Model Output Discussion 17th Dec.2013-12z onwards.

[nick sussex]

A very strange request from you Chionomaniac considering the great work and time you have put

in to educate posters about the importance of the state of the stratosphere in winter time and the

undeniable link it has with the troposphere and different synoptics seen in the troposphere and

on the NWP model output.

 

I think all cold winter weather lovers should be very pleased with the GFS 12z run from a

stratospheric point of view.

I agree, I sometimes use the zonal wind charts in here to show how they might be impacting on the models, and if people see something about the strat in here then they might become more interested to then go over to the strat thread.

 

It's a bizarre request, its model related and totally pertinent to this thread. I for one will continue to post references to the strat.

[Iceaxecrampon]

Rydal nr Ambleside today floods floods floods - A591 getting near impassable before White Moss  - walked up to the falls at Stockghyll quite impressed and near Niagara proportions -  and only just dried out.

 

Fresh snow on Fairfield looked tempting.

 

Heres an exciting Snow Risk near FI GIF at T+228 

 

 

Seriously still in the dishwasher for the next week or so.

 

Ian

 

 

[snowingtequila]

From when has this been just a tropospheric model thread? You can't discuss the models with no reference to the stratosphere unless no stratospheric indicators are included in the models.

[nick sussex]

Regarding this strat debate this chart is totally pertinent to the current modelling:

 

 

This is the  zonal winds for T240hrs from last nights ECM output, the blue for newbies shows a small reversal in the zonal wind at that level near the pole, this is helping with those high pressure lobes we're seeing there, the red area showing the zonal wind strength at the different levels, that has slowed it was 90 and is expected to slow to around 60.

 

If i'm going to be put off from posting these types of charts in this thread than I just won't bother posting at all, I'm now irritated!

 

 

[Mucka]

After my mini tirade re tonights ECM lets think positively here! The small high which looks no match for the PV could develop into a cut off feature here, it all depends whether that energy on the se part of the PV goes se.

 

It has though a low margin for error because the troughing over the UK  has taken so long to fill and disrupt, upstream is favourable, its just trying to get the pattern near the UK to play ball.

 

Yes, if we get that far down the road there is definitely scope for a cut off Icelandic high as the trough to the west of the Atlantic ridge disrupts with the possibility of a slider low as Steve M mentions.

I was beginning to lose all hope of some decent trough disruption in the second week of Jan with energy sliding NW/SE giving some heavy snowfall potential, albeit likely transient, but today's output has been more encouraging although I'm doubtful whether we could get as much Arctic air into the mix as I initially hoped when I was considering that pattern. The first week of Jan looks like being more mobile and stormy than I had hoped as well though I expected it to be unsettled.

No way of knowing which way this heading but it looks a little more encouraging than the EC32 updates were indicating a couple of days ago - mobile to end of time.

[Summer Sun]

ECM ensemble at day 10 once again highlighting the possibility of something less unsettled developing

 

 

Something to keep an eye on and see how it pans out amongst the other models

[Nick F]

It is more that this is the (tropospheric) model thread, cc, and I feel that we should concentrate on that in here and keep the strat influence in the strat thread. Granted, there will be some crossover - but I feel that there is currently becoming too much emphasis on FI strat charts in this thread. I think that we have reached a point where the influence of the strat on the trop is recognised by all and that I no longer need to labour that point as I felt I may have to have done previously. Therefore I am not saying that we should ignore the strat charts but perhaps modify the emphasis of them at this current time in this thread. In 10-15 days time there may be a lot more  correlation that is relevent to the trop output. It's a little bit too early yet though.

 

Very sensible idea IMO. We are no closer to the delivery of widespread cold and snow across the UK looking at the models this evening, with just teasers in FI to whet the appetite for now, so it's all too easy to look at the stratosphere forecasts for signs of a SSW to bring a change.

 

But, the stratosphere is not the only driver of our weather, teleconnections also play a big role in the wave patterns/upper flow in the northern Hemisphere. For example, despite a record cold stratosphere atm, the AO is forecasts to bomb negative thanks to +ve anomalies over the arctic - probably helped by ridging north via the Aelutian High. So we end up with a +ve to neutral NAO and -ve AO pattern.

 

Though there are signs that the arctic high, without help of a stratopheric warming, may help push the PV further south and perhaps split it, though maybe not favourably for us in terms in getitng cold and snow.

Edited December 30, 2013 by Nick F

[Mucka]

Woo calm down Nick, your input in here is invaluable and I'm sure Chion  comments are being taken out of context a little.  Good post showing how much impact wave activity is having on the Strat by the way.

 

Yes I agree. Chino is a victim of his own selflessness here I think.

I believe he was trying to say that FI strat projections are better suited for the strat thread in that they will not show up on typical diet of the MO thread which is pressure charts and trop charts which may cause some confusion.

I'm sure he is more than happy for the effect of any strat warming showing up in the pressure charts to posted and discussed here.

 

It doesn't matter to me either way but Chino is not the type to be elitist or exclussory, quite the opposite I think.

And Nick keep up the good work.

Edited December 30, 2013 by Mucka

[nick sussex]

Very sensible idea IMO. We are no closer to the delivery of widespread cold and snow across the UK looking at the models this evening, with just teasers in FI to whet the appetite for now, so it's all too easy to look at the stratosphere forecasts for signs of a SSW to bring a change.

 

But, the stratosphere is not the only driver of our weather, teleconnections also play a big role in the wave patterns/upper flow in the northern Hemisphere. For example, despite a record cold stratosphere atm, the AO is forecasts to bomb negative thanks to +ve anomalies over the arctic - probably helped by ridging north via the Aelutian High. So we end up with a +ve to neutral NAO and -ve AO pattern.

Yes but the whole point of this thread is to get people also more interested in other factors that perhaps they might not be that aware of.To fire up some interest in until recently an under researched area.

 

By having this no strat talk in here just ignores a large driver in our weather, of course we can't go into the fine detail in here but giving a few bits of info is hardly going to cause any problems, if people are more interested then they'll go along to the strat thread and importantly read the first page where Chiono gives a lot more info.

 

This will be my last word on Stratgate to everyones relief! I will continue to post easily digestible strat info! theres a lot in that thread that is quite mindblowing!

Edited December 30, 2013 by nick sussex

[mulzy]

Shame we can't see the ECM postage stamps at 240 hrs and 168 hrs but the 240 hrs ensemble spread is pretty interesting...

 

 

This suggests some members of the ensemble suite has similar or perhaps even more amplification than the operational.  Crumbs of comfort but still way out in FI...

Edited December 30, 2013 by mulzy

[SMU]

ECM 240 is roughly what I expected to see but not enough ridging NE - the jet would push that back

 

however at least theres some consistancy now!

 

S

[Nick F]

Yes but the whole point of this thread is to get people also more interested in other factors that perhaps they might not be that aware of.To fire up some interest in until recently an under researched area.

 

By having this no strat talk in here just ignores a large driver in our weather, of course we can't go into the fine detail in here but giving a few bits of info is hardly going to cause any problems, if people are more interested then they'll go along to the strat thread and importantly read the first page where Chiono gives a lot more info.

 

I'm not saying have no strat talk in here, I think Chino was merely remarking that there is too much emphasis on analyzsing the strat forecasts in here when there is a dedicated thread for that. I suppose, though, 'model output' does cover quite a broad spectrum of NWP forecasting sea level right up to 1hPa! All are interlinked, but normally the discussion here has always been about the slp/H500 charts.

[nick sussex]

I'm not saying have no strat talk in here, I think Chino was merely remarking that there is too much emphasis on analyzsing the strat forecasts in here when there is a dedicated thread for that. I suppose, though, 'model output' does cover quite a broad spectrum of NWP forecasting sea level right up to 1hPa! All are interlinked, but normally the discussion here has always been about the slp/H500 charts.

Lol! okay this really is my final word now, yes I'm not disagreeing with you. I certainly wouldn't expect some of the detailed strat talk in here otherwise you'd find the thread emptying pretty rapidly!

 

Generally I only ever use those zonal wind charts because they're easy to understand and just give a brief taster.

[bluearmy]

back to the models

 

i note the conversation re where the ecm op was headed post day 10. well the control is virtually identical and it goes onto develop an easterly and snow event as the iberian part of the trough moves ne and bolsters the euro trough. the cahrt for T300

 

 

of course it means nowt at that range

[Troubleatmill]

Shame we can't see the ECM postage stamps at 240 hrs and 168 hrs but the 240 hrs ensemble spread is pretty interesting...

 

 

This suggests some members of the ensemble suite has similar or perhaps even more amplification than the operational.  Crumbs of comfort but still way out in FI...

Yep, shows us (as often does) that the North atlantic is the hardest area of the entire Northern Hemisphere for forecasting weather systems, sods law we live here lol!

[IDO]

The ECM mean at T216 was  promising: 

 

But the mean at T240 flattens out the upper & surface trough; and the mean ridge, clearly follows the op, failing in one respect or another to sustain. Obviously at that range the trend at T216 is more relevant than the loss of amplification at the next frame, but a shame the lack of a trend:

 

 

The Dutch ens look like they are returning to normal temp wise in the extended range:  

 

The control one of the coldest runs.

 

But no sign of pending deep cold there. No change really then, the D12-15 region was when I was expecting more chances of cold, when that Canadian vortex was less volatile.

Edited December 30, 2013 by i'm dreaming of...

[nick sussex]

Does anyone have the control run on the ECM?

 

That does show some interest in terms of what could happen after the operational run, the wind goes northerly, ne  then easterly then se and then more southerly so perhaps the troughing sinks further se, some high pressure to the north before the Atlantic tries to move in again.

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

Edit that just seen BA's post!

Edited December 30, 2013 by nick sussex

[weather eater]

Don’t see any problem talking about the strat in this thread, the problem as I see it is that some people are seeing strat warming or strat warming projection in x days and assuming that it automatically means a guarantee of a change to a life in the freezer.

[draztik]

back to the models

 

i note the conversation re where the ecm op was headed post day 10. well the control is virtually identical and it goes onto develop an easterly and snow event as the iberian part of the trough moves ne and bolsters the euro trough. the cahrt for T300

 

eps_mslpa_c_exatl_51.png

 

of course it means nowt at that range

Hi BA, that sure is an interesting chart from the control. Any thoughts on the ens mean? Reference to the 10-15 day heights... ? For some reason weatherbell isn't opening on my mobile tonight.

[Frosty.]

Hey guys, we have some stunning pattern changing GEFS 12z perturbations for my fellow coldies to drool over tonight. I really believe a significant change to a more pronounced wintry tone will develop during the second half of January. The GEFS 12z mean shows a colder trend locking in by mid Jan so at the very least I would expect a spell of strong cold zonality and perhaps something arctic from the north / north east.  

[Captain Shortwave]

Well with the ECM ens out in reality we still face the same fork in the road (if the ECM and to a degree GFS are to be believed) as we did this morning. We either get enough amplification both east and west of us to bridge the Scandi and Atlantic ridges to develop heights to our north, and deliver an easterly, or it fails and the Atlantic rolls in as the Canadian vortex cranks up through the gears again.

[Nick F]

Not sure if someone else has already mentioned this, but one thing that struck me about the differences appearing between appearing between 12z ECMWF and GFS ops is that EC has a deeper mean trough over eastern N America 8-10 day range which in turn leads to more amplification downstream over the NW Atlantic, so we see a split between the trough migrating close to the UK and the main vortex of low heights over E Canada - with +ve height anomalies over Iceland/S Greenland 8-10day on EC deter. GFS has a less deep trough over eastern NAM and thus flatter downstream - without the proper split between the E Canadian Vortex and Altantic troughing near the UK.

 

http://www.meteo.psu.edu/~fxg1/ECMWF_12z/hgtcomp.html

 

So, big chunk of low heights extending east towards the UK form the main cold vortex over E Canada, but keep an eye out for how deep the trough gets over eastern N America which will determine whether or not we get amplification downstream and a closed upper low close to the UK which eventually sinks to allow height rises to the N and NE.

Edited December 30, 2013 by Nick F

[bluearmy]

Hi BA, that sure is an interesting chart from the control. Any thoughts on the ens mean? Reference to the 10-15 day heights... ? For some reason weatherbell isn't opening on my mobile tonight.

 

to me, the ecm ens seem to be, as i mused yesterday, clustering around different solutions, and the ens mean becomes more irrelevant as the run progresses.  the anomolys are also becoming less clear, apart from a persistent ridge off newfoundland.  although we want to know whats likely to happen, i think for the time being, its a wait and see job until the modelling settles down. exeter will clearly have, via vision of each member, a view of the clustering. i would suspect that the favoured option is for the ridge to be flattened post day 10.  however, i also think there will be quite a few scandi high solutions in there.

[Allseasons-Si]

@ Frosty,yes they look good,some of those look very simular to BA's chart a moment ago with the trough sinking into europe bolstering the high to ridge to our north,maybe there is more to the ridging in the atlantic than first thought,interesting model watching in the next few days as allways.

Edited December 30, 2013 by allseasons-si

[Joe Levy]

I wasn't around earlier as I was at a family do, so apologies if someone already posted this, but I thought this chart from the GFS 12z, showing such fantastic warming over Greenland was great to see. I appreciate there have been some comments about strat related posts in this thread, but I believe a balance is necessary to substantiate any claims we might make from model output!