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Model output discussion - 5th December 2016 - Into Winter we go


Paul

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Posted
  • Location: North West Leeds 124m
  • Location: North West Leeds 124m
14 minutes ago, Scott M said:

I just thought I would put a post up. I am not one for posting as I don't feel confident enough to post any charts so I thought I would ask for a bit of clarity first on the models, which I find very frustrating (from a coldie prospective). I have noticed that when there is a hint of cold weather in FI so to speak everyone gets pretty excited even my self but all I do is torcher my self feels like I have lost money or something, as do others am sure. What I would like to know is why do the models struggle to keep cold runs into reliable time frames without downgrading the 850s or anything else,but when it comes to mild mush they pick it up and keep it all the way out 384h to the reliable time frame. I mean this is like 3years on the trot maybe more I don't know, that North America gets all the snow and when they do it some how fire up the jet. I hope someone understands what I mean and would willing to share there thoughts. Sorry if this is in the wrong thread please remove if necessary thanks guys.

One of the reasons is that we are a small island on the edge of a large ocean. Because of the way the world spins our default wind direction is westerly therefore mild weather is our normal weather. That's just the way it is.

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
19 minutes ago, Scott M said:

I just thought I would put a post up. I am not one for posting as I don't feel confident enough to post any charts so I thought I would ask for a bit of clarity first on the models, which I find very frustrating (from a coldie prospective). I have noticed that when there is a hint of cold weather in FI so to speak everyone gets pretty excited even my self but all I do is torcher my self feels like I have lost money or something, as do others am sure. What I would like to know is why do the models struggle to keep cold runs into reliable time frames without downgrading the 850s or anything else,but when it comes to mild mush they pick it up and keep it all the way out 384h to the reliable time frame. I mean this is like 3years on the trot maybe more I don't know, that North America gets all the snow and when they do it some how fire up the jet. I hope someone understands what I mean and would willing to share there thoughts. Sorry if this is in the wrong thread please remove if necessary thanks guys.

Any weather we end up having, other than the seasons default weather will suddenly appear on the models between 144h and 192h,  I have never seen the weather move from FI to now. Gfs sometimes sees things way out in FI but loses focus and to see it again around 144-168h, ecmwf fi is just that but it will see things from 168-192 a bit more clearly.  No science this, just my experience comparing many (winter) model runs with actual outcomes 

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
1 minute ago, ArHu3 said:

Any weather we end up having, other than the seasons default weather will suddenly appear on the models between 144h and 192h,  I have never seen the weather move from FI to now. Gfs sometimes sees things way out in FI but loses focus and to see it again around 144-168h, ecmwf fi is just that but it will see things from 168-192 a bit more clearly.  No science this, just my experience comparing many (winter) model runs with actual outcomes 

I totally agree with your post, absolutely spot on.

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Posted
  • Location: Raynes Park, London SW20
  • Location: Raynes Park, London SW20

ECM extended eps - strong build up of heights across continental Europe.  Positive height anomaly moves from the southern Baltic Sea at day 12 to the southern North Sea by day 15 and even intensifies which is very noteworthy methinks.

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

ecmt850.192.png

This for me is the most interesting chart of the evening because it appears that if that low moving away from the Eastern Seaboard was slowed down sufficiently, it would mature as a separate system to the one by the UK, with some mid-Atlantic amplification helping the jet to dive into Europe, so increasing the scope for a secondary low to develop on the base of our trough and slide SE, giving the block to our east a chance to extend westward.

This kind of  'what if' assessment is all us southerners can really do when there's a westerly regime being modelled in December, even when there are some decent looking polar maritime incursions appearing; a wintry shower is about as good as it tends to get from that pre-January (and even then we struggle). 

Some may seek some enjoyment from stormy weather but even that aspect looks under threat to me as the troughs look increasingly disorganised nearer the time. It's a common issue for cyclonic storm fans that the models tend to overlook some of the smallest-scale shortwave features at the longer range, when such systems are capable of creating a more complex upper-air flow in which optimal development conditions are more intermittent - meaning the major systems get less time to intensify before they are 'choked off' (they need divergence of air aloft in order to 'breathe'; air is piling in at the lower levels and needs an exit route. This is why a weakening low is sometimes said to be 'filling').

So I'd not be surprised if we end up with quite a messy setup, but the question is whether within that we can see a secondary low or even shortwave riding into the base of a trough head down into Europe and facilitate a chill from the east. Even then, snow does not look easy to come by, but at least we'd be closer to the goal.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

A few recent posts have been removed-no  model discussion.Please use the other threads for chit chat or indeed maybe use the pm system rather than clog the thread up with off topic pleasantries.

Thanks.

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey
3 minutes ago, fergieweather said:

Plenty of interest starting to emerge in the spread of extended ECMWF clusters. Let's see if these nascent signs of pattern change into Jan (as per EC Monthly & GloSea5) continue to gather pace now in the ensembles from operational centres.

Nascent.....Word of the day Ian?  Mind you if you guys are looking at it there must be enough signs to be 'interested'.  I'm punting for a stratospheric warming around turn of new year for lower strat.  Landing point for main cold of winter mid Jan onwards

BFTP

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Posted
  • Location: Camborne
  • Location: Camborne

I wasn't expecting any great insights from the anomalies this evening and that is the case although the end of the ext period is certainly not without interest.

The 6-10 period really just confirms what we already knew and that is that the Xmas period looks like being quite unsettled with the upper trough  being negatively tilted from south east Greenland. There is still not complete agreement on the configuration of the complex vortex over the western Arctic, Canada, Greenland and thus the orientation of this trough and note the ecm has it slightly more progressive and consequently the high pressure further east But, as last evening, it has the HP ridging back NW which increases the amplification which should push the uppers winds more into a SW/NE flow which could well facilitate the track of the depressions to be further north and not impact too severely on the UK. Anyhow the detail of all of this will no doubt become more definitive in a day or two.In the meantime I think we can safely say a few days of unsettled quite wintry weather with strong winds is the percentage play.

610day.03.gifecm_eps_z500a_5d_nh_11.pnggefs_z500a_5d_nh_41.png

In the 10-15 period there are still strong indicators of retrogression from both the EPS and GEFS ( Again it may be because of the lengthy period with NOAA that it's not so obvious). They both have the vortex retrogressing to N. Canada and becoming more organized  accompanied by positive anomalies over Scandinavia once more and ridging to the east. So signs once again of more settled weather, certainly in the south.

814day.03.gifgefs_z500a_5d_nh_61.png

Edited by knocker
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Posted
  • Location: Norway
  • Location: Norway
Just now, BLAST FROM THE PAST said:

Nascent.....Word of the day Ian?  Mind you if you guys are looking at it there must be enough signs to be 'interested'.  I'm punting for a stratospheric warming around turn of new year for lower strat.  Landing point for main cold of winter mid Jan onwards

BFTP

 A strong wave1 is building at that time

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Posted
  • Location: Aberdeen
  • Location: Aberdeen

Hey thanks for the reply guys. So in all honesty which is the better model and what I mean by better is which one can pick up the weather furthest out and keep it into 144h or less. I only ask this because there is really only talk between GFS ,ECM and GEM other models include when it comes to cold. Correct me if am I wrong is GFS the one that likes to keep us in a zonal flow 

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Posted
  • Location: Loughmacrory, Co Tyrone. 170m asl
  • Weather Preferences: snow
  • Location: Loughmacrory, Co Tyrone. 170m asl

@fergieweather Hi Ian, really appreciate your input into this forum. You and many others have significantly improved my understanding of meteorology over the past years. 

Are the ECMWF clusters seeing interest from the east or from the North/N West? 

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Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
3 minutes ago, Scott M said:

Hey thanks for the reply guys. So in all honesty which is the better model and what I mean by better is which one can pick up the weather furthest out and keep it into 144h or less. I only ask this because there is really only talk between GFS ,ECM and GEM other models include when it comes to cold. Correct me if am I wrong is GFS the one that likes to keep us in a zonal flow 

If the ECM isn't on board. Forget it! Is my general guide. Unless it picks up a signal and the GFS refuses to play ball, then in recent times the ECM has backed off. 

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Posted
  • Location: st albans
  • Location: st albans

It's now pretty clear that the chance of the Atlantic trough maintaining it's Xmas strength against the Russian ridge is unlikely. the ridge retrogresses as it regains strength (probably using some ridging from the Atlantic to assist in crushing the low anomolies)  and the upper trough pulls back to mid Atlantic with low anomolies in s Greenland closest to uk. good consistency with the ec46. The sceuro ridge (again) the main player. Ian or Matt, with sight of the clusters will be able to give us best inisght once the model begins to settle on a route forward with the blocking. 

as singularity noted, there seems to be some opportunity to establish a euro low around day 10 if the jet plays ball but the timing has to be right.

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Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
3 minutes ago, KasimWeatherQuarnford said:

Perhaps the model's projected extension of the blocking was because it could not see a breakdown/ atlantic pattern after the projected blocked and colder spell we had in November which is usual becuase models have a hard time breaking down these patterns and predicting PV strength after a few days :)

I'm talking longer term than just the past few weeks though. I can't gives stats, but I'm a pretty avid model watcher, it just seems the ways of late. But I still stand by the fact that if for Example the GFS is showing and easterly and the ECM is having none of it, treat with extreme caution.

Edited by karlos1983
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Posted
  • Location: Essex, Southend-On-Sea
  • Weather Preferences: Warm, bright summers and Cold, snowy winters
  • Location: Essex, Southend-On-Sea
25 minutes ago, Scott M said:

Hey thanks for the reply guys. So in all honesty which is the better model and what I mean by better is which one can pick up the weather furthest out and keep it into 144h or less. I only ask this because there is really only talk between GFS ,ECM and GEM other models include when it comes to cold. Correct me if am I wrong is GFS the one that likes to keep us in a zonal flow 

Actually this year it's been the opposite! GFS going for the cold and blocked with the ECM having none of it, just seems that the GFS just doesn't like being right.

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Posted
  • Location: Loughmacrory, Co Tyrone. 170m asl
  • Weather Preferences: snow
  • Location: Loughmacrory, Co Tyrone. 170m asl
14 minutes ago, fergieweather said:

Both possibilities are strongly represented. By 31 Dec, only 6 members offer +ve NAO. That *shouldn't* be read as all the blocked solutions being colder (at least not at that timeframe: *may* be different further into 1st half Jan).

Cheers for the heads up, Ian. Here's hoping we get some joy out of the PM shots showing up around the Christmas period. 

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Just looking at the later GEFs for year end and there is a trend to rebuild heights across W.Europe/UK but no indication yet of anything more than what we have recently had ie.mid-latitude blocking.

A build north of the Azores high across our locale looks likely but as always a high building from the south of the jet brings with it mildish uppers and we don't have the Euro low heights to start with.We would be looking at surface cooling again until any heights can build further north. 

On the other hand Greenland -ve ht anomalies disappear so signs of that weakening and receding.

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Posted
  • Location: Emsworth, Hampshire
  • Location: Emsworth, Hampshire

Quite big changes from GFS 12z to 18z at +150h

12z                                                           18z

gfs-0-150_prr9.pnggfs-0-144_tgs0.png

Azores High trying to retrogress towards the UK. leading to this at 162... another change

gfs-0-162_xab2.png 

Edited by SnowMania
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

The GFS 18hrs run showing a move towards the ECM 12hrs run. The little ridge thrown ne ahead of the low, if that can build a bit further north with some ridging over the top of the incoming low that would help matters.

We really need the second low upstream to slow down and not phase with the one near the UK, that phasing pushes too much energy ne and then its difficult to get the jet angled more se through the UK.

Edited by nick sussex
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