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


Paul

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

Incidentally, after such a prolonged period of close broadscale agreement between runs of GloSea5 and ECMWF Seasonal, you'll note now how they finally bid each other farewell in their respective Dec updates and ride their own separate ways into J-F-M. Glosea fits with previous thinking (a marked switch away from -ve NAO 2nd half of winter); ECMWF continues similar to before. Of course, the combined 3-monthly means mask detail of how the journey unfolds, but it'll be intriguing to watch.

Glosea for me - its modelling of the strat is second to none and been faultless for a few years since its inception. mild to very mild winter overall for me.

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Posted
  • Location: st albans
  • Location: st albans
30 minutes ago, Nick F said:

The NOAA prognostic 8-14 day 500mb HGHTS/anomalies bears some resemblance to the 11-15 day 00z EPS 500mb mean below.

IMG_0016.JPG

They both actuallly advertise a pattern change from day 10 with the removal of the ridge over the Aleutains and replacing it with lower heights and a trough over the Gulf of Alaska and Western Canada, so we actually see the deep cold over northern U.S. and eastern Canada retreat west and a SE ridge develop. This *may* relax the jet downstream over the Atlantic heading NE to allow the Euro high to ridge further north. But we still need more energy/troughing to undercut over SW / S Europe - aka -NAO, something that seems to be increasingly hard to attain in winters this days.

But the fact that there is this pattern change upstream indicated, not just by EPS, but GEFS too, plus tropical forcing is pretty active over the maritime continent (SE Asia) despite the incoherent and conflicting MJO forecasts from many models, there is a glimmer of hope that we may see changes later in the month to shake up the stagnant and slow changes. 

Given that being the weekend, the NOAA chart will be automatic representation of NAEFS, methinks we have fair  agreement between the eps and NAEFS in the extended period. 

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Posted
  • Location: Brighton, East Sussex
  • Location: Brighton, East Sussex
7 minutes ago, feb1991blizzard said:

Glosea for me - its modelling of the strat is second to none and been faultless for a few years since its inception. mild to very mild winter overall for me.

Faultless? Thats a completely false statement, it's wrong just as much as any of the other top models! 

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

Cold air not far away in the days before xmas

IMG_3779.PNG

Better looking NH and just need a little height rise in the Atlantic to help

IMG_3780.PNG

And as if by manic winter arrives on Xmas day morning.

IMG_3782.PNG

Edited by Ali1977
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
13 minutes ago, fergieweather said:

 Of course, the combined 3-monthly means mask detail of how the journey unfolds, but it'll be intriguing to watch.

I hope the journey is more interesting than watching paint dry and will eventually bring some snow..that is what we are waiting for..well, most of us!:)

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Posted
  • Location: North Somerset, UK
  • Location: North Somerset, UK
14 minutes ago, Sawel said:

Do the Met Office put more credence in GloSea5 than they do the ECMWF Seasonal model? Like, say they were the only 2 models that existed and they're showing completely different scenarios.

Good question. Both are equally valued but of course, they are ultimately merely *guidance* like all models. The added value comes when specialists in seasonal/sub-seasonal forecasting tease-out all the vagaries of forcing mechanisms/drivers, and in doing so cast a critical eye over the model output to weight any solution accordingly. The ECMWF J-F-M output (sort of a reverse of original seasonal expectations!) raised some eyebrows, certainly; but that doesn't mean it's discounted. 

Edited by fergieweather
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Posted
  • Location: Camborne
  • Location: Camborne
5 minutes ago, bluearmy said:

Given that being the weekend, the NOAA chart will be automatic representation of NAEFS, methinks we have fair  agreement between the eps and NAEFS in the extended period. 

And how do you think that will work out blue? I don''t see any reason to be unduly optimistic if one is of the cold persuasion.

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
37 minutes ago, Nick F said:

The NOAA prognostic 8-14 day 500mb HGHTS/anomalies bears some resemblance to the 11-15 day 00z EPS 500mb mean below.

IMG_0016.JPG

They both actually  advertise a pattern change from day 10 with the removal of the ridge over the Aleutains and replacing it with lower heights and a trough over the Gulf of Alaska and Western Canada (+EPO) - so we actually see the deep cold over northern U.S. and eastern Canada retreat west and a SE ridge develop. This *may* relax the jet downstream over the Atlantic heading NE to allow the Euro high to ridge further north. But we still need more energy/troughing to undercut over SW / S Europe - aka -NAO, something that seems to be increasingly hard to attain in winters these days.

But the fact that there is this pattern change upstream indicated, not just by EPS, but GEFS too, plus tropical forcing is pretty active over the maritime continent (SE Asia) despite the incoherent and conflicting MJO forecasts from many models, there is a glimmer of hope that we may see changes later in the month to shake up the stagnant pattern.

Thanks for posting this chart - I echoed what you have said on Friday, less cold air being injected off the NE USA seaboard, and a ridge developing over central/east/se USA which should enable the euro ridge to build that bit further north - and a weaker perhaps split jetflow, with every chance of greater energy heading into the southern arm. 

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Posted
  • Location: Banbury
  • Location: Banbury

I have to say , I don't know what to make of everything I've heard prior to this Winter. Boxes were ticked in many areas giving us a hint of something to be optimistic about. I'm don't think anyone can be sure of J F or M to be honest .... is a  -ve NAO really the be all and end all with regards  something wintry for the BI , I doubt it .

Faux cold will do for me at the moment and as I type the OP throws this out

 

gfsnh-0-312.png?18

Edited by Banbury
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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
3 hours ago, blizzard81 said:

Well, the ecm day 10 starts to shows height rises to our north west. 

And so does the gfs 18z op, following on from the 12z control. Trends? :)

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Posted
  • Location: Camborne
  • Location: Camborne
1 minute ago, damianslaw said:

Thanks for posting this chart - I echoed what you have said on Friday, less cold air being injected off the NE USA seaboard, and a ridge developing over central/east/se USA which should enable the euro ridge to build that bit further north - and a weaker perhaps split jetflow, with every chance of greater energy heading into the southern arm. 

Running the EPS means through to the end there is no ridge developing over the central/east USA, just very weak positive anomalies in the south east. Downstream it has a upper flow from the W/SW and no ridging over Scandinavia.

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Posted
  • Location: Dundee - 140m ASL
  • Location: Dundee - 140m ASL
4 minutes ago, fergieweather said:

Good question. Both are equally valued but of course, they are ultimately merely *guidance* like all models. The added value comes when specialists in seasonal/sub-seasonal forecasting tease-out all the vagaries of forcing mechanisms/drivers, and in doing so cast a critical eye over the model output to weight any solution accordingly. The ECMWF J-F-M output (sort of a reverse of original seasonal expectations!) raised some eyebrows, certainly; but that doesn't mean it's discounted. 

Cheers for the reply Ian, like you say it will be intriguing to watch how the winter months unfold.

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Posted
  • Location: Burton-on-Trent (90m), Larnaka most Augusts
  • Location: Burton-on-Trent (90m), Larnaka most Augusts

Could even be seeing a retrogression in deep FI with lows disintegrating over Greenland. Here we go again...

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

The MAX in kent on the 20th was -6c with 30-40cm on the ground - nearer 60-70cm on the chilterns, apparently there was skiing !! - need a piste basher for that depth :)

In terms of the models- a fairly benign stalemate tonight at day 6 to day 10 with a slack flow & pretty chilly days with possible interest after that approaching xmas...

Unfortunately I think I would be piste thinking a repeat will happen!!!

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Posted
  • Location: Forest of Dean, Gloucestershire 98m ASL
  • Weather Preferences: Snow, Thunderstorms
  • Location: Forest of Dean, Gloucestershire 98m ASL
7 minutes ago, blizzard81 said:

And so does the gfs 18z op, following on from the 12z control. Trends? :)

The high pressure building into Greenland in FI like you say has been present in all today's GFS OP runs, becoming more evident as each one rolls out. Something to watch out for tomorrow and in the ensembles ...

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

BA the JMA later output ties in with your earlier post re the Siberian high giving the Euro high a helping hand nw and troughing digging se.

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

BA the JMA later output ties in with your earlier post re the Siberian high giving the Euro high a helping hand nw and troughing digging se.

Good shout - best op of the day that.

JN264-21_txd8.GIF

 

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
17 minutes ago, Mucka said:

If we get an Easterly by Christmas I'll run in the street naked.

And nobody wants that!

If I had a reputation, I would stake it on no Easterly.

I still think any small chance of cold for Christmas will come from the North and blocking to the West rather than from the East and a Scandi/Russian high. Even taking into account latest anomaly charts.

I would even happily accept the humiliation of being so wrong, should one crop up and give us a chance of snow at Christmas.

 

 

With the potential for the trop PV retreating west over Canada because of the +EPO / break down of Aleutian high I mentioned in my last post, certainly feasible for a high to the west as per 18z GFS FI, though equally the high may ridge north over or east of the UK, depending how the wavelengths adjust.

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