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Model Output Discussion - Colder spell ending, what's to follow?


Paul

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
37 minutes ago, Radiating Dendrite said:

Both those charts are completely different to what we have showing now and also both years had a very different set of background signals. Personally find pattern matching completely futile, the atmosphere is completely dynamic and never the same.

Except RD I wasn't pattern matching.Merely pointing out in a light hearted way how quickly things can change with my 19/12/1962 chart. I doubt any one would have forecast that the coldest winter since 1740  was only 4 days from getting properly underway based on that chart.

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Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth
1 minute ago, Broadmayne blizzard said:

Except RD I wasn't pattern matching.Merely pointing out in a light hearted way how quickly things can change with my 19/12/1962 chart. I doubt any one would have forecast that the coldest winter since 1740  was only 4 days from getting properly underway based on that chart.

Apparently back then on various Internet forums many were saying Zonal for the foreseeable.

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

ECM cluster (only 1 again so it doesn’t really add much)

212CC60E-B536-498F-9CE6-80A3388E78EB.thumb.jpeg.302180777c488c168b16695e711b28cc.jpeg

Except that member 48 is a peach!  

Edited by Mike Poole
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
25 minutes ago, Mapantz said:

You can get them for free now, just not quite in as fancy colours.


https://apps.ecmwf.int/webapps/opencharts

They only go out to 240 though, weathermodels.us go out to 360.

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Short term - still a relatively weak atlantic with low pressure coming unstuck somewhat and wanting to disrupt against heights to our east but unable to do so, thanks to the heights to our SE as well, but we do see some energy heading SE still.

Around the 120 hr mark, all models showing a more invigorated atlantic, with a larger low pressure system, this one taking on more the typical 'bowling low' shape some like to call it, with winds turning more to a longer fetch SW, a deeper feature, so a spell of wet windy weather on the cards.

What happens next, all conjecture at this stage. Much as said yesterday hinges on developments upstream, a more buckled flow of the Pacific jet will have knock on implications and force a more amplified flow over the Atlantic, this might be aided by MJO progression as well. All a matter of timing, the evolution looks prime to a low pressure system filling,  just as happened last week, but this time replaced by blocking. 

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Posted
  • Location: st albans
  • Location: st albans
2 minutes ago, Scott Ingham said:

We can see on the ECM weeklies from week 2 to 3 signs of lowering pressure into southern Europe and a retrograde signal from Scandinavia into Greenland. All is still well.

20201209205710-87ae237059db5e52aa77fb151fa27eba0d502b7a.png

That’s Monday’s run - this time tomorrow we have an update ...

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
Just now, bluearmy said:

That’s Monday’s run - this time tomorrow we have an update ...

Lets hope for an 0z eps suite that is well within the envelope so we then might be able to deduce something tomorrow night.

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Posted
  • Location: Glyn Ceiriog. 197m ASL
  • Weather Preferences: Snow in winter, good sun at other times with appropriate rain.
  • Location: Glyn Ceiriog. 197m ASL
1 hour ago, Broadmayne blizzard said:

So the ECM isnt showing snowmageddon in 10 days time .

 

The attached chart is so very  familiar isnt it? Stalled low to our west driving mild southwesterlies towards the UK, pesky  scrussian block to the east in the wrong place , and worst of all Azores high ridging into  Iberia.  Oh I forgot to mention big chunk of PV  North East Canada/South Greenland.

Absolutely the very last thing you want a week before Christmas eh?

Except of course that the attached chart is for the 19th December 1962.

 

NOAA_1_1962121918_1.png

these are the monthly Hadcet figures for ‘62’63, far lower than now.   Does that have impact on what happens?


 

1962 4.3 4.4 2.8 7.7 10.3 13.7 15.1 14.5 12.6 10.4 5.5 1.8 8.61

1963 -2.1 -0.7 6.0 8.7 10.6 14.9 15.2 14.3 12.9 11.1 8.2 2.6 8.52

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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset
5 minutes ago, feb1991blizzard said:

They only go out to 240 though, weathermodels.us go out to 360.

All medium runs go out to 15 days on ECM's site.

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Posted
  • Location: Rotherham, East Dene
  • Location: Rotherham, East Dene
3 minutes ago, bluearmy said:

That’s Monday’s run - this time tomorrow we have an update ...

Yeah I know im very interested to see where we might be. I suspect European heights might prove to be more stubborn but we shall see. 

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Posted
  • Location: North Yorks/Lancs border 180m asl
  • Location: North Yorks/Lancs border 180m asl
1 hour ago, Radiating Dendrite said:

Both those charts are completely different to what we have showing now and also both years had a very different set of background signals. Personally find pattern matching completely futile, the atmosphere is completely dynamic and never the same.

Of course. But I cannot see Greenland heights without remembering 78/9

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Posted
  • Location: Locksbottom, NW Kent 92m asl(310ft)
  • Weather Preferences: Warm summers but not too hot and colder winters with frost and snow
  • Location: Locksbottom, NW Kent 92m asl(310ft)

Just caught up on the last 10 pages and I sense a little frustration in people of a cold persuasion which is totally understandable.There is still potential for colder weather at 10 days away(yes I know) but the Russian high and the trough due to move into the UK And stall rather than move south east into Europe seem to be the obstacles that need to be overcome.Whether that happens or not is causing all the models headaches but in the meantime I will continue to enjoy the forum and try to improve my knowledge from the more knowledgeable posters who make this forum a great and entertaining place to visit

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
6 minutes ago, Steve Murr said:

Hi the link doesnt exist any more plus the locale we would want to look at isnt on that small chart!

Anyway evening All > Lots to be optimistic for tonight all detailed before the 18z

Is this winter any different / Any usual synopics? well noticably after many years of the AO/NAO blend looking great in Nov then all of a sudden literally on the Dot the AO / NAO turn positive > Well so far this month the opposite has happened... Look at the first of December

8FC78D8A-13F6-4971-8AC8-5E160698CE48.thumb.jpeg.963c8996318a26e423c8a22baea965af.jpegC205942F-7B3A-4CD0-B92E-3213310842AA.thumb.jpeg.2749be8205729b426db024d93ac922a0.jpeg

With the strong vortex we have been lucky enough to see low level blocking in the troposphere keeping the SPV from downwelling - infact the disconnect has grown stronger recently.

D1D0182F-C117-49DD-9E15-E2B8340A743A.thumb.jpeg.63b344c40134bc239bb5ea332c666a34.jpeg

In terms of the next 7-14 days can we continue that? - 

* Remembering the caveat that nothing in the UK cold wise is 100% Guarenteed *
 

The models especially the GFS have perpetually underestimated the strength of the polar & Ural heights > some referring to it as the imaginary line is ironically pretty close, its more like the models resolution becoming clearer with time.

To explain how bad the GFS has been V the UKMO for resolving polar heighst then the chart below sums it up well

D31408CD-0E93-4FD0-8644-245EA7432705.thumb.jpeg.8e041546d1840e911f34292cf38414fb.jpeg

 

Or maybe the GEFS mean for 168 a few days ago for Sun 08AM now today for Sun AM

60D25CC1-7B57-4110-A034-DB4C3D21D0F0.thumb.jpeg.f57849b0183876150ba2c252b4b44e20.jpeg

CEA37DC4-DD49-4BA1-B461-514DAB9B8E4F.thumb.png.555e5b9a2f04d407732b2ef5ba89eeb3.png

Look at how we have hit the 'unmute' button from the GFS over the pole.

So we switch our attention primarily to the Euros > In favour of the steady UKMO > then blend the EPS & Operational DET.

Whilst the DET has been mild over the last 24 hours its drawn to the UKMO with the Link up of the pressure ridge over Greenland & the Arctic high > creating a tidal wave of cold spreading west rather like the troposphere in a downwelled SSW > Maybe the tropospheric response pre SSW.

EPS mean now very supportive.

0B5B8A64-33FE-4707-8AE7-4C1D3D66F0C1.thumb.png.deea8079db9c34e66c3a6a42523ced2b.png56CC7844-C44E-4E55-9712-A51D29C5731E.thumb.png.41dd5de247c0966f8ac0a29911332098.png

Its now fairly odds on >80% that deep cold <Sub -16c / -20c will drop into Northern Scandi.

NB the tanking AO from the DET & EPs in harmony together

55D769D0-46FD-4045-B804-0D4DED7AE2A4.thumb.jpeg.8a2bf03d2269678668da13902d58cdef.jpeg62337849-3D33-49C2-9B6F-AD3381D3828E.thumb.jpeg.52fc01176ef68fe731bda8489182bede.jpeg

Currently then with the jet profiles from they are once we reach day 8-10 when that wave of cold is heading into Northern Europe the Uk will need to rely on a secondary phase of amplification to swing the cold our way.....

Chances of a Strong cold spell into Crimbo around 30-40% which is much much higher than the usual <5%
S

 

Great post Steve, but you do need to explain the UKMO GFS horse picture!

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Posted
  • Location: Rotherham, East Dene
  • Location: Rotherham, East Dene
6 minutes ago, Steve Murr said:

Hi the link doesnt exist any more plus the locale we would want to look at isnt on that small chart!

Anyway evening All > Lots to be optimistic for tonight all detailed before the 18z

Is this winter any different / Any usual synopics? well noticably after many years of the AO/NAO blend looking great in Nov then all of a sudden literally on the Dot the AO / NAO turn positive > Well so far this month the opposite has happened... Look at the first of December

8FC78D8A-13F6-4971-8AC8-5E160698CE48.thumb.jpeg.963c8996318a26e423c8a22baea965af.jpegC205942F-7B3A-4CD0-B92E-3213310842AA.thumb.jpeg.2749be8205729b426db024d93ac922a0.jpeg

With the strong vortex we have been lucky enough to see low level blocking in the troposphere keeping the SPV from downwelling - infact the disconnect has grown stronger recently.

D1D0182F-C117-49DD-9E15-E2B8340A743A.thumb.jpeg.63b344c40134bc239bb5ea332c666a34.jpeg

In terms of the next 7-14 days can we continue that? - 

* Remembering the caveat that nothing in the UK cold wise is 100% Guarenteed *
 

The models especially the GFS have perpetually underestimated the strength of the polar & Ural heights > some referring to it as the imaginary line is ironically pretty close, its more like the models resolution becoming clearer with time.

To explain how bad the GFS has been V the UKMO for resolving polar heighst then the chart below sums it up well

D31408CD-0E93-4FD0-8644-245EA7432705.thumb.jpeg.8e041546d1840e911f34292cf38414fb.jpeg

 

Or maybe the GEFS mean for 168 a few days ago for Sun 08AM now today for Sun AM

60D25CC1-7B57-4110-A034-DB4C3D21D0F0.thumb.jpeg.f57849b0183876150ba2c252b4b44e20.jpeg

CEA37DC4-DD49-4BA1-B461-514DAB9B8E4F.thumb.png.555e5b9a2f04d407732b2ef5ba89eeb3.png

Look at how we have hit the 'unmute' button from the GFS over the pole.

So we switch our attention primarily to the Euros > In favour of the steady UKMO > then blend the EPS & Operational DET.

Whilst the DET has been mild over the last 24 hours its drawn to the UKMO with the Link up of the pressure ridge over Greenland & the Arctic high > creating a tidal wave of cold spreading west rather like the troposphere in a downwelled SSW > Maybe the tropospheric response pre SSW.

EPS mean now very supportive.

0B5B8A64-33FE-4707-8AE7-4C1D3D66F0C1.thumb.png.deea8079db9c34e66c3a6a42523ced2b.png56CC7844-C44E-4E55-9712-A51D29C5731E.thumb.png.41dd5de247c0966f8ac0a29911332098.png

Its now fairly odds on >80% that deep cold <Sub -16c / -20c will drop into Northern Scandi.

NB the tanking AO from the DET & EPs in harmony together

55D769D0-46FD-4045-B804-0D4DED7AE2A4.thumb.jpeg.8a2bf03d2269678668da13902d58cdef.jpeg62337849-3D33-49C2-9B6F-AD3381D3828E.thumb.jpeg.52fc01176ef68fe731bda8489182bede.jpeg

Currently then with the jet profiles from they are once we reach day 8-10 when that wave of cold is heading into Northern Europe the Uk will need to rely on a secondary phase of amplification to swing the cold our way.....

Chances of a Strong cold spell into Crimbo around 30-40% which is much much higher than the usual <5%

This is best chart of the night rotated > EPS mean day 15

BE0D58E6-0EA9-4B97-8674-867A07EF168D.jpeg

S

** Expect the amount of cold GEFS ENS to significantly increase over the next 24 hours *

This is a much improved mean Steve in regards to angle and latitude of west European troughing and chances of a North Eastern flow developing 

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1 minute ago, Mike Poole said:

Great post Steve, but you do need to explain the UKMO GFS horse picture!

 It means @144 over the pole the ukmos clarify is still 80-90% resolution where as GFS at the same time of 144 has plots articulated by a child

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

The evolution to a  Scandi trough makes sense with the arctic ridge elongating towards Greenland. Such a development will be the trigger to squeeze the atlantic low heights southwards, high pressure to the west of the scandi trough will build. Watch the models begin to show a more stretched atlantic trough being forced ever further south due to developments over the Pole. Can already see signs of this in 12z GFS outlook. 

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Posted
  • Location: SE London
  • Location: SE London
4 minutes ago, Mike Poole said:

Great post Steve, but you do need to explain the UKMO GFS horse picture!

well, its a horse, something never seen on a model thread before  

perhaps its an interpretation of an omega block, just renamed as a nag  

 

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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

On to the 18s then, and ICON notably improved at T120 in terms of heights towards Greenland, compared with 12z at T126, 18z first:

B6DE3E3B-E70B-4F53-82B8-7B8B85E7571A.thumb.png.def1749aaf22791d4e2939804b6a9114.png9C57900D-CBA0-45FB-A9D1-1D6B3413C489.thumb.png.d03532045514b559bad541dd6bcc0326.png

Edited by Mike Poole
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Posted
  • Location: Dundee - 140m ASL
  • Location: Dundee - 140m ASL
6 minutes ago, Steve Murr said:

 It means @144 over the pole the ukmos clarify is still 80-90% resolution where as GFS at the same time of 144 has plots articulated by a child

I got the joke and it's the best chuckle I've had on here in a while! 

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Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL
49 minutes ago, Broadmayne blizzard said:

Except RD I wasn't pattern matching.Merely pointing out in a light hearted way how quickly things can change with my 19/12/1962 chart. I doubt any one would have forecast that the coldest winter since 1740  was only 4 days from getting properly underway based on that chart.

Yes, but if we had of had super computers spitting our weather forecasts as we do now, then we would certainly have known a significant cold spell was coming. 

I just don't think things suddenly 'pop' out of nowhere. The models can flip and flap in FI but within the nearer time the changes are more nuanced and usually fairly well signposted.

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