Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[Nick L]

Can we keep discussion regarding tonight's snow event (unless it is model related too) in this thread:

 

https://forum.netweather.tv/topic/82292-upcoming-cold-spell-discussion/

 

That includes "will it snow..." posts and discussions of Met Office forecasts. Thank you.

[winterof79]

This fax is showing the problematic front and probable snow to the north of the front disecting England 

 

 

 

 

Edit:Please move as necessary

Edited January 20, 2015 by winterof79

[mushymanrob]

Thats interesting, ive had this hunch that we might get a scandi high (and have said so) Although current models and the anomaly charts dont yet suggest a lasting strong scandi high, it has to be a serious consideration. Shades of 86 and that freeze in feb isnt something i relish, but there is a flavour of it in the air. And its not the type of weather i would like in feb

 

well me and my scandi high concerns look like they could be completely wrong if this chart verifies!

 

 

a potent northerly has cropped up afew times now, so must be a low consideration. low because its deep fi and has no support that far out.

in the meantime eyes are switching westwards towards a period of mobile unsettled pretty average weather which for late january is pretty chilly.

[Tamara]

To reason this further, I am cutting right through the noise suggested therein - and the signal that I am reading from extended ECM data, which has picked up on GEFS suggestions of late, points exactly to that pincer movement I discussed yesterday from one side of the pole to the other. So the Pacific side might lead as we have seen, but tropospheric action through recent +East Asian Mountain torque, plus displacement pressure on the vortex pushes the vortex balloon hard, rather borrowing Chiono's analogies , from the other side of the pole as well.   The pincer movement, as indicated within clusters of extended ensemble data.

 

Timing of all this perhaps not too long after the the new month arrives (not far away). Renewed MJO activity into the Western pacific towards Phase 6 remains quite possible - and thereby still implies renewed forcing activity.

 

Its worth watching GWO forecasts in this respect.  We could quite conceivably, as recently, see orbit progression through 3 back to phases 4/5 and engineer yet another +MT early in February. The stakes then go up yet another gear.

 

 

Sure enough first forecasted indications of longer term GWO orbit progression to  +ve frictional torque Phase 4 (and then I believe logically on thereafter to Phase 5) to initiate another +EAMT around early February time

 

.http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

 A switch back in the atmosphere to more Nino like tendency, such as we are/have been seeing this week, and a further +EAMT really will help our cause in the vortex pincer movement and increase chances of something better and more sustained for February.

 

A symmetry I think is likely to evolve to the previous Phase 4/5 orbit - and with atmospheric tendency more on our side by then, hopefully, don't rule out further MJO forcing into Phase 6/7 after tropical signal re-awakens

 

Less cold westerly phase recycle from end of the week, much as clearly factored in - but this continues to look to lead faster than previously back to increased troughing once more into Europe and then another likely Atlantic amplification

 

Shortening seasonal wave lengths will help our cause. It might be later than many would prefer, but despite apparent steadfastness in ECM 32 day model for more of the same as earlier in the winter, I remain optimistic for increasingly improved prospects through the coming month

 

Edit: @mulzy    GEFS latest available data suggests re-entry to Phase 6 and ECM a little further back. UK plot is shorter range. In context of what was posted above its still early enough yet in this respect - its a case of watching both MJO tropical and GWO atmosphere plots in the coming days

Edited January 20, 2015 by Tamara

[mulzy]

Excellent post as ever Tamara.  We still have 39 days of winter left so plenty of time...

 

Day 10 GEFS and ECM Ens anomalies shown below:

 

 

 

Broadly similar - a zonal pattern with both Pm and Tm influences.  If only that trough over the North of the UK would sink a little bit further south!

 

MJO not really helping (wrt to sustained cold weather) us at present - most forecasts suggest a period in the CoD (UK MOGREPS indicated here).

 

Edited January 20, 2015 by mulzy

[winterof79]

Sure enough first forecasted indications of longer term GWO orbit progression to  +ve frictional torque Phase 4 (and then I believe logically on thereafter to Phase 5) to initiate another +EAMT around early February time

 

.http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

 A switch back in the atmosphere to more Nino like tendency, such as we are/have been seeing this week, and a further +EAMT really will help our cause in the vortex pincer movement and increase chances of something better and more sustained for February.

 

A symmetry I think is likely to evolve to the previous Phase 4/5 orbit - and with atmospheric tendency more on our side by then, hopefully, don't rule out further MJO forcing into Phase 6/7 after tropical signal re-awakens

 

Less cold westerly phase recycle from end of the week, much as clearly factored in - but this continues to look to lead faster than previously back to increased troughing once more into Europe and then another likely Atlantic amplification

 

Shortening seasonal wave lengths will help our causer,. It might be later than many would prefer, but despite apparent steadfastness in ECM 32 day model for more of the same as earlier in the winter, I remain optimistic for increasingly improved prospects through the coming month

Thanks Tamara as ever.Looking good on the GEFS further out.A long way off granted but no mild Feb on anything i see.

You do know though that by Feb,the days will be longer and the sun stronger ..........just thought i would get that old chestnut out of the way before someone else does :whistling:N.B. not that i subscribe to that theory.

Edited January 20, 2015 by winterof79

[Continental Climate]

Not much joy to be had out of this chart really http://www.wetterzentrale.de/pics/Rtavn1681.gif!! We may be able to squeeze a bit of cold zonality out of this pattern but IMO thats about it. With a few exceptions this pattern seems to have been the default pattern of our winter so far with the fat azores high dominating. It really has been omnipresent throughout. 

[winterof79]

This seems to me to be the crucial/interesting time line when the ridging starts over the other side of the Arctic.It is modelled earlier on the 06z  than the 00z

Edited January 20, 2015 by winterof79

[winterof79]

The OP GFS looks like being on the milder side of its ensembles in the latter stages

http://modeles.meteociel.fr/modeles/gfs/runs/2015012006/gfsnh-0-384.png?6

 

GEFS

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=300   still trending cold by Feb.Some lovely arctic profiles showing.

Edited January 20, 2015 by winterof79

[Trom]

This seems to me to be the crucial/interesting time line when the ridging starts over the other side of the Arctic.It is modelled earlier on the 06z  than the 00z

 

Yes that seems to be a critical time.  Only 8 ensembles kept us with Westerlies at that date.  The rest showing NW to NE.  So it looks from this that if we are to see another cold spell it's going to be northerly rather than easterly based.

[Hotspur62]

The OP GFS looks like being on the milder side of its ensembles in the latter stages

http://modeles.meteociel.fr/modeles/gfs/runs/2015012006/gfsnh-0-384.png?6

 

GEFS

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=300   still trending cold by Feb.Some lovely arctic profiles showing.

There some great runs there for cold. My only concern is that on virtually all those the AH has not moved further West/North West.It might be me but so far this winter is just hasn't moved too much and to get established cold I would like it to move a good 1500-200 miles further West.I would feel alotmore comfortable/confident then of a proper cold spell then.

[Froze were the Days]

There some great runs there for cold. My only concern is that on virtually all those the AH has not moved further West/North West.It might be me but so far this winter is just hasn't moved too much and to get established cold I would like it to move a good 1500-200 miles further West.I would feel alotmore comfortable/confident then of a proper cold spell then.

Yeah more or less correct there mate - Azores high remains ever present, amplifying at times and at other times becoming flat and hence more zonal westerly conditions but the darned thing always stays in situ (more or less) plus Greenland PV plays a large part in this. Edited January 20, 2015 by DiagonalRedLine
Fixed the problem of your post appearing inside Hotspur61's quote box.

[Jason M]

Looking through the GEFS and GEM ensembles they can best be summed up by 'strongly zonal' in my opinion. Its possible to pick out an odd chart in isolation which shows promise but its a mirage really as if you run the sequence everything is moving rapidly west to east. In essence, its pretty much as expected.

A major feature of the ensembles is also the complete absence of any HLB. Given that the ensembles are tweaked slightly it shows that HLB is very unlikely indeed. This obviously fits in with how the METO see things going forward.

I tend to view the opps as showing the route we are headed down, with the ensembles showing the width of the road. In this case the road is a six lane motorway with no junction in sight!!

Do accept though that others will take a contrary view and of course the output can change :-) This pattern may give some interest for the north but probably not so promising for us down south.

[bluearmy]

I think at this stage any HLB will be away from our part of the NH which is forcing the jet further South and the mean trough with it. As has been the case so far this month, 'it's all about the Azores ridge'.

It could be encouraged into mid Atlantic by upstream trouging or even perhaps the Alaskan ridge splitting the viortex and getting Into n Greenland.

Certainly looking very mobile and potentially quite chilly or even cold. It wouldn't take too many adjustments on that to bring quite wintry conditions but then again, the Azores could ridge East or northeast and scupper that.

Edited January 20, 2015 by bluearmy

[No Balls Like Snow Balls]

From WSI

Possible temporary cold spell during 1st week in February according to GFS operational. Low confidence at present.

[Catacol]

The pattern does look westerly from here on in to February, and the MetO conclusion of a similar pattern out to mid Feb is gloomy for coldies. It has been a very frustrating first month of winter (I tend to think of winter as mid Dec to mid March) - even more so on the back of the shocker of last year. I guess there is inherent imbyism in that statement - because cold cyclonic conditions have brought snow to many in the north... but for the south of England we need something much more solid in terms of a continental flow or a proper block for the atlantic to rub up against.

 

At the same time so far the models have given us much more eye candy than is some years gone by. Strat watching has been very interesting - if again extremely frustrating - and we have seen all kinds of arguments breaking out on this forum because of different interpretations of the essentially amplified westerly regime. I hark back to RJS and his early winter forecast. He picks up a lot of flak from some, but to my eye his general sense of things is often very good, and an up and down westerly pattern with alternating PM?TM flows is exactly what we have got.

 

Where do we go from here? Tamara's last post was excellent I think: we have teleconnective factors still in favour of a colder solution to NW Europe, but I think we need to see an event in the strat come to fruition that supports a sustained disruption to westerly strat influence in the atlantic sector. If we dont get that then I think we may face several more weeks of this same kind of pattern - as stated today by IF. I'm hoping the Met may have underestimated the potential for strat disruption into February.

 

It's raining in Somerset again this afternoon and its cold. Cold without frost and snow is just a total waste in my book and so depressing. Here's to something appearing in the models in the next few days that might point to something of interest - the events of this week look to me to be turning into something that will barely hit the local news channels at all. Only 15 posts since 10am this morning says it all!!

Edited January 20, 2015 by Catacol_Highlander

[winterof79]

Saturdays frontal band not as clear cut as one may think, back edge and more with the undercut

 

 

Edited January 20, 2015 by winterof79

[Nick L]

Saturdays frontal band not as clear cut as one may think, back edge and more with the undercut

 

 

 

A little more back edge cold on this run, but I do think the Meteociel precip charts tend to overdo snow. It will be a "northern hills" job in my opinion.

[Captain Shortwave]

The GFS does develop a deep Euro trough by day 8

Just need to see what the op can do with this. The Azores high really needs to do one. We really need that Alaskan ridge to piece through the north pole and ridge into northern Greenland to allow a breather for the Azores high to ridge northwards.

Edited January 20, 2015 by Captain shortwave

[mountain shadow]

The GFS does develop a deep Euro trough by day 8

Just need to see what the op can do with this. The Azores high really needs to do one.

Indeed, but with low heights to NW and NE it has no where to go. We need something, anything to encourage it away from its natural home. It really is all eyes on this potential final strat warming of the Winter.

[Summer Sun]

The GFS does develop a deep Euro trough by day 8

Just need to see what the op can do with this. The Azores high really needs to do one.

 

24 hours later....

 

 

Still time yet for January to go out on a snowy note......

Edited January 20, 2015 by Summer Sun

[carinthian]

Well what a relief the 12z GFS and UKMO provides for many cold lovers. The heights set to remain low in the Med with a increasingly NWly flow by the last week of the month. That ties in with our forecast for the first week of February to turn much colder from the North with snowfall becoming widespread. Better amplification polewards of the Azores high expected with deep trough from Scandinavia low to affect much of Europe. Should see this development in tomorrows runs.

[igloo]

not to bad looking at +212h with HP trying to form at the denmark strait area. for sure a colder zonal run from this morning 6z

Edited January 20, 2015 by igloo

[karlos1983]

not to bad looking at +212h with HP trying to form at the denmark strait area. for sure a colder zonal run from this morning 6z

 

Sorry but I can't see a 212 chart and certainly no height rises in that area? Unless the Denmark strait is nowhere near actual Denmark?

[NorthernRab]

Sorry but I can't see a 212 chart and certainly no height rises in that area? Unless the Denmark strait is nowhere near actual Denmark?

The Denmark Strait is between Iceland and Greenland (which is an overseas territory of Denmark).