Pre-supposing the model output one way or the other is never a wise thing to do, Ian. You should know that by now.

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Shhhhhhhh Ian or I will get Fergie to put you in your place again 

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The classic big snowfalls in the UK are often marginal events. Later next week is a classic situation which may keep you guessing about what will happen, but some places would see an extreme event if the Synoptics were to verify. Without doubt there will be wobbles but what is clear is that uncertainty with the jet stream positioning is greater than normal, so anything 6-7 days away needs to be viewed with extreme caution.

 

CAN'T BE IGNORED!! Less than a week away now: - Looks like Thursday into Friday could provide a thunder snow' event!? That precipitation band won't be taken too literally but it does look like a lot of rain to snow event or wet snow for many and perhaps cold rain for the coast in the south?

The bottom line - frequent northerly blasts but snow not lasting long but at least many areas will see some wintry weather and lot's of cold zonality as the jet is taking a dive from the north west to south easterly direction most of the time.

SO far this start to the winter seems 10x more interesting mainly because we have weather to talk about! I like the change in patterns, storms, frost, sleet and snow etc and we are only a couple days in. Also THIS northerly looks like it has the support from other models too. Bare in mind during each northerly - the air is getting that notch colder as you know and any snow fall should have less chance to melt due to shorter days! On top of this we do have some Arctic blocking and Greenland block as well. - This was what was missing last winter 16/17. When, whenever we tried to pull in an easterly as models showed and build the scandi High pressure block, - it kept on being flattened and sank southwards thanks to strengthening LP in Iceland and Greenland and an Azores HP too! - Looking forward to the coming month and lets hope the SW sees some snow too. Also see signs of some minor warming in the stratosphere from next week no SSW but still a slight warming at 30hpa pushing up from Siberia into Arctic region. 

I am cherry picking a little but this combined with solar minimum, a negative NAO and - AO, an easterly QBO and weak La Nina (still cooling) - this look much more positive for cold and snow. Is it not a little bit early in the season to see any warming of/in the stratosphere? 

 

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GFS 00z ensemble mean at 132 just keeps on upgrading with great support now
http://modeles7.meteociel.fr/modeles/gens/run/gensnh-21-1-132.png?0 

T156 mean now at -8c for almost all of the UK

Again my advice would be to manage expectations. It’s likely to be cold and possibly stormy later next week but with the UKM text forecast tempering the impact of the forecast North Sea low, and the track and intensity still not in any way determined, I’m reluctant to forecast any detail yet - especially with respect location and amount of snowfall.
It could come to nothing, or it could be an historic event - it’s too early to call IMO.
It is fun to watch unfold though I’ll admit that 😉

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I do think somewhere is going to get disruptive weather which is the guilty pleasure of most. Where that will be is anyone's guess❄️💦❄️💦❄️

If I had a pound for every single time  there was much ado about a model run or three, which, at a range of 8 then 7 then 6 and then 5 days showed an apocalyptic amount of rain or wind or snow, I would be very rich. 

As we near t0 the models will get a handle, and sift out the real solution, which, 99% of the time is far less extreme than time-distant model runs indicate.

There is very little credibility to be had in excitedly expecting/ highlighting taht every single possibility will reach full throttle.  I guess people can claim some kind of self-deluded victory if on the 100th time they make their "call" something dramatic actually happens, for once!  Conveniently forgetting the 99 times they were led (and led others)  up the garden path.

I suspect posters and lurkers alike will draw their own conclusions and know the voices to listen to.

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Yup. I'd bet anything that the GFS ends up moving the North Sea low just a bit further north, which would reduce the risk of some biiblical falls of snow. Mind you, the raw GFS data isn't very exciting anyway down here - torrential rain and gales on Thursday, followed by a quieter and colder Friday and Saturday, with just the odd snow flurry.

The raw MetO just has light rain on Thursday followed by a dry Friday (and less cold than GFS). It keeps the low further north than GFS.

As for ECM, well... that has a cold day on Friday, before the pattern flattens. It also keeps the North Sea low much further north than GFS.

GFS sticks out like a sore thumb, in my view. It might be right (which is good for those "up north", who'd see plenty of snow) but I wouldn't stake so much as a hotdog on it.

 

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Agree Darren. Some people are getting hooked up again but the ECM still isn't really playing ball to the same extent. Your scenario above would, I believe, be the most likely outcome on this occasion but it has been fascinating model watching thus far. Our friends in the North look set for something potentially quite wintry but clearly the models won't have grip on this for at least another few days IMO.

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All the above words of caution seem very prudent, reflecting on past disappointments; but I also see the caution as an indicator of hope- since most of them are from seasoned posters. Perhaps when hope reaches its highest, the tension is too much- and we safeguard ourselves with a bit of reserve.

Whilst I tend to agree with the sentiment, there are things in the models of late that do not, in my opinion, reflect similar hopes for a good solid December cold spell in the past:

• 
  

  the number of days over which the tendency for a repeated or recharging or persistent arctic outbreak have been modeled;

  
  


• this general feel persisting in both GFS and ECM;


• the timescale: not at the end of the run, but currently less than a week for the next blast (remember we've had a snowy taster already in some parts of the UK so the first attempt delivered);


• Consistency in the GFS ENS (this has been reduced on and off but seems to want to default back to cold); this mornings is a good example.

https://www.theweatheroutlook.com/charts/gefs/gefsens850london0.png?cb=316

• Finally, the dominance and magnitude of the north/northeasterly airstream over the past few weeks north of 60N coupled with useful re-occurrences of elongated  HP over the N Atlantic or Greenland

This is all just opinion, of course, and I defer back to the wisdom in previous posts; but in an unscientific way, I feel more confident of seasonal weather than I have for the last 6 Decembers.

 

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Decent snow rows turning up for the 'event' on the 7th - 8th . But agree with others gfs is notorious for over doing snow events and it will probably come too nothing. Still good agreement on another cold spell.

 

 

 

 

 

 

 

 

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Bloody hell the nay sayers out in force today- I though mr IB had infiltrated everyones passwords for a minute

Its ok to be a bit cautious but the rationale shouldnt be 'it wont happen' or will be dumbed down- thats how lives are lost through complacency-
Since 2009 we have had many extreme events - how about the channel Is in Mar 13, or SW london/ Surrey getting 40cm of snow in 2009 ( 10? )in 6 hours-

A lot of IMBY viewpoints this morning-

The models show a double phasing event reaching the UK which is a rare event in itself-
http://modeles.meteociel.fr/modeles/gfs/runs/2017120200/gfs-5-120.png?0 

A very steep thermal gradient of about 14-16 degrees -

http://modeles.meteociel.fr/modeles/gfs/runs/2017120200/gfs-1-126.png?0 

The Fact that theres a near perfect allignment of deep cold polar air just reaching scotland at the point the low engages the UK is great if your looking for a decent undercut-

Id say the chances of a noteworthy event for some areas of the UK is pretty high TBH...

Good stuff as always Steve hope you are right.

 

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Yes regardless of the details all the models show the same basic set-up of a low arriving and engaging the cold air and deepening rapidly in the vicinity of the UK. That's an exciting event in itself and it's pretty futile pinning down details at this stage. It looks to be getting pretty wild and windy at a minimum with plenty of precipitation around. The nature and distribution of that is of course yet to be decided.

I recall last weekend the models were initially showing quite a snow event for the Saturday. In the end the precipitation ended up about 300 miles south into France!

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The raw GFS output here has the temperature falling from 12C at 6am to 3C by 3pm next Thursday! Sadly it also shows all the ppn falling as rain before the cold air arrives with no snow to speak of, but that would be quite a day!

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Good morning.

Absolutely top post btw. 

Putting the details of the LP aside, I’m just very chuffed with the prospect of bitterly cold, snow laden NW’ly winds. 🌨❄️

Hope it pans out like that. 

http://www.wetterzentrale.de/maps/GFSOPEU00_144_2.png

 

 

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Fun looking GFS run again this morning I see

ECM not terrible but equally nowhere near as nice to look at

TBH leaving aside the possibly epic snow storm (for some) that GFS is toying with the whole run is very easy on the eye - lows sliding south eastwards or simply fading as they make no progress east, ending with some solid blocking as far as the eye can see and in a nice position for (even more) cold.

Now I know it's unlikely to verify, mild always wins, blah blah blah, but it's what the model shows and it's good to be in a position where we've had a shortish, coldish snap with snow for some, we're looking at a possible repeat of some degree next week and the longer term looks filled with potential. It's not a Dec 2010 set up with T48 to go but it is loaded with potential and we've already had some cold weather - really can't grumble too much about that imo

On the ECM front it's definitely not as promising but whilst it does try to flatten the pattern it never goes properly flat and things are very sluggish in FI - hardly a relentless jet and LPS zipping past Scotland. Given it's also just the OP and I haven't see the ens I'll take it as encouraging when set with the GFS eye candy. It's also worth remembering that there's only a few occasions where any model is 'right' and the others 'wrong' - you usually end up with a less extreme half way house imo. Given how good GFS is both medium and long term, even if it does end up a half way house I'd imagine a few people will end up happy! 

 

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I know it is unlikely to happen but at the same time I'm excited! I don't think I've seen a single ramp in hear as posters are simply commenting on the output. In fact some of the output is so extreme many posts have been preceded with a a disclaimer. The chances of a major blizzard are slim but as a weather watcher, if can't get excited about some of the bonkers output then take up a different hobby.

Over the years GFS has very occasionally shown northerly out breaks way out in lala land and they have verified, although it has to be said, not recently. Just perhaps it's finally going to do something similar for late next week.

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I’ve always been a fan of your infectious enthusiasm at this time of year Steve but to refer to reasoned opinion as ‘nay sayers’ is a little unfair. Generally speaking you won’t get posters on here running around like toddlers on Red Bull at every turn of an isobar like another forum I could mention. Speaking for myself I’ve seen countless epic charts of predicted apocalypse fizzle to nothing and incredible events like the ones you mention almost spring up from nowhere. The vast majority of the time the former occurs. 

So I follow the charts and trends with interest, but with the expectation that the outcome will be a significantly modified version. If the GFS solution is still there on Monday, and backed-up by UKM interpretation, I might seriously become engaged with it. 

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I would agree with much of what has been posted and there is a nagging doubt that with the mixing of the air due to the strength of the wind things may end up cold and wet for most (myself included) rather than cold and white.

It is however very interesting viewing, albeit 6 days out.

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Poor ECM with a toppler, in line with what Ian said last night. Any snow will be gone in a flash

 

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Yes I'm really surprised at some of the stuff I'm reading this morning, both ECM and GEM show what is by far the most likely outcome after the initial northerly. I don't know if people are getting excited by the steep thermal gradient and the prospect of back edge snow, but anybody who has been watching the charts for any length of time should be able to see where this is heading, a window of opportunity for snow showers in the usual places before milder weather returns from the NW next Saturday - as per the METO update. 

Are we looking at easterlies, prolonged cold or battleground events ? No, to be honest not much really to see here. 

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I wish you two would get a room. 🙄

In all seriousness though. Yes ECM is the “poorest” run today, but even this has this evolution at t+144 http://www.wetterzentrale.de/maps/GFSOPEU00_144_2.png

and it ends like this at t+240 

http://www.wetterzentrale.de/maps/ECMOPEU00_240_1.png 

So chilly with snow potential.

The 12z ECM ens were also cold. 

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How did he do that ? I pointed out that the METO update for cold 'early next week' was erroneous given the NWP on the Wednesday just gone. He waffled a bit about broadscale output then admitted he had nothing to do with the Exeter update. 

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