.(quite Important)

This continues apace with Aleutian Ridge intensifying as well as the one in the Atlantic whilst the aforementioned trough phases with the Russian lobe and eastern European trough and sinks some cold air over the UK. After that things rapidly get back to normal with a strong westerly jet.but that's getting ahead of ourselves.

 

Edited December 23, 2016 by knocker

[snowangel32]

3 minutes ago, Mucka said:

Happy New Year!

From GFS

 

Our first taste of Winter, Is it finally on?

Atlantic ridge at day 9, can it make it into day 7 and nearer.

Beat me to it Mucka. Gfs saying Happy new year with a Greenland high and the PV under a two pronged attack. Also the building blocks are in place for the ridge in the semi reliable time frame so it's not in lala land I am not to concerned about what will come after as we will see a lot of chopin and changing but once that high is in place they can be stubborn as we have found out. Great charts for coldies and such a quick turn around from a few days ago.

[Mucka]

17 minutes ago, snowangel32 said:

Beat me to it Mucka. Gfs saying Happy new year with a Greenland high and the PV under a two pronged attack. Also the building blocks are in place for the ridge in the semi reliable time frame so it's not in lala land I am not to concerned about what will come after as we will see a lot of chopin and changing but once that high is in place they can be stubborn as we have found out. Great charts for coldies and such a quick turn around from a few days ago.

Yeah after talking up a trough digging into N/central Europe and saying I fancied an Atlantic ridge a few days ago I was beginning to give up on the idea until later into January because any amplification was looking like being overrun so it is quite a turnaround.

Fingers crossed it is not yet another false dawn and we don't start seeing spoiler shortwaves modeled SW of Greenland as we get closer as is so often the case.

Edit.

Only around 25% of 00z ensembles support the op with such a clean transition but somewhat encouragingly quite a few others find their way to something cold later.

Edited December 23, 2016 by Mucka

[IDO]

30 minutes ago, Mucka said:

Happy New Year!

From GFS

 

Our first taste of Winter, Is it finally on?

Atlantic ridge at day 9, can it make it into day 7 and nearer.

There were signs last night that there was potential, and the amplification on the 0z is even earlier this morning. This suggests the GFS is responding to some background signal, rather than just a rogue run.

Looking through the GEFS last night it is apparent there are 2-3 clusters and this is one. This morning's GEM is the other:

Its all about how that second wave of heights from the Azores builds in the Atlantic sector from around D8. Very complicated on the GFS to get where it goes, where as the GEM keeps it simple and pumps that wave into the UK high to reinforce. However the GFS op scenario was not without support the last couple of runs, with variations on that theme, so hard to ignore as a possibility at the moment.

Looking at the upstream pattern and there remains a build up of an Alaskan Ridge, and the members promoting this certainly suggest it is very favourable for cold air and disturbances for the UK regions as the NH profile shuffles and the trough closes in to the UK. Last night's mean at D13 highlights this:

 0z D10: 

An excellent mean for a significant cold flow.

The trend the last few runs suggest cold is on its way, though at the moment how that manifests is sketchy and the op this morning looks to best case scenario. At D11 you can see the cluster split between the two main options, GEM like or GFS op like: here But the trend at the moment is good.

Edited December 23, 2016 by IDO

[snowangel32]

2 minutes ago, Mucka said:

Yeah after talking up a trough digging into N/central Europe and saying I fancied an Atlantic ridge a few days ago I was beginning to give up on the idea until later into January because any amplification was looking like being overrun so it is quite a turnaround.

Fingers crossed it is not yet another false dawn and we don't start seeing spoiler shortwaves modeled SW of Greenland as we get closer as is so often the case.

Shortwave should be in the Netweather Swear filter lol. I wonder if we could get a link up of the two ridges it gets pretty close on this run but I think it's in the realms of possibilities.

 

[Duane S.]

Nice GFS00z and we have some much craved consistency. Not withstanding it could be consistently wrong of course!

Certainly seems a plausible evolution as long as that ridging into GL isn't purely a knee reaction to its MJO forecast heading into phase 1 (which is FAR from set in stone). Great to see though, let's hope the ECM keeps with theme later this morning. 

 

[Mucka]

6 minutes ago, s4lancia said:

Nice GFS00z and we have some much craved consistency. Not withstanding it could be consistently wrong of course!

Certainly seems a plausible evolution as long as that ridging into GL isn't purely a knee reaction to its MJO forecast heading into phase 1 (which is FAR from set in stone). Great to see though, let's hope the ECM keeps with theme later this morning. 

 

Hopefully not. I think it is just that upstream amplification is coming into closer resolution.

UKMO 144 a little fast but upstream amplification is modeled.

[knocker]

Some perspective

[Polar Maritime]

Some interesting charts as we head into the New Year from the the GFS this morning, With ridging into Greenland bringing a cold N-N/E flow.

Edited December 23, 2016 by Polar Maritime