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Model Output Discussion - cold spell to end Autumn


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: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
3 minutes ago, CreweCold said:

:good:

npst30.png

Good to see the warming still showing up on the GFS

npst30.png

An improvement after a couple of runs that were slower and a little weaker with the warming & height rises into Canada.

Still uncertain whether it will be enough for the tropospheric response to place blocking high close enough to our NW, but I've seen ECM looking reasonably close to GFS for days 9-10, which offers some encouragement.

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Posted
  • Location: uxbridge middlesex(- also Bampton oxfordshire
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(- also Bampton oxfordshire
4 minutes ago, chris55 said:

As has been pointed out GFS 264 is a peach for those in the "middle". Way to far out to take seriously but deffo worth a chart upload :):):)

IMG_2908.thumb.PNG.48f52c065f355b12aaef994c69939657.PNG

Yeah' fully agree.

Absolutley no point getting hung-up on the battle ground scenario that far out!

Its a t-24hrs thing!

Thats if this evolution even playsout at all.

Gfs could go anywhere after 196...

Over to ecm 12z for 'perhaps' some clearer options.

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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset
15 minutes ago, Daniel* said:

Somewhere in Southern England does not lose the -0c isotherm once on GFS 12z from now all the way to the present frame T288 - that is quite something indicative of a prolonged cold spell with not much ease.

Hi Daniel

Did you mean the dam thickness? As you'd usually look at the 0°C isotherm heights (in the short term)

 

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
1 minute ago, Singularity said:

npst30.png

An improvement after a couple of runs that were slower and a little weaker with the warming & height rises into Canada.

Still uncertain whether it will be enough for the tropospheric response to place blocking high close enough to our NW, but I've seen ECM looking reasonably close to GFS for days 9-10, which offers some encouragement.

I do wonder if we are indeed following the '62-'63 template strat wise as @bobbydog has pointed out? A minor warming early December, followed by a technical SSW in January.

Obviously, even if this was to be the case, there is no saying conditions on the ground will follow a similar template.

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
4 minutes ago, Mapantz said:

Hi Daniel

Did you mean the dam thickness? As you'd usually look at the 0°C isotherm heights (in the short term)

 

Hi Mapantz, did not word that well the T850 temps. :good:

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

Control run highlights what can go wrong if things don't play ball upstream

gensnh-0-1-192.png

HP struggles to gain latitude sufficiently and the trough to the NE can not drop far enough S

Edited by CreweCold
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Posted
  • Location: st albans
  • Location: st albans
35 minutes ago, tight isobar said:

??

Its been flagging up ...

Via gfs last couple of days now!!!

Yesterdays 12z...)

23844591_1768957139812854_6613245166533457591_n.jpg

No idea why I posted that TI (and feb1991) - though it is varying run to run (ops inc ecm) and I guess it’s something we need to pin down as it could promote a west based neg NAO if it verifies too far west 

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Posted
  • Location: Tyrone
  • Location: Tyrone
4 minutes ago, CreweCold said:

Control run highlights what can go wrong if things don't play ball upstream

gensnh-0-1-192.png

HP struggles to gain latitude sufficiently and the trough to the NE can not drop far enough S

But it gets there in the end.:D

gensnh-0-1-252.png

gensnh-0-0-252.png

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

Control run highlights what can go wrong if things don't play ball upstream

gensnh-0-1-192.png

HP struggles to gain latitude sufficiently and the trough to the NE can not drop far enough S

And still manages to deliver a stonker!!

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
2 minutes ago, feb1991blizzard said:

And still manages to deliver a stonker!!

Not really a stonker Feb...would be much better if those Mediterranean heights could be erradicated

gensnh-0-1-276.png

The longevity would be increased ten fold if heights could just lower there and we could pull troughing further south. Residual heights over S Europe will be our undoing in the longer term if we can not get that HP far enough N in the shorter term. We don't want any residual heights left behind at a southerly latitude.

Edited by CreweCold
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

In fact this is the best ensemble suite of the season so far, just hope it looks good in Graph form with some genuine flatliners (around -10c for a few days or more).

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
1 minute ago, CreweCold said:

Not really a stonker Feb...would be much better if those Mediterranean heights could be erradicated

gensnh-0-1-276.png

The longevity would be increased ten fold if heights could just lower there and we could pull troughing further south

Its a right dumping for large swathes of the country with no sign of high ssinking - in fact you would grab it with both hands - you get buried!

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
1 minute ago, feb1991blizzard said:

Its a right dumping for large swathes of the country with no sign of high ssinking - in fact you would grab it with both hands - you get buried!

Haha

Would take something very special to get buried with snow here. Most I've ever seen lay is 10cm!

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

Haha

Would take something very special to get buried with snow here. Most I've ever seen lay is 10cm!

I really am beginning to feel a Dec 1990 event coming on here, I know its a long way off but.......

Meanwhile we have an ensemble mean showing a stationary 3 wave pattern deep into FI - oh and we're on the right side of it as well!!!

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
6 minutes ago, CreweCold said:

Haha

Would take something very special to get buried with snow here. Most I've ever seen lay is 10cm!

I bet you only got that by adding all the last 5-years' accumulations together!:D

PS: Frosty's not alone in having used up all his 'reactions'...shut up, lassie!:D

Edited by Ed Stone
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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
2 minutes ago, Ed Stone said:

I bet you only got that by adding all the last 5-years' accumulations together!:D

I wouldn't even get that much if I did that!

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Now we have the latest UKMO T+144 on today's 12z run and their evolution to the next Arctic reload is just starting to show. This should become much more evident by tomorrows 12z run. I am very pleased to see more or less what I had expected - that UKMO were more or less singing from the same hymn sheet as GFS and ECM, just at the slightly later time frame. This is definitely not a "mega" shift - it's a minor one with the latest chart (the current T+144) for the more critical period just coming into view I shall have one final go at showing what I said in my earlier posts on pages 250 and 253 of the 1.9.17 Autumn thread by way of a comparison of UKMO's current and last 2 runs:.

UKMO 26.11.17 12z:

                              T+96                                                                 T+120                                                              T+144                                           T+168 Western Atlantic view

 

    UN96-21.GIF?26-00         UN120-21.GIF?26-12        UN144-21.GIF?26-12       ukm2.2017120312_168_lant.troplant_prp_fc

 

UKMO 27.11.17 0z:

                             T+96                                                                   T+120                                                             T+144                                          T+168 Western Atlantic view

 

   UN96-21.GIF?27-00          UN120-21.GIF?27-00       UN144-21.GIF?27-00       ukm2.2017120400_168_lant.troplant_prp_fc  

 

UKMO 27.11.17 12z:

                            T+96                                                                   T+120                                                          T+144                                           T+168 Western Atlantic view

   UN96-21.GIF         UN120-21.GIF        UN144-21.GIF          @Summer Sun will post later this evening!

We need to keep in mind that yesterday's 12z runs are 24 hours earlier. For example: the 26.11.17 12z T+144 is the same time frame as today's T+120. The 0z run is a halfway house at a 12 hour interval. Anyway, just run through the charts and you'll see what I've been on about with only small changes. The main message is that we all need to be cautious about making assumptions about how the UKMO runs might evolve after T+144, especially when there is a critical period coming up for a pattern change - in this case, looking for the next Arctic reload around early nest week.

Right, I think I've run this subject into the ground. I'll accept that a few of you might continue to take a different view but at least we can all agree that UKMO are now in the "generally cold" outlook camp for most of next week, following the milder blip around this weekend. I'll be back to my more regular features with my next post later this week (unless something else irresistible crops up in the interim!).

Finally, I watched Gavin's extended outlook on page 255 of the 1.9.17 Autumn model thread and I think even Gavin queries how progressive the CFC model is in bringing a mild Atlantic stormy period in before Dec 10th! I think that we can all agree that we should really discount such long term model output. The models have been struggling from around D5 onwards recently in trying to get to grips with the unusual set-up. There is some broad cross model agreement for continued blocking over the next 2 weeks and for mostly cold weather but may be with several brief less cold interludes. With the CFC we need to coin a new term - FI is okay for around post D10 and up to T+384 on the GFS runs but what should we call the CFC T+500? Perhaps VGF - virtually guaranteed to fail! 

 

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

Getting interested now in next weeks potential northerly, just hope no shifts east on ECM, as it is still FI, and at T252, 19th Nov 96 style low, but Tuesday 5th Dec, just hope we get the initial northerly

h850t850eu.png

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

Good to see the UKMO dropping it’s underwhelmimg output and after the shortwave frenzy this morning the mists are beginning to clear slowly.

However we’re not there yet and so my Code Red remains!

Its not so much that we won’t see some build of pressure near Greenland but getting that clean northerly flow south is still subject to shortwaves upstream behaving .

Overall so far this evening an upward trend for coldies.

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