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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: Weymouth, Dorset
  • Location: Weymouth, Dorset
3 minutes ago, Leo97t said:

The golden rule of getting cold in the uk is a mild eastern states/Canada so this is particularly surprising 

A very simplisitc and one dimensional viewpoint.

Sometimes it can be the case regards a firing up of the Atlantic with the thermal differential, at other times other factors will override / negate its effect.

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Posted
  • Location: HILL OF TARA IRELAND
  • Weather Preferences: SNOW ICE
  • Location: HILL OF TARA IRELAND
2 minutes ago, Steve Murr said:

Now ive actually walked in the door & looked- The UKMO is fine in terms of sustaining cold, however isnt quite as good as the ECM-

Also we are only talking a couple of hundred miles correction we cant expect perfection @144 all the time-

GFS is poor again- it just cannot see whats happening- but the transitional 24-36 hour window still applies

Next focal point is FV3 - looks very good @78!

It looks stuck on 78 meteociel. 

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Posted
  • Location: st albans
  • Location: st albans
3 minutes ago, January Snowstorm said:

Over to the ECM to save the day.

@nick sussex no shares in GFS Nick but weren't you saying about 2 weeks ago that the ECM was very poor this season?

Well it didn’t cover itself in glory on yesterday’s two op runs by mishandling the Atlantic profile ....

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

The GFS is much too quick with the shortwave which runs end from Texas .

2 minutes ago, January Snowstorm said:

For me across all models (awaiting ecm) there's no proper heights to our North. I know weaker heights can sometimes deliver but in general a proper cold spell needs either a strong Greenland or Scandinavian high. Even on the morning runs a proper analysis for me was that things could go wrong and it was marginal.

Also we've been mentioning the 20th January for a while now as the starting point yet that date is in view now and it ain't great.

Over to the ECM to save the day.

@nick sussex no shares in GFS Nick but weren't you saying about 2 weeks ago that the ECM was very poor this season?

Yes after day 7 but not before. I’m not lauding the ECM it has been dodgy this winter in the later timeframe so far but still beats the GFS within the day 6 timeframe . The early part is important because that helps develop a small wedge to the ne . So if the GFS is wrong at day 6 the rest of its output can go in the shredder . 

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Posted
  • Location: HILL OF TARA IRELAND
  • Weather Preferences: SNOW ICE
  • Location: HILL OF TARA IRELAND

If FV3 is replacing Gfs why do we get hung up on such bad consistency from Gfs

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
4 minutes ago, bluearmy said:

I always find this an odd thing ..... gfs is a better model in the USA than the other models cos it’s a us model ..... and the euros are better over Europe .... is there actually any evidence? Surely it’s more a case of the model bias being exposed in different geographical locales ???

In any case they're global models so any bias early is going to be magnified downstream tenfold later in the run, we aren't talking about the Euro 4 which is built to model one area.

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

I think GFS tries for a feasible outcome if the MJO stays quiet, in which we have Canadian-Siberian vortex lobe exchanges taking place while west-Scandinavian blocking keeps us under a cold continental feed, but the usual bias (zonal flow too strong, not enough recurve of the jet under the block) led to it looking much less appealing than it could have done.

If, instead, the MJO manages a bit of activity over the C. Pacific then a ridge to our NW becomes more probable.


Odds are, we'll have a much better position in a week's time than GFS has us down for anyway, so I've little concern with it this evening. Same goes for D8+ of GEM though it's hardly a poor outcome with the new trough diving sharply into Europe on D10 and another easterly on the way; it's just that it would be preferable to keep our existing cold pool going.

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Everything is looking too flimsy and marginal on all models at the moment to set up any much awaited hlb. Although I still expect an improvement, it's gonna have to happen soon before we are locked out again

Edited by Leo97t
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I have today taken a look at the GEFS T850 06z model and the GEFS Precip Run 06z for the next few days. From what I can make out a fairly cold spell will hit from late Wed Evening and last into Friday AM. Late on Thursday and AM Friday, a band of fairly heavy precip will sweep in from the West. It looks to hit the UK around midnight. I would say that given the cold temps shown in the models this will fall as snow in most places. The above models show the precip in a heavy band top to bottom of the UK marching east. A warmer air mass will follow but especially if the band makes landfall at night, the chances of a decent snowfall look good before we get into the warmer air

 

 

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Posted
  • Location: Dundee - 140m ASL
  • Location: Dundee - 140m ASL
12 minutes ago, FiftyShadesofSnow said:

Gfs seems to model NE USA and Greenland much better than the Euros, due to locale...12z concerning if it's spotted the flatter pattern due to the Canadian lobe an stronger jet...it's flat.

image.png

Very misleading and completely wrong. The ECM consistently outperforms GFS when it comes to snowstorms and hurricanes around the east coast of the USA - the pros over there always slate the GFS! ECM is their go to model when big weather events are incoming.

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Posted
  • Location: leicester
  • Location: leicester
3 minutes ago, Steve Murr said:

GFS 12z out to 108 are about 2c colder in the extreme SE due to the slider having a more tilt to it-

The ENS will be fine ??

Steve where do you think that snow line from the slidee would be on ukmo at 144 hours!!am thinking south wales west country maybe!!

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5 minutes ago, Sawel said:

Very misleading and completely wrong. The ECM consistently outperforms GFS when it comes to snowstorms and hurricanes around the east coast of the USA - the pros over there always slate the GFS! ECM is their go to model when big weather events are incoming.

Yes correct 

Anyway having analized every output tonight - this is where I think we will end up around 144... ( in 6 days )

4983AE06-5A2A-4BAB-B7E7-6E51AB77FF03.thumb.png.a6a2969bcf56d716cb179a996b59396b.png

Edited by Steve Murr
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Posted
  • Location: sheffield
  • Weather Preferences: cold ,snow
  • Location: sheffield
1 minute ago, shaky said:

Steve where do you think that snow line from the slidee would be on ukmo at 144 hours!!am thinking south wales west country maybe!!

Please don't do this!!!!!!

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Posted
  • Location: Manchester City center/ Leeds Bradfor Airport 200m
  • Location: Manchester City center/ Leeds Bradfor Airport 200m

I'm not seeing much to get excited about if you live in the south, cold zonality doesn't deliver here. If I was back up north 200m asl I'd be more enamored with the runs but at present it's pretty underwhelming 

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

The GEFS at T138 are all over the place, and it is clear these sliders at this range are a lottery. Assuming ECM has it correctly modelled maybe presumptuous, though I expect it to be nearer than the GFS op:

gens_panel_occ2.png

 

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

I"ve done a couple of paintjobs to explain the differences between the UKMO and GFS:

So as you can see on the former the low southern tip Greenland and the small wedge of high pressure to the ne of it circled orange. The direction of energy is se , you're drop down point will be through or just to the west of the UK. Its also slower upstream and sharper and also slower with the low heading ne out of Texas, this feature then runs towards the east coast later developing a deeper feature.

UN144-21.thumb.gif.34c8d8e61302dabc55624e54dd97f7cb.gif

Now if you look at the GFS for same time day 6:

You'll note its flatter with the low southern Greenland , little if any wedge to the ne and the direction of energy is more east se.

gfsnh-0-144.thumb.png.ad25a3ab731a6749e8c88a6181398310.png

Given the GFS bias which has been documented by the makers of it and often referred to in the NCEP discussions its a very unlikely solution.

 

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl

GFS is absolute balls again, GEM and UKMO right idea, sliding the low, hopefully GFS will soon bin the mild fest Friday

UW120-21.GIF?13-17gem-0-120.png?12gfs-0-114.png?12

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4 minutes ago, nwextremeweather said:

I have today taken a look at the GEFS T850 06z model and the GEFS Precip Run 06z for the next few days. From what I can make out a fairly cold spell will hit from late Wed Evening and last into Friday AM. Late on Thursday and AM Friday, a band of fairly heavy precip will sweep in from the West. It looks to hit the UK around midnight. I would say that given the cold temps shown in the models this will fall as snow in most places. The above models show the precip in a heavy band top to bottom of the UK marching east. A warmer air mass will follow but especially if the band makes landfall at night, the chances of a decent snowfall look good before we get into the warmer air

 

 

Then after that the GEFS T850 06z and the GEFS precip run 06z show the 21st Jan as the coldest day on the model run. However I cant see much precip around on the 21st. Most weather sources such as the Met Office are pointing to the 21st so that should be encouraging

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

The GEFS at T138 are all over the place, and it is clear these sliders at this range are a lottery. Assuming ECM has it correctly modelled maybe presumptuous, though I expect it to be nearer than the GFS op:

gens_panel_occ2.png

 

There's only a couple of bad ones, while there are subtle differences, those differences don't mean there will be a poor outcome, it might not be quite as good as the 6z suite, but thats not to do with this suite, we were coming off a very high base.

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9 minutes ago, shaky said:

Steve where do you think that snow line from the slidee would be on ukmo at 144 hours!!am thinking south wales west country maybe!!

I think much depends on whether the precip band hits at night or in the day. If night, most could wake up to snow before the warmer air and the rain take over

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