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Model output discussion - Post SSW - Will it turn cold?


Paul
Message added by Paul

Please only post model discussion in this thread. 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

Thank you!

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent
1 minute ago, bluearmy said:

Not much to say really

7F44F42C-DF8F-4F4D-AAD1-4F7C40A345E6.thumb.jpeg.f1936141531b204b4f1fde5cc508c329.jpeg

Probably the coldest yet, GFS really a massive outlier there. I can see an entire GFS ENS being wrong but I'd struggle to accept an entire ECM ENS being wrong, personally..

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Posted
  • Location: East Ham, London
  • Location: East Ham, London

Morning all :)

Well, another day of twists and turns as the output oscillates from the stellar to the not-so-stellar.

Before my daily analysis of the mid-term prospects, a thought or two on the evolution to a more blocked pattern and how it was going to happen.

Originally, the models offered the Azores HP moving north then north-east to the west of the British Isles into northern Scandinavia. That then became the Azores HP ridging NE through the British Isles into Scandinavia and finally it was an area ridging SW from northern Scandinavia into the North Sea.

Any one of these combined with the so-called "trigger" LP dropping south down the North Sea into Europe would pull in the fabled Easterly.

Yet as of last evening, GFS and UKMO were moving away from any notion of height rises to the NE in spite of the MJO being in high amplitude phase 7. ECM< which had originally been reticent, had, however, come on board strongly (though to be fair its ENS had always been in support).

So, three evolutions to bring height rises and all failing - why ? A thought for another day perhaps but let's see where we are now and where we might be going forward (with all the Shannon Entropy flying about for good measure) to Monday February 26th.

Starting as always with ECM 00Z OP at T+240:

ECM1-240.GIF?16-12

The cold air is heading away north as the HP in Scandinavia slips SE but heights remains strong to the north at this time in the face of a deep LP in mid-Atlantic. After a period of snow the day before, much milder and wetter conditions moving up from the south. Note the lack of low heights over Europe but the jet remains focussed to the south so undercuts and sliders not off the agenda but the evolution looks milder at this time.

GEM 00Z OP at the same time:

gem-0-240.png?00

A ridge from Greenland down SE into central Europe keeps most of the British Isles fine. Deep LP in the Atlantic is stationary and a secondary feature far to the south is in development but where will it go ? A secondary colder LP is tracking south over the Baltic States but whether the very cold air behind us can make any progress westward remains to be seen. It's a bit of a stand off between west and east to be honest.

GFS 00Z OP at the same time:

gfs-0-240.png

A very different evolution but not a million miles away from the 00z of yesterday. A piece of the PV detaches from the main vortex and moves east to the north of the British Isles allowing heights to rise over Greenland. HP is over the south west of the British Isles with a large slow-moving deep LP in mid-Atlantic so a fairly mild and benign outlook for most with perhaps any rain or showers restricted to the far north of Scotland and the Isles. Further into FI and the remnant PV lobe is shunted further west allowing pressure to rise over Greenland and the prospect of a mid-Atlantic block in early March with winds over the British Isles shifting more NW as colder air approaches.

GFS 00Z Control at T+240:

gens-0-1-240.png

A mild or very mild SW'ly airflow covers the British Isles with HP over central Europe and weak areas of LP to the west and north running across Scandinavia.  Further into FI and the unsettled theme continues with the jet edging south and the PV dissipating over Northern Canada.

To bring us right up to speed, the GFS 06Z OP at T+234:

gfs-0-234.png?6

A taste of spring rather than winter with a benign SW'ly airflow covering the British Isles with HP over Europe and parts of Scandinavia and LP tracking NNE on a northerly jet. Further into FI and there's very little change with a broad Atlantic domination and no sign of heights to the NE or NW even as the PV weakens and heads more toward the Pole.

00Z GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

A significant away from the easterly-dominated suite of yesterday morning though it's fair to say the easterly option is still there on a number of members. A growing number have eschewed height rises to the NE and keep the Atlantic in charge with deep LP heading toward Iceland. Further into FI and it's fair to say a growing number are showing heights over Greenland so that might be the next wild goose for us all to chase.

00Z GEM ENS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=1&mode=1&ech=240

Plenty of cold and indeed very cold option still on the table.

In summary, the arrival of the SSW has brought model volatility on an unprecedented scale. Some output seems to be ignoring it, some seems to be embracing it. So what appears to have gone "wrong" with what seemed a huge prospect for an Easterly (and let's not forget ECM is still very much playing that tune) ? Well, perhaps it's three strikes and we're out in terms of the three routes to Scandinavian height rises all of which according to GFS have failed. GEM keeps heights as does ECM so it's far from a lost cause at this time.

The downgrade in the GEFS 00Z is worrying so what and why ? My only theory is the wave 2 attack on the Canadian vortex isn't causing its immediate disruption and re-location as many hoped and surmised but is instead causing a temporary strengthening as we've seen from vortex attacks in the past. The initial tropospheric response has been to strengthen the PV in situ for 7-10 days before it finally weakens and shifts away.

Perhaps in all our excitement about the SSW we've forgotten the basic physics of the wave 2 attack and the initial reaction which seems, according to GFS, to be happening irrespective of zonal wind flow reversal. So, to annoy us even further, we have the 10-14 day lag from the initial SSW augmented by a 7-10 day lag from the wave 2 assault which would put us into early March which seems to correspond with both the GFS output (some of it) and Glacier Point's excellent analysis from a couple of days back.

It's also worth noting some of the quality Hi-Res models such as ARPEGE are still bringing in the E'ly via Route 3 (northern Scandinavian HP building SW) as early as T+102 so it's a model standoff worthy of Bun-fight at the OK Tearooms and one or more is going to end up looking like a crazed omelette.

If you have any nerves left prepare for them to be shredded further in the next 48 hours.

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Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex
1 minute ago, bluearmy said:

Not much to say really

7F44F42C-DF8F-4F4D-AAD1-4F7C40A345E6.thumb.jpeg.f1936141531b204b4f1fde5cc508c329.jpeg

Indeed Nick....

And the coldest suite I've seen this season from De Bilt!

image.thumb.png.d8a07ba5049ee133e5e3b816527de7fd.png

:cold:

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

That is some set of ensembles on ECM.

They are conclusive.

Can't be coincidence this is after this mornings delay and the data issue, or can it?

 

 

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Posted
  • Location: oldham
  • Location: oldham
2 minutes ago, Mucka said:

That is some set of ensembles on ECM.

They are conclusive.

Can't be coincidence this is after this mornings delay and the data issue, or can it?

 

 

No data issue with the running of the model, just how certain web sites get the data.

Think this easterly should be know as Schrodinger's Easterly

Edited by frosty ground
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Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex
Just now, Mucka said:

That is some set of ensembles on ECM.

They are conclusive.

Can't be coincidence this is after this mornings delay and the data issue, or can it?

 

 

Mucka - The problem was related to data being made available via GRIB on the FTP servers that the non-institutional sites use, not any problem with the run itself. Sites which have a raw feed of ECM data (such as the Dutch) had the ensembles etc available at the same time as normal. 

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Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
Just now, Mucka said:

That is some set of ensembles on ECM.

They are conclusive.

Can't be coincidence this is after this mornings delay and the data issue, or can it?

 

 

Datagate! 

Have we ever seen such a difference in the ens suites? I don’t recall a time! One is going to be making an extraordinary climb down fairy soon.

C1F6E2C4-1953-40CC-9687-8349EDFE01B2.thumb.gif.f7c593bf78f747442cb04c7b5bf4af7a.gifB38C6299-25B2-4071-A62A-64840F64ABF7.thumb.gif.61b5cb9aa2a8233c741a0e3c96cc5b10.gif

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester
Just now, karlos1983 said:

Datagate! 

Have we ever seen such a difference in the ens suites? I don’t recall a time! One is going to be making an extraordinary climb down fairy soon.

C1F6E2C4-1953-40CC-9687-8349EDFE01B2.thumb.gif.f7c593bf78f747442cb04c7b5bf4af7a.gifB38C6299-25B2-4071-A62A-64840F64ABF7.thumb.gif.61b5cb9aa2a8233c741a0e3c96cc5b10.gif

I had a feeling today would be the day all the models went cold but had my doubts when I saw this mornings UKMO and GFS.

I really do think we have turned the corner now though, and GFS ensembles will flip cold rather than slowly come on board.

It has been an unbelievable saga, let's hope it's over and we get snowy end to Winter.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
14 minutes ago, bluearmy said:

Not much to say really

7F44F42C-DF8F-4F4D-AAD1-4F7C40A345E6.thumb.jpeg.f1936141531b204b4f1fde5cc508c329.jpeg

If the ECM ensembles are wrong, this will be a bigger fail than "That ECM" in Dec 2012. But on the other hand, we need several hands on which to count all of the GFS fails from over the years. 

I'd also like an explanation as to how the GEFS had the ECM pattern for days and has now ditched it! Is it something to do with the GFS tending to overblow lows in the D5-D8 period? Or is the ECM again showing its weakness for overdoing Scandi heights between D5 and D8, something which has crept into the model in the past couple of years?

Not sure I've ever seen such a big D9 difference on the mean charts. ECM has a 1036mb mean Scandi high (probably near 1040mb) - GEFS, well, it's more like April than February

EDM1-216.GIF?16-12  gens-21-1-216.png

Nightmare

Edited by Man With Beard
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Posted
  • Location: South Norfolk, 44 m ASL.
  • Weather Preferences: Varied and not extreme.
  • Location: South Norfolk, 44 m ASL.
13 minutes ago, bluearmy said:

Not much to say really

7F44F42C-DF8F-4F4D-AAD1-4F7C40A345E6.thumb.jpeg.f1936141531b204b4f1fde5cc508c329.jpeg

From my POV as someone with a science degree but only amateur-level meteorological knowledge, all I can say is that uncertainty is exceptionally high at present and FI is the 20th or 21st depending on the degree of Shannon entropy you're prepared to accept.  Having said that, the weight of the ensemble members trends towards the ECM op. run rather  than the GFS - I presume these ensemble members are EPS rather than GEFS?

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester
7 minutes ago, Purga said:

Mucka - The problem was related to data being made available via GRIB on the FTP servers that the non-institutional sites use, not any problem with the run itself. Sites which have a raw feed of ECM data (such as the Dutch) had the ensembles etc available at the same time as normal. 

Wasn't suggesting there was a problem with the run, but perhaps with previous data for some reason.

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Posted
  • Location: Kilburn, NW London
  • Location: Kilburn, NW London

That is some difference indeed.  I bet mother nature hasnt decided which model is correct yet though, depends on butterflies flapping somewhere I read lol

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Posted
  • Location: Tonbridge, Kent
  • Location: Tonbridge, Kent
2 minutes ago, Man With Beard said:

If the ECM ensembles are wrong, this will be a bigger fail than "That ECM" in Dec 2012. On the other hand, we need several hands on which to count all of the GFS fails from over the years. I know which one I'm backing but it's nervy!!

Not sure I've ever seen such a big D9 difference on the mean charts. ECM has a 1036mb mean Scandi high (probably near 1040mb) - GEFS, well, it's more like April than February. EDM1-216.GIF?16-12  gens-21-1-216.png

Indeed Polar (pun intended) opposites

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Posted
  • Location: st albans
  • Location: st albans

I would add a caveat on the eps - they are prone to following the op solution more than the gefs do. I am reasonably comforted that the gems are closer to the eps than the gefs (although watch for a renewed pulse of heights to our south around day 10 - presumably a respnse to the Azores low stalling rather than sending the jet further east into Europe - it’s an option and probably larger than the eps currently indicate)

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Posted
  • Location: st albans
  • Location: st albans
3 minutes ago, chrisbell-nottheweatherman said:

From my POV as someone with a science degree but only amateur-level meteorological knowledge, all I can say is that uncertainty is exceptionally high at present and FI is the 20th or 21st depending on the degree of Shannon entropy you're prepared to accept.  Having said that, the weight of the ensemble members trends towards the ECM op. run rather  than the GFS - I presume these ensemble members are EPS rather than GEFS?

They are eps - the blue line gfs op (which should be ignored)

in my experience, that’s a run with low entropy as far as temps are concerned, especially given that this time of year will throw out some vast diffs depending on the set up. Adding in that eps/op ec caveat again !

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Posted
  • Location: South Norfolk, 44 m ASL.
  • Weather Preferences: Varied and not extreme.
  • Location: South Norfolk, 44 m ASL.
Just now, bluearmy said:

They are eps - the blue line gfs op (which should be ignored)

in my experience, that’s a run with low entropy as far as temps are concerned, especially given that this time of year will throw out some vast diffs depending on the set up. Adding in that eps/op ec caveat again !

Thanks.  My comment on entropy was based on comparing ECM + EPS vs. GFS.

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
9 minutes ago, Man With Beard said:

If the ECM ensembles are wrong, this will be a bigger fail than "That ECM" in Dec 2012. But on the other hand, we need several hands on which to count all of the GFS fails from over the years. 

I'd also like an explanation as to how the GEFS had the ECM pattern for days and has now ditched it! Is it something to do with the GFS tending to overblow lows in the D5-D8 period? Or is the ECM again showing its weakness for overdoing Scandi heights between D5 and D8, something which has crept into the model in the past couple of years?

Not sure I've ever seen such a big D9 difference on the mean charts. ECM has a 1036mb mean Scandi high (probably near 1040mb) - GEFS, well, it's more like April than February

EDM1-216.GIF?16-12  gens-21-1-216.png

Nightmare

For a while GEFS still had the MJO hanging around for almost another week in high amplitude phase 7 while EPS was decaying it steadily.

So I wonder if we saw a run of runs (ha) that were actually using the supposed continued high amp MJO to get the Scandi ridge, and then applying some SSW impacts on top of that. This would allow for the model having never actually predicted as much SSW impact as EPS.

It doesn't explain the longer-term loss of strong negative NAO response following the second warming though. For whatever reason, they're just not taking down the Canadian vortex as effectively as before, despite the second warming having if anything trended stronger in nature. On the 06z op run at 30 hPa for example, the warming seems to get wrapped into the stratospheric high before it can slice into the vortex - so the vortex undergoes further warming and hence weakening, but remains more 'neat' than was being shown; less distorted and stretched.

 

Generally though, the situation is officially ridiculous. Unless you ignore all of the past 72 hour's worth out output but the EPS. That'd be a way to ease the nerves but at risk of a nasty shock by next Tuesday :laugh:.

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Posted
  • Location: Mid Welsh/English Border
  • Weather Preferences: Snow! Exciting weather!
  • Location: Mid Welsh/English Border
20 minutes ago, Man With Beard said:

If the ECM ensembles are wrong, this will be a bigger fail than "That ECM" in Dec 2012. But on the other hand, we need several hands on which to count all of the GFS fails from over the years. 

I'd also like an explanation as to how the GEFS had the ECM pattern for days and has now ditched it! Is it something to do with the GFS tending to overblow lows in the D5-D8 period? Or is the ECM again showing its weakness for overdoing Scandi heights between D5 and D8, something which has crept into the model in the past couple of years?

Not sure I've ever seen such a big D9 difference on the mean charts. ECM has a 1036mb mean Scandi high (probably near 1040mb) - GEFS, well, it's more like April than February

EDM1-216.GIF?16-12  gens-21-1-216.png

Nightmare

If you turn the gfs one upside down its actually very similar to the ecm?

 

All down to interpretation!?

Edited by stratty
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Posted
  • Location: st albans
  • Location: st albans
6 minutes ago, Singularity said:

For a while GEFS still had the MJO hanging around for almost another week in high amplitude phase 7 while EPS was decaying it steadily.

So I wonder if we saw a run of runs (ha) that were actually using the supposed continued high amp MJO to get the Scandi ridge, and then applying some SSW impacts on top of that. This would allow for the model having never actually predicted as much SSW impact as EPS.

It doesn't explain the longer-term loss of strong negative NAO response following the second warming though. For whatever reason, they're just not taking down the Canadian vortex as effectively as before, despite the second warming having if anything trended stronger in nature. On the 06z op run at 30 hPa for example, the warming seems to get wrapped into the stratospheric high before it can slice into the vortex - so the vortex undergoes further warming and hence weakening, but remains more 'neat' than was being shown; less distorted and stretched.

 

Generally though, the situation is officially ridiculous. Unless you ignore all of the past 72 hour's worth out output but the EPS. That'd be a way to ease the nerves but at risk of a nasty shock by next Tuesday :laugh:.

Excellent point !!

i wouldn’t trust the gefs in the strat/trop coupling so perhaps it’s the MJO signal which was promoting the amplification rather than any response to downwelling 

If so, the current gefs output set against the gems and eps is more understandable (and more easily dismissed).

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

I used Derby as somewhere fairly central, this is the forecast using ECM. Ice days from next Fri, really cold by next Wed. Gives us an idea of how cold it can still get late Feb with a good Easterly flow. 

17D1D610-D5F4-40C0-AEBF-F09BA30A9EE3.png

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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl

maybe for now we should just stick to hi-res short range models for the time being. try to analyse the smaller changes which may lead to the bigger ones. the 00z run of the Arpege is very similar to the ECM-

arpegenh-0-102.thumb.png.3ea8c20f0a9109ecbcef23da2d05093f.png

ECH1-96.thumb.gif.aa03952dec8824e9414277cc5068108f.gif

as for the GFS... maybe all this rapid changing data, 4 times a day, is burning out their server....

image-1.thumb.jpg.b5dbc2b8833dcd9e07989b1ddc3cc9b8.jpg

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Posted
  • Location: North East
  • Weather Preferences: Thunder , Lightning , Snow , Blizzards
  • Location: North East

The GFS has form recently at ‘busts’ in regards to verifications ? 

54F8A29D-17D4-4109-B483-42469707DEDF.jpeg

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Posted
  • Location: DL
  • Location: DL

The ECM mean evolution:  3 days ago it predicts blocking heaven for next Friday:

ec13th12z.thumb.gif.df4a74d22a50c468858789f3ae19d874.gifec13th00.thumb.gif.edf1573bc9aad7081d0e88e88cc079a0.gif

This prediction then adjusts to become blocking purgatory as geo heights lower near Greenland:

ec14th12z.thumb.gif.b2c30066c2269e0f9adc9514e688c4d8.gifec14th00.thumb.gif.6cce5a5d6cd692df30b5a0af8ab92f3c.gif

But the latest run has the block to the East fighting back:

ec16th00.thumb.gif.f03e231f86e4990d8ccfca1e37c95d4a.gif

So the ECM hasn't quite returned to what it was showing 3 days ago, because of differences around S Greenland.  But the block to the east is nonetheless fighting westward.

A JMA mean for the same day and a few days later shows the blocking starting to win to the north as battleground/undercut scenarios develop:

temp.thumb.png.0565f6aeb398b392c92c684cc4728632.pngtemp2.thumb.png.db8936d57da9b6f4a83c3028e5e8d944.png

ECM mean is similar to JMA mean, but slightly more easterly:

temp4.thumb.gif.b5a68e6db1f78da8e2acca8746d81b95.gif

The differences between JMA and EC now seem to be narrowing down to speed of evolution more than anything else.

No doubt everything will change again this evening.

 

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Posted
  • Location: Hertfordshire
  • Weather Preferences: SNOW AND FREEZING TEMPS
  • Location: Hertfordshire

Well the ecm charts that look like this - looks likely to be right according to the pro's . Another nice update this afternoon and sticking to there guns ??. If these charts come off it's going to be freezing. 

IMG_1513.PNG

IMG_1514.PNG

IMG_1515.PNG

IMG_1516.PNG

Edited by ICE COLD
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