SW Saltire

The GFS did forecast the breakdown of the 2010 spell from afar, however, that was only a result of its tendency to overemphasise te strength of the Atlantic which actually turned out to be correct. I could rebuttel you with a far more recent example of the converse. Late march 2013, a low was due to track (according to GFS) through the north of Scotland bringing milder uppers. Incredibly slowly did the GFS start to 'slide' the low. It ended up only just fringing into Southern Scotland being huge drifts to myself and many others. The centre of the depression was somewhere near Central England, thus I believe is strong evidence of the GFS having a bias towards introducing zonality wherever it can. The GFS seems to be 'correct' according to some, by default. It did not fully come inboard therefore it was correct is their reasoning. However, I am of the opinion that if a model is incorrect upstream and that the broad scale pattern presented previously was completely incorrect then it has not verified very well either. The ECM has failed us on a micro scale but in a wider context has been far more accurate the GFS

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...

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

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!

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.

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

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

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

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

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!

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

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.

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

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?

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

Is your time machine free tomorrow?

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...

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

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

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.

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