Model output discussion - Closing in on Christmas

[mushymanrob]

57 minutes ago, Weather-history said:

Isn't that anomaly chart  you posted just of the operational run?

Should we be looking at the mean anomaly chart?

Yep..... which isnt that different is it! Either way theres a mean Northerly.

[Man With Beard]

It seems the typical collapse of North Atlantic heights is about to happen again - though, to be fair, the models had a sniff of this quite some way out. It's always interesting to compare progression from T240 down to T0 - currently Christmas Day is around T168 (which is still too far out to call), but look at how the GFS/ECM ops have done so far for modelling it:

GFS Tuesday vs latest run

   vs  

ECM Tuesday vs latest run

   vs  

Absolutely typical - the models corrected the Atlantic low up to 1000 miles east between T240 and T168. 

However, something else is also typical - the models have corrected the new Atlantic low so much that Atlantic heights remain in situ, leading to the possibility of a second bite at the cherry a few days later. This morning's ECM clusters between T192 and T240 show a good number of ensembles going for the super-Scandi low plus super-Atlantic high.

Either way, it's going to get messy from 24th December onwards. Probably good for snow on Northern and Western hills - for coldies at sea level, enough to keep us interested, though it's starting to look like any potential snow may not be possible on Christmas Day itself. 

Still a bit to go, though!

 

[mushymanrob]

1 hour ago, Portsmouth Sun said:

Unfortunately the hyperbolic nonsense spouted about D10 charts that never verify get in the way of some informative posts. Looking ahead at what is developing is a cooling down from the NW around Christmas Day. What follows could very well be a screaming northerly as shown in unreliable timeframe charts or a return to something milder from the Atlantic.  A computer is never going to predict what mother nature has in store. 

Actually i disagree with this..

Day ten charts or something close to them often verify when there is consistency between the models and especially when theres Anomaly support. Any individual D10 chart wont verify, but they can be close. Its not the detail that should be taken as gospel, but the general theme successive charts are predicting. After 15 years of model watching online, id be shocked if the current charts for c 10 days time were far from broadly verifying.

I wouldnt rule out computers vs mother nature. Mother nature acts within the bounds set by the laws of physics. Complicated though that may be, the more we discover the better computer programs can be written. The accuracy of the models today is astonishing compared to when i started watching the weather charts on tv in the late 60's.

Edited December 18, 2020 by mushymanrob
typo

[Vikos]

15 minutes ago, Jon Snow said:

Sorry I cannot add any more reactions today..but Vikos..great post, hell I love Germany, I have German relatives...anyway, enough waffle already!...I am veery happy with the trends sofa today (especially the Gfs 0z op..omg)....it looks like a colder spell is on the way..wunderbar..Ja..das ist gut..Ja..das wetter ist gut Ja!

Guten Tag, you're welcome

[alexisj9]

1 hour ago, swebby said:

I know this is the hunt for cold thread (i've no problem with that) so this will probably get lost in the noise but a question for the likes of those trained in looking at these charts, e.g. @johnholmes etc:-

Having looked at the 0Z ECM output for post Xmas, and using Day 10's post above of the GEFs at the same period as an illustration.

Would this low that forms off the eastern tip of Greenland and then, whilst deepening, drops down into the North Sea ending up between East Anglia and Holland be a major flood risk for Eastern England and the Low Countries?  I want snow as much as anyone else on here but to my untrained eye, some of these charts look particularly worrisome for north sea coastal communities?

I would imagine so, has storm surge written all over it. Fingers crossed it won't happen like that. No expert though, just my opinion, and also knowing of some issue's with other storms less strong. 

[northwestsnow]

17 minutes ago, Man With Beard said:

It seems the typical collapse of North Atlantic heights is about to happen again - though, to be fair, the models had a sniff of this quite some way out. It's always interesting to compare progression from T240 down to T0 - currently Christmas Day is around T168 (which is still too far out to call), but look at how the GFS/ECM ops have done so far for modelling it:

GFS Tuesday vs latest run

   vs  

ECM Tuesday vs latest run

   vs  

Absolutely typical - the models corrected the Atlantic low up to 1000 miles east between T240 and T168. 

However, something else is also typical - the models have corrected the new Atlantic low so much that Atlantic heights remain in situ, leading to the possibility of a second bite at the cherry a few days later. This morning's ECM clusters between T192 and T240 show a good number of ensembles going for the super-Scandi low plus super-Atlantic high.

Either way, it's going to get messy from 24th December onwards. Probably good for snow on Northern and Western hills - for coldies at sea level, enough to keep us interested, though it's starting to look like any potential snow may not be possible on Christmas Day itself. 

Still a bit to go, though!

 

Agreed...

Fascinating model watching...

Fortunately for me with my paltry 200m elevation I have hills  around me at  350m so feeling pretty confident the hills will be white locally before the new year.

Edited December 18, 2020 by northwestsnow

[Just Before Dawn]

1 hour ago, swebby said:

I know this is the hunt for cold thread (i've no problem with that) so this will probably get lost in the noise but a question for the likes of those trained in looking at these charts, e.g. @johnholmes etc:-

Having looked at the 0Z ECM output for post Xmas, and using Day 10's post above of the GEFs at the same period as an illustration.

Would this low that forms off the eastern tip of Greenland and then, whilst deepening, drops down into the North Sea ending up between East Anglia and Holland be a major flood risk for Eastern England and the Low Countries?  I want snow as much as anyone else on here but to my untrained eye, some of these charts look particularly worrisome for north sea coastal communities?

The tides aren't scheduled to be that high on the 28th (5m along much of the east coast - in 2013 locally I think the pre-storm predicted tide height was 6.5m it eventually topped out around 8.3m). The atmospheric pressure data posted would only lift that by 30-odd cm, the forecast wind speed would be 16-25mph NE, a problematic direction but not that strong, that's if it all verifies - it also needs crackerjack timing for the wall of water pushed ahead of the LP to arrive around high tide - here in 2013 it arrived around an hour before high tide, which probably saved some of the villages on the Northern Lincs coast.  Something to keep an eye on if that output ends up repeating itself over the next week or so for sure, but I'm not expecting my evening of necking Baileys and watching Bond movies on the 28th to be knocked on the head by work just yet.  Could there be some big waves on parts of the east coast and a few defences being over-topped? That's possible. Would that be like 2013? Pretty unlikely based on that output. The 2013 storm really was a monster, as was the one that caused the 1978 east coast storm surge. 

Edited December 18, 2020 by Just Before Dawn

[Guest]

A cold snap verses cold spell all depends on the energy being swept up the eastern side of Greenland. If that energy is sharp and clean it supports a robust high pressure in the atlantic. I think we are in for more cold modelling over the coming days before this is settled yet...better than last nights 18z too....

[Purga]

Decent bit of snow for London at year's end maybe?

[terrier]

Well not long now till this evening model output from the icon ukmo gfs & ecm. I still have that feeling we are been slightly lead up the garden path again by the output. Because the latest met musings are nothing like what the models seem to be churning out at the moment. But I guess there are still in the reaches of +8 days away yet for anything intriguing. And for those who have been around a while now will know these things can go wrong at t72 hours. Anyway let’s see what tonight’s output brings. But I must admit not having the met on board is a worry. But as ever time will tell. 

[Downpour]

4 minutes ago, terrier said:

Well not long now till this evening model output from the icon ukmo gfs & ecm. I still have that feeling we are been slightly lead up the garden path again by the output. Because the latest met musings are nothing like what the models seem to be churning out at the moment. But I guess there are still in the reaches of +8 days away yet for anything intriguing. And for those who have been around a while now will know these things can go wrong at t72 hours. Anyway let’s see what tonight’s output brings. But I must admit not having the met on board is a worry. But as ever time will tell. 

The Organisation’s 0400 update looks fine to me. Chilly, with snow showers mentioned. Would appear largely in line with the model output. 

[Frosty.]

Ok..I’m dreaming of a cold Christmas..and looking at the ECM 0z ensemble mean, that’s what we’re in for!...a colder Northerly arctic flow with snow showers to exposed parts of the N & E for a time and increasing amounts of frost..oh my, Darren Bett will be unhappY!!!!!!...ps..scope for colder into the end of the year and early 2021..,or is that wishful thinking?..I don’t give a 510 / 492 dam!

Edited December 18, 2020 by Jon Snow

[offerman]

3 hours ago, markw2680 said:

Finally a down to earth post, some people just set them selves up for a massive fall, yes of course we all want cold and snow but let’s be realistic here, after all it is the uk

Spot on ! 

[Skullzrulerz]

2 minutes ago, Downpour said:

The Organisation’s 0400 update looks fine to me. Chilly, with snow showers mentioned. Would appear largely in line with the model output. 

Who's "The Organisation" sounds top secret XD

[Battleground Snow]

Icon looking nice and amplified at just 126 hours 

 

[Mucka]

ICON showing why I don't much rate it unless it is pulling off a coup along with UKMO

 

This is a big difference upstream for just 108 hours.

With ECM leaning more toward GFS with a much faster and flatter upstream I would expect ICON and UKMO to be wrong. UKMO may switch this afternoon.

If that is the case then these runs still showing a more amplified initial Atlantic ridge can be ignored and attention turn to how the low phases with the ScEuro trough and upstream amplification beyond that 144+

[That ECM]

13 minutes ago, terrier said:

Well not long now till this evening model output from the icon ukmo gfs & ecm. I still have that feeling we are been slightly lead up the garden path again by the output. Because the latest met musings are nothing like what the models seem to be churning out at the moment. But I guess there are still in the reaches of +8 days away yet for anything intriguing. And for those who have been around a while now will know these things can go wrong at t72 hours. Anyway let’s see what tonight’s output brings. But I must admit not having the met on board is a worry. But as ever time will tell. 

Are you expecting an extended outlook that simply say “chew chew”?  

 

something akin to this with high maybe a little further north? 

[Jeremy Shockey]

ICON 12z for Christmas morning

@mucka ,,,,,,,,id take that for 0700 hrs on 25th Dec from your friend the ICON

[PiscesStar]

23 minutes ago, terrier said:

Well not long now till this evening model output from the icon ukmo gfs & ecm. I still have that feeling we are been slightly lead up the garden path again by the output. Because the latest met musings are nothing like what the models seem to be churning out at the moment. But I guess there are still in the reaches of +8 days away yet for anything intriguing. And for those who have been around a while now will know these things can go wrong at t72 hours. Anyway let’s see what tonight’s output brings. But I must admit not having the met on board is a worry. But as ever time will tell. 

I have also noticed this. Its hard not to when all the met allude to is typical fayre sadly 

 

23 minutes ago, terrier said:

Well not long now till this evening model output from the icon ukmo gfs & ecm. I still have that feeling we are been slightly lead up the garden path again by the output. Because the latest met musings are nothing like what the models seem to be churning out at the moment. But I guess there are still in the reaches of +8 days away yet for anything intriguing. And for those who have been around a while now will know these things can go wrong at t72 hours. Anyway let’s see what tonight’s output brings. But I must admit not having the met on board is a worry. But as ever time will tell. 

I also noticed this and it is a worry. Surely they won't ukdnt be late to the party.... Surely not. 

[Kasim Awan]

Iconic Xmas day run from the ICON 

Would produce a white xmas for many

Sadly it is the icon..

[Battleground Snow]

How it ends. Would be at the top of @bluearmy envelope for cold prospects?

[Purga]

Let's see what the 12z's bring in the light of the latest extended METO text forecast which is now mentioning possible snow and later wintry precipitaion in the SE.

[TSNWK]

Is ICON the German based model that replaced DWD ? I think so and if it is I wonder if Vikas? From Frankfurt who has posted recently can share a view on its reputation?

 

Edited December 18, 2020 by TSNWK

[Mucka]

6 minutes ago, Jeremy Shockey said:

ICON 12z for Christmas morning

@mucka ,,,,,,,,id take that for 0700 hrs on 25th Dec from your friend the ICON

 

You would be sacrificing a potential true cold spell for a brief cold snap and chilly but mainly dry Xmas day.

As I say, if GFS and ECM are right then you can ignore it because it is wrong by 96h let alone anything after.

This is the difference when it doesn't have a flatter initial ridge and a faster low phase with the trough.

ICON/GFS

ICON would not go on to produce a cold pattern from there with the jet powering over the top, though you may be able to maintain the cold for a couple of days and if very lucky rebuild blocking later.

 

[Frosty.]

I think a colder Pm / Am flow for crimbo eve is probably a good bet as things stand..according too the GEFS 6z mean anyway..followed by a crisp crimbo day..followed by a possible colder shot between crimbo / new year?..call me out if you disagree but I think there is more potential for cold this year than the pathetic last several!