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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: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
3 minutes ago, phil nw. said:

Well a couple more cold days to come with hard frosts over the snowfields-it's been a while since we could say that!

So we now look ahead and the rest of the week looking less cold but still fairly chilly until the end of the week but Atlantic fronts from mid-week finally modifying our pool of Arctic air.

The 12z runs still showing the demise of the upstream Alaskan ridge for a few days from around day 6.This frees up the Canadian trough to drive east flattening the Atlantic ridging,at least temporarily in week 2.The ens charts do show that after the north westerly next weekend we should expect a less cold westerly pattern for a few days

graphe3_1000_263_93___.gifgraphe_ens3.php?mode=0&x=263&y=93&run=12

 

Day 9 means

gensnh-21-1-216.pngEDH1-216.GIF?10-0

The later eps/gefs do indicate the return of the Alaskan ridge quite quickly though so along with the ongoing cross polar +ve height anomalies we are certainly not looking at our usual mid December strong zonal pattern around the globe.

Time will tell whether that resurgent ridging upstream will translate into the Atlantic. 

Also noticed the dip in temps right at the end of gfs and ecm ens -25th Dec :)

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Posted
  • Location: King’s Lynn, Norfolk.
  • Weather Preferences: Hot and Thundery, Cold and Snowy
  • Location: King’s Lynn, Norfolk.

Quite a few times it's been hinted by the models that the block over Eastern Europe may well show some resistance with most of the Atlantic energy going up and over the top of scandi. This would prep the Russian high further. I wouldn't be surprised if we start seeing easterlies being modelled within the next 2 weeks. 

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

NOAA seem to think the troughing in the east USA could well return the week after next and dependent on the amplitude of that this could downstream deliver some interest to the UK.

The possible renewed upstream amplification could well be in relation to the lagged MJO effect, have the models got the correct timing of that if does verify?

In terms of tonights ECM op it is at times both a pressure outlier aswell as the warmest solution for London and I wouldn't discount the GFS 12hrs trend just yet.

 

 

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
12 minutes ago, nick sussex said:

NOAA seem to think the troughing in the east USA could well return the week after next and dependent on the amplitude of that this could downstream deliver some interest to the UK.

The possible renewed upstream amplification could well be in relation to the lagged MJO effect, have the models got the correct timing of that if does verify?

In terms of tonights ECM op it is at times both a pressure outlier aswell as the warmest solution for London and I wouldn't discount the GFS 12hrs trend just yet.

 

 

- mmm I think the models as I said earlier are going to struggle in the coming days - underplaying the generally amplified flow, ECM is hinting at renewed amplification 19-20 Dec, and there is a signal for a deep long wave trough once again to anchor down through NE USA/E USA.

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Posted
  • Location: Grays, Thurrock
  • Location: Grays, Thurrock

pub run interesting at 132, better heights to the north, vortex further west and trough disruption  to south of Iceland. interesting trend, maybe we get another slider on subsequent run tomorrow.

gfsnh-0-132.png?18

 

Edited by pages
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Posted
  • Location: Camborne
  • Location: Camborne

Just a glance at NOAA this evening. Not to say much else as nothing has changed from this morning but the 8 14 does illustrate the strong upper flow from the eastern seaboard that becomes more diffuse in the east for reasons already given. Neither the GEFS or EPS mean anomalies this evening contradict this suggested pattern in any significant way

610day_03.thumb.gif.9cb9aea0578e5fe3f3186bbeb19b7245.gif814day_03.thumb.gif.317a4dd079d0f1faedfbc0798a8aab4c.gif

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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.
1 hour ago, Paul_1978 said:

But we've known this for quite a few days now Frosty. Everyone knows we're going to have a milder or "less cold" spell. 

The post suggested a worry about longer term outputs and I don't know why when many of our learned posters have suggesting a return to colder weather late in Dec/early Jan. Again we've known this for some days now. 

Now is the time to relax and wait and not unduly worry about the short/medium term output in my view. We are only 10 days into winter after all. 

2

For anybody wondering, we humans and current computer modelling techniques do NOT allow us to know anything for certain, as denoted by what has just happened over the past 24 hours with the snowfall. Not an attack on you, per se but your highlighted sentence above should perhaps replace the word "knows" so that it states "supposes" or "forecasted" i.e. guesswork. Yes, it is the best advice we have on offer currently and all of us will interpret things differently as do all the various weather models and their individual members runs. I would suggest others follow who or what model they want to but never take anything for granted. My prediction is the milder zonal blip will be brief in duration and to be fair, we can't even predict what will happen tomorrow yet with any great certainty either. The bigger stratospheric effects are often lost on me so I'll take on board others views there but I will never take any forecasts post D4 with high confidence levels, more especially so at this time of year.

 

Night all, enjoy the snow where you have it and do take care out there during that morning commute. :hi:

Edited by gottolovethisweather
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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
14 hours ago, nick sussex said:

 

 

Looking within closer range, Thursday is looking quite interesting, signs of some form of secondary low development splitting from the main low due to move through north Scotland, this could have the effect of building in a stronger ridging of the azores northwards and hold back the trough trying to dig across from eastern seaboard, another NW-SE slider may form again.. 

Thursday could deliver some low level snow to anywhere ahead of the low/trough development.

 

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
14 minutes ago, knocker said:

Just a glance at NOAA this evening. Not to say much else as nothing has changed from this morning but the 8 14 does illustrate the strong upper flow from the eastern seaboard that becomes more diffuse in the east for reasons already given. Neither the GEFS or EPS mean anomalies this evening contradict this suggested pattern in any significant way

610day_03.thumb.gif.9cb9aea0578e5fe3f3186bbeb19b7245.gif814day_03.thumb.gif.317a4dd079d0f1faedfbc0798a8aab4c.gif

Yes, a confluent trough in the west and slightly diffluent exit for the 500 mb flow over the UK. This may mean not only a westerly flow over the Atlantic but with large temperature contrasts, surface features will form just east of N America and deepen in the diffluent area around the UK. So maybe a rather stormy period?

Edited by johnholmes
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Posted
  • Location: blackburn
  • Weather Preferences: heavy snow/ heatwaves
  • Location: blackburn
36 minutes ago, pages said:

pub run interesting at 132, better heights to the north, vortex further west and trough disruption  to south of Iceland. interesting trend, maybe we get another slider on subsequent run tomorrow.

gfsnh-0-132.png?18

 

Please please not another slider.

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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
22 minutes ago, johnholmes said:

Yes, a confluent trough in the west and slightly diffluent exit for the 500 mb flow over the UK. This may mean not only a westerly flow over the Atlantic but with large temperature contrasts, surface features will form just east of N America and deepen in the diffluent area around the UK. So maybe a rather stormy period?

At least that would raise hopes of some colder polar maritime shots with wintry ppn and frosty nights mixed in with the milder, wet and very windy spells..could be worse, hopefully one of the colder shots will coincide with christmas!:santa-emoji: 

Edited by Frosty.
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
2 minutes ago, booferking said:

Vortex sheared in half again late in FI.:shok:

Screenshot_20171210-225525.png

And a huge chunk of it stuck over Greenland.

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Posted
  • Location: Kendray,Barnsley,God's county.
  • Weather Preferences: Snow freezing fog heatwave thunderstorm
  • Location: Kendray,Barnsley,God's county.

So after a mad day off radar watching. It's looking like a trend to see a mild spell from GFS and ECM after the next weekend if they are correct. But has other have posted wouldn't take anything for granted with the models has they could all change overnight. I really love the thread as it gives me a chance to talk about what I love and enjoy without getting told to shut up by our lass ha ha. Back to the weather anyway. I think 2017/18 could be a great winter and will be more ups and downs and would not want to spend it anywhere else than in here. Cheers.

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Posted
  • Location: Islington, C. London.
  • Weather Preferences: Cold winters and cool summers.
  • Location: Islington, C. London.

Even if we do have a milder, more cyclonic spell in the latter part of December, that wouldn't necessarily be bad. A lot of famously (or infamously) cold winters have had milder, even stormy periods at some point during December. I'm staying hopeful and so should you lot! :)

Edited by LetItSnow!
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Posted
  • Location: Liverpool - 23m ASL
  • Weather Preferences: Cold, snowy winters and hot, sunny summers!
  • Location: Liverpool - 23m ASL

npsh500.pngnpsh500.png

Extreme FI of course so just for a bit of fun, but the GFS 18z throws out this, erm, extreme chart at around the +360h timeframe.  Wonderful HLB in place but unfortunately we still manage to catch the zonal maglev! 

In seriousness though, it's interesting to see a relatively persistent pattern of HLB blocking modelled in the longer range, should provide encouragement that something cold could be on the cards post-Christmas. 

 

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Posted
  • Location: Calgary, Canada. Previously, Saffron Walden (Essex/Herts border), United Kingdom
  • Weather Preferences: Continental:Warm dry summers, cold snowy winters
  • Location: Calgary, Canada. Previously, Saffron Walden (Essex/Herts border), United Kingdom

0Z GFS seems to have Atlantic powering through but not as strongly as the 18Z. Hints at high building to the N/NE but quickly snuffed out by the atlantic at 200H. Seems they're overegging these lows. Saw a 935mbar low just off greenland. seems unlikely. However if that 935mbar low helps some WAA west of the UK, that could be interesting. Going to make for an interesting week of model watching

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
6 minutes ago, CanadaAl said:

0Z GFS seems to have Atlantic powering through but not as strongly as the 18Z. Hints at high building to the N/NE but quickly snuffed out by the atlantic at 200H. Seems they're overegging these lows. Saw a 935mbar low just off greenland. seems unlikely. However if that 935mbar low helps some WAA west of the UK, that could be interesting. Going to make for an interesting week of model watching

Not had a look at the models in a while but certainly intriguing with the eagerness to build +ve heights to north / east, perhaps this is the lag result of high amplitude MJO phases and there’s room for models to play with more amplification - we could enter something much colder before Xmas. I for one think that is plausible, model watching this year has taken a decidedly different turn to what we have been used to. :) 

92B6C834-FE95-4CAD-90F3-A1B65DAE23E1.thumb.png.908a0bd71dff2483d2185439fca83f20.png

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Posted
  • Location: ipswich <east near the a14> east weather watch
  • Location: ipswich <east near the a14> east weather watch

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

morning  looking  at the  gfs  is hinting  of a poissible cold snap after xmas could eaisly get  a white  new  year

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Posted
  • Location: Camborne
  • Location: Camborne

I haven't had much chance to look at the outputs this morning but there is nothing surprising about the ecm contours and anomalies. And I can confirm that SIdneys cockles are warming nicely

ecm_z500a_5d_nh_11.thumb.png.c3a6d28ebb117c6e445125b6dc0ed282.png

ecm_t850a_5d_natl_11.thumb.png.e6a798a889552f107736eeddcd49d8ad.png

Edited by knocker
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Posted
  • Location: Wakefield, West Yorkshire
  • Location: Wakefield, West Yorkshire

Interesting GFS this morning. 

Whilst the ECM goes "mild" at T+144 and stays mild, the Atlantic never gets in on the GFS til low res. 

Lots to be resolved and although  you would feel the return to milder weather may have the odds in its favour, it's not an open and shut case. 

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2 minutes ago, Paul_1978 said:

Interesting GFS this morning. 

Whilst the ECM goes "mild" at T+144 and stays mild, the Atlantic never gets in on the GFS til low res. 

Lots to be resolved and although  you would feel the return to milder weather may have the odds in its favour, it's not an open and shut case. 

I think you're right. There's huge ensemble scatter again but a lot of the members are mild, it has to be said.

5a2e369db6460_ScreenShot2017-12-11at07_40_19.thumb.png.124888a0db30a4afb4fb916f5b33bc45.png

A lot to play though for with such uncertainty beyond T144

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