[Cold hunt - models and chat]

5 minutes ago, Rocheydub said:

It's a "trop" for a start. Sorry if that sounds smartass. It's short for troposphere.

No probs it's my predictive text lol

[Cold hunt - models and chat]

20 minutes ago, Catacol said:

Nope - that isn't what I would ask because an answer sits already within your first sentence. If you don't know anything about the background signals that are regularly discussed then it might be as well not to risk suggesting they are a waste of time. Dark Arts - no. If it was dark arts then we wouldn't even have NWP because science wouldn't apply either. 

There are a lot of helpful guides on this site, and a number of places you could go to begin growing an understanding of what drives the atmosphere, and then your contributions would be more useful. Either you are genuinely interested in what is going on and are frustrated and not being able to explain/understand the processes, or you are here to act as a deliberate lightning conductor for the frustrations that some are feeling right now - and that is an approach which is unhelpful. Whichever it is it seems a huge waste of time, because non-engagement with the processes means intellectual stagnation or attempting to magnify forum frustration means marginalisation from the real debate. Neither approach will take you anywhere.

 

Catacol hope I got this statement correct , ssw come in 2 different styles a ssw or a dsw the difference between the 2 is that a ssw can influence the strop in 9 days where as a dsw can take upto 4 weeks to influence the strop,thus was a dsw why we are waiting a long time for its effects to be felt,please feel free to correct me on any of this ,

[Cold hunt - models and chat]

2 minutes ago, ICE COLD said:

Let’s hope so Kev really want this to come off but I’ve just lost faith . I mean look at this ECM mean 00z Friday . It’s the nuts . 

We all said rock solid and it was and look what happened . So the day 10 means are looking great again but not as great as that and if it can go wrong at t144 what chance do we stand at day 10+ . Maybe are be more positive tomorrow. I feel a bit of a sado being so annoyed but I just love freezing snowy weather .

IC all I can say is I've been watching the weather for 60 years and models flip but Mother Nature never flips,bring back winters in my youth in the staffordshire moorlands  ( Brutal ) lol

[Cold hunt - models and chat]

40 minutes ago, ICE COLD said:

I suppose it’s all about expectations on here . The ecm run is ok , the better the north you are but I’m wanting something a bit more tasty as I’m sure everyone is . Don’t get me wrong the EC run is better than having sw winds . But with all the background signals etc etc we should be expecting a bit more than a N wester or a fleeting Northerly . Don’t get me wrong I’m not exspecting last years beast but something in between would be good . It’s all a bit half hearted at the min . Don’t shoot me down I’ve been positive all winter , just losing the faith a bit now

IC don't lose faith it's going to happen,the first attempt was flawed because no back up from Mother Nature,but the second attempt at end of Jan / beginning of February will succeed because the birds are going into panic mode looking for food.

Also going to make a big statement we better get use to ssw events because they will become more frequent as the planet warms up ( but more research needed on this one) so as the planet warms we will get colder winters.

[Cold hunt - models and chat]

7 minutes ago, CreweCold said:

Just a shame it's happening back end of winter (last month of the season) I'll take anything I can get at this point though. 

Don't worry about time it will be brutal,it would lol live in your memory.

[Model output discussion - cold proper on the way?]

17 minutes ago, northwestsnow said:

The blow of losing the easterly is raw but i believe we will see north westerlies and the hope, not expectation , the hope, is we see heights building in the N Atlantic...

Which is what i suspect Exeter are signposting in their updates...

Hey NW keep the faith m8 because the second attempt at 384 on gfs will succeed ,it's screams total northern blocking greenie and nice cold ridge coming down to Scandinavia and it's the new moon on the 4th Feb,my old man always said if the weather turned cold on a new moon it would be the dominant feature for 30 days,but not everyday will be cold,keep the faith.

[Model output discussion - cold proper on the way?]

14 minutes ago, in the vale said:

There are very few composite analogues available for DSWs; even SSWs only have a small number to factor into their physics. All the more reason to distrust lower level/surface NWP currently. 

We'll distrust at your peril there is information about dsw available,when it delivers it will prevail for 30 days,not every day will be cold  but the majority wil.

[Model output discussion - cold proper on the way?]

4 minutes ago, in the vale said:

This is a key post. The SSW commenced with a reversal at 10hpa around Xmas if I recall, with discussion at the time that, on average, it takes around 2 weeks for that to make it's way down a long, long way to be felt at the surface. This downwelling seems to have been quite a bit slower than expected. I think the models struggle with this transition period - starting data may not be easily parsed when dealing with conflicting obs at different atmospheric levels (strat, trop, surface) that are perhaps unrecognisable to the steady-state, normal conditions that models deal with - i.e. the transition period is going to throw up some strange anomalies, especially as the downwelling gets closer to the surface and more obs are factored in. ECM with it's higher vertical resolution may actually be more confused than any other model. Until the downwelling is complete - next week - and the models can 'recognise' an obs pattern that their physics can recognise as a start point, they are going to thrash around like a mackerel just off the hook.  I would not put much faith in any output beyond 68h. The big picture seems to remain unaffected by the transition - low to our South, high somewhere North - those keep us in the game. 

This was always going to be a slow response because it was a DSW not a normal SSW,it will happen but not until 3/4 FEB,research a DSW .

[Model output discussion - 7th January onwards]

5 minutes ago, ghoneym said:

Maybe not Spain or Africa but forecast to move away from a pole ward jet towatds the equator, yes in the zone for the jet to fired up slightly but it certainly won't be a raging jet, low enough latitude wise so as too not cause us many issues going forward. 

By the 28 Jan we are still on the warm side of the jet,so it's February for cold.

[Model output discussion - 7th January onwards]

25 minutes ago, knocker said:

Merely an observation because of it's strength but at the end of the ecm the jet is impressive

 

11 minutes ago, MattStoke said:

Up to +192 hours I thought the ECM looked quite similar to its seasonal model output (which has done well so far this winter), with high pressure to our west/south west. Further ahead the seasonal model has a strong signal for higher than average pressure to our north west, so I wouldn’t worry too much that daily model shows something different and less favourable for cold. Plus the fact it’s so different to this morning’s update (unlike the very consistent seasonal model output).

Good observation,can anyone on this forum show me evidence of the jetstream going on its hols to southern Spain or North Africa ,if not forget a very cold spell the jet rules uk weather end of.

[The Hunt for Cold continues 02/01/19]

2 hours ago, TEITS said:

Nothing to do with luck. If we do not see any cold weather this winter then obviously the variables that dictate our climate were not favourable and those variables were misinterpreted.

Very disappointing output. Just when we were hoping we may see some form of blocking/Cold Spell to hit the UK around Mid Jan, the models are currently suggesting the reverse with an unsettled outlook looking likely with gales. The most disappointing aspect is I see nothing that suggests any form of blocking will develop towards Greenland, infact the complete reverse!

I value your opinion but mid Jan too early ,end of Jan early February should deliver but what do I know,weather science can make you look silly.

Happy model watching.

[The Hunt for Cold continues 02/01/19]

2 hours ago, Bring Back1962-63 said:

MY CURRENT VIEWS ON THE MODELS AND THE OUTLOOK

That was a great post @Kirkcaldy Weather and should be read by all those who are moaning about the output.  I have very little time now or for a few days - so rather than show loads of charts, I'll make a few bullet point statements on the background signals, the model output and several general comments.

• No two SSWs are alike - I do not know how many times that has to be said.
• In my last two posts I tried to show what to look out for with comparisons to the current set up and charts with the 2018 and 2013 SSWs (part 3 on 2009 with likenesses and differences to 2019 to follow by next weekend).
• What those archived charts showed was just how quickly the HLB patterns developed and the whole northern hemisphere set up changed and evolved.
• I noted John's @johnholmes comments this morning wrt examining archived "forecast" charts prior to earlier SSW events - something I suggested too - they're available for most of the models now and certainly the big 3.
• John also queried whether or which previous SSWs had failed to deliver any significant cold here in the UK.  I'll just repeat a table here:

• We know that 2018 and 2013 delivered big time and they were split SSW events (2013 displaced and then split) and so did 2008//09 and 2009/10 both also split. The last displaced SSW was in 2007/08 and I believe that can be considered a failure but for that and earlier events, we need to check the archives - and I haven't got time for that but anyone can go by the table above and check the archive charts for the whole SSW period.  Here's the link again:  http://www.meteociel.fr/modeles/archives/archives.php?mode=2&month=1&day=20&year=2008&map=4&type=ncep  I set it to Jan 20th 2008 to get you started.
• We can take comfort in the fact that most (perhaps almost all) split SSWs have produced decent periods of HLB which have delivered cold to the UK.
• The teleconnections have NOT let us down at all and contrary to what the usual suspects might be saying through their impatience. 
• In fact they are almost spot on in terms of what we expected from them - there's a slight problem over precise timing but that's always the case with SSWs and such dramatic pattern changes (which the models cannot handle). 
• The next three comments were confirmed to me by @Tamaraby PM and I hope she doesn't mind my referring to them as she will continue to avoid this thread with all the confrontation and I fully sympathise with her (our loss).
• The tropical/extra tropical cycle and forcing has been sufficient to amplify the tropospheric pattern and it's just that the polar field has not "yet" been conducive for HLB and stratospheric dimuition. 
• She thinks that in January 2013 the tropopause was more receptive  at this stage than it has been so far this time.
• She feels that "its still barely into the second week of January and there is far too much overreaction in general".  
• Back to my own comments: That means in both directions - no cold patterns showing or a Siberian wasteland - we're somewhere in the middle right now. 
• We've a substantial split event ongoing and the best news is that this SSW seems likely to be very protracted, perhaps approaching the 2013 record length and some records are already being achieved up there.  
• We should have at least two or three bites at the cherry.  
• The lagged impacts of the MJO through phases 6, 7 and now into 8 may show up within the next 7 to 10 days - favouring HLB.
• I see that for once the GEFS (bias corrected version) and the ECM are both in broad agreement for a change (long may that last but do not hold your breath) and week 2 MJO forecasts and notoriously unreliable..
• Although they dive into the COD soon, they both look set to re-emerge in phase 6 and maybe for a quick "rinse and repeat" through phases 6, 7, 8 and 1 again in early Feb.(perhaps later). Something to keep an eye on for sure.
• The lagged effects of the GWO in phases 5 and 6, albeit at slightly weaker AAM than we had expected is still strong enough to have +ve impacts for the next two weeks. This cycle is likely to repeat in or by early Feb too.
• The temporary weakening in the El Nino seems to be over and it looks sets to strengthen again - a better tropical state with a weak Nino - gentle forcing but not too strong like the 2015 super Nino..
• Meanwhile, the SPV destruction continues and may take many days, weeks or perhaps not at all to reform into a more organised fashion.  
• Overall - an exceptional and truly fascinating period for all the atmospheric processes with an extremely high chance of cold patterns setting up later this month and perhaps for much of February too..
• We are about to see a transition to a less settled phase but this is probably a sign that there are changes to feed through from the Arctic and towards the mid latitudes - merely timing issues IMHO.
• Looking at the models, I see that a good number of ensemble members show charts which develop HLB blocking patterns - some as early as day 7/8 and building on the Arctic outbreak, others do this later on in the run.
• If you study those charts from 2018 and 2013 and indeed some other pre/during/post split SSW events, you'll see that the initial impacts can almost always be seen close to the pole. 
• Several GEFS ens show a "yellow" HP - a strong sign of a full reversal reaching the surface.  Some show heights building towards a proper Greenland HP and some towards Scandinavia.  
• Do not worry about the TPV still looking immovable on our side of the Arctic.  What should happen is as (when - not if IMHO) the wind reversals reach the surface is that those low heights are displaced southwards - almost bulldozed out of the way.  Quite often a lobe drops into Scandi and it "looks" like we'll see a true northerly but that would likely be short-lived and transitory but not the normal "toppler type" either.  What happens is that HP builds around the top of the LP and pushes that south into central and southern Europe.  Then that opens the pathway for Siberian and Russian heights to push westwards (which occurred in dramatic fashion to create the "Beast" last Feb/Mar.). Although easterlies have been a rarity in the last 30 years they were much more common back in the '60s to '80s and even mild winters saw several outbreaks. Those associated with SSWs are usually very potent. Then the HP can build towards Iceland and Greenland letting in a true Arctic air stream with north to north east winds - many of our coldest winters see an easterly/northerly combo.
• When will all this happen? I'm very confident of "this" winter and well before Spring.  No guarantees - there never can be but the current set up is on the verge of something quite dramatic. Frankly, with the strat state as it is and taking account of the other teleconnections, I'll be astounded if we do not see a memorable cold spell in much of Europe, the UK and eastern CONUS, eastern Canada as well as large parts of Asia/Russia/Siberia - not all at the same time but we should all see periods of extended wintry weather. 
• So, please, please be patient and accept that the models will struggle - which I and others have been saying for a while and I've shown that there has been a slight delay - not for weeks on end!.   

When I'm on here again at the end of this week, I hope that we can all be focusing on some much more attractive output in the mid term. 

David  

Top post top man so level headed,if we don't get any cold this winter it will be the most unluckiest winter on record.

[The Hunt for Cold continues 02/01/19]

38 minutes ago, Kirkcaldy Weather said:

GFS 12z gets the above average heights toward Greenland and colder air moving south across the UK at the end of the run so the next step would be / is for this to keep being shown and gradually getting nearer within 200h , 100h etc and also for those above average heights to get stronger and slightly better positioned which I believe have a good chance of happening within the next few weeks

   

some from the 0z run of the ensembles FNMOC/NOGAPS (note the blocking / above average heights signal over Greenland / to our north) (couldn't find a north hemisphere view)

 

now to see what the 12z GEFS show

This is backed up by the jet,puts us on the cold side at last.

[The Hunt for Cold continues 02/01/19]

15 minutes ago, WhiteFox said:

I applaud those who produce long range forecasts; they often put a lot of hard work into their posts, place their neck on the block and are far too often decapitated. As a result, some unfortunately take their efforts elsewhere.

It's worth differentiating between probabilities and exact outcomes. A split in the TPV looks probable, but not guaranteed (unless I've missed some information). If this does happen, then it increases the likelihood of cold air dropping south and affecting the UK. The SSW has not yet propagated down to the Troposhere and until (or even if) it does we cannot be sure of the effect it will have on our weather. At the moment, the models are starting to play around with various scenarios based on hugely complex interactions through multiple levels of the atmosphere, so is it any surprise we are seeing swings in the latter stages of output? 

Most LR forecasters I've read are based on the SSW impact. Until we see the effects we cannot judge accuracy and even if they are wrong, its a learning process based on a huge effort which is largely unrewarded and even criticised. 

Give people a break!

 

Well said that man,we were never going to get QTR because we did not get a SSW we had a DSW ,one feature of a DSW is very slow down welling to trop but when it happens it could be long lasting,( research a DSW fascinating.