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

[IDO]

Well a big step back on the 06 GEFS with just 3 members now supporting the Atlantic ridge around D10. On this run the trough is further east due to the Azores not being able to ridge towards Greenland. The UK remains in a zonal flow:

 

D10 mean:  D12 mean: 

 

Clearly in this type of setup we are relying on many factors to be right to get that transient ridge in the right place for a brief UK cold spell. Obviously only one run but this shows how easy it is to go wrong. The synoptics remain the same but the UK is on the wrong side of the Euro trough, again! And of course we lose the colder mean uppers in this scenario.

 

 

 

 

[pureasthedriven]

Going to post the ECM mean at +240 to show you what we need to see in future outputs. Forgive the rather crude drawings but you will get the gist.

Right so note the PV (B) & © we need to see this split with this highlighted by the arrows. This is turn will allow heights across the pole (A) to extend S. Now note (D) & (F) we need to see the trough extend as far S as possible whilst low pressure (D) tracks N towards the W side of Greenland. At the same time this will allow the Azores HP ridge N. All of this combined will allow a sustained flow from the N.

ECM N Hemisphere.jpg

In essence, all the cogs need to turn in the appropriate direction, pushing and pulling, pushing and pulling... Hard to see how any of that can click into gear with the progged Jet profile - and rightly or wrongly, that's where I always go first and if that looks unfavourable, tend not to look any further, which may well be very amateurish but, to paraphrase Kennedy, 'It's the jet, stupid,'

Nice post, TEITS.

Edited January 21, 2015 by pureasthedriven

[seaside 60]

Fortunately don't think tides are predicted to be particularly high because there would be North Sea storm surge risk from the charts at the end of the month that have been appearing for a while -

 

The big spring tides are now till sunday then they start to drop off, by the end of next week they are neap tides.

[winterof79]

The ensemble for Manchester is keen on a steep temp gradient following the passage of the front Saturday after that there is solid agreement on there being some form of weather........seriously though the clustering offers cold zonality around the 29th for five days.

[bluearmy]

There really is no chance of getting the 'right side' of the euro trough in the next couple weeks.

However, the amplification showing at day 10 was not really expected until four or five days later ( prior to yesterday's output) so to show week 2 ops as being evidence that x or y can't happen is unwise.

The theme remains the same - the nuances wide and varied.

[winterof79]

Well a big step back on the 06 GEFS with just 3 members now supporting the Atlantic ridge around D10. On this run the trough is further east due to the Azores not being able to ridge towards Greenland. The UK remains in a zonal flow:

 

D10 mean: gensnh-21-1-240.png  D12 mean: gensnh-21-1-288 (1).png

 

Clearly in this type of setup we are relying on many factors to be right to get that transient ridge in the right place for a brief UK cold spell. Obviously only one run but this shows how easy it is to go wrong. The synoptics remain the same but the UK is on the wrong side of the Euro trough, again! And of course we lose the colder mean uppers in this scenario.

Lets compare the 12z GEFS  IDO see if its a blip.They are pretty awful at 240z but hey ho.

Edited January 21, 2015 by winterof79

[fergieweather]

Cautionary note not to take nature of any trough disruption/resultant northerly broad flow and longevity of this, plus timing of subsequent return to flatter zonality, too literally.

Models will inevitably show great divergence in how this is handled, including run-to-run, as is typical in any such scenario. The one we are currently experiencing epitomised the difficulties even to short lead times.

[BLAST FROM THE PAST]

Forgive me for saying but doesn't that contradict your previous post. Synoptically you are describing what we have seen already this winter i.e brief colder spells. The problem with this is that without HLB the N/NW,lys are not sustained enough to bring the very cold air S. What generally happens is upper temps of -5C arrive which generally only give snow showers to Scotland especially over higher ground. What this winter has taught us is we need to see HLB to bring severe wintry weather across the UK.

Not really Dave, the trough has been to our NW, main trough to be more over us or Scandi.  With AZH ridging in Atlantic or backing west it would allow for more N'ly flows or cold sub lows coming down western flank of trough....I've posted enough model images to illustrate the idea.  So no I'm not describing same synpotics.  How many times have you heard people mention the deep cold piling into Atlantic to our west but being modified?  Shift the pattern east.  It won't happen overnight but early Feb is target with the movement towards and descent into such a set up around end of month.

 

But on the post you responded to I can see the lack of clarity.

 

BFTP   

Edited January 21, 2015 by BLAST FROM THE PAST

[bluearmy]

BA what do you make of the PV split? The GFS 06hrs run almost gets there and looks like its edged towards the ECM. I think most would be happy to just get a couple of days of non-marginal snow, which has been difficult so far this winter away from more elevated areas of the north.

 

nick, just been looking at the extended eps again and its noticeable that the really important part of the run re sthe split co incides with the drop in resolution of the ens at day 10.  given that andrew has shown on the strat thread that this upcoming euro trough is indeed strat driven (we did wonder yesterday when the trop modeliing began to reflect the strat profile at a similar time), i would be cautious about placing too much store in the extended ens until we begin to see the split from the pacific side relaxing pre T240.

 

if the ops are showing the same broad solution at day 8/9, they may prove to be a more useful tool than would normally be the case at this timeframe when viewed in conjunction with the ens.  it may well be that the split will close up and the canadian continue to be the major player but i'm hesitant to say so based on the above musings.

 

what is clear from andrew's posting is the close coupling between the upper strat and trop as has seemed to be the case for a while now. only a few days delay for parts of the pattern to show although its not a clean reproduction down below.

[Tamara]

Re-emphasis on yesterdays points remains the same as then and recent days - despite the rapid oscillations in recent days. More changeable conditions ahead - but it remains questionable at this time that there is any sustained return to westerlies. 

 

In terms of the atmosphere -AAM lead it is logical that upstream developments stem from the Pacific side in terms of the ridge there and the downstream mid latitude ridging which is advertised in this mornings 7 to 10 day period.

 

At the same time as the pattern adjusts back, we have previous, current and future vortex perturbment that is piling up a hemispheric vortex ambush (not Pacific dominant, from both sides of the pole) courtesy of a lagged and laddered programme that ask questions of the re-cycling long term sustainment of this repetitious westerly pattern

 

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.

 

Ensemble means, most especially are rendered misleading and far too over smoothed in my opinion at this time

 

For me, it remains the strongest extended signal and is backed up tropospherically and stratospherically

 

It is hard obviously at this range to suggest exactly how this might play out synoptically. But such a pincer squeeze strongly supports a series of significant NH amplifications as cross polar ridging occurs and displacement activity stresses the upper vortex to our NW as pressure rises right over the pole.

 

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.

 Another day, and further clear evidence that this is not any sustained flat pattern re-set such as we saw after the late December mini Atlantic amplification.

 

A clear cyclical -AAM NH pattern advertised so far this winter with the GWO for the most part locked into a Phase 1,2,3 and reverse 3,2,1 phasing  - we had that late December minI amplification, then the extended zonal gap to the current post mid month January amplification, and now the much narrower gap indicated between this and the next amplification already coming into view to coincide as suspected with the turn of the month.

 

This next amplification features the promise of a better embedded European low anomaly - much as many others have said. Stratospheric mid upper level log jams are at last beginning to assert some authority on the underlying tropospheric Nina type Pacific lead on the winter pattern - even if they haven't ( yet) overturned them. 

 

I think this undisturbed pattern has, until the last week or so, supported extended ensemble clustering keeping the solid handle on the pattern that it has had for the first part of the winter, while the seasonal Nina type hold on the atmosphere has prevailed.

 

No surprise though that usual continuity, and also in my own opinion, reliability in extended ensembles has started to break down within the last week. The emerging changes in the troposphere/stratosphere role-play relationship alerted suspicions some days back that longer term ensemble data might become less reliable  - this presaged mostly by the very recent +EAMT and break out of the GWO into orbit phases 4/5 round to 8/1 which has added a missing dimension this winter to a type of NH vertical wave activity supply that at the outset was assumed to play a much greater part in the winter pattern. 

 

So, in respect of the implications of GWO/torque behaviour, a good illustration here of the value and importance in these tools when attempting to make forward suggestions as to the path that NWP might take and evolve towards. Also in this respect, very useful in trying to decide when longer term ensemble data might be heading in a questionable direction, or, at the least, when cyclical seasonal pattern trends might be overstated or even on the verge of changing path completely.

 

There are clearly other culprit factors (that would take the post O/T) as to why the very positive SIA,SCE feedbacks haven't been utilised - but essentially the atmosphere hasn't wanted to play El Nino and provide the Siberian High feedbacks, suggested possible by these catalytic autumn indicators, and which were very reasonably argued and anticipated to give us a colder hearted winter.

 

So, stratospherically there is now good support for a tanking -AO and pronounced euro trough allied to vortex displacement. We then also have vortex action of +EAMT and another +EAMT likely sometime in the early part of February which greatly assist TPM action *trademark registered*

 

At face value the models don't suggest any upper ridge holding over the Atlantic sector, but there are increasing signals that the atmospheric pattern wants to attempt the sort of break-out that often blends itself towards a colder later part of a weak El Nino winter. A second GWO Phase 4/5 orbit following up the recent one is a good clue in this respect.

 

So, I am also suspicious about the lifespan of any far flung ensemble suggestion of returning further westerly mobility to follow early February amplification. Actually more suspicious than I was of the suggestions the other day of the impending return to less cold westerly mobility which, as suspected, is looking shorter than assumed

 

Stratospheric and better atmospheric lead -assistance should be accentuated the longer that time goes on by the natural processes of late winter seasonal wave lengths shortening - and this teleconnects further favourably to increased MJO amplification assistance. 

 

I'm reasonably anticipating the Atlantic to increasingly be disposed to increasingly further meridional patterns through February and lead on to more definitive upper blocking

 

@shotski - pm message

Edited January 21, 2015 by Tamara

[Polar Maritime]

The GFS looks Wintry to me.. By Saturday we see a cold Pm N/Wly bringing a Snow risk for Wales and the Midlands North.

 

 

 

Monday also see's a Snow risk for N/Midlands & Scotland. Out in the run towards the end of the Month the GFS & ECMWF both show a cold Northerly flow over the UK .

 

[legritter]

good afternoon all ,must admit i,v just taken the last day off model watching .gone to bed and just looked outside at the weather [and no surprises ]feel refreshed today after sleeping .but its nice to see the possibility of a rather cold zonal later next week .hoping that we can get much more from either a good n/westerly or even northerly If we get lucky .but each day will continue to be a rollercoaster but with plenty of winter left perhaps we can at last get some deeper cold into n/west Europe and some lower 850 temp of say minus 10 .Model watching should come with a health warning but it is self inflicted when will i ever learn .read the instructions before looking at charts ,be aware of the side effects ,illusions of snow ,MOOD swings ,feeling tense ,Sleep disturbances ,all this aside we do have a very good crew on Net Weather so lets enjoy the next Hunt for Cold synoptics ,Roll on tonights charts and Stellas all round ,Currently future charts looking good ,  

[SnowBallz]

I see the omnipresent February signal for blocking prevails in recent CFSv2 output

 

CFSv2 always appears to favour this type of broad synoptic for the latter end of winter, for whatever reason - seldom verifies, I hasten to add.  There has been some real Steve Murr eye-candy over the last few days.

 

Alas, none is currently supported by GS5 outputs; advertisement of average to very slightly below, is a broad theme; perhaps drier than average too.  Not a great deal of confidence though, so not worthy of any wrist-slitting.

 

ECM is a bit of a turn-up.  If that has legs...

[shotski]

Thanks Tamara , another great post and very in depth. Who needs Glacier point. So basically you see another MLB to our west with a possible ridging north as it evolves ? Or have I read it wrong.

[carinthian]

Good afternoon latest thoughts over here go with a deep trough into Europe and east of the UK by the end of this month with a snow scenario into the first week of February. By mid - February some interest in a major pattern change with the semi- permanent Azores high increasing amplification and Siberian high on the move poleward with Arctic Oscillation turning to negative phase. A reasonable high confidence for this to take place around 15th of February with a resultant flow of AC airmass to become established across much of Europe. How this will impact on the UK will have to be seen, albeit a little late for cold impact for some, better late than never especially after last winters best efforts .

C

[bluearmy]

I see the omnipresent February signal for blocking prevails in recent CFSv2 output

 

CFSv2 always appears to favour this type of broad synoptic for the latter end of winter, for whatever reason - seldom verifies, I hasten to add.  There has been some real Steve Murr eye-candy over the last few days.

 

Alas, none is currently supported by GS5 outputs; advertisement of average to very slightly below, is a broad theme; perhaps drier than average too.  Not a great deal of confidence though, so not worthy of any wrist-slitting.

 

ECM is a bit of a turn-up.  If that has legs...

Nice to see some more more Informed opinion SB.

Did GS5 see this upcoming displacement ? If so, does it also see a quick down welling into the euro trough as per the current trop nwp?

[Continental Climate]

Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

Edited January 21, 2015 by Continental Climate

[chionomaniac]

MJO forecast improving every run!

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[SxK]

MJO forecast improving every run!

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

 

You thinking the increased amplification from the potential MJO solutions could assist us here Chio?

[frosty ground]

Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

Indeed that chart shows that it's all over until the 2nd week of February..... any charts that follow this and don't show that should be ignored.

Confirmation bias...... 

[IDO]

The GFS op moving towards the GEFS 06z mean now, so at D8: 

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

Edited January 21, 2015 by i'm dreaming of...

[seaside 60]

Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

The chart is dated 27th Jan, whats that got to do with the second week of Feb.

Sorry confused, as tomorrow it might be showing a northerly deep freeze.

[mountain shadow]

The GFS op moving towards the GEFS mean now so at D8: gfsnh-0-192.png

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

Yes IDO, i mentioned that a couple of days ago. Any ridging into Greeland should be taken with a large pinch of salt whilst a PV segment remains in that local, as invariably a bit of short wave energy spits of the vortex and cuts off the Northerly flow.

 

The only time I ever believe a proper Northerly is on the cards is when proper upper heights are modelled over the Greenland plateux and the PV has retreated NW away from Greenland.

 

The projected possible lower heights into Europe will not therefore bring any sustained cold as the Azores ridge will continue to be pushed East by the shortwave energy.

[Summer Sun]

UKMO shows high pressure building in over the weekend and into early next week if it did build in it frost and fog could return

 

[winterof79]

The GFS op moving towards the GEFS 06z mean now, so at D8: gfsnh-0-192.png

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

The GFS op at 240z  compared to the 06z mean