Duane S.

It seems a lot if people are missing the point. While there is the sort of short term divergence such as is graphically displayed between the UKMO, GFS and GEM, how can we be sure if anything? Everything is far too messy to draw any conclusions. As for upgrades not being likely because of today's output. I don't buy it, with the current uncertainties, I see no reason why not.

Worth remembering that despite my recent derision of ENS versus OPs, this is where they do come into their own. If there is a problem with starting conditions then the Hi Res OPs will quickly head off down the wrong path. With this sort of setup and taking into account the teleconnections, i.e. the monster +global AM spike, the OPs are likely to be literally be all over the place for a few days yet. What a great time to be chart watching I say!

I hope the 06z has highlighted the uncertainties of this upcoming cold spell to those already writing it off on this forum. Not a stella run by any stretch of the imagination (up to D7) but it handles the deep (relatively speaking) sub tropical low differently (that will become a common theme) and et viola we are heading off down a different route again mid term... Going to be some wild variations in the offing over the next few days I feel. Those of a nervous disposition should take a break for a while.

I'd agree with that Nick. If even a partial move to a more amplified solution isn't shown on the 06z we should probably expect a watered down UKMO this afternoon. Either way, I do feel this evolution to cold has got a lot of twists and turns left in its locker yet.

Firstly, No idea why I am quoting Roger J Smith, I can't seem to remove it from my post. Coincidentally I do agree with his thoughts though. I went through the charts this morning and yep, knew this place would be full of grumpiness and sycophantic back slapping for those who had urged caution. Do me a favour, these same people 'urge caution' no matter what occurs. Plus umm nothing occurred yet either Back to the charts and yes, if we are looking for a swift uncomplicated start to a cold spell with no likely quick breakdown to follow then the MO probably gives us the best chance of that. But, reality check, we are STILL looking at a decent strength cut off Greenland high here. Who wouldn't have sold their Grandmother for that 2 weeks ago!!?? We are not looking at the usual collapsing Mid Atlantic ridge, we are looking at something that doesn't come about very often and whilst they dont guarantee a proper prolonged cold spell, a heck of a lot start just like this. So yes we may not get the proper cold winter weather in as early as some of the models had led us to believe but we get a Northern Hemisphere profile with a hundred times better potential than December! AND it is all happening at the right time of year. Good times ahead .Keep the faith!

I haven't been able to keep up with proceedings very well over the past few days due to a lack of signal. But seeing as the plus side is spending all day surrounded by powder snow in the Alps, heck I can live with that. I just wanted to say though how painful reading the past few pages have been. In amongst the plenty of excellent posts from the usual few, there has been some frankly ridiculous attempts to point score. Possibly to try mask over their own previous forecast fails... Also it does seem that once certain people have latched onto an milder or colder viewpoint, boy do they stick with it! Anyway, people need stop fretting about the detail (discuss by all means though), it can and will be changing daily in circumstances like these. Things are rarely straightforward when we in the midst of a pattern change to cold (and we are) and this time around is certainly going to be no different. Let's just enjoy the next few weeks, however things may turn out, after all these synoptics (and IMO they are VERY interesting indeed for mid month onwards) are why 99% of us frequent this forum every winter in the first place isn't it!?

Quite agree that on the face of it, this is not too dissimilar our December pattern and it is easy to wonder, did we just miss out?? I very much doubt it. I am not a great believer in simple year-on-year analogue comparisons. There are just too many drivers in force and it is their mind-blowing complex interactions with other that keeps us from being able to forecast the weather any better than we are currently able to (and in my view, ever will be able to). So as is almost always the case when doing these,it does seem things were running differently back in the run up to that event, so with the small amount of relevant (or maybe not, who knows?) data available, the differences were, IMO, not insignificant... We are in a declining W-QBO pattern, Jan87 was in an inclining E-QBO pattern. We are in the midst of a strong El-Nino peak, Jan87 was in a moderate inclining El-Nino state. The temperature in the higher latitudes has been running at about 10 degrees C cooler than back in Dec'86-Jan87, in conjunction zonal winds have been stronger this winter as well, this vortex on paper looks a much tougher nut to crack than the one back then. There was a strong wave2 peak mid December, I suspect this could have helped split the tropospheric vortex shortly afterwards, we on the other hand, have had very low wave2 action thus far this winter. There was moderate to strong (and maybe crucially, constant) wave1activity from Mid December '86 onwards, this is closer to what we have had but Dec'15 has been more sporadic in nature. Although, this is probably looking to increase as we head into January. Jan '87 delivered because the atmospheric drivers / state listed (combined with numerous others not listed) came together ( with nigh-on perfect timing) to give us that remarkable event. So whilst a repeat of that cold spell will no doubt appear again (at some point) in similar guise on the 500hpa charts, it will never be as a result of that exact combination. There were/are some pre-requisites though and we can at least look out for those. Vortex disruption, established heights in and around the Arctic area, subsequent severe cold pooling to our NE and most crucially the nosing down (as opposed to a ridging up of a Mid-lat high) of a fully fledged Arctic high. So currently with meandering heights around the pole, very cold pooling to our NE it is not impossible to think that, for all we know... with slightly different underlying conditions, a Jan'87 repeat was (still is?) as close to repeating this year as any year since. Hence why I was very interested by the unusual vertical WAA surge to our east up into the pole and what happened next, any time that happens in winter it opens up a rare window (however small) to an extreme event like the early Jan-87 event. Anyway, probably all irrelevant as the the next cold spell (should it appear at all) looks far more likely to come from a more 'conventional' route, aka Greenland hight rises mid month onwards.

Not really the full story though is it. Absolutely pointless showing mean charts from the low res GEFS that far out. There are plenty showing decent ridging in that area, the mean is skewed by those showing very deep low pressure in the same area, this chart better reflects it better...

For goodness sake, where does it say that?? Read it again.

Cheers guys, some great info there, many thanks! Decision made. I suspect that those starting to return home after spending Xmas/New Year there would have given their right arms for these conditions compared to what they have mostly had to endure. So I'm thinking I should just be grateful that there is decent snowfall forecast at all! On that basis, we will be heading out Sunday :-)

Cheers Blessed. Assuming we go and don't postpone till later Iater in the season, I will make sure I upload a couple of pics, hopefully depicting a winter wonderland!! :-)

I am planning on going to Samoens next week. Whilst there obviously is going to be some very decent snowfall for next week in that area, I am concerned that I could lose a couple of days with the very low base being built up / and or if there is a whiteout day. Then add to that it potentially turning back to rain over the Thursday and Friday as well, and I could only end up with a couple of skiable days! Hopefully I am just being over pessimistic about things, any thoughts?

Bottom line, with such a huge surge of warm air into the Arctic circle (as is currently underway) expect the unexpected. The only thing I do expect is very little consistency from the models in the coming days, I can see a situation with them running with one mid-term outcome for a few runs, then suddenly ditching it and going with a very different one! Whether short term we can squeeze out a cold spell I am not so sure but 2nd half onwards of Jan is getting more and more interesting.

Poor charts this morning but expect them to be all over the place in the next week or so. Nothing has changed, a quick route to cold following the impressive WAA surge in towards the Pole over to our East was always going to be a long shot and so it still seems. There is a window at D5 but the jet puts pay to that, slamming it firmly shut. Mid Jan still for me, let's get a -AO in first and see where it takes us.

As is normally the case, there are 2 ways of viewing the charts, take the 12z GFS Op as very much case in point. 1) At face value. This will bring disappointment if you are looking for cold in your back yard. 2) With the bigger picture in mInd. In order to get to sustained cold to the UK from where we currently are, we would (in all reality) need to go through a transitional period where the building blocks are laid, aka the dismantling of the vortex, HLB setting up in the Northern Hemisphere, a better aligned jet, vortex displacement etc. From there lies the true potential, no certainties by any stretch of the imagination but instead of needing to roll a double 6 we could get away with rolling a, say, 8,9,10,11 OR 12. i.e. No matter how good the background signals and NH profile in terms of copious amount of ridging and blocking, we will ALWAYS need a bit of luck. Best we can ever do is reduce that element required to as low as possible.

The GFS gives us a strong wave3 attack, delivers a complete Northern Hemisphere pattern change, sends the tropospheric vortex scarpering in all directions and would in all likelihood set up a very interesting 2nd half of the month, cold-wise for the UK. Shame it is only one variation of many!

At +240 GFS looks like it wants to ridge in behind the cutoff vortex and join with the pole heights.

Pole heights are going to cause FI mayhem in the coming days I think.

Much better from the GFS, slight Atlantic buckle in the jet and we have things on a more southerly trajectory. Opened up the positive possibilities in this run from here on in. UKMO, oh my....

All is good to my eyes and the bigger picture. Step 1 to cold is underway, warm air surging towards the pole will upset the status quo and create some nice robust HLB. Whilst this does not impact us directly right now, it is unlikely to disappear anytime soon. So wth increasing heights to our South West looking likely as we head into January and the MJO sat in a pretty decent place, the stage is surely set for a potential mid Atlantic ridge. With a probable -AO in place by then plus the vortex being attacked, at the least, from the bottom upwards, a link to drifting heights via Greenland looks very plausible to me. Suspect it will take us to around Mid Jan but wouldn't be surprised to see more and more of the GEFS members pick up on this in the coming week.

Indeed. Wave2 looking decent but only in the context of this winter really. Hopefully we will see an uptick in intensity over the coming couple of weeks. It would be nice to see charts like this again this winter. From this... to this in a couple of days... been a while since we've seen a profile like this on the horizon... And how about this for a gradual drop off in U winds and high flux activity... ! Interesting that the onset of the January 09 vortex split was relatively sudden and had followed on from a period of strong zonal winds and was in a declining W-QBO. Maybe it is wishful thinking but I do think we have the ingredients for something similar to occur again this winter.

Spot on. On this occasion there has been no ramping, no going OTT, just grounded discussions surrounding the chart output. Of course, plenty of cold bias and optimism added into the mix but it would be a bit dull in here without that aspect. I for one welcome all genuine objective arguments against but don't welcome the seemingly inevitable Devils Advocate element from some. With a vortex as tight, frigid and positioned as the one we have, I am sure most on here realise we are always going to be up against any sort of decent cold spell reaching our shores. Therefore when there is a window of opportunity, such as what happens next after the now set in stone WAA surge northwards over Scandinavia, why the heck shouldn't people speculate, hypothesise and dream? It's all part of the fun and, more importantly, the whole point of this winter thread isn't it??

Ha ha, brilliant, exactly the same here with me Nick :-) Think I will get away with another 5 minutes or so... Yep, like you, am pinning my hopes on the MJO here. With other background signals as they are, at the moment, it is probably our best hope. If we can get get enough warmth up towards the Arctic with that vertical plume, what happens next could get very interesting...

It takes zero skill to keep 'forecasting' mild for the UK and get it right the majority of the time, the real skill comes in spotting the signs that will lead eventually to a cold spell here in the UK. I love the ups and downs that go with watching a potential cold spell come to fruition (or more often than not, not!). We have some really interesting developments going on at the moment and on the way. It may all lead to nothing for here in the UK, but may, just may, be one of those rare times where things actually go our way and delivers some proper cold to our shores as a consequence. I'm sure a lot of you would agree that the fun is as much about (if not more about) the lead up to the event than the actual event (should it materialise) itself!

Thanks, I am familiar with confirmation bias. I can't argue that the fact that the mean of the ENS suite fluxuates to the same degree as Op runs do, of course not, but (perhaps poorly) the point I was trying to make is that on numerous occasions the ensembles have proved as useful as a chocolate fireguard, predominately clustered (with or without the Op) for days on end only for them to switch, job lot, overnight and point to a completely different scenario. Don't get me wrong, when looking out for the next cold spell I always take in the Ens data, they very much have their place but I would take op + control over the ens every day of the week. By which I mean if the op and control show one thing and the main Ens cluster another, I know where my money is going.