Model output discussion - Into 2021

[Tim Bland]

GEFS ensembles show the mean now above average by the end 

[Lukesluckybunch]

Just now, Tim Bland said:

GEFS ensembles show the mean now above average by the end 

Yes I don't see this spell being particularly severe..as I said a few lucky people may see some snow but widespread snow and bitter weather I just don't see it.

[nick sussex]

If the best in terms of a renewed Atlantic surge is the ECM and GFS day ten charts then really I fail to see any cause for concern.

It looks like a feeble attempt. There is no Atlantic surge and we could easily see high pressure further north .

 

[Dorsetbred]

4 minutes ago, Tim Bland said:

GEFS ensembles show the mean now above average by the end 

Reading from another european provider, the suggestion is that two weeks is probably as good as it'll last (from now) and then as GEFS suggests a general warming across the western part of Europe, whilst the colder weather digs in to the European North & East. So figure we need to make the most of the next two weeks...

[BLAST FROM THE PAST]

1 hour ago, Tim Bland said:

GFS looks good at t144 and doesn’t show any signs of mild though Fred...

Disagree Tim.  The movement to that point one can see that Atlantic HP will not ridge further north.  The elongated trough in Iceland and the shallow HP heights over Greenland means it’s going nowhere or will sink.

now look at UKMO and Iceland

 

BFTP

Edited January 2, 2021 by BLAST FROM THE PAST

[moorlander]

I find the ups and downs of the different models very informative as they try to get a grasp of what the ssw will do.

And love @chionomaniac

Way of showing what may happen with a simple stoke of a pen, very helpfull indeed to

.

[Jason H]

49 minutes ago, Tim Bland said:

GEFS ensembles show the mean now above average by the end 

Thankfully over 2 weeks away. And that also applies when it trends colder too. Too much emphasis being placed on these "far out" ensembles.

Edited January 2, 2021 by Jason H

[Penicuikblizzard]

1 hour ago, Tim Bland said:

I agree, there could be a light dusting for some and very locally enough for a snow ball but the disappointment comes at the prospect of seeing a prolonged widespread snowy spell in the heart of winter and I just don’t see that happening now. IF we were to get to the below position we are at least a week away from a cold setup , that takes us to February. 

A met office forecaster in one of the papers has said there is a El Niño building in the Pacific which could contradict the current situation and end up giving us milder wetter conditions, any views on this comment??

[mountain shadow]

3 minutes ago, Penicuikblizzard said:

A met office forecaster in one of the papers has said there is a El Niño building in the Pacific which could contradict the current situation and end up giving us milder wetter conditions, any views on this comment??

If you read Chinos post above the oncoming SSW, it's hard to see how a developing El Nino can scupper it.

SSW occur during El Ninos too and we've benefited.

[MATTWOLVES 3]

19 minutes ago, Dorsetbred said:

Reading from another european provider, the suggestion is that two weeks is probably as good as it'll last (from now) and then as GEFS suggests a general warming across the western part of Europe, whilst the colder weather digs in to the European North & East. So figure we need to make the most of the next two weeks...

Really!!! We have a warming event taking place,meaning things could get very exciting a couple of weeks later..but we need to make the most of the next 2 weeks. Thats quite bizarre. Yes the GEFS  are going milder towards the end,but again,massive swings in output look likely the coming days..this is one of the most interesting set ups I've seen for years,yet it appears some are getting ready with the white towell! I'm vexed...I truly am.

Edited January 2, 2021 by MATTWOLVES

[Penicuikblizzard]

Just now, mountain shadow said:

If you read Chinos post above the oncoming SSW, it's hard to see how a developing El Nino can scupper it.

SSW occur during El Ninos too and we've benefited.

Ok thanks for the reply, I don’t have the knowledge about these situations just what I read this morning.

[nsrobins]

4 minutes ago, Penicuikblizzard said:

A met office forecaster in one of the papers has said there is a El Niño building in the Pacific which could contradict the current situation and end up giving us milder wetter conditions, any views on this comment??

Can you reference that as it’s clearly incorrect. ENSO still in La Niña phase (waning) and not forecast to go neutral until March at the earliest.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

 

 

[SLEETY]

It's understandable posters getting frustrated with still no snow for many and now with the ops trending milder at the end, but they haven't factored in SSw yet, so their is every chance the charts will resemble the BFTE from two years, if the SSW goes in our favour. 

So keep the faith and watch for some insane cold runs in the days ahead, remember we got minus 16 upper air from BFTE and that was in MARCH! 

[winterof79]

Just been for a bike ride and have come back to disaster it seems.....oh wait i will check .....phew its only 8 days of snow chances

 

 

Edited January 2, 2021 by winterof79

[Matt H]

19 minutes ago, SLEETY said:

It's understandable posters getting frustrated with still no snow for many and now with the ops trending milder at the end, but they haven't factored in SSw yet, so their is every chance the charts will resemble the BFTE from two years, if the SSW goes in our favour. 

So keep the faith and watch for some insane cold runs in the days ahead, remember we got minus 16 upper air from BFTE and that was in MARCH! 

Completely agree with this. We know how volatile and uncertain the current situation is and it’s going to get very tedious in here over the coming days if people keep getting upset and wound up over GFS operational charts over 300 hours away showing mild weather returning. There’s no denying that there has been a trend for a relaxation of the cold weather by mid-month, but it’s still too far away to know for sure and so it would be great if we could stick to looking for trends rather than emotional posting.

Edited January 2, 2021 by Frosty Winter

[Scott Ingham]

1 hour ago, chionomaniac said:

I have had a good look at the strat charts this morning and there appears to be a lot of guesswork as to how the SSW may affect the trop.  All indications to me are that we have a good propagating event already in the early days after the SSW.

One would expect normally a flushing down of westerly winds to the trop and therefore an increase in a flatter trop pattern for a while. But to me this is just not happening. This is the picture as of yesterday:

We have the weakened residual positive u winds at the top to middle strat about to be crushed by the developing SSW. What is of particular interest here, is the fact that prior to the SSW, the middle to lower strat positive u winds are either very weak, or on the case of the troposphere, none existent. These (strong) lower strat winds would normally act as a barrier to propagation, or will be flushed down trop wards as the SSW takes hold. But as they are not present the SSW can propagate right down to the trop almost ‘unopposed’.

So by day10 we have this:

The whole polar field from strat top to trop bottom almost one complete negative anomaly. Not only is it likely that the quick propagation of the SSW will continue to deliver a more meridional NH trop pattern, but where cold is transported south to mid latitude areas the cold will likely be severe and long lasting. The effects of this SSW are likely to be felt for some time yet, probably til spring.

What we can’t be sure of yet is how we are likely to be affected, though early indications suggest a continuation of the winter pattern we have seen so far. But with cold reinforcements added in for good measure.

 

edit - just to explain that u winds are mean zonal mean winds at any given latitude and height.ie where when travelling around the earth at say 60°N and 10hPA height, the net winds are positive (westerly) or negative (easterly)

I agree i said the same to Blue mate. There is nothing to flush. 

[phil nw.]

Sad to have to say that a couple of recent sniping posts have been removed.

These sort of comments are neither welcome or anything model related.All folks are doing is giving their views so anyone who can't accept that then please desist from posting in here.

I thank you.

 

[Harsh Climate]

A note to anyone dissapointed in what the gfs shows, yes we want to see those brutal cold charts and not mild but look on the essembles.

Cleary a 50/50 split or a 60/40 split in favour of cold (how ever good your eyes are) after 12th january, that is 10 days away and a trillion light years away in terms of what is FI!

Had the gfs control run been one of those down at -9 for days, this place would be in jubilation! lol

[Biggin]

39 minutes ago, mountain shadow said:

If you read Chinos post above the oncoming SSW, it's hard to see how a developing El Nino can scupper it.

SSW occur during El Ninos too and we've benefited.

Does he mean El Nina as that has been in place since Octoberish ?

[Flake news]

38 minutes ago, Penicuikblizzard said:

Ok thanks for the reply, I don’t have the knowledge about these situations just what I read this morning.

I'd love to know the source for this simply so that I know to completely disregard them in the future.  Sounds a bit Piers Corbyny.

[stodge]

Afternoon all

I've come on here over the past couple of weeks every evening and done a thorough analysis of the post T+120 picture (FI is from then in my view currently for looking at the larger picture, not for the "is it going to snow in my street?" question which is for the hi-res models and there are plenty who swear by them and indeed swear at them).

FI itself splits into two in my experience - stage 1 FI is T+120 - T+240. That's the important time when looking at the trends, the signals, the themes. The divergences across and within the models increase from then as each scenario plays out but within that range you can see the immediate consequences of different scenarios - some runs you get a smaller series of variable outputs, sometimes the differences are much greater. By T+240 therefore there are a small "cluster" of recognisably similar scenarios (ECM and GFS and indeed other models all have these). It's unlikely any of the clusters will verify exactly at T+240 as shown at T+0 but it's more about a direction of travel.

The next couple of days will show if some of what we are seeing in Phase 2 of FI (of which more anon) manifests in Phase 1 - if it does, it will attract growing support across the Ensembles as we move down to T+144.

Phase 2 of FI is beyond T+240 - over the past 10 days, I've seen all sorts from GFS - a breakdown from the south, a breakdown from the north, a breakdown from the west, the arrival of deep cold from the east, the arrival of deep cold from the north etc, etc. Between Parallel, OP and Control (let alone the GEFS) there are a huge number of evolutions to view. ECM has 50 and if you look on weather.us and go through them at T+360, you'll find any number of divergent evolutions.

In short , looking beyond T+240 is, as Peter Snow used to say on election nights, "just a bit of fun". T+120 to T+240 is the period of interest and what you want to see is consistency (I only look at the 12Z output - if someone else concentrates on the 00Z output that's fine) both across and within the models.

Sometimes we have it, sometimes we don't:

Yesterday's 12Z from GEM, GFS OP, GFS Parallel and ECM at T+240

[Cold Winter Night]

8 minutes ago, stodge said:

Afternoon all

I've come on here over the past couple of weeks every evening and done a thorough analysis of the post T+120 picture (FI is from then in my view currently for looking at the larger picture, not for the "is it going to snow in my street?" question which is for the hi-res models and there are plenty who swear by them and indeed swear at them).

FI itself splits into two in my experience - stage 1 FI is T+120 - T+240. That's the important time when looking at the trends, the signals, the themes. The divergences across and within the models increase from then as each scenario plays out but within that range you can see the immediate consequences of different scenarios - some runs you get a smaller series of variable outputs, sometimes the differences are much greater. By T+240 therefore there are a small "cluster" of recognisably similar scenarios (ECM and GFS and indeed other models all have these). It's unlikely any of the clusters will verify exactly at T+240 as shown at T+0 but it's more about a direction of travel.

The next couple of days will show if some of what we are seeing in Phase 2 of FI (of which more anon) manifests in Phase 1 - if it does, it will attract growing support across the Ensembles as we move down to T+144.

Phase 2 of FI is beyond T+240 - over the past 10 days, I've seen all sorts from GFS - a breakdown from the south, a breakdown from the north, a breakdown from the west, the arrival of deep cold from the east, the arrival of deep cold from the north etc, etc. Between Parallel, OP and Control (let alone the GEFS) there are a huge number of evolutions to view. ECM has 50 and if you look on weather.us and go through them at T+360, you'll find any number of divergent evolutions.

In short , looking beyond T+240 is, as Peter Snow used to say on election nights, "just a bit of fun". T+120 to T+240 is the period of interest and what you want to see is consistency (I only look at the 12Z output - if someone else concentrates on the 00Z output that's fine) both across and within the models.

Sometimes we have it, sometimes we don't:

Yesterday's 12Z from GEM, GFS OP, GFS Parallel and ECM at T+240

Many nervous posts these days about Ops at day 10 and ensemble means at day 14. As if a day 10 chart is as reliable as a day 3 chart.

Everybody keep in mind that the reliability goes down rapidly as you go further ahead in time.
Adapt your expectation level accordingly.

Great chances of cold and snow at +24h? Be very excited, not much can go wrong.
Great chances of cold and snow at +72h? Be excited, with a tiny bit of caution.
Great chances of cold and snow at 168h? Sure, fun to watch, but stay calm and be aware that the ECM correlation of 500hPa heights is only around 80%, so placement of highs and lows may change considerably. In our favour, or against it.

Below the correlation of 500hPa heights at 3, 5, 7 and 10 days. Good to see that ECM improved over the years, but day 10 charts have a long way to go before they reach 100% (they never will).

It would be nice though if everyone got at least some snowflakes just to calm the nerves as we await the main event.
Here in Holland I haven't seen snowflakes since Feb1, 2019 and the last time I went skating was in 2017.

[Daniel*]

12 minutes ago, PolarWarsaw said:

Why are we seeing 'The wheels are off posts' 3 days before an SSW even starts? 

Sorry but there needs to be some frank reminders and realistic thinking in here.

If you are talking odds wise - the chances of having a 2 week cold spell that for example, would be notable enough to remember in 10 years without an SSW is probably 1000/1, WITH and SSW it's probably 100/1. 

Your odds are laughably off. So you are saying in an average winter, the chance of a memorable cold spell is 1 in a 1000 years, where do you think we are North Africa? A SSW markedly increases our chances, you only have to look back to recent ones 2009, 2013. 2018 all with La Niña backdrop likewise this one. The January 2019 SSW didn’t couple that wasn’t La Niña, this one is expected to couple, there isn’t a blockage of strong westerlies lower down in trop. The literature says El Niño is better for SSW and coupling but in 21stC it’s been La Niña all the way.  

[Polar Maritime]

Can we please only discuss what the Model Outputs are showing please in here, lots of posts are more suited to the Winter thread.

Thankyou all.

[2010]

34 minutes ago, PolarWarsaw said:

Why are we seeing 'The wheels are off posts' 3 days before an SSW even starts? 

Sorry but there needs to be some frank reminders and realistic thinking in here.

If you are talking odds wise - the chances of having a 2 week cold spell that for example, would be notable enough to remember in 10 years without an SSW is probably 1000/1, WITH an SSW it's probably 100/1. 

Not sure how many 100/1 bankers I can recall happening in my life? You still need absolutely everything to go our way, an SSW can bring all forms of weather, it's arguably as likely to be bad for the UK as it is good. 

Frankly, the key thing here - the most important thing is that a handful of people forecasted an SSW against all seasonal models. Taps on the back and a brilliant forecast by those people. However, what actually happens after an SSW is the bit that nobody can predict, forecast, worry about etc. 

So how can the wheels be coming off something that's not happened or may not ever happen? 

I'm absolutely hoping as much as anyone that we get a repeating bitterly cold spell lasting from now until April, but from a genuine health aspect of this thread and the future of this thread - it might be better if this SSW is a complete failure in terms of bringing cold. Perhaps next year the entire thread could focus on current weather and not be diluted by 'Ignore tonight's charts, there's an SSW forecast for 8 weeks time mate, come back then for the boom charts'. 

As I mentioned I can completely understand why, but for me SSW's are the largest 'Jam tomorrow bait' that we can possibly have in this country. Not because people ramp, or forecast Armageddon as such - but because all conversation is so overtly positive that it's only natural expectations are built up.

SSW's are also long, drawn out, very fickle and quite often change at that last minute to become weaker/shorter lasting (as has happened this week). They also allow people to ignore the here and now and brush over crap current output, the likes that we had to put up with for the entire of December just because 'don't worry an SSW is happening in 6 weeks mate' - nonsense IMO. 

We need to stop worrying about something that is 100/1 to happen and focus on the fact that 2/3 days ago next week looked wet, now it looks white for a vast majority. Should next week be snowy then that would be virtually 2 weeks of frosty nights, cold days and snow opportunities for virtually the entire country. 

This WOULD represent a longer, colder and snowier spell for the UK than in most winters....it's just that nobody is taking any notice. 

As I mentioned before....the last few days and next 10 days will provide the coldest, longest and snowiest period of winter IMO - ignore it and you will miss winter.

But only talking about current weather defeats the object of the thread. There are other places to discuss current conditions. The model output thread is highly enjoyable and utterly frustrating at times but that is why we come back year after year.