Model Output Discussion - New Year and Beyond

[Tim Bland]

At least the PV is shifting away from the North west , if we can tap into it there’s some brutal cold to the north east 

Edited January 1, 2023 by Tim Bland

[Allseasons-Si]

The control has trough disruption just east of the UK,...wouldn't take much to correct it west a tad...

the gfs did the same but not as good,...i feel there is still leg room in this,beyond this is anyones guess untill this scenario gets sorted out

goin to the wire this one.

[Derecho]

5 minutes ago, s4lancia said:

I couldn’t agree more. From a fairly meh chart on the face it, in fact a bit of underestimated upstream amplification could release that lot towards us Jan’87 style! Not likely of course but interesting nonetheless.

Yup its impressive cold to the NE but we need some trough disruption or our side and a favourably alligned high. Would be nice if we can keep the cold there waiting in the wings, the depth of it is impressive.

[Rain All Night]

I've been watching the EPS Z500 outputs for Barcelona for the past week or so, and today's 12z run is the first time I've noticed members which bring heights lower than 550 (which would be green on Meteociel's map plots) earlier than day 10 - although none of them for very long.

(Today's 0z left, 12z right)

[Daniel*]

28 minutes ago, zubzero said:

.? It's about average if not slightly below compared to the ens

https://www.meteociel.fr/cartes_obs/ecmwfens_display.php?x=274&y=54&run=12&type=2&runpara=0&mode=1

 

 

I said day 10 and it’s  ~2C warmer than mean so I’m not sure about that! 

 

[MATTWOLVES 3]

55 minutes ago, Eagle Eye said:

It's a shame that we have to hear this so often because it's true so often. If only the Atlantic wasn't such of a dominant force...

Rrrrr.....but the Atlantic had been sluggish for well over a year EE,and its been far from a dominant force. Keep in mind last Winter we had a sluggish Atlantic yet still missed out on cold. The significant cold plunge out of Canada is what woke up the Atlantic. I wouldn't be at all suprised to see it die a death again for large parts of this year. 

As long as there remains a reduction in the temperature profiles between the equator and the poles,this is something that could worsen...obviously the thermal gradient is greater at this time of the year so there will be episodes when it's running full steam ahead.

[swfc]

Day 10 on gfs control is building some serious cold to the ene. See if the oz runs esp ecm pick it up and run with it

[BlueHedgehog074]

32 minutes ago, Tim Bland said:

12z Vs 18z ..couldn’t be more different, finger in air time

While it’s far into the dreamland, it’s literally gone from a Scandinavian High to a Scandinavian trough!

What I think all the cold weather fans should do is track down the shrink ray in Despicable Me, point it at both the European High and Atlantic Lows. Then hopefully the Atlantic Lows will be too feeble to fight the modest Scandinavian High and just take a trip into mainland Europe drawing Polar Express weather towards the UK.

[frosty ground]

Happy New year 2003 
Flash back to the early days of weather forums.

The talk of the winter so far is the December CET being above average which would lead to January and February being above average as was the pattern since the great storm of autumn 87 which for some reason has changed the weather leading to a run of mild snowless winters. 

Mild snowless winters or the large teapot as it will be called is being caused by several factors…. global warming which will mean no snow in the U.K. by 2020, no below zero CET months ever again.

there is also a curious case of low heights being attracted to the GIN sea Greenland Iceland and Norway, these low height stop high pressure forming and moving back west therefore high level blocking is impossible.

Of course the Barttlet high is now a common occurrence with the expansion of the Azores high into Europe meaning winters like 98 will be the norm.

In the 00’s the winters of 2009 and 2010 where no longer possible snow would no longer exist.

it’s been interesting reading some of the comments over the last week, one could be forgiven for thinking we where back in 2003 with the exception December CET came in below average,

What makes model watching fun is the unpredictability of it all even with the long range forecasts by forum members  that have come on leaps and bounds and a much greater understanding of global drivers, forecasting 2 weeks ahead is always fraught with surprise.

 

[offerman]

3 hours ago, Catacol said:

Shooting from the hip at those who try and make sense of what drives our weather is probably not the way to go. Nobody I have seen try and come up with an analysis ignores the reality of Hadley Cell movement and the increasing dominance of the sub tropical high pressure belt. It is a known context. And clearly there is more we need to do to try and comprehend what impacts the Euro High specifically. For many years data and forecasting has looked almost entirely at the Pacific- and for good reason. The Pacific drives the Rossby Wave pattern that most obviously impacts the major centres of Western population namely the US and Europe. But little to no time is given analysing what is happening over the Atlantic or perhaps over the African continent. Do research papers exist that target the Euro High? I haven't seen any. Perhaps we will start to see some soon.

Those who use teleconnections and who you identify as "ignoring" the Euro High context presumably also include NWP output itself which also got it wrong. As did the Met Office. Sometimes a forecast is a bust because it is a bust - because we are yet to know enough to forecast accurately beyond 5 days.

But to try is better than not to try. There are no prizes for raising the white flag and having a chip at those who got it wrong.

Excellent post Catacol.

I also mentioned once before I saw a program on the BBC and I just can’t remember what it was called. But they were discussing particularly strong magnetic areas subsurface that could affect above the surface creating strong high-pressure systems. So it looked like it was the InnerWorkings effect in the outer above sea level synoptics. There were about six identified around the planet and the Hadley cell was one of them.

it does seem like an invisible force field when strong telekinetic‘s spoken about which in the end I just like a soggy teabag in texture when it comes up against a high-pressure systems . These high prices just seem to want to constantly deliver mild southerly or south westerly wins with low prices that get caught up in the flow just to keep reverting .

sometimes it’s a big sways of cold air coming down from Canada or the western side of Greenland and it’s freezing cold right down into the Atlantic and as soon as it sweeps towards us just as it’s about to hit us on so many runs I noticed that it takes a sudden directional change to go from south-west to north-east due to the effect of the euro slug.

 

if anyone wants to know or see the effects of the high-pressures ( despite kinetics)  then place your finger on the slider bar , in my case I have an iPhone and if you scrub that bar all the way to the end and back again do that quite a few times you’ll see like a timelapse of the weather systems ebbing and flowing but the general trend is look at how much the high-pressure systems have in controlling majority of it most of the time either deflecting low pressures or guiding them right over the top of us but the general trend of directions are more often the same and any cold potentials are just that they often get water down or dematerialise. 
 

once Euro highs become established it’s extremely difficult to get rid of them summer or winter. same goes for the placement of the Hadley cell Azores high,Iberian high. 

[offerman]

2 hours ago, Froze were the Days said:

See the ever present limpet short wave low close to the Norwegian coast is becoming a feature too when ever we get some sort of Scandi High, interesting also how the isobars seem to follow the contour of the coast rather than go westwards (probably due to the large difference in temps from land to sea) as per 222z on tonight's ECM op run...thoroughly depressing.

Fantastic post/ point of which I noticed happening in recent years as well. 
it does seem such a small little feature but can really block the easterly which I could remember with the flow I suppose all the way from Siberia right across over to us and rarely were there any small low features like this does seem to be relatively new feature over the last 5 to 10 years. not that winds from this direction I’ll come in anyway but if there is a hint of a high-pressure lead into a potential easterly the short wave often knocks on the head diverts it. 

[Allseasons-Si]

And a good 1st day of the new year to you all,not posted much today as i had 1-2 too many last night and stayed in bed most of the morning/first part of the afternoon

some good analysis in here today and thanks to @mushymanrob, @knocker, @Catacol and @Eagle Eye for the explanations of the strat/ EAMT and how to read the NOAA anomaly charts so thank you,i have learn't quite a bit over the past 11 years whilst i have been on this forum

Just a question to the more knowledgable,i have hightlighted this black circle around this number,does it represent the dam as in 528 dam because if it does then the 528 dam line is somewhere between Orkney and Shetland or am i reading this wrong

a good chart though with +ve heights over the pole with linkup of +ve heights NE America and -ve heights over Scandi and again a fuel charged by a powerful jet NE PAC -ve height anomaly

 

ext'd EPS as above with temp anomalies colder the further north you go UK wise but average further south,...this could change as we go through the latter half of the month,...it has trended cooler than previous runs though so a step in the right direction.

Edited January 1, 2023 by Allseasons-si
typo

[tight isobar]

Mass scatter! But ya need the mean-And the green linked together... and even those plots- have ina nutshell lost the plot!.. The drivers are not dictating, it’s honestly a suck it n, see... we can pick perturbations from either side-@ Mobile- mild-@cold- epic!! However they will nigh on Always be there if you seek them- but ya need big %age agree for a possible more defined forecast!.. atm it’s we are all a tad worse for wear and intoxicated ! So we’ll chuck up everything.. And nothing!. It’s certainly got the feel of something is gonna give... 

[Rain All Night]

23 minutes ago, Allseasons-si said:

And a good 1st day of the new year to you all,not posted much today as i had 1-2 too many last night and stayed in bed most of the morning/first part of the afternoon

some good analysis in here today and thanks to @mushymanrob, @knocker, @Catacol and @Eagle Eye for the explanations of the strat/ EAMT and how to read the NOAA anomaly charts so thank you,i have learn't quite a bit over the past 11 years whilst i have been on this forum

Just a question to the more knowledgable,i have hightlighted this black circle around this number,does it represent the dam as in 528 dam because if it does then the 528 dam line is somewhere between Orkney and Shetland or am i reading this wrong

a good chart though with +ve heights over the pole with linkup of +ve heights NE America and -ve heights over Scandi and again a fuel charged by a powerful jet NE PAC -ve height anomaly

 

ext'd EPS as above with temp anomalies colder the further north you go UK wise but average further south,...this could change as we go thruoough the latter half of the month,...it has trended cooler than previous runs though so a step in the right direction.

My understanding is that that 5280 is the number of metres above mean sea level that 500mb pressure is reached (i.e. the 500mb geopotential height), whereas the similar metric that you are thinking of would be the number of decametres above the height where 1000mb is reached that 500mb is subsequently reached (i.e. the 500mb-1000mb thickness). The latter being the metric which is shown as a dashed red line on the fax charts, and where a value lower than 528 gives snow hope:

I also understand that at any point on the map where the mean sea level pressure happens to be exactly 1000mb, the 500mb geopotential height would be exactly equal to the 500mb-1000mb thickness in that location.

Edited January 2, 2023 by RainAllNight

[Rain All Night]

I know it's too far north, but it's still fun to watch this bad boy do the limbo!

[Kasim Awan]

12 hours ago, Catacol said:

HNY everyone - festive season pretty much over...time to return to "normal" (whatever that is...) 

It has been a grim 2 weeks for cold hunters. I have checked into a few charts and data sources over the Xmas period and frankly if it could go wrong - it has gone wrong. Pacific forcing arrived as expected and it has prevented the slide towards a Nina dominated atmosphere. AAM has pushed back up into positive territory

and the GWO orbit started to rise once again, avoiding a slide into flat, Nina territory.

We have even ended up in the fabled ground of MJO phase 7 as many suspected might happen despite the usual crappy MJO model forecasts.

This was probably about as big a jump back up of AAM in a positive pacific context as we could expect. Looks pretty good! We are even looking at a scenario which sees the North Pacific High replaced by some quite long last low pressure....a good precursor for strat forcing

But just take a look - as though we need to - at pressure over Europe. I posted JMA monthly charts that saw this draining away. EC charts showed it draining away. And here we are with the Euro High firmly embedded. It has forced the jet stream further north so that only the Highlands are now seeing what - at one stage - some of us thought much of the UK could see during this current period. Go to the outer reaches of useful EPS modelling and not much change. Euro High in charge. 

It is indeed grim. CC modelling of global patterns over the next 80 years or so sees the growth of the Euro High as a core feature. The fact that we are seeing it so much already, as early as 2022/23, is depressing. Germany breaking temperature records....we had our 40 degree summer just gone. Both courtesy of this growing anomaly. As the world warms the regional implications of this Euro feature are going to become quite profound I suspect.

Where does this leave UK winter? Searching for a SSW. I don't see any way out of a westerly pattern now without a SSW. Really substantial amplification might possibly do it but remembering the failure of the GP +4SD "torpedo" years ago I am not sure modern climate patterns produce the same kind of response as was the case 30-40 years ago, at least in Europe where we have a semi permanent high anomaly bedded in to our south.

A proper SSW - like 2018 - would do it. In such circumstances downwelling impacts of vortex collapse overcome tropospheric forcing and these scenarios are the ones that really significant winter cold will rely on going forward. To have any chance of this in our current winter we could do with seeing high pressure reemerge over Scandy or the Urals as we had in November to pair up with low pressure over the Aleutians which is modelled. As more than one poster noted a month ago - it would have been much better for our winter overall if the Scandy High in early December hadn't retrogressed so swiftly to Greenland. Much better for stratospheric forcing. Right now only half of this pairing is in place - the Aleutian Low. It is forecast to produce quite a significant wave 1 stretch of the vortex and there is a chance going forward of a displacement warming....but a wave 2 split would be much better for us. Note the current 3D modelling of the vortex in 10 days' time - stretch is quite clear and visible.

So - forget the first half of January. I would almost suggest everyone take a week away from the models, maybe even 10 days, and come back and see if any change is in the offing. Pray that the Euro High ridges towards the Urals in the meantime.

Excellent post. Mirrors my thoughts exactly re euro heights and searching for a SSW etc.

[Daniel*]

Morning all, well I’m still chasing for a miracle a more convincing Scandi high compared to 12z stronger and oriented further south which is better. It’s interesting how unresolved this area still is models clearly struggle. Still, it seems unlikely  to stop the bowling ball of doom. 

[Daniel*]

The stronger more resilient Scandi high is having an impact here. Compare day 6. Interesting….. the euro heights are being dragged up could be beneficial in this case.

Edited January 2, 2023 by Daniel*

[Eagle Eye]

I'm going to copy over my pretty much non-biased (hopefully) texted forecast long-term to one of my friends...

Firstly, we have the Atmospheric Angular Momentum (AAM) which is the amount of torque or rotational force in the atmosphere. Positive AAM (+VE means positive and I'll be using that) typically results in a pattern where +VE temperature anomalies move poleward and see we have hotter than average temperatures over the Arctic whereas the cold from the Arctic falls to the mid-latitudes (including us) and we see negative(-VE) anomalies there (known as Nino-esque). It's important to note that +VE AAM doesn't cause -VE temperatures everywhere in the mid-latitudes, it depends where the warmer air moves into(advects or WAA) the poles and therefore the cold partly falls on the other side of it to somewhere. If this happens over North America that can potentially fire up the Atlantic and for the UK that means the mild and wet that we've been getting recently though we may still get a visit from the Polar Maritime air for a bit. Whereas if we get WAA into Greenland that can often result in the Atlantic effectively being shut off and can lead to cold air falling to the UK in the form of say an Easterly or a Northeasterly and with that there's the threat of snow. It's what happened in early December this Winter.

There's also negative(-VE) AAM which results in a fairly flat and 'normal' system (known as Nina-esque) where we in the UK usually get mild and wet though it depends on the strength of the -VE AAM.

Right now though, it's fairly neutral and so we're relying on 'events' of gain of torque to increase or decrease the AAM and this is where we get to first know the EAMT or East Asian Mountain Torque. A +VE EAMT event is where warm air hits the Himalayas and we find Him a laying in the Stratosphere wave activity moves vertically up into the Stratosphere and we see the gain of AAM in the Trop-Strat this way. On the other hand we have -VE EAMT where cold hits the Himalayas and there's a loss of momentum into the Earth....

With such a fairly neutral AAM it's unlikely to be the main driver but as a basic signal it's fairly good at explaining how things work.

Right now and in the mid-term forecasts, for the end of the first week of January it's looking like we will get warm air moving upwards into the Himalayas and a propagating vertical wave vector into the Stratosphere fairly quickly which results in a +VE EAMT event and an increase to +VE AAM. This will probably result in an extension of the zonal jet in the Pacific. Normally, an extended jet globally is the last thing that we want but just over the Pacific it's fairly good and as I noted +VE AAM tends to drive poleward warm air influence and we don't want that to be over the Pacific (an extended Pacific jet tends to stop that from happening) and instead would prefer it to be towards Greenland for cold for us. 

Now it's time to combine this with the MJO signal...

Combining the MJO with an EAMT event is fraught with danger because that event can shift the Rossby wave (a ridge and a trough or rather a high on one side then a low on the other sort of) pattern from each of the MJO phases and Rossby waves help shift energy throughout the Atmosphere. Luckily, the Atmosphere is being fairly helpful to me and offering me two patterns that come to roughly the same conclusion with the +VE EAMT and MJO phase.

 

There are 8 different MJO phases

 

Phase 1 is fairly non-descript for us though I find it to usually be mild and wet may just be because that's how the 'average' part of Winter is for us.

Phases 2 and 3 tend to drive the mild and wet muck that not many people like and you can probably include phase 4 in that. As these seem to help +VE Azores region Hadley cell development and the Euro high tends to form because of this.

Phase 5 is fairly non-descript.

Phases 6 and 7 are heralded mostly by UK cold lovers because they help with warm air advection towards Greenland (known as a -VE NAO) or sometimes Scandinavia(?) and that often results in a colder pattern for the UK as air can move in from the East/Northeast.

Phase 8 drives high-latitude North American blocking and potentially a west based -VE NAO as well. Though a west based -VE NAO is dangerous for cold as it leaves the door open for the Atlantic as well and so in a strong westerly system (depending on how the East of North America evolves as well) it can end up being a 'wasted' solution and we revert back to type (mild and wet). Although, this type of far west based -VE NAO (so far that it doesn't count) can still be cold with quick shots of Polar Maritime air as it's more North West centred so the air coming down is potentially from a colder place with a steeper gradient and so areas such as the North and Scotland do best from this and even places as far as the south might be able to escape the mild and wet. Instead it may be cold and wet or if it gets cold enough, cold and sleety/snowy. Polar Maritimes aren't always the best but they're the best we're probably going to get soon...

Currently, the forecasts suggest that the +VE EAMT event will coincide with phase 7/8 and high latitude North American blocking looks to be the most driven solution out of this despite both being fairly under amplified because putting them together and you've got yourself poleward driven warm air around North America. This is slowly evolving now with the MJO phase 6/7 lag over the coming days building mid-high latitude blocking and as phase 7 properly pushes in, I think long-term and we'll get increasing Polar Maritime(PM) potentially as this acts like a far west based -VE NAO. It doesn't look overly like zonal mild and wet though a quick Southeast US trough linking up with the Canadian low may mean that for a time that returns very strongly.

So still looking fairly mild and wet long-term especially in the south but further North may actually fare quite well and I don't see why some of the cold can't make it far south enough to bring the midlands or even the south some snow for a time. I think the GFS going for a large -VE NAO long-term is fairly dubious. My thoughts are more along the lines of the MJO progressing more quickly than the forecasts are showing into Phase 8 and that continues to interact with the +VE EAMT reaction forming North American blocking but no large -VE NAO. Though, if the current MJO projections are correct then we stay largely in Phase 7 with it amplifying for a time and so maybe we can get a -VE NAO and cold via an Easterly/Northeasterly that way. If it does interact with how the Pacific jet evolves that way then we can get excited about Tropospheric based significant cold potential for late January but for now I don't think it's going to be amplified enough nor under-progressive enough for that to happen. Instead PM may be our best chance of cold at least away from the Stratospheric pattern...

The Strat pattern continues to show signs of displacement as the main part of the vortex appears over Greenland area and displacement is a good thing as it generally leads to the weakening of the Strat westerly winds (zonal winds) due to abnormal Rossby wave thermal transfer and the resultant net easterly force from Rossby waves. So, a slowing down due to displacement but not a sudden warming just yet. A sudden Stratospheric warming (SSW) is characterised with the reversal of the Strat zonal winds between 60-65N (apparently) and typically that happens with a large displacement or a split. Generally a split right down the middle of the vortex, perhaps a displaced vortex is more associated with a major SSW and a large displacement with minor SSW's but I think I've heard of one or two major SSW's that were displacements but I don't think it's enough to just rely on a displacement especially to get one in the first place. The polar-night jet formed very strongly recently and we have an anomalously +VE Strat zonal winds in the first place so to get a SSW from just a displacement alone is probably unlikely though it does look like it's going to weaken it quite a lot to perhaps below average but beyond that relies on how the Trop pattern evolves...

If Wave-2(2 warming areas, Wave-1 is 1) increases then a split considering the initial displacement is fairly likely if we can get a strong Wave-2. Recent trends have had it increasing at the end of the run going into mid January but nowhere near where need it to be. As the large Pacific wave connects up with the North American response to the +VE EAMT and MJO phase 7/8 event, it should start slinking away from Siberia which may be a good thing. A +VE Ural Block (UB) in the Trop pattern could provide the upward wave flux we need for a Wave-2 signal though I think it probably needs to be a lot stronger than where it is currently at on the models, at least it's a start. The 2018 SSW had a persistent UB pressuring the Strat beforehand plus it was Wave-2. A UB isn't the best indicator as it may be the only vertical wave flux and so Wave-1 signal such as the 2019 one which seemed to mostly have been UB based with no other real intense blocking and at the time the forecasts were showing a displacement event. It's important to note that SSW's do evolve relatively slowly as the pressure and displacement increases (especially Wave-1 followed by Wave-2 events) and then the snap happens. 

In the current scenario a split would only really happen if Wave-2 increased fairly significantly and that would possibly be to do with the timing of the UB omega (?) block expansion and the initial warming Wave moving towards the Pacific/North America perhaps negating the need for an Alaskan blocking in the Trop but for now the UB times itself just too early and instead focuses itself on strengthening Wave-1 similar to how 2019 evolved, I think that was a former UB on top of a re-strengthened UB. 

So in other words, it's possible that even if a SSW does happen it could be similar to 2019 but importantly, at this time the zonal wind looks to be around average so this wouldn't be the onset of a SSW, just something to keep it displaced for now. It seems like a wasted +VE UB block but it's important in keeping up the pressure on the Strat and also for the secondary displacement towards Greenland where it looks to shrink back a little bit. This leaves room for what would be the most helpful thing considering the placement of Wave-1. A Scandi high would split the vortex in two but when we need it there's no real sign of it, yet. Although, the stretching of the Strat and the general movement of the Wave-1 heights would suggest that a UB a few days after the end of the GFS run would be a good way to split it  with the increasing Wave-2. It's at times like this where you get a little bit mad at your luck. 

This has looked the case on recent runs but it's still quite far out. Given how everything is timing itself though it does like an increasing of Wave-1 towards North America with the vertical wave flux propagated by the +VE heights over North America and combined with the +VE UB doing similar, the Wave-1 continues to get a lot of support from below it and keeps the Strat Vortex displaced and stretched but no real signs of an increasing Wave-2 strength largely just yet. That's shown well on the image below.

Why do we want a split and major SSW instead of a displacement?

Mainly want a split rather than a displacement because split's generally increase the chance of getting a major SSW and so the zonal wind reversal reaches the Troposphere which is an important area for the evolution of our weather systems. A split rather than a displacement also usually favours a colder pattern for Europe with a displacement favouring North America with it's downwelling effects. It's also the reason that we want Wave-2 more than Wave-1 as Wave-1 displaces the Strat but often a strongly amplified Wave-2 will split the Strat and that's much better for getting a SSW in the first place and for it's efffects for Europe in terms of helping to bring us a generally colder pattern.

Why does a SSW typically bring colder weather to the mid-latitudes?

I sort of touched on it earlier, it's mainly to do with the reversal of the Stratospheric zonal winds and as Rossby waves attempt to move vertically, the reach the reversal, impart their easterly force and break up and this continues until the easterlies are in the Troposphere.

What are some SSW past events?

January 2009 SSW (thanks to Simon Lee's blogs) and the relatively quick revert to the Easterly for the UK though it didn't last for too long, it was a major SSW (I think).

February 2018 (also thanks to Simon Lee), this also occurred right after very strong polar-night jet happened as the Tropospheric Eddy-driven jet pushes up thermal wave flux and we saw the development of a strong Wave-2 split.

So what's coming up?

I think for the Strat it's the case of wait a while and see where we are. The best signs continue to be long-term and there's still no real signs of a SSW just a return to average, perhaps slightly above or below average. Though, the initial warming Wave which is followed by backup is now with about a week but what happens beyond that depends largely on how quickly the North American and Eurasian patterns evolve which I generalised above but there's a lot of potential difference with the actual timing, if it happens at all. That may have a fairly big effect on how things evolve. So for now, it's going to be waiting but I'm still going to be updating you on the trends with how timing is evolving, these are just my general 'musings' that my friend had to listen to me talk about this morning.

Edited January 2, 2023 by Eagle Eye

[Daniel*]

No joy slips east still think there is some mileage in this. The Scandi high has been consistently trending stronger and more steady, if any model which would identify it first it will be ECMWF. The stronger the block the more the lows should disrupt.

V 

 

Edited January 2, 2023 by Daniel*

[nick sussex]

5 minutes ago, Daniel* said:

No joy slips east still think there is some mileage in this. The Scandi high has been consistently trending stronger and more steady, if any model which would identify it first it will be ECMWF. The stronger the block the more the lows should disrupt.

V 

 

The problem is the high isn’t orientated favourably. It needs a ne sw alignment to face head on the  troughing .

The ECM at day 5 was quite encouraging and had the best set up . The UKMO the worst as it blows up the shortwave over the UK day 4 and doesn’t easily absorb the one to the north day 5 .

 

[Daniel*]

Day 10 GFS and ECM they’re at very different places…. the EPS mean well represented this run last night with Azores on an axis which is much more conducive to more sustained colder PM shots, so you can have a bit more confidence in this solution. I don’t even think day 4 is sorted though! 

[Ali1977]

The GEFS in FI are showing more and more blocked charts each run, here’s a few from the 00z.

 

Edited January 2, 2023 by Ali1977

[Sky Full]

Understandably, many on here continue to look for signs of an imminent arctic blast accompanied by widespread heavy snow which remains possible for at least another 10 weeks.  However, this is also the time of year for Atlantic driven wind storms and with the increasingly turbulent atmosphere and warming seas we could see record breaking storms in the same way we have seen record breaking high and low temperatures in very recent times.  I will be keeping an eye out for the earliest signs of Atlantic storms over the next few weeks, like these charts from the GFS (way into FI but worth watching….)

   

Edited January 2, 2023 by Sky Full

[nick sussex]

Regarding the Scandi high .

I think one more days outputs should decide whether even though unable to directly influence the weather on the ground as it edges east it could hang on in a more favourable position and add more forcing to direct the jet more se into the UK.

After the Scandi high moves  east the models paint an unsettled picture . Some variation though in how much suppression we see of the Euro high .

By day ten the ECM has the more favourable upstream pattern with a better chance of a more potent PM shot .

I’d remain wary though of the Euro high in the later outputs as the models seem to going on recent performance have been premature in either flattening it or displacing it further west and north .

The movement of the MJO does though favour some change so I’d say the odds slightly favour the more amplified upstream solutions .