Model output discussion - another cold spell on the horizon?

[pyrotech]

5 minutes ago, Tim Bland said:

Have we really got that desperate it’s like the old days ..discussing the country file / long range forecasts...I can phone ‘weather call’ & check teletext if that helps They (Meteogroup) just present the ECM

I do not think that is fair Tim, Meteogroup utilise all the models not just ECM, they are also in agreement with Met O when severe weather warnings are issued. They have  MOU between them to ensure public gets the correct non conflicting messages.

With a SWW event i think its best to use every tool in the toolbox because this will have many twists and turns.

Icon and JMA all come into play if just for comparison

GFS often picks a trend in Fi but then drops it to bring it back last minute, the only things i do not use are piers Corbyn and the Express news paper.

Experts will be watching this very closely, a severe cold spell will put huge strain on NHS at best of times so people need to get it right. 

 

[SMU]

1 minute ago, IDO said:

Hi

If only statistics was as easy as you make it sound! You have to build into that 17/17/17 the ratio of those d10 Greenland highs, Atlantic ridge or Azores high being the solution by T0. Of course, we know that a d10 GH rarely lands at D0 so we would factor this in with an equation with those odds, ditto the other two possible outcomes. 

So although a 33% chance sounds great for a GH, the reality is that in a large sampling the chances are significantly less by d0. There are obvious caveats, but the mean is a balance to any "out there" solutions. If this was a plume from sub-tropical forcing then we would maybe have sub-set binning to qualify any results. Or if this is the imprint of an SSWE and we knew that for sure, then we would bin that factor. 

I think what we can say is that if the means are synoptic-wise correct (Scandi trough) then we should see increased chances of forcing to the Greenland region if we get a clean evolution. A real-life GH though, mostly in my dreams or in models in FI sadly!

@chris55 If you really really really simplified it & made all the pressures equal & had 3 fixed points

1) Greenland high for 17

2 ) Atlantic ridge for 17 

3 ) Flat pattern for 17 then of course the mean would show an atlantic ridge.

At the moment the 216 > 240 Means show the 552 contour level with ireland. 

That means the significant weighting is for 2-3 & a minor cluster for 1.

My next port of call then would be compare the 192 Mean 12z tomorrow with the 216 12z mean from today to see if there is any backtrack to a more amplified pattern.

The reality will be somewhere in the midpoint ....

[phil nw.]

42 minutes ago, Man Without Beard said:

I'll post images of some of the ecm ensembles later to show if there are any true Greenland Highs (haven't looked yet for 12z)

Correct me if I'm wrong but the definition of a high is when an area of pressure is higher than the pressure that surrounds it - is everyone working off the same definition? (For Greenland it is important that this is taken at 500mb)

I always refer to a proper GH as an enclosed cell up there with the jet all running underneath further south.

Anything else to me is a N Atlantic /Greenland ridge depending if the crest touches Greenland or not.

 

Edited January 10, 2021 by phil nw.

[london-snow]

18 minutes ago, CSC said:

I see a lot tonight suffering from post Chart watching depression. Remember this is ONE run. Albeit, it didn’t go the way some may have hoped but it’s ONLY ONE run. Wait until tomorrow before having any more predictions!

I think all scenarios are still on the table and even t120 no one knows, so for those guessing what’s happening in 6 weeks time saying cold is gone and our hopes our lost, baffle me to be honest. 

Cold is in our sights and I believe one way or another, it is coming in it’s masses! Best opportunity here in a long time. Heads up NW community! Onto the pub run now...

6 weeks time takes us up to mid-late February,

I have been keeping an eye closely on the models since mid November as well as this fantastic forum with great input from the strat lads & lasses however we cannot seem to strike it rich so to speak! 
 

However some are quick to dismiss a possible cold outbreak circa 19th-22nd of January are a bit quick to jump the gun imo as we have seen the past days of ensembles scattering on or just after the date mentioned so imo very much all cards on the table.

Lets see where we are at come Monday morning..

Stay Safe

Edited January 10, 2021 by london-snow

[Battleground Snow]

Isn't it the descending Arctic high which helps advect the cold uppers west from Siberia? So is it vital we get a "true Greenland high" won't general heights in the Greenland area do the same job?

[Tim Bland]

By day 3 the EPS has a huge range! FI is currently mid week!

[MATTWOLVES 3]

12 minutes ago, bluearmy said:

Seriously - if it’s flipped back westerly it’s marginal and would it make any difference ..... its still reversed at 61N. The chat about tech ssw is imo full of naval gazing. Looking at the whole strat is way more important than the particular zonal flow specifically at 10hpa at 60N 

it will remain reversed in much of the strat above 60N for the next 10 days .....

 

 

Yes Nick you make a good point..Its been pointed out to Marco that its still reversed at 61N..Tomorrow its Becoming Estly again at 60N 10hpa..The vast portion of the strat above 100hpa and 60N is reverse zonal flow today and will remain that way for some time...further warmings are only going to keep that trend going..Regardless of whether it incurs further splits,its good to see its displaced in a big way.

[Man With Beard]

5 minutes ago, phil nw. said:

I always refer to a proper GH as an enclosed cell up there with the jet all running underneath further south.

Anything else to me is a N Atlantic /Greenland ridge depending if the crest touches Greenland or not.

 

Phil, thank you, I will follow suite in future and refer to a non cut-off area of heights over Greenland as a "ridge" rather than a Greenland High. I think that will clear up the terminology!!

In which case, looking through the whole 51 ensemble set at D9, there are 8 true Greenland Highs, 15 with heights that ridge to the centre of Greenland, and 28 ensembles that do neither. So odds slightly against a Greenland High or ridge at D9 tonight.

I'll move on now

 

[Scott Ingham]

14 minutes ago, Steve Murr said:

@chris55 If you really really really simplified it & made all the pressures equal & had 3 fixed points

1) Greenland high for 17

2 ) Atlantic ridge for 17 

3 ) Flat pattern for 17 then of course the mean would show an atlantic ridge.

At the moment the 216 > 240 Means show the 552 contour level with ireland. 

That means the significant weighting is for 2-3 & a minor cluster for 1.

My next port of call then would be compare the 192 Mean 12z tomorrow with the 216 12z mean from today to see if there is any backtrack to a more amplified pattern.

The reality will be somewhere in the midpoint ....

Fair post this Steve

[Vikos]

Greenland high, Greenland high... better use WZ charts! Meteociel isn't always too acuarte...

 

[knocker]

6 minutes ago, MATTWOLVES said:

Yes Nick you make a good point..Its been pointed out to Marco that its still reversed at 61N..Tomorrow its Becoming Estly again at 60N 10hpa..The vast portion of the strat above 100hpa and 60N is reverse zonal flow today and will remain that way for some time...further warmings are only going to keep that trend going..Regardless of whether it incurs further splits,its good to see its displaced in a big way.

But not at Lerwick at 60N

Edited January 10, 2021 by knocker

[Tim Bland]

15 minutes ago, pyrotech said:

I do not think that is fair Tim, Meteogroup utilise all the models not just ECM, they are also in agreement with Met O when severe weather warnings are issued. They have  MOU between them to ensure public gets the correct non conflicting messages.

With a SWW event i think its best to use every tool in the toolbox because this will have many twists and turns.

Icon and JMA all come into play if just for comparison

GFS often picks a trend in Fi but then drops it to bring it back last minute, the only things i do not use are piers Corbyn and the Express news paper.

Experts will be watching this very closely, a severe cold spell will put huge strain on NHS at best of times so people need to get it right. 

 

I’m sure they do look at all the models but for BBC the graphics they supply are 100% just the ECM, it’s an old ECM as well. I have  just watched Chris fawkes with his awefull blue suit and pink tie & they are showing the 00z ECM. Tomorrow morning they will be showing this evenings. Have a look for yourself..save the precip images from tonight’s ECM and I guarantee you they will present this up until lunchtime tomorrow. At around 3pm they will start showing the 00z... I have far to much spare time on my hands

[Griff]

For anyone who might be interested, I've asked Simon Lee for his thoughts on ECM/GFS-gate... 

 

[Scott Ingham]

2 minutes ago, Griff said:

For anyone who might be interested, I've asked Simon Lee for his thoughts on ECM/GFS-gate... 

 

Whats interesting about the emsembles he shows is they are identical on the 19th with greenie heights. 

So maybe the ECM gets there a couple of days slower due to the orientation of the wave break.

[chionomaniac]

I can’t believe I’ve read 5 pages of weather there will be a Greenland high or not.

With the propagation of the SSW, we have certainly seen an early divergence in the trop modelling. And this we have seen many times before has led one or more models down a garden path. Initially it looks that any Greenland high in the next ten days is unlikely, but with a resurgence of negative winds at the top of the strat, I wouldn’t discount this for too long.

In a superstitious way, I wouldn’t rule it out either. The number of times I have seen Steve rule a scenario out and then see the models reverse within 24 hours are too numerous to mention. So I’m happy with that too.

[DanDorsetUK]

Some crazy reactions on here today I feel. Take a ten minute breather and watch vid 2 then relax.

 

[Barmada_Casten]

58 minutes ago, Harsh Climate said:

I think if your going to be neutral and give a balanced view it's clear to see that we are going to be in somewhat middle ground, between colder air to the North east and milder air from the west/ southwest. Unfortunately it looks like we are going to be just on the wrong side, with Denmark looking prime position.

I see a lot of hopecasting going on, there's people who have predicted these 'holy grail' winter setups are just around the corner since late December and just keep cherry picking the best charts/ data to back themselves up ignoring all the negative signs. You just know there going to keep bashing that battered drum until there's nothing left of the bloody thing, we're in May or by the law of averages they get lucky a month later .

You can see who the experienced long serving members on here are because it only takes a fleeting look at gfs, ecm and ukmo to know when things aren't that great for us coldies because we've seen that many charts/setups and letdowns you pretty much can give a good analysis from just the quick feeling you get from those 3 models. 

Its clear to see that from the big 3 models iv mentioned any blocking looks transient for the next 10 days or so, we will have cold and mild shots with maybe some transient snowfall probably on high ground. There is no suggestion of a meaningful Greenland high thats going to set up a corner shop for any meaningful length of time and the Atlantic just has a little too much bite at this time.

After that though my opinion is we should start seeing more blocking into February as the SSW comes into play and the Atlantic starts losing its bite. But that is still no guarantee any deep cold will be channelled our way. Patience is required here im afraid.

 

This is one of the best posts I have ever read on this forum! .... I love What you said about the experienced posters, as one myself I am feeling the pain every time I come to this thread.

 

Please can I copy the post and put it in the NW regional thread?

[East_England_Stormchaser91]

The thing is, you don’t necessarily need a full blown Greeny high to get snow and cold. Of course it helps no doubt, but you can get different ways of distributing the cold over here. Scandi or Svalbard highs can deliver it, or a European trough can too. Greenland highs are a lot more prone to going wrong too, if for example it disappears off west too quickly giving the dreaded W based NAO. Any Northern blocking basically acts as a release valve for cold to flood into mid latitudes, be it an Arctic high, East Canadian, Greenland, Aleutian, Svalbard or Scandinavian. 

[markw2680]

10 minutes ago, Rapodo said:

Some crazy reactions on here today I feel. Take a ten minute breather and watch vid 2 then relax.

 

Cheers for that, definitely worth a watch before the pub run gets going

[Battleground Snow]

Icon looks okay at 120

I think anything after this time period is a long way from decided. Let's enjoy the rest of the runs tonight

Edited January 10, 2021 by Battleground Snow

[Djdazzle]

Just now, Battleground Snow said:

Icon looks okay at 120

 

Shame there’s no 144 chart - that may be more useful as to whether this run is taking the GFS or ECM route - or maybe a different one altogether!

[Harsh Climate]

21 minutes ago, Barmada_Casten said:

This is one of the best posts I have ever read on this forum! .... I love What you said about the experienced posters, as one myself I am feeling the pain every time I come to this thread.

 

Please can I copy the post and put it in the NW regional thread?

Yeah no problem mate.

Yes and for those that have seen it all you notice these different style of posters, each year a new member pops up and takes on that roll . Whether its to bang on the coldies 'perfect winter setups coming' drum, be argumentative or come on with a load of highly technical wording and phrases to merely look good, but when you disect what is said very little sense is made nor is any opinion given .. lol 

Thats why if I'm scanning through the model outlook section without time for a propper look at the charts I keep an eye out for the posts of old wise heads like Steve murr, northwest snow and TEITS to name a few. Sorry about the old

Edited January 10, 2021 by Harsh Climate

[Allseasons-Si]

I am just going to post the 500mb geopotential height anomalies from the ECM/GEFS mean at day ten...,along with the EPS/gefs for the same time,now tell me that there is nothing wrong with regards to getting a cold spell towards the UK from those.

i would bite anyone's arm off for those and sell them for a good head.

[Mapantz]

Nothing to see here!

Back to discussing the models. 

[damianslaw]

Reliable timeframe, all models showing a weak atlantic influence, colder conditions in the north at times, milder further to the south and south west. Some snow in the far north and places with height, perhaps further south into eastern and central parts for a time. 

As we move into the upcoming weekend, both ECM and GFS show azores high amplifying towards Greenland and a colder flow from the north, with deep longwave cold trough setting up shop over Scandanavia and NW Russia bringing a plunge of very cold air to these parts.

Changes beyond with the GFS building very strong robust Greenland heights, and a southerly tracking jet, cold and wintry. ECM loses the Greenland heights crashing the atlantic back in, the warm air advection through west greenland disapates. Usually it is the GFS that would collapse the heights quick and bring the atlantic in, rather than ECM.

The old adage, GFS tends to outperform ECM when it comes to developments to our NW springs to mind. GFS was more bullish on the height rises to our NW around christmas, ECM eventually came on board. Ensembles don't seem to support ECM operational run either. ECM tends to do better with continental blocking to our east, GFS often too keen on pushing things east and retracts.