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Model Output Discussion 29th December - Into mid-Winter.


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Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire

Well - the mid latitude / uk high was nailed by uk met earlier in the week - top performer in the medium term - if you want cold then look to the met office - the best in the world !!

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

Look at these strat zonal wind profiles. No strong Vortex Intensification here,

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php?plot=all&alert=1&lng=eng#fig1

We have been used to far stronger zonal winds in previous winters and have had to rely on a SSW to break the cycle. This year not so, and this means that the strat does not override the trop influences as in years gone by.

   And the forecasts suggest that the strat vortex will stay subdued allowing the trop patterns more 'freedom' to express themselves.

I think that we would all like to see some more icicles this winter as seen in my twitter profile pic, and I certainly wouldn't rule it out at this stage.

Would we be better off with a top down SSW though or not? so that the strat 'makes' the trop do something more favourable?, I would be wary of a displacement one though although given I haven't got all that much confidence that this winter will deliver. I would take my chances, obviously a good split SSW would be the preference and given the time of year could practically guarantee a blocked pattern in the NH for the rest of winter (Jan / feb 09 an eg that nothing is totally guaranteed)

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Posted
  • Location: Aberporth S W Wales
  • Location: Aberporth S W Wales

Could just be a personal opinion but, the UKMO goes to 144 for a reason I Guess?  GFS past 144 has been all over the place this winter, ECM,  in my opinion is embarrassing in that it seems to predict an outcome at day 10 and sticks with it until it is plainly obvious it's wrong..then the cycle starts again. Yep, if your of a nervous disposition stick to UKMO

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Posted
  • Location: st albans
  • Location: st albans

looking for fi op consistency from the ec op to show a route away from the extended range sou'wester. still not there.  The GEFS and geps continue to build the euro heights late on althogh for a while the geps looked like they might go a different route. Rather hoping the eps will show the Canadian ridge further east into the extended period in the next twenty mins 

 

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Posted
  • Location: Waterford Airport
  • Weather Preferences: Extremes
  • Location: Waterford Airport
17 minutes ago, KTtom said:

Could just be a personal opinion but, the UKMO goes to 144 for a reason I Guess?  GFS past 144 has been all over the place this winter, ECM,  in my opinion is embarrassing in that it seems to predict an outcome at day 10 and sticks with it until it is plainly obvious it's wrong..then the cycle starts again. Yep, if your of a nervous disposition stick to UKMO

Or look at all models up to 144 only! 

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Posted
  • Location: Runcorn
  • Location: Runcorn
7 minutes ago, Summer Sun said:
 

 

So we should see the OP's continuing to  shift southwards then, again that's of no surprise whatever.

Edited by Anon90
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Posted
  • Location: st albans
  • Location: st albans

You have the story from Matt but no change on the eps - a more zonal flow to return although when these charts appeared in December, the zonal train wasn't very long lasting. No sign of a pattern that could deliver cold unless the east Canadian ridge is badly modelled and the Siberian vortex doesn't return a lobe back to nw Greenland thereafter 

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
5 minutes ago, Anon90 said:

So we should see the OP's continuing to  shift southwards then, again that's of no surprise whatever.

Yes I think we are getting that rammed down our throats today, whether that is the result is another debate

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

Here's a thought. D10 ensembles trying to persuade us nothing is going to get through to us through Iceland. How often has that prediction been wrong down the years and indeed this year? Yes, the vortex has been under its usual par at times this year - but the models have overdone this signal consistently.

So let's assume they're under-estimate it again. Let's assume that Atlantic trough at around D7/8 will not stall in the Atlantic and will actually go over the top. Let's imagine that silly little void over the UK will actually end up squeezed out by an incoming low.

Trigger low for the Siberian vortex?

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Posted
  • Location: Broadmayne, West Dorset
  • Weather Preferences: Snowfall in particular but most aspects of weather, hate hot and humid.
  • Location: Broadmayne, West Dorset
6 minutes ago, bluearmy said:

You have the story from Matt but no change on the eps - a more zonal flow to return although when these charts appeared in December, the zonal train wasn't very long lasting. No sign of a pattern that could deliver cold unless the east Canadian ridge is badly modelled and the Siberian vortex doesn't return a lobe back to nw Greenland thereafter 

I wonder if the METO have a different feeling about things. Model wise . John Hammond on the latest BBC week ahead going for the possible return of cold northerlies next weekend. 

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington
1 minute ago, mcweather said:

I wonder if the METO have a different feeling about things. Model wise . John Hammond on the latest BBC week ahead going for the possible return of cold northerlies next weekend

Yep here's UKMO extended for next Friday

ukm2.2017012012.168.lant.troplant.prp.fc

Difficult to see the full picture given it's angle but it doesn't look like they are poised on that chart?

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

It's amazing when you put together a list of all the tweaks that would have produced a much colder outcome from the south than the model consensus now is for next week;

  • Initial Euro Low formation further W and/or N
  • Initially Euro Low dropping S more cleanly with no trailing disturbances interfering with the initial push west of the cold air.
  • Shallow low dropping S on Sunday doing so further west either via a sharper mid-Atlantic ridge (ECM was keen on this once) or the longwave pattern just being further west
  • Mid-Atlantic trough next week firing WAA straight NE - an unusual one this as we usually want straight N or better yet W or N to help build blocking to higher latitudes, but in this case the WAA firing straight NE was what set up a very elongated ridge right across Scandinavia. The model assumptions of a simple flat jet arrangement in this case are of serious note.
  • A straight section of jet through Iceland and on east through there - this is the most recent loss in the GFS and to a lesser extent ECM output, having been spotted by UKMO a day or so sooner. It's tied in with the mid-Atlantic trough becoming more amplified; an overall distortion of the jet configuration away from straight and true has occurred.

That's as many as I can think of right now, and the reason why it seems to me that the more you know of meteorology, the more disappointing the trends of the past few days seem, as opposed to if you're someone who simply expects the worst regardless, which must be a dull but relatively painless life :pardon::laugh:

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Posted
  • Location: Bexhill-on-Sea, East Sussex
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Bexhill-on-Sea, East Sussex
24 minutes ago, Anon90 said:

So we should see the OP's continuing to  shift southwards then, again that's of no surprise whatever.

No surprise whatsoever, we get sucked in year after year. If I had a pound for every post that read close but no cigar in the last 10/11 years on here, I would probably have a small warehouse filled up with boxes of Romeo & julietta Cigars. The models do verify after T144, BUT only when the weather is a mobile Westerly-Atlantic driven type, as for GFS, it throws out four runs a day so when we have blocked scenarios it can show up everything including the Kitchen sink. ECM has its two runs a day but still manages to leed us down the garden path past T144 particularly where Easterlies in Winter months are concerned at any rate.

 

I must say that this chart does look pretty strange to me, but I will not say close but no cig..., It looks as though it should deliver something special if we can get that block a bit further East, come on ECM stop winding us up for once!;)

ECH1-240.png

Edited by snowray
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Posted
  • Location: .
  • Location: .
Just now, mcweather said:

These are presumably the same ens that gave full 51 member support to the full on easterly a day or so back.

mmmmmmmmm

To be fair models usually struggle with blocking patterns.

Which isn't the same as saying it's going to happen :( 

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Posted
  • Location: st albans
  • Location: st albans
1 minute ago, mcweather said:

These are presumably the same ens that gave full 51 member support to the full on easterly a day or so back.

mmmmmmmmm

and they are right - just suppressed further south  

the eps have done very well on the current drop in euro heights, counting down from 2 weeks out (as did the gefs )

the extended eps have had a bust on a couple of occasions this winter (generally the right pattern but further east ) and this upcoming 11/16 days period could go in our favour if we can get a wedge of heights to hold to our wnw and deflect the southern arm to our south. The mean and anomolies say otherwise at the moment. 

Don't nt shoot the messenger !

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Models showing a return of the mid atlantic block settling just to our south/southwest having tried to build eastwards - the jet is predicted to go very weak, so no forcing on the high, suspect we will see a cooling down through next week, surface cold once again, some frost but nothing severe. Very unsure where things might go thereafter, too many possibilities. At least we have lots of options, and not the default westerly atlantic onslaught looking the form horse. It is turning into a very unpredictable winter weatherwise.

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Posted
  • Location: Carmarthenshire
  • Location: Carmarthenshire
1 hour ago, s4lancia said:

That's weird. I ran through the Jan to Feb 91 cold spell evolution yesterday evening as I suspected it may contain similarities. It did indeed . Almost 26 years to the we day embarked on 3 odd weeks of a meandering UK / mid Lat high, until finally as we went into Feb we finally got one of the best cold spells in the past 30 years. These are not standard winter charts,  I maintain we will be unlucky if we do not cop a sustained cold spell before winter end.

That's an interesting observation - it reminded me of this post from @Catacol I read earlier which suggested that based on MJO forcing we may see an increasing likelihood of high lat blocking into Feb.  I'm not sure what the MJO evolution was in Feb '91, could it be a similar evolution to that currently being modelled perhaps?

 

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Posted
  • Location: Bexhill-on-Sea, East Sussex
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Bexhill-on-Sea, East Sussex
17 minutes ago, West is Best said:

To be fair models usually struggle with blocking patterns.

Which isn't the same as saying it's going to happen :( 

They never seem to struggle with Greece's freezing temps and blizzards though do they, even from way out, funny that. In fact its often modelled to be heading our way initially and then it heads down South, sometimes very slowly towards Greece....and Southern Italy, Turkey etc where it never misses. :nonono:

And Greece is a lot smaller than the our small Island.

Edited by snowray
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1 minute ago, snowray said:

They never seem to struggle with Greece's freezing temps and blizzards though do they, even from way out, funny that. In fact its often modelled to be heading our way initially and then it heads down South, sometimes very slowly towards Greece....and Southern Italy, Turkey etc where it never misses. :nonono:

And Greece is a lot smaller than the our small Island.

Hi yes since following models 5 years or so , when it becomes within 7 days has always happened as pretty much shown from beginning

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

They never seem to struggle with Greece's freezing temps and blizzards though do they, even from way out, funny that. In fact its often modelled to be heading our way initially and then it heads down South, sometimes very slowly towards Greece....and Southern Italy, Turkey etc where it never misses. :nonono:

And Greece is a lot smaller than the our small Island.

By definition they must struggle then.

Not right in the firing line of an Atlantic Jetstream and close to polar airmasses at the same time though.

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