Stravaiger

Amazing to see the sea ice surround the Svalbard archipelago for the first time in a long while. Beautiful images coming off the webcams around Longyearbyen, showing how influential all the snow and ice is on the albedo of the High Latitudes at this time of year: BOREALIS LIVECAM PORT OF LONGYEAR 360 (kystnor.no) When you consider how jaffa cakes poor the UK's "winter" has been, it's encouraging to know that Scandinavia and the most northerly extremes of Europe have still managed to get some goodly cold in.

GEM's gotta be the pick of the bunch from this evening's deterministics. At Day 10 (yes a long way off) that high over Scotland is only heading in one direction....northwest. If it can get properly established up that way, cold uppers will eventually swing in down it's eastern flank and for southern UK, where pressure will be lower, Atlantic incursions might produce some interesting battleground events. We can but hope, eh? At the very least, some dry, settled weather with nightly frosts depending on where the stratocumulus ends up drifting.

@Penrith Snow - totally agree. I think the bottom line is that the impacts of CC are manifesting in the increased frequency of certain weather patterns in the winter, as @Catacol alluded to. My simplistic understanding is that GHGs stop heat escaping from the troposphere into the strat, cooling the strat, which in turn gives us a tighter sPV and tPV, with the polar jet pulled poleward, which allows HP to ridge north into southern Europe. Fascinating discussion though and just hope the tropical forcing comes to our aid soon. Thanks all!

This - 100%. So often climate change isn't looked at as a driver but it has fundamentally changed the game. Expansion of the Hadley cell, GHG and CFC-induced stratospheric cooling leading, etc., all of these factors are uniting to increase the likelihood of strong, coherent PVs and a northward push of the sub-tropical high into Southern Europe during winter. Of course there will be times when other drivers can override these factors and we get pressure in Europe to fall - we've seen it a few times since November - but the winter season is fundamentally changed by the increased likelihood of long periods where really high heights to our south effectively block any cool or cold air from covering the British Isles. The way I think about it is that we're playing the same game but the cards in the deck are different now, with many more leading to anomalously mild conditions. We'll still occasionally get to play great hands but the odds of them appearing have lengthened considerably. Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5022916

This - 100%. So often climate change isn't looked at as a driver but it has fundamentally changed the game. Expansion of the Hadley cell, GHG and CFC-induced stratospheric cooling leading, etc., all of these factors are uniting to increase the likelihood of strong, coherent PVs and a northward push of the sub-tropical high into Southern Europe during winter. Of course there will be times when other drivers can override these factors and we get pressure in Europe to fall - we've seen it a few times since November - but the winter season is fundamentally changed by the increased likelihood of long periods where really high heights to our south effectively block any cool or cold air from covering the British Isles. The way I think about it is that we're playing the same game but the cards in the deck are different now, with many more leading to anomalously mild conditions. We'll still occasionally get to play great hands but the odds of them appearing have lengthened considerably.

Fantastic to hear this - thanks for the updates MIA - and to see ice forming in places we haven't seen it for a while. Bit further south but almost looks like the Odden ice tongue is emerging once again to lick at the Greenland Sea. Proper old school winter in Scandinavia, too, might even see the Gulf of Riga ice over if this winter keeps on going. Would be great to hit 14K km2 before Feb this year, maybe even an above 15K maximum is on the cards.

How about this for a November snow extent? We've come a long way since September. Best start to the European winter I've seen for a long time...the question is, will it last?

Although it doesn't look great on the face of it, I'm really encouraged by the GEM evolution on today's 12Z. It ends up with the heights/cold in Scandi holding firm, forcing energy from the Atlantic to disrupt SE into C. Europe, which will ultimately open the door to heights in the north retrogressing and, at the very least, giving us coolish zonality without the awful Iberian / Bartlett high that has plagued recent winters. Plausible outcome and preserves the awesome Scandi cold pool - we could do worse!

Yeah the Scandi cold is really noteworthy this year...started early and has been sustained for a long time now. Very old school, as you say MIA ! Temps currently below -30C in parts of Lapland and that cold air will be sucking heat out of the Gulf of Bothnia incredibly fast, leading to further expansion of sea ice in the northern and coastal parts of the Baltic. If the pressure anomalies persist and keep pressure low in Central Europe this cold spell could go on for a while yet. I think an eQBO is partly responsible for this set-up but doubtless there are other factors... In any case, been a good long while since I've seen a November chart that is so devoid of of warm air at 850hPa on both sides of the Atlantic. Great for the alpine ski resorts - long may it continue!

We're about to see a big expansion of snow cover across central and even parts of western Europe. Some bits of the alps exposed to the north winds will see over a metre of snowfall in the next 48 hours. Not bad for autumn and likely to push NH snow cover extent above average again - just in time for the start of meteorological winter !

Really interested that you look at the total sea ice area chart and see that as "performing strongly". When I look at it, I see that, yes, the negative anomaly is decreasing but we're still currently 2 million km^2 below the 1990s average for total sea ice area... That's an enormous loss of sea ice. I'm not trying to be doomster at all...I'm delighted the Arctic ice is doing ok this autumn, esp. pleased to see it doing better in the Barents than in previous years, and I'd love for there to be evidence that these decadal trends are starting to reverse. But we need to be eyes wide open about where we're at in relation to even just 30 years ago so we don't lose perspective on how our cryosphere is changing. Sorry if that brings the mood down in this thread - not my intention! I get as excited about the boreal autumn's expansion of snow and ice as the next man, which is partly why I mourn the losses.

Good to hear the ice is rebounding quickly up north this autumn, would be great to see ice extent hitting 1980-2010 mean levels again. It's been solidly below average for years now. The situation across the cryosphere as a whole is pretty dire, though. NH snow extent is now back to being below average and Antarctic sea ice continues to chart a new course of record low extents for the time of year. The crumb of comfort for us in Blighty is that Scandinavia is having a cold and very snowy autumn, with persistent low temps since October now. If we can tap into that pool of cold air or, better still, draw it across the still warm North Sea, we might see some good amounts of snow and ice ourselves

Quite remarkable lack of snow for the time of year in Canada, as this anomaly chart from Rutgers University shows. It will all change in the next week, as polar air sweeps southeastwards on Monday and Tuesday but notable to see at the current time. Likely to see some colder air getting into Western Siberia in the next week too, helping to boost snow cover across that swathe of Russia and bring Eurasia up closer to average levels for the time of year.

Yeah I would 100% bank the GFS run for snow up here, esp. over the hills where it is sorely needed after a mild and snowless February. Problem is, betting on Iberian heights dissipating seems a tall order given how this winter has been. Much as I’d love to be wrong, I’d bet those heights will be more bullish than first reckoned on and drive a more positive tilt to the angle of Atlantic attack, allowing milder air to get further north, for longer between successive low pressure systems. Time will tell and there is still scope for the GFS solution to come good. Lord knows we deserve it !

Well done the 06Z...it's pulled the @nick sussex Holy Grail out of the bag! Cut-off high to the north, with energy (low heights) going underneath. Shame the succeeding pattern doesn't hold. Encouraging to see this sort of output nonetheless - I would pay 100 English pounds for the first 330 hours to verify as per that run.

Thanks for this post - really informative and it seems like this disconnect will be key to any impact the SSW has! Do you expect the SSW to impact the troposphere ultimately? Or is it possible the disconnect will mean this event never downwells below the tropopause?

Mmm hmmm…what did I tell ya But seriously, kudos to the GEM for picking this up. Seems like the MJO is helping to put our limpet heights into a much better position for cold, with the flow mostly north of west for a change. Still a fair way to go to realise these synoptics but hopefully the SSW then obliterates the tPV to the northwest and our high continues to retrogress opening the door to a southerly tracking jet and all the goodness that will bring. Lord knows the mountains of Europe (and Scotland) need a snowy March if the snowpack is to survive what will doubtless be another anomalously hot summer.

Surprised there isn’t more chat about the GEM this evening. It ends up in a good place, with the core of high heights finally retrogressing and allowing a NW-SE aligned jet, bringing PM air masses over the UK and helping pressure to finally drop over Europe. It has good support from the ECM operational too, albeit the latter is slower to bring in the cold NW’ly. I for one would be very happy to see the core of the tPV’s low heights dragged eastwards and a reloading mid-Atlantic high bringing seasonal fare until the SSW shows its hand. A trend to watch over the next 24/48 hours for sure…

I’m praying for March 2006. I recommend treating yourself to a scroll through that month’s charts on the archives if you want to remember what low heights and cold 850s look like

Delighted to see the 18Z brings the tPV down to our neck of the woods from Day 8 onwards. I’d give my right arm for that run to verify and winter to resume in our snowless hills.

Cheers Mushy...who creates these anomaly charts? Are they not a composite of model output? Really mild weather at this time of year is terrible news for wildlife. It messes with the timings of plants, insects, amphibians and birds, often leading to mismatches in when species and their prey breed. We always want closer to average weather, because that's what our ecosystems evolved to cope with.

I'm interested in what the ECM's picked up on the last 12 hours. As I feared, the forecast lowering of heights as a lobe of the tPV moved towards us from the NW has been replaced by a renewed surge of heights from the south. But why? What signal has it picked up on that's caused a complete reversal of yesterday's output, which also had support from the GEM. Hoping it will flip back, but expect that it won't. The AGW curse of relentless high heights will take some breaking.

Latest output all converging on the idea of lower heights moving into the UK from the NW in 8 or 9 days time. Atlantic feed so it won’t be cold, but close to average with plenty of snow over high ground in the north if it verifies. The dream would be for this cool zonality to be pushed away by heights building out of the north as the forecast SSW perhaps takes hold. Either way, after a pleasant, settled spell for the south of the UK, I’ll be ready for lower heights to return and cloak Scotland’s mountains in snow again

Can someone tell me what the route to (non-surface) cold is from there? Looks terrible, with more unstoppably high heights pushing in from the south. @Eagle Eye are you still expecting heights to rise near Greenland around the 15th and pressure to fall over Europe?

As expected...the GFS backtrack begins with the high unable to get as far north due to the energy running across the top of it. The run still ends up being ok because high pressure sits close to or over the UK, which is always nice, but the risk of an ECM 0Z solution, where long-fetch southwesterlies are never far away, is palpable. Still want the PFJ kicked well south and for pressure to fall on the continent. Instead it's running across the north of Scandinavia ! We'll wait and see what the second half of February brings.