Model output discussion - is the beast awakening?

[bluearmy]

6 minutes ago, ICE COLD said:

Was just thinking we should no by tomorrow morning roughly where we’re headed ? But will we ? I hope we do . As @nick sussex would say just book us into the ritz for dinner ECM and not the premiere inn lol . 

It won’t be sorted by the morning ....hopefully some agreement by tomorrow evening but even then, surprised if all models on same page 

[Arrows1986]

I would imagine that the high pressure is more than likely going to push sustained cold into Europe giving France and Germany a good seeing to. Im hoping im wrong.

 

Best scenario would surely be for a decent high pressure to build NE pushing decent cold towards us and lock it in. Problem is everyone is referring to 2005 2013 but to put that into perspective we're talking 16 years and 8 years ago respectively.  I want to be so wrong but I can see a regression of this cold snap as the days go on. We keep speaking about 7 or 10 days time frame. This never goes down to 5 or 4 days ahead. 

 

I think come 3 days time or so we're going to know where we stand 

[Allseasons-Si]

The ECM op/control where def mild outliers to the rest of the pack in terms of temp and dew points...

De-built.

the EPS clusters at day ten

^two with Atlantic ridge pattern(violet boxes) and one blocked Scandi(red box).

 

Edited January 30, 2021 by Allseasons-si

[sebastiaan1973]

indeed allseasons-si

Winddirection shows more or less the same.

[Jason M]

6 minutes ago, Allseasons-si said:

The ECM op/control where def mild outliers to the rest of the pack in terms of temp and dew points...

De-built.

Can't completely ignore it though. Often not a good sign when both Opp and Control don't go along with the ensembles. 

Edited January 30, 2021 by Jason M

[Allseasons-Si]

1 minute ago, Jason M said:

Can't completely ignore it though. Often not a good sign when both Opp or Control don't go along with the ensembles. 

Yes that is true and i hope to god come tomorrow that they won't show the same.

[ItNeverSnowsInWindsor]

45 minutes ago, ICE COLD said:

Yep 3 runs in a row . I would be very worried if the last  3 runs had been similar to each other but as they’ve been completely different it makes me feel a little calmer and it must be struggling. 

We need to get rid of low heights to our North. Simple as.

No matter how many nirvana output we see, if one is not agreeing then sods law tends to apply for UK especially the South!

Midweek next week will tell us the story.

[Stu_London]

all good - uppers supportive of severe weather for a good 6-7 day period. very cold at the surface unless there is a dramatic breakdown from the west or south for a few days after that. 

Uppers were no great shakes for the second half of the Feb 1991 spell - but is was darn cold on the snow covered ground

Edited January 30, 2021 by Stu_London

[SqueakheartLW]

A bit of a mixed summary here for both the GFS 12z and GEM 12z

GFS 12z

First here's the latest average charts for the peak of the predicted cold spell at 168 hours away

At this stage we are still seeing an average easterly flow over the UK so at least still on track for this possible outcome. The 850hpa average of the 12z came in at a new low of -9.1 which is even colder than the 06z showed which was -9.0 so a further upgrade to the colder spell on average again which is -7.6 colder than the long term mean. This cold anomaly shows up well on the anomaly chart on the right with those deep blues over the UK.

Mildest 3 charts at 168 hours away

3rd - Member 15     850hpa temp -7.2

2nd - Member 9     850hpa temp -7.2

1st - Member 5     850hpa temp -6.3

Coldest 3 charts at 168 hours away

3rd - Member 14     850hpa temp -11.0

2nd - Member 23     850hpa temp -12.0

1st - Member 2     850hpa temp -12.7

Mildest doom and gloom chart from 12z GFS

Member 16     +324 hours     850hpa temp 8.0

Coldest fantasy chart from 12z GFS

Member 11     +240 hours     850hpa temp -15.4

GEM 12z

Time to compare today's 12z GEM to what was showing on today's 00z

The peak of the colder spell on GEM 12z is at 162 hours away with an average 850hpa temperature of -6.5 which is -5.1 below the long term mean. Not as keen for deep cold as GFS nor for as long either which looks less promising. This compares with the average of -6.6 from the 00z so a further backtrack of 0.1 towards less cold on the 12z runs

Mildest 3 charts at 162 hours away

3rd - Member 11     850hpa temp -2.7

2nd - Member 9     850hpa temp -2.4

1st - Member 19     850hpa temp -1.5

Coldest 3 charts at 162 hours away

3rd - Member 12     850hpa temp -9.9

2nd - Member 18     850hpa temp -10.2

1st - Operational     850hpa temp -11.0

Mildest doom and gloom chart from 12z GEM

Member 12     +372 hours     850hpa temp 14.5

Coldest fantasy charts from 12z GEM

A tie and shared honours here as two runs gave a tied lowest 850hpa value on the 12z GEM

Member 2     +276 hours     850hpa temp -14.9

Member 6     +324 hours     850hpa temp -14.9

[stodge]

Evening all

A bleak day in lowland East London with plenty of cold rain - if anyone has had snow good luck to you, whether we see any as the front comes back south overnight remains to be seen. I'm not hopeful and it looks as though any colder interlude will be done with by Monday as milder air returns. From there, many of the models were looking at just a 3-4 day milder interlude before a return to something colder by next weekend. ECM was on its own last night with a messy evolution but it got cold in by T+240 to align with other models.

From there, GFS OP quickly broke down the cold spell but both Parallel and Control went for extended cold spells lasting to mid month.

T+120 tonight takes us to Thursday February 4th.

12Z GEM: by T+120 there's quite a complex synoptic evolution. Heights have built from the north east and over Scandinavia while the Atlantic trough is now extended from near Greenland south east and then south to the west of the British Isles and down to Iberia.  Upstream there's a mid-Atlantic ridge before a storm system just exiting North America. An ESE'ly flow extends across Scotland and the north of England with lighter winds further south. Positive uppers confined to Devon and Cornwall by T+120 with 850s of zero to -4 over much of England and uppers below -8 over northern and eastern Scotland as well as the Northern Isles. Moving on and heights transfer readily to Greenland with 548 DAM air in situ by T+180. The Atlantic trough has been forced south and east into Europe but remains close to the Channel Coast at T+180 and this serves to intensify the E'ly flow over the British Isles bringing in very cold air with -8 uppers widely and -12 uppers over central northern England. From there, the European trough never shifts too far from southern Britain extending back west and then pushing a new LP east into France. For most of the British Isles, the E'ly persists to T+240 with strong heights over Greenland and ridging south east from Iceland.  Uppers below -8 for the Midlands north and while it's less cold further south, 850s remain negative.

That's about as good an evolution as you could want for snow-starved southerners. It may be the south coast will be marginal but you can forget M4 corridors - even I would expect snow from that set up.

12Z GFS OP - possibly the most progressive of the models yesterday evening breaking down the cold spell quickly by T+240 but let's see. At T+120 it's not too different from GEM though I note the Atlantic trough is a smidgen close and the storm coming off North America is already throwing energy east to test the upstream amplification. Cornwall keeps positive uppers with 850s of zero to -4 for most and uppers below -8 over northern and eastern Scotland. From there, the heights to the develop differently to GEM with a distinct HP cell over or to the north east of the Faeroes but with a ridge to Greenland and south to the west of the British Isles. The trough has moved south east but phases with an LP moving north out of north-west Africa and ends up over central France with a strong NE'ly airflow on its north west flank over southern and eastern Britain. A lobe of energy from the storm over North America has exited north east forming an LP which is now off SE Greenland. By T+180 850s are below -8 across most of the British Isles with a wedge of -12 uppers in the North Sea. Moving on, heights persist over south west Scandinavia to T+240 with the Atlantic trough first moving south east and now trying to break down the block as a new Atlantic storm moves out of Newfoundland. A SE'ly air flow covers the British Isles. Positive uppers are inching their way back in from the south west and have just reached Cornwall but cold air persists over most areas with uppers still below -8 over northern and eastern areas. 

OP screams battleground but as last night, you'd put your money (which I imagine is nice money) on GFS sending the Atlantic through by T+312 despite the trough heading south east on a negative alignment.

12Z Parallel - after a sticky start, this was the coldie's best friend especially in far FI. Let's see how it is tonight. At T+120, it has already diverged considerably from GEM and GFS OP. The trough which sits to the west on the other models is over the British Isles with a cyclonic flow. Upstream amplification is in place but a lobe of energy has already broken off the North American storm and looks to be heading NE towards Iceland or Greenland - I'm not sure I like where this is going. 850s of zero to -4 for most parts with the last vestige of positive uppers for the far south east and uppers below -8 over the far north of Scotland and the Northern Isles. From there, the evolution becomes more complex - the trough never really clears the British Isles re-invigorating over the North Sea and by T+180 sits as a small LP over North East England and East Anglia. Heights persist to the north east. Meanwhile, the trough out of North America has moved to the south west of Iceland, deepens in situ and now looks to be heading SE at T+180 while heights persist over the Azores and a new HP has come out of North America - confused, that makes two of us!  Uppers between -4 and -8 over the British Isles at T+180 with milder air trying to come in from the west. From there, the new HP out of North America pushes higher DAM air into Greenland raising heights and by T+240 a new HP sits over SE Greenland. The trough is forces south east and then south and by T+240 is to the north east of the Azores with an ESE'ly flow over the British Isles. By this time, most of northern Britain is under -8 850s while -4 to -8 850s covers southern areas.

Parallel gets there in the end in some style but it didn't look a convincing evolution to this observer.

12Z ECM - last night's party pooper - the mood after the equivalent run was ridiculous and not helped by some less-than-stellar EPS which brought about the usual doom-and-gloom trolls, let's see if tonight's offering is a cause for celebration or lamentation. Once again, T+120 is uninspiring - the trough remains just to the west of the British Isles but extends back towards Greenland. The upstream amplification is in place despite the first signs of energy transfer off Newfoundland. Heights remain to the north east. Over the British Isles the air flow remains from the south west. Positive uppers cover most of southern England with uppers of zero to -4 for most other areas so ECM clearly the mildest option at T+120. ECM option develops very differently to the other models up to T+192.  The upstream amplification doesn't quite happen but the trough does clear through the British Isles pulling down a brief N'ly but by T+192 the Atlantic trough has elongated east to Ireland as a shallow but complex feature. Heights persist to the north and north west with milder air returning from the south west. Positive uppers have retuned to south west England and Ireland by T+192 with colder air confined to eastern areas.  The next shallow LP crosses southern Britain and by T+240 is over Holland with a weak NE'ly over eastern Britain leaving a new Atlantic LP spinning in the ocean as heights try to build down from the north and from Iberia. 850s of -4 to -8 from the Midlands north, less cold air further south.

 

Two nights running and it just doesn't happen with ECM which looks on its own tonight. It's a concern of course but ECM isn't the be-all and end-all of models as we know.

 Back to GFS and the OP and Parallel runs at T+312 (Feb 12th) and T+384 (Feb 15th) respectively 

Plenty happening on both evolutions - OP ends with a cold trough over southern Britain and renewed upstream amplification while Parallel finally breaks down the easterly from the south. Neither evolution is in any way convincing. Control goes very anticyclonic with HP over Scandinavia and eventually migrating to the British Isles.

Conclusion: ECM looks on its own tonight sending too much energy into the Atlantic to allow the amplification to take hold and build heights into Greenland. The other models all get there in one form or another with GEM the best for snow fans at T+240. The lack of agreement form ECM is a worry and with differences starting as early as T+120 we'll soon know who is the big cheese and who ends up with egg on their proverbials. To be honest, looking at both JMA and UKMO at T+144 I'm also none the wiser so, as we always say, more runs are needed.

[stainesbloke]

31 minutes ago, ICE COLD said:

Was just thinking we should no by tomorrow morning roughly where we’re headed ? But will we ? I hope we do . As @nick sussex would say just book us into the ritz for dinner ECM and not the premiere inn lol . 

Premier Inn is fine, just not the Travelodge 

[stodge]

25 minutes ago, bluearmy said:

It won’t be sorted by the morning ....hopefully some agreement by tomorrow evening but even then, surprised if all models on same page 

Indeed, the range of options as early as T+120 suggests clarity is in very short supply this evening. I think it might not be resolved until Monday at the earliest.

[Bradley in Kent]

12 minutes ago, Radiating Dendrite said:

The models don't control the weather, they simply to try to show the most likely outcome.

This thought came across my mind earlier as well. 

Like many I get slightly frustrated how cold or hot spells get conjured up only to then vanish. But in reality, they don't exist because they haven't happened yet. 

You can of course argue against this in scenarios where the hot or cold air is already in place, but models are only, as you say, reacting to current inputs and algorithms and are there to predict the most likely outcome based on such information. 

It's because of this that in my opinion models are susceptible to overplaying those inputs, settings off wrong trajectories with more wrong trajectories on top giving more extreme forecasts than reality. 

The supposed Beast which might awaken according to the threat title won't happen here, as models to me underestimate the power of the Atlantic and overestimate cold synoptics 

[SqueakheartLW]

Had to comment further on this individual GEM 12z fantasy cold chart

Points to make here

1 - Is that a record strong area of high pressure for Scandinavia if it came off at 1075mb?

2 - Who needs to worry about Iberian heights at 1020 to 1030mb with a Scandi high that strong?

3 - What depth of low and jet stream speed would be required to shift a block that big?

Edited January 30, 2021 by SqueakheartLW

[blizzard81]

Battle royale there between Squeakheart and Stodge for the accolade of the longest posts

[Stu_London]

1 minute ago, SqueakheartLW said:

Had to comment further on this individual GEM 12z fantasy cold chart

Points to make here

1 - Is that a record strong area of high pressure for Scandinavia if it came off at 1075mb?

2 - Who needs to worry about Iberian heights at 1020 to 1030mb with a Scandi high that strong?

3 - What depth of low and jet stream speed would be required to shift a block that big?

Its 1045 over scandi

We've had over 1050 before. 

[SqueakheartLW]

8 minutes ago, Stu_London said:

Its 1045 over scandi

We've had over 1050 before. 

 

 

 

 

Edited January 30, 2021 by SqueakheartLW

[ANYWEATHER]

Gfs has been quite punctual in its output in the last few days with the same continual theme,  Ecm has been quite sick in its output , so what model would I put my money on , Answer none!  But if I was to be held at gunpoint and had to make a decision I would put my money on wait for it........GFS .....!!!

[MJB]

1 hour ago, StingJet said:

The ECM is unfortunately always correct. Especially when you cross reference its outputs with the Beeb and MetO extended outlooks, which tend to be aligned with the ECM out to 240.
I spent many years running the UK Stormtrack Topic on the GPS Speedsurfing Website , with the primary objective of calling off Speedsailing events here in the UK, the ECM / MetO have always been the form horse and tend to verify more often than other models such as the GFS .. .as you would well know mate

You have clearly forgotten when ECM took everyone up the garden path to cold and then incredibly dropped it ........ , no  model is always correct 

Edited January 30, 2021 by MJB

[Methuselah]

23 minutes ago, Allseasons-si said:

Yes that is true and i hope to god come tomorrow that they won't show the same.

Well, as the world-famous model-watcher of yore, Napoleon Bonaparte, liked to say: Keep your ice-skates close, and your charcoal briquettes closer?

[Stu_London]

8 minutes ago, SqueakheartLW said:

Think I put the wrong chart in. These are the ones I should have put in

Points to make here

1 - Is that a record strong area of high pressure for Scandinavia if it came off at 1075mb?

2 - Who needs to worry about Iberian heights at 1020 to 1030mb with a Scandi high that strong?

3 - What depth of low and jet stream speed would be required to shift a block that big?

 

I think that would smash the doors off the records for Finland, Norway, Sweden and Denmark in terms of millibars

On that basis, very unlikely to verify - or might even be an error

EDIT - would smash the UK record too

 

Edited January 30, 2021 by Stu_London

[jules.p]

I think Sunday evenings 18z will give a slightly clearer direction of travel. E/NE is going to be the end result but to what extent is not clear at present.

Edited January 30, 2021 by jules.p

[Stu_London]

GFS 12z op is the goldilocks run for the south east - 36 hours of moderate snow from next Sunday morning in a near gale. 

[Daniel*]

6 minutes ago, Stu_London said:

Its 1045 over scandi

We've had over 1050 before. 

We’ve had 1060+ before highest atmospheric pressure on record in region 1064mb in Sweden on 23rd January 1907 It’s worth noting the strength of blocking doesn’t necessarily make it more stubborn, many times I’ve seen strong blocking over Scandi quickly bowled away/sink. 114 years ago this happened and brutally cold air very quickly moderated good thing there was no Netweather forum then.  

 

[MJB]

The ECM debate is an interesting one for sure , MET are onto the cold and the latest BEEB monthly update is as good as you can expect ( very good ) , surely the model will come around in the 24 hours , I expect it to any how