[Model Output Discussion - 30th November onwards]

..with such split agree GFS/ECM (+ various).one could suspect halfway house scenarios,may not at this time likely outcome.imo it will clearly go one way or other ie ecm/ gfs route. The split agree is v, pronounced,and to my eye as again It's a 50/50 road. I'm sure there will be firming shortly for mid term likelihood.And also alignment of more cross model agree rather than the messy split in front of us presently ....

I suppose from a broad scale then you are correct the high will happen or it won't but from a UK pov the high could occur but the cold may not be advected far enough westwards to get deep cold, as ever this is just speculation on a trail that is only just beginning...

[Model Output Discussion - 30th November onwards]

Yes wait till its happened. But even from my untrained eye the current output makes the ECM data look poor. Thats twice in a few weeks ECM have overdone the cold. We have to take this into account when looking at anything past T120 with them now, otherwise many casual viewers to this forum will get led up the garden path again. A model split as to the possible next cold spell with GFS saying no to a Scandi and ECM yes. We will see...

What is the middle ground scenario between no Scandi high and a high, a ridge? Would we have a drift of the continent? The GFS will not accept the high, it can spot trends at t-300+ but for some reason in nearer FI it will flatten all who halt the Atlantic train. As you say, the ECM may well show a strong high but that must be treated with more scepticism than previously thought. Most likely a middle ground scenario will win out

[Model Output Discussion - 30th November onwards]

Beggining to lose a bit of faith in the ECM now. That's twice in a short period that's it's been off the mark, now it's going for a Scandi High, and we are not far off a year since it failed big time on an easterly. I will be waiting for UKMO to join that party before I even begin to get interested.

Agreed, the 'daddy' ECM has shown a possible bias in showing overamplification perhaps at times. This is rather frustrating. It does lend itself to better model watching with the GFS rolling about for run after run after run... And the ECM producing great charts for coldies. Thus, it would seem imperative that the UKMO must be inside in order to be confident in any cold spell or pattern change in general. The GEM I don't believe has been performing as well as when it was touted as one of the 'big three' it seems to be just as poor as the GFS at times. Also, well done BA on 5,000 posts!

[Model Output Discussion - 30th November onwards]

People always say I think the mist will clear etc, tbh the water has got even more murky. The northerly has been in general shunted further East but still there are large disparities between the models, no real agreement yet with the ECM still championing a more potent blast. Then we are left with a probable southerly which would seem necessary in order to achieve a Scandi high. One think is certain, this month will be very hard to call and this fence is looking very appealing

right now Although, I believe at least a ridge will be thrown to Scandi but whether full retrogression occurs is dubious.

[Scotland Regional Discussion - 29/11/2013 ---->]

It may be quieter in here due to te 12z suggesting a reduced risk of snow really. The cold is nailed and will be very potent for the time of year but without the magical white stuff it won't be particularly memorable. Certainly from an IMBYism Stirling and Dumfries were never well placed and now it would seem very unlikely that either would get a covering but you never know. If I was living in the NW highlands I would be a different story, also uppers usually get upgraded as the time gets nearer so temperatures with any snow cover and clear skies in the long nights could be at least double digits below possibly -15

[Model Output Discussion - 30th November onwards]

I think that they are dancing happily together presently - the strat is behaving as would be expected per analog years and the tropospheric response measures up quite well too. Wave activity rebounds into the strat every winter and this is no different. CH's excellent post earlier in the thread shows this very well. I suspect that any strong Scandi ridge signal may be slightly over emphasised by the output - but later on in the season I wouldn't.

Thank you for the reply, I suppose we are a significant way from the Scandi high possibly verifying so it's a waiting game. Your winter prediction have been made crystal clear which is very brave but your confidence I believe is not misplaced. Still, I did think December was predicted to come in above average by quite a few due to background signals becoming more favourable for cold later on, whereas currently it would appear we are going to be at least a bit below average for the first third of the month, with an easterly at least seeming plausible and definitely 'on the table' so to speak, which would take us towards mid month. I am well aware this is only the first of December and a lot can change to those who believe December will be 'zonal' or whatever that is

[Sunday 1st December- General Weather Chat]

An unexpectedly sunny day, the predicted cloud didn't move in until almost sunset. A very mild feeling day despite the themometer only reading 8c. Dry once again

[Model Output Discussion - 30th November onwards]

A question (I am sorry if this has already been answered and maybe this should be posted in the stratosphere thread but here goes) Do we have any indication as to why this year has had a disconnect between the stratosphere and the troposphere, obviously as chionomatic's fantastic post stated that the two 'dancers' don't mirror one another all of the time but all the stratospheric signals were not very encouraging until 2014 maybe even February whereas we are at least getting some cold in early December. Once again I apologise if this is either in the wrong thread or has been answered, thanks in advance, Andrew

[Model Output Discussion - 30th November onwards]

Away for a day - over 800 users online, and page upon page of skim reading required. You can always tell when winter is in full swing on NetW - come here in the summer and we barely get to a new

page each day!

 

Fascinating watching this uncertain scandy evolution develop. I'm still in the camp that thinks it will not quite

make it, but for those that

saw my post of a day or so ago showing wave 1 warming slap bang over the uk, what we are now beginning to see is the models wrestle with this

data. The warming at the top

of the atmosphere will propagate downwards thus by day 9

 

 

Zonal winds at the moment are here - notice around 30m/s around 60N in the middle strat

 

 

dropping to around 20 m/s at

the same latitude by day 9

 

 

Remember that the warming

is in our sector of the NH, so this reduction of zonal winds is likely to be most exaggerated over the uk

 

Vortex impact? Some very

interesting images today at

day 9 once again. First at 100hPa - almost into the troposphere:

 

http://users.met.fu-

berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/ecmwf100f240.gif

Not quite a vortex split, but a

definite separation of sorts and as we have seen recently a marked meridional pattern. Higher up at 30 hPa in 10 days time, the same strat support for height rises

in our part of the world:

 

 

Note here the warming is a little further to the east, but helping to drive zonal winds away from the scandy sector in the days following this image - or so I would guess.

 

Conclusion? Scandy height rises look on the cards following the cold shot

coming - the evidence was

there a day or so ago - but just how great that ridging will be is uncertain. However if energy at the heart of the vortex is separated at 100hPa as on that 10 day

chart then chances increase all the time. Not enough to convince me yet, but enough for a definite loading of the dice towards that possible solution. One thing I dont think it will be is a return to

zonal at all. Another period of uk high with stagnant dross is my best guess but I would put proper scandy height rises into second place with zonal atlantic very much third.

 

For all strat doubters note again that the energy that has kicked this off was a wave 1 warming forecast at 1hPa and propagating downwards. No disconnect

here - once again,.

Fantastic post, very informative. It would lend itself to more drama in here as you point out that the effect of this warming will be exaggerated over the UK and thus, eye candy should start to appear on the NWP although this does not mean it will verify!

[Model Output Discussion - 30th November onwards]

Whether people on here admit it or not after a very brief colder spell thurs - sat we are looking at a period of 2weeks before any sustained cold may set up. Imo its a case of come back in two weeks to see if our prospects have improved.

Well, if you have been following the forum recently and not the express then this should have been obvious. Nobody has suggested HLB on this forum in the near future. Only recently have some knowledgeable members such as BA and Nick Sussex et all noticed the idea of a Scandi high gaining support. Therefore, we are doing quite well with regards tocold with a not that favourable a pattern at present. Cold northerly shots will keep the lions at bay while the larger picture is shaping up nicely with the continent forecast to cool significantly. The fact that the polar vortex is not dominating our weather at present is rather encouraging and has been a theme for the past 5 or so winters

[Model Output Discussion - 30th November onwards]

I've got a competition for all of us.

 

Who on here can post for the longest period without mentioning another poster's name i.e. SM said this, Ian F said that, Ian B thinks this. All well and good I suppose

and yes, I too am

guilty of falling into the same trap. However does it truly add anything other than perhaps alienate someone else. Anyway, for purposes of the competition, I will

exclude myself and the

winner will receive a free NW radar subscription (best confirm with Paul firstly) try it, you make like the idea. http://f1.nwstatic.co.uk/forum//public/style_emoticons

/default/give_rose.gif.pagespeed.ce.Kn3bzvYGxF.gif

 

This is the MODEL OUTPUT discussion thread, NOT the PERSONALITY discussion thread.

I repeat, yes I've done it and

hopefully refrain from doing so as muchly as possible.

 

ECM 12z is rolling, is it not?

The two are intrinsically though. Unfortunately the posters bias has to be analysed in order to ascertain a true depiction of what the models are showing.

[Model Output Discussion - 30th November onwards]

It would be best if people refrained from posting one liners, 2 seconds into a run. At least supply charts if you are going to make claims

[Model Output Discussion - 30th November onwards]

After the cold snap, I think the High pressure moving north-east to Scandinavia and merge with the Siberian High. Massive low at the west of UK tries to push in. I think December is going to be a interesting month for

weather.

 

 

I think we maybe heading for a battleground scenario as the high to the east getting established. I really hope this setup will come in fruition. It

is a short term pain for long term gain!

Agreed, as Crewe cold mentioned previously, since this is being shown on the GFS it is very intriguing. Of course watch the GFS flatten the high every single time with shouts for 'zonality' being heard.

If it came off, the snow would have a longer lasting effect than in the epic late march spell that simply had a sun that was very strong.

I add the caution, that this is only one possible outcome, I suppose raging zonality is an equally plausible option although I ask, for how long?

[Model Output Discussion - 30th November onwards]

Oh I wish I was born earlier,I could have lived through the early 2000s with zonality. I mean, according to certain people's predictions we should have had zonality for recent weeks. The loch froze over a few days ago, I am a new member of this forum so bare with me but I never knew a loch could freeze over with SWly winds and strong rain and very mild uppers of course I'm sure more knowledgeable members could help me out

[Model Output Discussion - 30th November onwards]

well well well did someone say were into the realiable timeframe for this cold spell???its also worth noting that ian brown did say this was a very possible outcome looks like hes on the money return to much milder air after next weekend at this rate maybe before the weekend has even started as for nice start to winter im not so sure it is to be honest its been a horror story for nearly a month now. vortex vortex vortex its running the show this winter.and the models really cant cope with the strength and depth of this vortex another near miss for some but others have something wintry to look forward to I don't think I can spend winter with all these downgrades as ian f said they didn't use the ecm to be honest the ukmo is the best and the others are just absolutely rubbish. absolutely bang on ian brown.

Is your time machine free tomorrow?

[Model Output Discussion - 30th November onwards]

GFS 12z progressive and mild as usual in FI & positive will not let an easterly develop come hell or high water!

Oh no! If you think the GFS was kicking and screaming (it still is!) with regard to coming round to the idea of a northerly then an easterly.... This could be a long winter...

[Model Output Discussion - 30th November onwards]

GFS ensemble is rolling out now

Looks like the northerly will still happen but it could be shorter lived than previously thought

I think we should really (we of course won't!) wait until upstream developments

are understood as this will determine the extent of our northerly. I mean, you could

have 10,000 GFS ensembles but if they are all fed a low that we later find out does not take that path in the US then they will all be incorrect so their change in longevity or intensity of said northerly is rather irrelevant.

It is rather concerning that Ian F said that the MetO went with a GFS/GEM blend, from a cold pov let's hope that changes!

Btw this is in no way having a go at your post summer sun as you are just the messenger

[Model Output Discussion - 30th November onwards]

A dissapointing start to the 12z so far. From a larger scale point of view the UKMO has supported its 00z run and does not side with the GFS. It is a least better to see this eastward shift now when there are many more runs to come in which we could see a shift westwards. Of course this run by UKMO may be a rogue run so to speak. Maybe Ian F can be very generous in suggesting where the run sits in its ensembles....

All eyes will be on the ECM for sure, however, this northerly seems like the starter at best, as long as the Scandi high resulting in a subsequent easterly trend continues to grow then there is no need for despair on only the first day of winter

[Model Output Discussion - 30th November onwards]

Have to agree the ECM can seem a little to smooth sometimes especially when your looking at the 850's . but I would still choose it over the GFS between 168 and 240 hours for general trend.Definately, I also meant weeks not years as to the northerly that was watered down significantly. The GFS seems to predict trends well I.e. Blocking at 300+ hours but when it trickles down it is subsequently dropped only for the ECM to start to run with it and this leads to a t96 turnaround from the GFS (actually it would be better if the GFS switched but it excruciatingly painfully makes minute concessions that cumulatively combine and backtrack towards te solution of the Euros

[Model Output Discussion - 30th November onwards]

Hello everyone, I've avidly followed this forum for almost exactly 3 years. If it hadn't been for the ECM's recent backtrack on the severity of the northerly that occurred a couple of weeks ago then the GFS backtrack would have been almost a formality. Thus, it must be noted that the GFS can be correct with its tendency to reduce blocking and increase the strength of the Atlantic and put the tilt of lows against any 'sliding' occasionally but in the main the ECM (along with the UKMO) is more often right than wrong. The UKMO seems to be a good check on the possible oversimplification of the ECM.

[Sunday 1st December- General Weather Chat]

Hello everyone, long time lurker (3 years) who finally has an account.

An unexpected, very sunny start to the day, a little chilly 5.5c, dry