Duane S.

Typical! The control would probably bring TOO much snow on the days I’m off skiing in 10 days! I’d take that every day though, over the opposite I’ve often endured early Jan at low-mid altitude

I viewed the GFS Op first this morning. A quick scan through the corresponding GEFS dispelled any real concerns though. The ECM Op is stunning, we can but hope... I’m off for a few days skiing in the NW Alps in 10 days time, so naturally I’ve been checking the charts with that in mind as well. The trend has definitely been my friend in that respect. And… I may just have the cherry on top, upon returning to the UK We await the 06z with interest.

You’re an odd bunch at times This is disappointing?

Just got in and checked the GEFS. Some absolute belters in there! Cold of sorts is firming up.

Seriously, you are posting a mean chart from D16 as some sort of justification? Give it a rest. Anyway, I did muse earlier that we may have bottomed out on the rollercoaster To that, I think we should all be very content with the 12zs

I definitely have to agree with this Certainly some of the wilder zonal wind and warming predictions have tailed off over the past 48 hours, but we are very much in the game as we look towards and through January. The 06z still showing a very strong warming up top but it doesn’t get much below around 5-7mb with any great gusto. Worth holding our nerve, to see if we’ve ’bottomed out’ on the rollercoaster today…

There’s an odd vibe in here today. Absolutely no kudos awarded to the few doomsayers if this cold spell doesn’t materialise for us, most cold spells don’t for us, even those chases with everything in our favour. A shame because we are facing a great few weeks of chart/teleconnections viewing, with (hopefully) some wintery weather to follow. This forum should be buzzing because most Christmas periods looking forwards, are nowhere near as promising as this one. Again…there is no silver bullet / tipping point / threshold to cold, caused by an SSW (as in a U wind reversal at 60N / 10mb). Also, it is never a linear process when viewing data down to D0. Never ever. There are many other factors, that won’t change, still in our favour as we head towards and through January. Too much emphasis and focus on one aspect going on. I would be nice if forecasting our weather was quite that easy. For instance, I’d rather see us just miss a technical SSW in a E-QBO state than hit an official SSW in a strongly W-QBO state.

Just the small anomaly then… A serious Northern Hemispheric shake-up incoming folks

The Control wants in on the action as well ️

Isn’t it great just to have this potential showing as early winter as it is now. No point micro-analysing every frame of every run or looking for any reason it wont happen (there will always be plenty of those). Just be happy we’ve got a real shot at cold (or should that be, a shot at real cold?) as we head through January… Happy Christmas Day everyone

Top to bottom stratosphere snapshot of the split (the GFS 00z Op’s take of it anyway )

Hot hot hot at the top of the Strat Edit: I’ve just realised I chopped off some details. This is the GFS 12z day#13 @ 2mb

I've picked P09 purely as how I think we could see something colder develop, going through the 1st week of Jan. Clearly… I’ve picked a cold one, my point isn’t to predict it will occur like this, just that it is, IMO, a viable route to cold, without extensive northerly blocking. Compared to this Op, it’s a bit of a slower burner but a progressively colder run. Day #8: the Jet is heading on a more southerly track and we are in a cool westerlies. Day #9.5: The little low of the ESB is caught in the JS and steers this away from the longwave trough detached and heading over the UK on a SEE trajectory. This enables a perfectly breeding ground for a high to form above it. Day #12: And so it does. The Jet becomes more disorganised and whilst it consequently doesn’t run the low underneath, it is actually perfect timing to drive the energy over the top in this case Day #14: Lovely little Mid-Atlantic ridge and a Genoa low thrown in as a consequence of previously Day #16: That ridge is then allowed to threaten becoming a full-blown Scandi high, with proper slider activity to follow on. No doubt longevity would be questioned (looking to the NW) but actually it’s not over GL and probably perfectly placed for a real cold spell to develop. Back to reality and of course things won’t pan out like that (and highly unlikely AS good as) but… I think it shows very well how cold set ups are possible without raging reverse zonality in place and/or a fully blown down-welled SSW.

A cracking 06z run by the GFS. Best of all, at no point is the Op the coldest... Maybe a bit of a best case scenario? Before the anticipated effects of the U wind slow down and warming hits later on in January.

A step in the right direction, or just another ‘random’ D10 output? OK, yesterday’s 12z was a low bar but I think we are going to vast improvements in the outlook by the time we get to the big day.

The correlation between jet strength/alignment has been shown in recent findings to be a pretty strong one. As in, stronger solar activity tends to strengthen it and the jet heads on a more northly track. +NAO I assume that it has been mentioned on here already, but a few days ago the sun emitted its biggest solar flare in 6 years. It registered as a pretty significant X2.8 on the scale. Fortunately it wasn't a direct hit on the earth, more of a glancing blow but I suspect it may well have made it's presence felt in more than one way. An event like this has the capability of knocking the favourable moderate Pacfic activity / E-QBO / El-Nino combo for six unfortunately. Remember that ECM of December'12 that never was (a badly timed flare was suspected of de-railing that one as well!). Although... the following Jan didn't turn out badly to be fair

A follow on from my last post, at the end of November... As expected the influential player remains the Azores High and we now have that wet and stormy period. The signal to pull back the high to a more favourable position thereafter is a bit more surpressed than I anticipated going into Christmas day. That said the Maritime passage is often an unpredictable (think, local topographical issues) and thus it is often a poorly reflected one. So, watch this space for increased amplitude, maybe more 'BOM'esque from the GFS and ECM in the days to come. Albeit, nothing of any great consequence I doubt. I had expected to see the models continuing to drop systems SE into Western/Central Europe, but without the Pacific aid, this becomes difficult, and I can see SE Europe getting the pick of the seasonal weather for the festive period now. So, I'd say it is currently unlikey that we will have the forcing to progress away from a cold NW flow (at best) by the time the big day arrives. There are also the pre-conditions for a return to a very stormy period as well through the Xmas week. But... 2 weeks is a long time and a couple of tweaks (or rather, the up-to-date starting data being more favourable towards us), we are still in the game. Many a year by this time it's a flat no chance. And of course, thereafter, well then things do start to get more interesting...

I posted this 10 days ago and looks about right so far, that relaxation of favourable ridging/retrogression... "I posted a couple of weeks ago about the likelyhood of a displaced Azores high becoming a real feature around our neck of the weeks (good & bad?). The good being plenty of Atlantic ridging and retrogression POTENTIAL. IMO this could be a bit of a feature this winter, even in early winter. Pretty much what we are seeing so far. The Jet seems to be displaced more southerly than usual, that could be no pain no gain scenario (An October/November washout being the pain!?). Albeit I wouldn't be surprised to see a relaxation of this just before Mid-December and we endure another short stormy spell, before we go again around Xmas. I've seen a lot of posts questioning where the amplification signal is coming from recently. Well there will always be a lag effect from the MJO and corresponding Pacific activity. Obviously its influence on a small Island situated on the other side of the globe will massively vary on each occasion, for a whole host of reasons, but we would normally expect to have to wait usually around 7 - 10 days. Looks about right to me. Of course lag alone is only a part of the story, accuracy of the plots and coupling will impact effect massively. Same really for the recent +EAMT as Rossby waves help amplify ridging around the Western Canada region." That 'relaxation' and potentially a more Atlantic-dominated period now coming into view. I am liking the idea of diving SE jet at the end of the GFS again. This I think will be a pre-cursor to our next window of opportunity, as we go through the festive period. Snowing in Weymouth first thing this morning, virtually unheard of in November. A good sign of things to come this winter hopefully ?

Yep, very unusual sight. I’d have spare fingers left if I counted the times I can remember snow here in November on one hand, and I’m in my 50s.

Smallish flakes but pure snow it is, and snow in Weymouth in November is a rare sight. In a place where not seeing a solitary flake all winter is far from uncommon. No doubt that the slight Northerly element to the Easterly is what’s doing it here.

I've just spent a quick spare 10 minutes looking at the overnight runs and fancy the ECM has the next 10 days nearest the mark. 'Nearest', not necissariliy 'near' of course I don't see super deep (and thus potentially more north tracking) low pressures later this week, more of a slacker, thus southerly affair. But certainly better for cold retention. Thereafter, it ought to more difficult for northerly blocking to gain much of a foothold through early - mid December. Again, I think the ECM reflects this quite well. But lets get this into perspective, I am seeing this as two major drivers at force (E-QBO and the ENSO state) to ensure low amplitude Pacific / -AAM periods are producing a much higher 'low base' for us (if that makes sense!?) in terms of waiting for the next window of opportunity, which ought to emerge as we head towards Xmas. IMO, a pre-dispostion of a southerly tracking jet (with diving systems SEwards later on?) off a displaced and relatively very mobile Azore high (with accompanying -NAO signature) hopefully will continue to be a theme for the winter. A stagnant Euro high / long-lasting flabby bulging hadley cell situations should be largely surpressed as a result I'd imagine. A classic winter indeed this could be...

Certainly a very interesting 12z suite there folks! A few musings... I posted a couple of weeks ago about the likelyhood of a displaced Azores high becoming a real feature around our neck of the weeks (good & bad?). The good being plenty of Atlantic ridging and retrogression POTENTIAL. IMO this could be a bit of a feature this winter, even in early winter. Pretty much what we are seeing so far. The Jet seems to be displaced more southerly than usual, that could be no pain no gain scenario (An October/November washout being the pain!?). Albeit I wouldn't be surprised to see a relaxation of this just before Mid-December and we endure another short stormy spell, before we go again around Xmas. I've seen a lot of posts questioning where the amplification signal is coming from recently. Well there will always be a lag effect from the MJO and corresponding Pacific activity. Obviously its influence on a small Island situated on the other side of the globe will massively vary on each occasion, for a whole host of reasons, but we would normally expect to have to wait usually around 7 - 10 days. Looks about right to me. Of course lag alone is only a part of the story, accuracy of the plots and coupling will impact effect massively. Same really for the recent +EAMT as Rossby waves help amplify ridging around the Western Canada region. The NAO looks like going into positive territory for the first time since early September then swiftly dropping back. It matches a pre-disposition it may well have to stay mostly negative this winter. More negative than many recent winters anyway. The monthly IOD and ENSO forecasts from BOM Australia show little change to expectations. With the ENSO state to drop away from an El Nino & into the neutral zone around April time, and the +IOD to become neutral around January (nearer truly neutral a couple of months or so later). With an E-QBO to likely remain through the winter (and a real primary driver IMO, added westerlies would surely only serve against us here), I think we have a half-decent set of teleconnections. Interesting to read as well that the current Solar Cycle is likely going to be shorter than previously expected. As in the solar magnetic poles are expect to flip a year earlier (2024 instead of '25).

Actually BA you’re right. As a Spurs Season Ticket Holder and frequent winter contributor to this forum, the comparison is uncanny. If I supported Man City and lived in Canada, life would be boring. That’s what I tell myself anyway

To me, teleconnentions (specifically ENSO, E-QBO, +IOD) point towards an influential but often displaced Azores High theme for us. South westerlies yes, but also Northerly blast opportunities and toppling highs. Retrogression and something a little colder can’t be ruled either. I’d certainly rather this any day, over a stagnant Euro high.

I love this time of year. We’re all still full of eternal optimism. Of course, the reality is we have a deepening vortex, but only really in line with what to expect this time every year. What to expect? Easy to say El Niño = mild and wet first half, end of story. Certainly a likely contender but I’m not convinced that’s the whole story. To pick out the forthcoming winter’s primary drivers, their interactions with each other, and downstream effect is always the trickiest part. But winter first half, I’d be looking out for an influential Azores high driven by an ENSO footprint, +IOD and ISM combo. South westerlies at times for sure, but also I could see periods (rather, opportunities) of retrogression, with some potential fun and games. I think if we factor in the E-QBO, this should aid this as well. I’d say the teleconnections are pretty favourable all in all. It’s worth remembering, having every primary driver seemingly in our favour is never a guarantee of anything either. If only it was that straightforward! As always, It’s all about how they interact/conflict/supersede/merge/cancel out etc etc and then to what degree. And then you need a little sprinkling of good timing (luck) It’s no wonder the models will always struggle, and when you factor in the inherent inaccuracies with the start data, I actually marvel at how good they actually are! Anyway… it’s all aboard the crazy winter train for another year!