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Model output discussion - 7th January onwards


Paul
Message added by Paul

Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

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Posted
  • Location: oldham
  • Location: oldham

gfs-0-228.png?12

That's one hell of a cold pool over Europe, a few hundred mile shift east and we are out of the game, but as this post says maybe not

7 minutes ago, Radiating Dendrite said:

The models tend to have an eastward bias as shown with the slider over the next couple of days. At one point it was sliding down the coast of Norway. 

Im sure the pattern for next week will be further west given known model bias. 

 

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Posted
  • Location: Morecambe
  • Location: Morecambe

I think some runs are showing if you dont have enough amplification in the Atlantic then it is a struggle to eject true cold westwards even with any height rises up in Scandinavia.

The main trend of dropping a trough over the UK is still there but big question marks of how much cold air will be mixed in by the time it gets here which of course will determine just how widespread any snow event could be.

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Posted
  • Location: Camborne
  • Location: Camborne

The gfs has the trough a tad further west at T120 and  and then subsequent to that the strong ridging north east is not put under much pressure until the energy sweeping up the eastern seaboard (160kt jet) and around the Bermuda high pressure pushes it south east by T192 and thus the cold advection into the UK is snipped with the very cold air left over Poland

gfs_z500_vort_natl_21.thumb.png.125efe7212a3bef515354ddcca229539.pnggfs_z500_vort_natl_29.thumb.png.1003a0aa1117c8a1d602d5e5deec3f2c.pnggfs_z500_vort_natl_34.thumb.png.276399ae48e50041fed218be12603671.png

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
6 minutes ago, FetchCB said:

Interestingly The Met mentioned in their Media output that a system of the West Coast of the US which is due to become a Nor'easter and firing up the Jet is the cause of the uncertainty

Yes that storm has always been important  to us in Western Europe .

But there’s two factors at play that and the high pressure developing to the ne. After this storm there’s another Pacific shortwave due as more amplification develops over the central USA.

As that runs east it will effect energy to the west of Iceland as a little ridge builds ahead of the shortwave over the ne USA.

The first output re the current storm  to phase correctly the north and south jets was the ECM.

I’d take the lead from that upto day 6.

 

Edited by nick sussex
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Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL
2 minutes ago, frosty ground said:

gfs-0-228.png?12

That's one hell of a cold pool over Europe, a few hundred mile shift east and we are out of the game, but as this post says maybe not

 

Confused - if that pattern was further west we would benefit. I was predominently referring to pressure patterns anyway.

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Posted
  • Location: oldham
  • Location: oldham
Just now, Geordiesnow said:

I think some runs are showing if you dont have enough amplification in the Atlantic then it is a struggle to eject true cold westwards even with any height rises up in Scandinavia.

The main trend of dropping a trough over the UK is still there but big question marks of how much cold air will be mixed in by the time it gets here which of course will determine just how widespread any snow event could be.

I think the issue was to much amplification in the Atlantic, the Wedge of heights was in place
gfs-0-126.png?12 

Atlantic high gets toppled east ulike the 06z run which sank back before amplifying with a new serge of heights. 

gfs-0-150.png?12
 

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Posted
  • Location: Lincolnshire
  • Weather Preferences: Snow, freezes, bitterly cold and icy. Thunderstorms and heatwaves!
  • Location: Lincolnshire

To summarise, no one on planet earth knows what’s happening past about Monday with any certainty. Upgrades, then downgrades. I wouldn’t get to run down on the any model run currently. The weather will do what the weather wants. And right now it’s cold, there’s been some snow in some parts and it’s remaining cold for the next 5 days Atleast. Winter is here

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Posted
  • Location: oldham
  • Location: oldham
2 minutes ago, Radiating Dendrite said:

Confused - if that pattern was further west we would benefit. I was predominently referring to pressure patterns anyway.

If the patter was backed west then the cold pool would be further west nearer the UK.

 

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Posted
  • Location: Liphook
  • Location: Liphook

The PV over Canada is just too far east and the storm out of the US elongates and starts to phase when really we need it discrete.

IF we aren't to get an easterly, there maybe other shots at cold, seemsbto be a pattern for cutoff lows dropping into Europe right now.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

The second shot after D10 is cold and snowy by D14-D16:

gfs-0-372.thumb.png.e576f1bdd3d46d2381dcdfd94c73f363.png

Not sure if model fatigue would have taken hold by then...?

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Posted
  • Location: Aldridge, West Midlands (180M)
  • Weather Preferences: Snow, Snow, Snow and Cold
  • Location: Aldridge, West Midlands (180M)

 

This relates to the model output, as expected ECMWF is No.1 An important ECMWF 12Z.

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

Well having trawled through that lot and read various frame by frame interpretations i thought I'd look myself.

Cold / V cold on the table.

Sod wether we get an Easterly ......yet

It WILL get very cold next week.

Thinking Sisters been on the lash and is chucking up all over us

 

anim_mjq9.gif

anim_crg8.gif

anim_sea4.gif

anim_kid5.gif

Edited by winterof79
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Posted
  • Location: Liphook
  • Location: Liphook

Overall still a good run.

This shows that as long as we can get those cutoff troughs diving into Europe one will eventually take hold.

Several snow chances on the 12z before that, though sadly those very likely are over cooked as per the GFS norm on a W/NW type airflow.

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Tonights outputs so far show why a low dropping se and ridge building over the top are rare .

Its always that last hurdle that’s the hardest . However the track of the low will continue to change and there’s another one after that we’ll have to watch .

There is a little bit of insurance because originally the models weren’t that keen on much going on to the ne . The high pressure wedge there will help to disrupt energy away from low pressure near the UK and force a more se jet track .

So certainly things haven’t got off to a flying start this evening but there’s time for changes.

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Posted
  • Location: Liphook
  • Location: Liphook

Worth noting the 12z GFS is almost identical in terms of timing of the next cutoff troughs diving into Europe right in the back end of January.b

Despite the dislike for the 06z para, it was actually a reasonably snowy run when you look through it.

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Posted
  • Location: Sunderland
  • Weather Preferences: Hot Summer, Snowy winter and thunderstorms all year round!
  • Location: Sunderland
2 hours ago, johnholmes said:

You are not really correct. They 'look' at it but do not use it as a main model, their own and ECMWF are the main sources of model input.

E mail them and ask if you want proof.

 

John, you've misinterpreted my post, see further post on thread where I reposted the exact quote from a met office source 

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

Looking at the D5 GEFS viz the complicated pattern US storm -v-Atlantic Ridge -v- trough -v- wedge-gate, we see entropy in the handling:

gens_panel_okp9.png >>> D8: gens_panel_gdv3.png

Although TBH the trend this evening is so far not great, there are plenty of options on the table that play out better in the GEFS. Though there are some even more progressive than the op to flatten the pattern (eg Control). So as we were, the second low diving SE and then maybe blocking, may be flat, maybe something in between!

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Posted
  • Location: Reading/New York/Chicago
  • Location: Reading/New York/Chicago
17 minutes ago, nick sussex said:

Tonights outputs so far show why a low dropping se and ridge building over the top are rare .

Its always that last hurdle that’s the hardest . However the track of the low will continue to change and there’s another one after that we’ll have to watch .

There is a little bit of insurance because originally the models weren’t that keen on much going on to the ne . The high pressure wedge there will help to disrupt energy away from low pressure near the UK and force a more se jet track .

So certainly things haven’t got off to a flying start this evening but there’s time for changes.

Upstream is important of course. I think for the first attempt we are reliant on the upstream flow playing ball. However, with MJO forecast to go into phase 6 by around 23rd I think that we will be less reliant on tiny differences upstream.

In short, probability of much colder air increases with each subsequent system dropping SE. At the moment we are totally reliant on SSW overriding MJO signal and the correct phasing of energy over the US. With MJO onside,  we should start to see more outcomes favour better variations no matter what happens upstream (although of course there is still linkage).

Edited by WhiteFox
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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Day seven looks crucial: if we tap into the cold pool straight way, as was indicated by the 06Z, the cold would most likely last a good wee while; the 12Z, however, suggests a more convoluted, messy evolution...One that, from experience, might never happen at all...?

12Zimage.thumb.png.ccbdd79b810958ee19f127bceb045f77.png   

06Zimage.png

Edited by Ed Stone
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