Model output discussion - Closing in on Christmas

[sebastiaan1973]

Just now, Snowman. said:

Likely serious vortex stress too...

One can only hope..

Most members don't have a SSW.

[Allseasons-Si]

9 minutes ago, sebastiaan1973 said:

Excellent update from EC46. Europe cold after Christmas.

I repeat......

what a stonking update that is.

P.S,can i get back to doing other stuffs now lol.

Edited December 14, 2020 by Allseasons-si

[sebastiaan1973]

The temperature charts.

Here you can see the ENS members http://apps.ecmwf.int/webapps/opencharts/products/mofc_multi_eps_family_stamps?base_time=202012140000&parameter=mean sea level pressure&valid_time=202101030000

 

[LRD]

8 minutes ago, sebastiaan1973 said:

Excellent update from EC46. Europe cold after Christmas.

Booooo - week of 4 Jan looks dry

Seriously, that is an impressive update

[TSNWK]

3 minutes ago, sebastiaan1973 said:

Most members don't have a SSW.

Good! As Frankly if that EC46 is correct I'm more than content to stick and reject any SSW disruption...

Edited December 14, 2020 by TSNWK
.

[SLEETY]

those ec46 charts flip-flip all the time and  arent worth taking much notice o

f,just four days ago they were showing all of europe mild in january lol

Edited December 14, 2020 by SLEETY

[chris55]

Right I’m ordering a few sledges from Amazon now while they are cheap. If I leave it any longer... either they’ll be out of stock come New Years, or I’ll be using them as a sun lounger hahahah ! 
 

better safe than sorry lol.... (always next year if needed ha) 

[Penicuikblizzard]

10 minutes ago, sebastiaan1973 said:

Excellent update from EC46. Europe cold after Christmas.

There is only one chart showing UK cold on those charts that I can see, could  someone explain why they are good charts ? 
many thanks 

[northwestsnow]

There's an easterly in there...

[sebastiaan1973]

Just now, Penicuikblizzard said:

There is only one chart showing UK cold on those charts that I can see, could  someone explain why they are good charts ? 
many thanks 

Two. > 28 december 2020 till 10th of January.

[Allseasons-Si]

2 minutes ago, Penicuikblizzard said:

There is only one chart showing UK cold on those charts that I can see, could  someone explain why they are good charts ? 
many thanks 

Heights to the north and pressure dropping into mainland Europe.

[Skullzrulerz]

3 minutes ago, SLEETY said:

those ec46 charts flip-flip all the time and  arent worth taking much notice o

f,just four days ago they were showing all of europe mild in january lol

Don't ruin it

[Daniel*]

I think the boat is moving into calmer waters 00z > 12z.

 

[Nick F]

If anything, 12z EPS mean has strengthed the mid Atlantic ridge anomaly in the extended range compared to previous runs, which bodes well for those worrying about a northerly toppler.

Ideally we want the ridge robust and/or building NE toward Scandi to keep the cold locked in. Toppler from the NW will continue to be a concern if the Atlantic ridge north is not robust enough.

[LRD]

5 minutes ago, SLEETY said:

those ec46 charts flip-flip all the time and  arent worth taking much notice o

f,just four days ago they were showing all of europe mild in january lol

True but better to have it on the cold side than not though

[Mike Poole]

4 minutes ago, Penicuikblizzard said:

There is only one chart showing UK cold on those charts that I can see, could  someone explain why they are good charts ? 
many thanks 

They are mean charts of many runs over a week so could hide all sorts of interesting things on individual runs, but the main theme is high latitude blocking, if that happens, we can work out the details from the op runs closer to the time!

[BLAST FROM THE PAST]

1 hour ago, Tim Bland said:

Sorry mate you don’t get off that easily. It was a Blast / beast’ from the EAST that you forecast. It’s looking better than it was a week ago though! ECM looks like it’s borderline of it will topple or lead to an 

God you are so harsh!   Let’s see what develops 

 

BFTP

Edited December 14, 2020 by BLAST FROM THE PAST

[Matt H]

Yes the ECM monthlies are beautiful, quite surprised to see the blocking signal extending well into January.

[MATTWOLVES 3]

16 minutes ago, Penicuikblizzard said:

There is only one chart showing UK cold on those charts that I can see, could  someone explain why they are good charts ? 
many thanks 

The ensemble mean is only out to Sunday at this stage, we are looking at a whole batch of members 50 I think,which all start out with different initial outcomes. Keep in mind the longer range forecasts will be significantly less accurate as the lead time increase. The ensembles may be able to pick up periods of warmer or colder conditions 3 or so weeks from now,but wouldn't be able to nail down a significant weather event till around a week out. The main focal point being these ensembles are aimed at evaluation of temperature trends. So they remain a good guideline for trends,but should not necessarily be taken as the be all and end all...they can make a complete dogs dinner of it...some years they nail the pattern rather well,others they can be shocking.

Edited December 14, 2020 by MATTWOLVES

[Allseasons-Si]

.........And the cpc are starting to come on board now in the extended

and the NAO/AO still in neg territory

i will give that a third clap...

great upgrades today...

please keep it up

 

[MATTWOLVES 3]

1 minute ago, Allseasons-si said:

.........And the cpc are starting to come on board now in the extended

and the NAO/AO still in neg territory

i will give that a third clap...

great upgrades today...

please keep it up

 

Brilliant stuff si...now go and get ya dinner done before the dog eats it ..

[stodge]

Evening all

It's probably something I've just made up but in model terms Sunday's hope is often Monday's despair. A new week seems to bring a reset away from optimism to pessimism (or realism if you prefer). Let's see if the new week and new models tell a new story..

12Z GEM: No surprises by the weekend (T+120). The Atlantic LP has two centres - one already over the Faeroes and the other close to the Hebrides. In their circulation showers and rain off a mild SW'ly for England but a change to a PM airmass apparent further north and west. Heights over SE Europe and a new LP developing far to the SW.  By T+180, the LP is churning its way slowly towards the British Isles while a ridge builds over Iberia , pressure remains high far to the east while a shallow but extensive trough covers Scandinavia. The PM airflow is gone and a weak HP ridge ushers in a new mild airflow for southern Britain.  By T+240, the evolution is getting messy as everything slows. The LP fills and meanders toward NW Britain while heights develop over both Iceland and Scandinavia as well as over southern Europe. It's still mild for most of the British Isles and there's a new Atlantic LP but this evolution has a lot of paths from here.

12Z GFS - after a bit of a nothing run from GEM, what will the Americans offer us this evening? At T+120, slight but subtle differences to GEM. The PM airmass covers the whole of Britain with the complex LP still to the north-west.  By T+180, the differences are more pronounced. The original LP is only just to the north of Scotland and secondary features have developed. One has moved across southern England and the LP we saw 60 hours earlier much further to the SW is coming in faster and deeper towards the British Isles. A new mid-Atlantic HP is trying to form at the same time. As expected, therefore, a very different T+240 with the LP crossing Britain and developing over southern Scandinavia as a complex feature. This draws a NNW'ly flow down across Britain which would be pretty cold you'd imagine. Heights from Greenland south to a new HP in mid-Atlantic are under pressure from a new LP coming out of Canada. We get a cold Christmas for a change and by T+324 the HP has finally built in across Britain with a ridge to Scandinavia.  LP over Spain helps to support a ridge but clear signs of the PV gathering over its usual place. Nonetheless, the cold evolution does well with the HP heading to Scandinavia and throwing a cold E'ly back across Western Europe.  Minus 8 850s suggest the white stuff not the wet stuff. 

12Z ECM - well, the GFS OP will have cheered many and the key is how it plays that LP coming from the far SW- Phasing it into the original LP allows time for amplification while a slower approach may not but let's see where ECM goes. T+120 has few surprises and T+168 is the key chart on this output. Note how the LP to the SW has phased in to the circulation of the original LP (as GFS also suggested) and the whole feature looks set to move NE across southern Britain with heights building upstream. The T+240 chart shows how that impacts and we get a chilly Christmas Eve chart with a NNE'ly flow for many parts with the LP over the Low Countries. Much colder sir moving in from the north as you'd expect and it should mean a cold Christmas for all and perhaps a White Christmas for some.

Looking elsewhere, the 12Z OP showed the continued strong 10 HPA warming for the period between Christmas and New Year and perhaps a third warming developing from the European side to start 2021. It's all good news for those looking for a disrupted vortex.  From an unpromising situation, the 12Z Control ends on a very cold note with a Scandinavian HP and a wedge of -12 850s coming our way. 

Conclusion - after a bleak end to last week, this week has started with some much more pleasing output for cold fans. It's always helpful to see GFS OP and ECM Master looking so similar and the former (supported by Control) looks a very nice route to something cold. ECM gets to cold but whether it can keep the cold is debatable. GEM is much less convincing and shows what could happen if the phasing of the LPs doesn't happen. We need to LP to the far SW to phase into the main LP and rush through to allow upstream amplification . If that happens, with a weak and disorganised PV in our vicinity, we have a chance to build heights to the North-West. The other option whereby the Atlantic HP transits to Scandinavia also works for those wanting cold. However, caution and patience must be the watch words - we are an eternity away from all this and so much, as we know, can still go wrong. If this is still on the cards at T+24 we can begin to enjoy it but for now, it's nice to look at but that's all.

 

[Mike Poole]

Just over 10 days from Christmas, and things are starting to look interesting.  So to take a step back from the main op runs for the moment, what interesting things are happening?  

AAM - increasing to just above average according to CFS model (wish I had access to this from better models than CFS!):

This responsible for the increasing Atlantic ridge signal in the ECM EPS ?  Likely.

MJO - ECM EPS 0z take:

Only moderate enthusiasm for progression into favourable 7-8 at any amplitude (is this at odds with AAM above?).

Strat, vortex ramping up but forecast to slow down:

NAM plot shows continued disconnect with the trop:

Repeated minor warmings showing e.g. on GFS runs, 12z:

SSTs:

La Nina east based, no noticeable IOD (thankfully), cool in Atlantic (probably not great), but warm in North Sea, which would aid convection if we ever got that Easterly.  

Well how all that pans out waits to be seen, but the model output has been increasingly promising for cold, we will see...

 

 

Edited December 14, 2020 by Mike Poole

[Anthony Burden]

Although a lot of individuals might look at the ECM monthly and disregard it,the technology 

that is used is the best you can hope for at that time frame.My personal opinion is not to take 

as gospel but as encouraging.

 

[feb1991blizzard]

The AAM charts are still only indicative of temporary ridges been thrown North by the looks of things.