Model output discussion - The Hunt For Cold

[Mike Poole]

Something stirring up top, maybe, on the 12z FV3 at T384?

[Allseasons-Si]

25 minutes ago, Mike Poole said:

Something stirring up top, maybe, on the 12z FV3 at T384?

The gfs showed some displacement too and has been showing it for a good few runs now,ok it's not a warming but i would take everything that keeps that pv from dominating this winter.

 

[Met4Cast]

4 hours ago, Geordiesnow said:

Four different posts from 4 different members posting a 384 hour low resolution GFS chart to illustrate about this so called cold potential, I think that is straw clutching in the extreme. I don't know if its still the case now as it used to be but the GFS goes into a lower resolution(so prone to be less accurate) after 240 hours so for any new members out there, those charts you just seen posted are completely irrelevant and meaningless.

Instead of cold, we could be looking at November 2018 potentially being one of the warmest on record giving the current outputs and the potential for a very warm(for the time of year) southerly which the models are keep on hinting at in the medium term. 

Sorry, but no.

Firstly this is the "hunt for cold" thread, so it's hardly a surprise members are posting.. you know, cold charts. Secondly, there is a good basis to expect blocking to begin appearing within the models in the extended. I've been saying for over a week now that I expect blocking charts to become increasingly frequent for the end of November and that seems to now be happening. 

Reasoning?

For almost the entire season so far we've had blocking somewhere over Scandinavia/Siberia/Europe that is disrupting the usual West>East movement of the jet stream, we've seen some unsettled weather but largely down to low pressure stalling to the West of the UK as per the chart above, this has allowed continuous warm flux of air into the polar regions which has this week caused a minor disruption to the Strat Vortex (though, only minor) with it temporarily displacing closer to Siberia.

The Strat/Trop disconnect is continuing and I suspect will do so until the +QBO decends through the Atmosphere during the second part of winter. The trop vortex isn't firing despite what was at one point a record breakingly strong Stratospheric vortex.  

EC/GEFS are both trending colder in the extended, despite the large amount of scatter there's very clearly a downward trend there, the signal is there but due to the huge amount of scatter (often happens when a pattern switch is taking place) it's rather muted.

The ECM clusters tell a more telling story, the majority 37% going for a huge Scandinavian block

MJO forecasted to move through phase 4 which signals heights to the North/North-East

So, no. We're not "straw clutching" we're predicting what the models are likely to show based on a number of factors and the models do seem to be picking up on that trend today. There's a few of us going for a cold end to November and the fact the models are now starting to show that is rather encouraging. 

I don't expect record breaking cold by any means, but certainly a switch to something below the seasonal average for the last third of the month, cold possibly deepening as we go into December thanks to further attacks on the PV.

[Allseasons-Si]

Big changes from the latest cpc 8-14 day outlook,yes my eye's are fully wide open,check this out

last night's had a trough from Newfoundland extending towards the BI,now look,big Scandi high and the trough receeded to mid Atlantic

this at the moment is a game changer.

 

[Geordiesnow]

Just now, Daniel Smith said:

Sorry, but no.

Firstly this is the "hunt for cold" thread, so it's hardly a surprise members are posting.. you know, cold charts. Secondly, there is a good basis to expect blocking to begin appearing within the models in the extended. I've been saying for over a week now that I expect blocking charts to become increasingly frequent for the end of November and that seems to now be happening. 

Reasoning?

For almost the entire season so far we've had blocking somewhere over Scandinavia/Siberia/Europe that is disrupting the usual West>East movement of the jet stream, we've seen some unsettled weather but largely down to low pressure stalling to the West of the UK as per the chart above, this has allowed continuous warm flux of air into the polar regions which has this week caused a minor disruption to the Strat Vortex (though, only minor) with it temporarily displacing closer to Siberia.

The Strat/Trop disconnect is continuing and I suspect will do so until the +QBO decends through the Atmosphere during the second part of winter. The trop vortex isn't firing despite what was at one point a record breakingly strong Stratospheric vortex.  

EC/GEFS are both trending colder in the extended, despite the large amount of scatter there's very clearly a downward trend there, the signal is there but due to the huge amount of scatter (often happens when a pattern switch is taking place) it's rather muted.

The ECM clusters tell a more telling story, the majority 37% going for a huge Scandinavian block

MJO forecasted to move through phase 4 which signals heights to the North/North-East

So, no. We're not "straw clutching" we're predicting what the models are likely to show based on a number of factors and the models do seem to be picking up on that trend today. There's a few of us going for a cold end to November and the fact the models are now starting to show that is rather encouraging. 

I don't expect record breaking cold by any means, but certainly a switch to something below the seasonal average for the last third of the month, cold possibly deepening as we go into December thanks to further attacks on the PV.

Again, I will say posting a chart at 384 to prove it could be a linkage to any background signals is straw clutching and does not prove any trend, theres a reason why the professionals don't like going too long range as theres too many variables in the weather. What you going to say if the GFS18Z shows a flatter pattern in FI? It might not but whatever it shows, its meaningless imo. 

The first chart you posted showed that potential but the models are CLEARLY trending towards flattening the pattern, there is a bit of WAA heading towards Svalbard but the piece of PV that is heading into Siberia is going to lope back in towards the Arctic Ocean which results a major strengthning of the PV and the Scandi block is forecast to completely flatten and the medium term all models are showing a rather flat NH pattern. The UK staying on the warm side of the jet throughout so no forecast of anything below average for a while yet. 

We shall see in the next 2 weeks if any of these background signals show up in the output that people are thinking that could happen. I would'nt rule it out by any means though. 

[Met4Cast]

6 minutes ago, Geordiesnow said:

Again, I will say posting a chart at 384 to prove it could be a linkage to any background signals is straw clutching and does not prove any trend, theres a reason why the professionals don't like going too long range as theres too many variables in the weather. What you going to say if the GFS18Z shows a flatter pattern in FI? It might not but whatever it shows, its meaningless imo. 

 The first chart you posted showed that potential but the models are CLEARLY trending towards flattening the pattern, there is a bit of WAA heading towards Svalbard but the piece of PV that is heading into Siberia is going to lope back in towards the Arctic Ocean which results a major strengthning of the PV and the Scandi block is forecast to completely flatten and the medium term all models are showing a rather flat NH pattern. The UK staying on the warm side of the jet throughout so no forecast of anything below average for a while yet. 

We shall see in the next 2 weeks if any of these background signals show up in the output that people are thinking that could happen. I would'nt rule it out by any means though. 

But it's not, because it's what we've been expecting to see within the models for that time period, the time period myself and a few others are expecting things to turn colder is only just coming into range of the models so the fact we're seeing charts that we are expecting to see show up is a good sign that things are getting in the right direction, that's the point I'm making here. 

Of course, at that range charts are likely to massively chop and change and I'm certainly not saying the 12z has it nailed on at 300+ hours, merely that those are the types of charts we were expecting to be seeing show up.

The models have been "trending towards" a flatter pattern for quite literally weeks now, then as soon as things move into the more reliable timeframe the models realise the block is stronger and the Atlantic is held back, I haven't seen anything to suggest that, that is going to change. Anomaly charts point towards a robust block in the 8-10 day period, certainly nothing there suggesting a flat pattern to me.

24th-30th November is the period of interest, just outside the models range so the fact we're not seeing bitterly cold charts at T144 is hardly shocking to anyone.

Edited November 7, 2018 by Daniel Smith

[Seasonal Trim]

Oh god can we just leave this alone now! @geordiesnow, this is the "hunt for cold thread"! I'm quite happy, along with countless others, for +300 charts to be used in the hunt for said cold. I really don't know what your problem is for those of us enjoying the discussion! Regardless if it involves mostly FI charts!

 

[Allseasons-Si]

5 minutes ago, Geordiesnow said:

Again, I will say posting a chart at 384 to prove it could be a linkage to any background signals is straw clutching and does not prove any trend, theres a reason why the professionals don't like going too long range as theres too many variables in the weather. What you going to say if the GFS18Z shows a flatter pattern in FI? It might not but whatever it shows, its meaningless imo. 

The first chart you posted showed that potential but the models are CLEARLY trending towards flattening the pattern, there is a bit of WAA heading towards Svalbard but the piece of PV that is heading into Siberia is going to lope back in towards the Arctic Ocean which results a major strengthning of the PV and the Scandi block is forecast to completely flatten and the medium term all models are showing a rather flat NH pattern. The UK staying on the warm side of the jet throughout so no forecast of anything below average for a while yet. 

We shall see in the next 2 weeks if any of these background signals show up in the output that people are thinking that could happen. I would'nt rule it out by any means though. 

So we should discount the Met office 16 to 30 day outlook then,if it wasn't any good then they shouldn't produce it,ok it's not a dead cert but i would side by them

this is not a dig at you as i am a balanced person and i respect all views on here

the signals are looking good but i am on the fence for now as we all know things do change so lets wait and see.

 

[johnholmes]

14 minutes ago, Allseasons-si said:

Big changes from the latest cpc 8-14 day outlook,yes my eye's are fully wide open,check this out

last night's had a trough from Newfoundland extending towards the BI,now look,big Scandi high and the trough receeded to mid Atlantic

this at the moment is a game changer.

 

There is still a 500 mb trough from south of Greenland/Canada that shows  not 'mid Atlantic' as you suggest but running down towards NW Iberia. Yes it has moved but not a huge amount and yes the ridge towards Scandinavia remains there rather more in fact than the 6-10 showed on Monday.

There has been a certain amount of shifting of emphasis on the 3 anomaly models I keep records of throughout the year. At the moment I would rate the probability of some kind of cold blocking developing as about 25%, just a shade higher than I felt about a week ago.

 

[bluearmy]

Eps clusters headed to 70/30 scandi upper ridge against euro slug ....

 easterly/ continental feed becoming cooler over time looking current favourite ......would expect some cold pooling into w Russia by the end of week 2 

[Geordiesnow]

Just now, Daniel Smith said:

But it's not, because it's what we've been expecting to see within the models for that time period, the time period myself and a few others are expecting things to turn colder is only just coming into range of the models so the fact we're seeing charts that we are expecting to see show up is a good sign that things are getting in the right direction, that's the point I'm making here. 

Of course, at that range charts are likely to massively chop and change and I'm certainly not saying the 12z has it nailed on at 300+ hours, merely that those are the types of charts we were expecting to be seeing show up.

The models have been "trending towards" a flatter pattern for quite literally weeks now, then as soon as things move into the more reliable timeframe the models realise the block is stronger and the Atlantic is held back, I haven't seen anything to suggest that, that is going to change. Anomaly charts point towards a robust block in the 8-10 day period, certainly nothing there suggesting a flat pattern to me.

24th-30th November is the period of interest, just outside the models range so the fact we're not seeing bitterly cold charts at T144 is hardly shocking to anyone.

But they have, the Atlantic for this week at one point in the output was struggling to make inroads and I/we talked about the potential of a continental feed(not a cold one) at one point but the models had the first trough(which hit today) edging eastwards which in turn helped the broad low to head further eastwards which is forecast to make an impact during Friday and to a lesser extent during the weekend.

We might see re-new heights over scandi  which the GFS has hinted at but the main bulk of the heights looks like it will be more towards Europe hence the Euro high and the potential for yet another spell of very mild Southerlies for next week. 

Yesterday runs had a slightly more amplified Atlantic than today's runs sadly but I would not rule out this changing again just yet, its a case of watching and seeing and of course patience. 

[Allseasons-Si]

4 minutes ago, johnholmes said:

There is still a 500 mb trough from south of Greenland/Canada that shows  not 'mid Atlantic' as you suggest but running down towards NW Iberia. Yes it has moved but not a huge amount and yes the ridge towards Scandinavia remains there rather more in fact than the 6-10 showed on Monday.

There has been a certain amount of shifting of emphasis on the 3 anomaly models I keep records of throughout the year. At the moment I would rate the probability of some kind of cold blocking developing as about 25%, just a shade higher than I felt about a week ago.

 

Undercuting scenaro?

Edited November 7, 2018 by Allseasons-si

[ICE COLD]

Well it has to be said this is very good consistently from the GFS 18z pretty much the same at day 10 as the 12z run and same as the ECM . 

[Mike Poole]

This looks a strong Scandi high developing on the GFS  18z at T264:

Holds position at T324:

Probably not much cold with that easterly initially though.  Good to see these solutions cropping up with ever greater frequency.

Edited November 7, 2018 by Mike Poole

[ICE COLD]

Wow look at this block by day 12 . 

[Allseasons-Si]

Cool pool advective west.

 

[Geordiesnow]

1 minute ago, Allseasons-si said:

So we should discount the Met office 16 to 30 day outlook then,if it wasn't any good then they shouldn't produce it,ok it's not a dead cert but i would side by them

this is not a dig at you as i am a balanced person and i respect all views on here

the signals are looking good but i am on the fence for now as we all know things do change so lets wait and see.

 

I'm not discounting any potential but posting a random FI chart to prove the potential is showing a bit of despration imo. As for the Met Office forecasts, I respect them but we know they can be voilitile and incorrect for both mild and cold so its not something I would ever over analyse on. 

As for the GFS FI, it shows if the high sets up in such a way, then we may see a set up where the weather on the ground could actually be colder than the 850hpa temperatures indicate.

[East_England_Stormchaser91]

One thing for sure is that the GFS isn’t backing down with the idea of the development of a huge Russian high, one of the biggest I’ve seen modelled certainly this side of the shortest day. Feb 2012 would take some beating though. 

As a result, we see a massive build up of impressive surface cold, despite mediocre upper air temps. 

Goes to show how the Eurasian continent can cool very quickly given the right setup I.e no modification from the South, West or even the North from warm-ish bodies of water relatively speaking. 

[markw2680]

have to admit i like this time of year knowing that we have time on our side to get the cold goodies in, especially when the bigger members start mentioning things getting interesting etc.

but unfortunately there’s always a couple that like to get on the wind up for a reaction of some sort trying to hold on to the mild crud. Anyway here’s to a freezing December.  

we live in hope

[WalsallWeather123]

Another seriously impressive end of GFS run for cold weather. I know it's FI and I am normally one of the biggest critics of long range charts but there is model consensus at T240 from all models and it is obvious that we are going to get a cold spell at the end of November. The building blocks are being built and you just have to put up with some mild southerlies for a while and things will cool down quick time.

[ICE COLD]

Nice run from the GFS again . Keeping up the high pressure theme . Oviously varying from run to run . It ends well too . ( and yes this is a T384 chart lol ) 

Edited November 7, 2018 by ICE COLD

[Mapantz]

1 minute ago, markw2680 said:

but unfortunately there’s always a couple that like to get on the wind up for a reaction of some sort trying to hold on to the mild crud.

It happens from the opposite side as well. But, let's not get bogged down with things like that.

Keep it to the models folks, plenty of relevant threads for other discussions.  

[Geordiesnow]

Just now, markw2680 said:

have to admit i like this time of year knowing that we have time on our side to get the cold goodies in, especially when the bigger members start mentioning things getting interesting etc.

but unfortunately there’s always a couple that like to get on the wind up for a reaction of some sort trying to hold on to the mild crud. Anyway here’s to a freezing December.  

we live in hope

Would never wind people up Mark, just saying the reality that the outlook is mild and trending towards very mild again perhaps into next week, the models has been very consistent in this in all fairness so only saying what they are showing. 

Of course we can have a month of 2 halves so a colder 2nd half of the month can't be ruled out but certainly no significant signs of that yet. Would not rule out surface cold appearing in the outlook similar to the GFS18Z run if the Euro block alligns itself which brings more of a continental feed in. 

[Met4Cast]

The GEFS are going to be interesting this evening

[feb1991blizzard]

1 minute ago, Geordiesnow said:

Would never wind people up Mark, just saying the reality that the outlook is mild and trending towards very mild again perhaps into next week, the models has been very consistent in this in all fairness so only saying what they are showing. 

Of course we can have a month of 2 halves so a colder 2nd half of the month can't be ruled out but certainly no significant signs of that yet. Would not rule out surface cold appearing in the outlook similar to the GFS18Z run if the Euro block alligns itself which brings more of a continental feed in. 

But there are - even the 18z, which is nowhere near as good as the 12, could easily throw up a ridge to Greenland or Iceland, i doubt that there would be brutal uppers but could still be cold enough for snow from the N or the NE.  You are right that the outlook is very mild in the short term but we are looking longer term.