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Model output discussion - winter proper underway


Paul
Message added by Paul

Please only post model discussion in this thread. 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

Thank you!

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Posted
  • Location: Brighton, East Sussex
  • Location: Brighton, East Sussex

There's forcing on the PV from all angles really but if anything it's strengthening over Canada/Greenland on the GFS.

In fact the FI pattern on this run is probably my least favourite winter sypnotic, Atlantic lows spawning from the PV, barrelling in and stalling over us because of the Russian/Euro high type setup. YUK.

edit: Looks like it's going for it right at the end, of course haha:D

Edited by Weathizard
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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
1 minute ago, Weathizard said:

There's forcing on the PV from all angles really but if anything it's strengthening over Canada/Greenland on the GFS.

In fact the FI pattern on this run is probably my least favourite winter sypnotic, Atlantic lows spawning from the PV, barrelling in and stalling over us because of the Russian/Euro high type setup. YUK.

I have noticed though that the pv over north east Canada is only blown up in the low resolution part of the runs. When it runs down to the 6/7 day timeframe, it is nowhere near as powerful as it was originally modelled. I put this down to model bias giving far too much consideration to average climatology. 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
9 minutes ago, s4lancia said:

And I would disagree wholeheartedly disagree with that. That's 14 days time.

Even saying meaningful cold between now and Christmas is a bust would be on dodgy ground, albeit, yes, odds on to be correct, but not 'bust'.

I was about to write a post this morning regards the upstream amplification, associated-EPO and the MJO, all of which gives us, if nothing else, hope, of a cold spell incoming. Throw in the solar state and -QBO and we do at least have a ticket to the raffle. I didn't because Nick F put it all, far better than I could, on the previous page!

Assuming upstream amplification doesn't drastically recede, I do believe we are going to see a jet digging further and further south off the ES/ Mid Atlantic and are on the cusp of some very easy on the eye model evolutions over the coming week or so, bringing the end of month firmly into play. I wouldn't say it's going to happen at all, but no way can that period be written off at this stage with teleconnections as they are.

Don't disagree that's the time we COULD begin to see favourable changes manifest themselves (indeed they already are on the 0z GEFS suite) but anything like 25th 26th 27th for meaningful UK cold I'm afraid is wide of the mark.

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
6 minutes ago, Daniel* said:

‘Split vortex’ all the way out in GFS 06z cross polar flow? I foresee some very interesting charts to come. :) 

A72A22F9-C0C1-4732-BDB3-17A1CCD553F9.thumb.png.2a1421896911ca61ba072ef7d46a3b4b.png

I hope so Daniel long term. In the meanwhile a horrible run from 6h GFS. Much too mild over Europe with heights maintained. Hope this is a rogue run.

C

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
34 minutes ago, Bring Back1962-63 said:

SOME MISLEADING POSTS

I'll comment on some of the much improved 0z output later today with another cross-model analysis. In several recent posts I have tried to persuade a small number of other posters to be careful about commenting on the broader pattern while showing only the "Europe" view chart(s) and not the "Northern Hemisphere" view charts which are essential for viewing the upstream pattern. This minority continue to mislead us with this practise. Well, we have a perfect example of what I'm on about with today's ECM 0z T+240 charts:

          Europe view:  ECM1-240.GIF                                                                                                 Northern Hemisphere view:  ECH1-240.GIF?16-12

Several comments referred to the first chart stating that the ECM looks dreadful towards the end. It might look like a train of LPs and a full on Atlantic but this would be an extremely inaccurate conclusion to come to. Look north!  There is a strengthening PNA  and a huge cut off HP over the Pole. HP is ridging down through Greenland and looking set to link up with the vast Azores HP as the Atlantic LP pushes eastwards. It's looking like this LP will be the last in the train with none appearing behind it. There is also a large belt of HP from northern Asia, through Siberia and ridging into the Arctic. In fact this whole ECM run is considerably more amplified than any of its last few runs. They "may" at last be sniffing out the broader pattern changes that GFS has been toying with (very inconsistently) from run to run over the last few days. This ECM 0z run pattern would first pull in a northerly behind the Atlantic LP (around D11/D12) but then all the indications are (from the positioning of the HPs) that this would veer to an easterly a few days after that (around D15/16). It's not surprising that the newbies to this subject and/or this model thread can get very confused. Those of us posting must try to provide proper context and accuracy to our comments and charts. Having said that, I must end with my usual warning:

CAUTION: One model, one run so do not get your hopes up too much just yet.

 

In the de Bilt ensemble I can see a few members going for variations of easterlies, more so than yesterday evenings run but not a lot

Screenshot_20171216-105539.png

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Posted
  • Location: Camborne
  • Location: Camborne

Pretty reasonable agreement between last nights NOAA and this mornings EPS and GEFS anomalies in the medium term. Some differences upstream vis the alignment of the ridge/trough axis which may have some impact downstream.

Keeping it brief we are looking at one vortex lobe Siberia with a trough into the Pacific, Alaskan ridge and the main vortex lobe northern Canada with associated trough orientated down North America and a conduit east to the Scandinavian trough thar runs down eastern Europe.

Thus we have a strong westerly upper flow leaving get the eastern seaboard but this gets modified in the eastern Atlantic by the Azones HP ridging in the vicinity of the UK. The precise orientation and intensity of this will obviously influence the UK weather during this period and will need to be sorted by the det runs but the percentage playe is for a quiet spell with Temps slightly above average tending to a N/S split with systems running around the high pressure. Sunshine may be at a premium under the high

gefs_z500a_5d_nh_41.thumb.png.b1eec5e2fb5c4f353eefa8bc2aed90a0.pngecm_eps_z500a_5d_nh_11.thumb.png.87a8a564fe7dbdfcfe23091f3536e6e1.png610day_03.thumb.gif.17964eae57b03f6cd929dd5b20134237.gif

In the extended period it is not so much a pattern change but an adjustment of the existing pattern with the Canadian  vortex spreading it's wings south east into the Atlantic and suppressing the Azones ridging and thus backing the upper flow westerly. This would ported generally more unsettle weather with Temps around average. The EPS is the most progressive with the Atlantic trough.

 

gefs_z500a_5d_nh_61.thumb.png.4a51cb4262aea1933efed4df5ce227f9.png814day_03.thumb.gif.8c3cbced1dc4b132a5fe94f3e7b1807b.gif

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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl
Just now, carinthian said:

I hope so Daniel long term. In the meanwhile a horrible run from 6h GFS. Much too mild over Europe with heights maintained. Hope this is a rogue run.

C

i wouldnt say it was that bad, its a step back in the right direction from yesterdays output. i doubt we'll see a sudden leap to cross model agreemrnt for cold. if the uncertainty is due to the models getting a handle on the MJO phases, then we will likely see gradual nudges towards the right solution.

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
5 minutes ago, carinthian said:

I hope so Daniel long term. In the meanwhile a horrible run from 6h GFS. Much too mild over Europe with heights maintained. Hope this is a rogue run.

C

GFS 06z ramps up Euro high very unsightly 7-10 days at least of torment it looks. Xmas day itself is fairly seasonal on GFS 06z very stagnant under HP, probably a good frost for most Christmas morning. I think that’s as far as a white Christmas we’re going to get for many of us not sure why this time of year tends to be mild. 

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
1 hour ago, feb1991blizzard said:

Disagree TEITS,

Disagree, any (meaningful) cold spell between xmas and new years is a bust, the only way any time afterwards will be via a scandi high.

So are you ruling out any cold air from the NW or N with that comment? What proof have you got that the only way will be via Scandinavia please?

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Posted
  • Location: Hernia Bay
  • Weather Preferences: Heavy Snow
  • Location: Hernia Bay

gfs 06z doesn't provide coldies with much cheer but at least it should be sunny and pleasant to get Christmas shopping done! What is promising (to my novice eye) is it really is a similar pattern  repeating itself....the only difference being is that the high is in the wrong place (or over the UK) !! As opposed to the west of the UK !!

Edited by snowfish1
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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

The outlook for week 2 still looks pretty mobile.The ECM model more bullish in pushing the jet further south in it's extended ens because of the greater effect of the Alaskan ridge heading deep into the pole and forcing the Canadian pv this way.

This could bring something of interest further on if we can develop better ridging from the Atlantic pattern but currently the best chance for anything is transient north westerlies which would favour places further north and over higher ground.The retreat west of the Azores high indicated later would help with the angle of the jet enabling it to head more se.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

06z has a 14c in the SW on Tuesday and Wednesday afternoon

ukmaxtemp.thumb.png.ecae2834b66b837c29a1cabc714f27d2.pngukmaxtemp.png1.thumb.png.b94287161ffd65b2f5e9a49ab5809761.png

Thursday which is the shortest day of the year sees temps widely in double figures Midlands south with single figures in the north

3.thumb.png.c44c431ae51ba33a69236fd626fb0db3.png

Friday sees a colder blip before a return to milder temps on Saturday

ukmaxtemp.png4.thumb.png.6677a0231ff03937d86f7a48472e585d.pngukmaxtemp.png5.thumb.png.16f6bc4850f2208b4d167310a7b410c4.png

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Posted
  • Location: DL
  • Location: DL
15 minutes ago, johnholmes said:

So are you ruling out any cold air from the NW or N with that comment? What proof have you got that the only way will be via Scandinavia please?

He/she says 'meaningful' and 'spell'... his comment doesn't rule out colder snap... seems fine to me.

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

So are you ruling out any cold air from the NW or N with that comment? What proof have you got that the only way will be via Scandinavia please?

In the short term after 1st Jan yes, depends what you call cold, a slushfest that we had Wednesday at 600ft in the pennines from a WNWerly does not constitute a cold spell in my eyes, I believe we should actually be routing for the GFS because any transient ridge will not be enough to stop upper strat zonal westerlies downwelling, the 2 wave (almost cross polar flow) showing on a lot of 0z (and some of 6z) GEFS, would even if they didn't achieve an Easterly straight away, would buy us more time.

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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

Don't know why my post was removed, I was only agreeing with Gavin about the largely mild / very mild outlook from the 00z / 6z output!!!:santa-emoji:enjoy it guys, I thought this was an all inclusive forum for mild and cold and not cold only hopecasting!:)

Edited by Frosty.
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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.
34 minutes ago, phil nw. said:

The outlook for week 2 still looks pretty mobile.The ECM model more bullish in pushing the jet further south in it's extended ens because of the greater effect of the Alaskan ridge heading deep into the pole and forcing the Canadian pv this way.

This could bring something of interest further on if we can develop better ridging from the Atlantic pattern but currently the best chance for anything is transient north westerlies which would favour places further north and over higher ground.The retreat west of the Azores high indicated later would help with the angle of the jet enabling it to head more se.

I hope your analysis comes to fruition, Phil. I suggested something similar having spent five days or so on the sidelines, watching things unfold and by not commenting on developments around the key period. 

 

"As at least getting about, rarely being soaked to the skin and a general dryness is a far more pleasant winter weather type than predominant southwesterly driven moisture-laden onslaught. I think this HP dominance will gradually push Northwards and perhaps, allow a return of the NW-SE diving shortwave scenarios in time for the Christmas break. A Boxing Day wintry breakdown from the NW possibly? Could well be the case, so watch this space! :friends:"

 

I'm quite chilled about things as they stand as I don't see a zonal onslaught anywhere, bar the extreme NW, yes some rain tomorrow but then a largely dry run-up to Christmas and then things could develop nicely, just don't go expecting a BIG FREEZE any day soon guys.

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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Well after a few weeks of interesting weather it looks like in for a spell of boring nothing type of weather with mild temperatures and grey laden skies. Bonus if we get any sun next week. Deep lala land does show a bit more interesting weather. GFS with it's normal deep lows blowing the uk away while the ECM doesn't go quite so extreme as it doesn't so far out but at least we do have some transient cooler slots with may produce some wintry weather. Hopefully we will get more application and different types of weather everyone will find interesting. However the emphasis is on the mild side of things.

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Posted
  • Location: Southend-On-Sea, South East Essex.
  • Location: Southend-On-Sea, South East Essex.
13 minutes ago, Frosty. said:

Don't know why my post was removed, I was only agreeing with Gavin about the largely mild / very mild outlook from the 00z / 6z output!!!:santa-emoji:enjoy it guys, I thought this was an all inclusive forum for mild and cold and not cold only hopecasting!:)

Frosty has your account been hacked by Ian Brown? What am I missing here? ?

Regards the models, looks like a spell of milder conditions, with brief cooler shots for the next 10 days or so. Small signs of something on the colder side appearing as we go into 2018. Good time for a model break I think to re-charge and go cold hunting over and beyond the festive period.

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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
3 minutes ago, Southender said:

Frosty has your account been hacked by Ian Brown? What am I missing here? ?

 

Nope, I'm just accepting the situation and adding a bit of christmas humor, seems some are lacking a sense of humor though..shame:santa-emoji::)

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Posted
  • Location: Raynes Park, London SW20
  • Location: Raynes Park, London SW20
4 minutes ago, Frosty. said:

Nope, I'm just accepting the situation and adding a bit of christmas humor, seems some are lacking a sense of humor though..shame:santa-emoji::)

I want the old Frosty back posting snow charts from the GFS in deep FI!!

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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
7 minutes ago, mulzy said:

I want the old Frosty back posting snow charts from the GFS in deep FI!!

This is frosty 2.0..new, improved and realistic:santa-emoji:

The mods show a largely mild outlook, accept it, all the hopecasting in the world won't bring us another decent cold spell during the rest of 2017.

Edited by Frosty.
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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl
21 minutes ago, Frosty. said:

This is frosty 2.0..new, improved and realistic:santa-emoji:

The mods show a largely mild outlook, accept it, all the hopecasting in the world won't bring us another decent cold spell during the rest of 2017.

As long as it's dry Frosty, I don't mind, cannot moan at 13C and dry, biggest rain hater in the world here, dry charts rule Frosty! -2C or 13C don't care

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Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
Just now, Frosty. said:

This is frosty 2.0..new, improved and realistic:santa-emoji:

The mods show a largely mild outlook, accept it, all the hopecasting in the world won't bring us another decent cold spell during the rest of 2017.

I think I prefered the old Frosty too. lol.

I'd be very wary of accepting any operational charts for the xmas into new year period at face value at the moment with the background signals that have yet to feed into the nwp. As we know the abilities of nwp beyond 7 days are really rather limited  

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