Model output discussion pm 13/01/2016

[Tamara]

Yet further reasons for perspective:

1) Regarding the next 10 to 15 days, let alone the rest of the winter, knee-jerk reactions to unpalatable model output has not come without any previous cautionary note against them  I know my previous post at the weekend attempted to pre-empt this by saying that NWP would produce some underwhelming roll-outs this week. Exactly what is occuring....

These simply reflect the expected changes with regard to the renewed strengthening of the polar stratospheric vortex prior to the ongoing observation over a displacement of some unknown order (at least at this stage unknown) . The changes also reflect, as discussed previously, the tropospheric fall-out effects from a recent drop in relative angular momentum, which, combined with the position of the vortex back towards Greenland during this transition intensificstion period is inevitably adding to the polar jet and keeping the pattern flat in the 10 day period. Notwithstanding trying to state in advance that these hurdles need to be jumped, I am not sure what more can be said while a wait is in progress for further changes

2) The key to the question of further amplification lies, obviously, in when further upturn in AAM occurs (to re-amplify the Atlantic sector) and also tied in with the question of timing and strength of the much discussed vortex displacement. At present the 10 day NWP is occupied with the higher energy flatter state, and, being the evening of the 19th January, as cited above, we should not be surprised to see uninspiring output for this time-period at the very least!

3) Monitoring progress of the tropical signal in the Indian Ocean is only one part of the story (related to ebb in AAM) but watching the progress of the Global Wind Oscillation will tell the whole story regarding the total momentum budget and ultimately put the current lull into true perspective. The tropical cycle is on course to transfer eastward toward the Maritimes, but with continued low frequency Nino signal underpinning angular momentum. With this in mind, at present the GWO is according with expectations and treading some water in a slowly lowering amplitude Phase 7/6/7 pattern - with the westerly inertia across the Pacific counteracting AAM tendency fall ahead of expected further rise as we get into February. A cue for this rise to be further augmented when the MJO arrives at Phase 5 and then more especially beyond through Phases 6 and 7 during February, as it heads through the Pacific again (as it did during this month) by which time the effects of the suggested weakening and displacement of the upper stratospheric vortex should be already verifiable.

4) This is all still at least a couple of weeks ahead and more, so we must be aware in the meantime that any amplification potential in the Atlantic will be offset by the current placement of the vortex, and consequently whilst the upper zonal winds are still prohibitive, of allowing poleward ridging to take high pressure northwards and take the AO back to negative.

5) In the meantime however, the continual wave 1 activity from the Kara Sea height anomaly persists - the same activity that helped elongate the lower stratospheric vortex in the last couple of weeks and facilitate the amplification potential and provide the well signposted and anticipated -AO signature of much of the first half of January.

6) Its sometimes advisable not to get too hung about a definitive SSW - although obviously against the background of the strengthening and return to +AO of anticipated upper vortex disruption, it would certainly help on this occasion if we got one! However, an adequate displacement allied to persistent wave 1 trop/strat activity plus the MJO arriving in the Pacific should still be the cue for the best opportunity for a return to cold - and this maybe why the METO have cited the period from mid month as most likely for any colder weather. However, as deemed possible in recent posts, this is not at all to say that a colder pattern won't return before then - just that the chances increase through the month. Speaking personally, I am not sure that anything otherwise has been stated in terms of future possible prospects - albeit it has to be accepted the most optimistic prospects of the 83 Jan/Feb analogue suggestion being ahead of time no longer look so feasible

7) It would be very very easy to spend time discussing the worst scenarios that can happen - I think this post viewed as a whole, recognises and answers that anyway if one reads between the lines sufficiently.

Time instead for looking at the best case scenario, which still remains - but with further evidence to hand, as just stated above, its one that demands caution and probably has to be adjusted back further into the new month:

Taking a working assumption that the sum total of factors progress favourably, then the matured Nino forcing continues to evolve helpfully towards a pattern that favours greater cold than this initial spell. The tendency being for the GOA low to retrograde westwards, and downstream longwave responses being to remove any sibling lobes of vorticity over Greenland and NE Canada left over from displacement. This, allowing a more functional stronger height rise towards Greenland and Iceland than an ordinary amplified Atlantic ridge - and in tandem with upstream tropical forcing arriving back in the Pacific as Feb progresses, a greater and greater chance of securing a more east based NAO than attempted in January. However, the degree of success and extent to which this best scenario occurs, and of course any colder scenarios as a whole as well, will of course be brought about by significant enough damage to the upper vortex being secured in addition to the persistent troposphere>stratosphere interactions we have seen so far.

 Eight) Retrospective analysis has already been thoroughly covered and answered in respect of the changes from the New Year period and what has verified to date. However, beyond any persisting objective that might remain to find descrepancies with other members suggestions/predictions, if the main 'beef' is simply that not enough snow has fallen 'IMBY' from the recent Atlantic ridge and Scandinavian trough pattern, after the anomalous warmth of December, then there is a simple answer to that:

Whilst one can certainly suggest a likely large scale pattern based on study of the longer range tools available to assist in doing so, it remains the case that for a country as small as the UK is in relative terms to the Northern Hemisphere, it is completely impossible to superimpose a larger macro scale pattern onto a micro street level atlas for each county (country-wide) and make surface condition predictions for each of them! This seems to get said every winter, if/when we get into the second half of the season and some people are feeling 'short changed' by the weather vs what some 'forecasts' appear to promise.

 9) So, all in all, best relegate 'winter is over and the clock is ticking' doomwatch prophecies as an entirely uneccesary and excessively self- purgative exercise . Also not holding other members (whoever they may be) accountable for how much/or otherwise it snows, or doesn't snow - as the case may be. Keeping personal frustrations in some sensible, proportionate and mature perspective is far more helpful. Its the weather after all and not something we can intervene with and change

Edited January 19, 2016 by Tamara

[Timmytour]

Going through the GFS ensembles, the encouragement I take out of them is not that any are showing any particularly stella charts at T180, but that there is a degree of disagreement between then.   Maybe similar themes but enough disagreement to suggest that there are still options both being modelled and not being modelled that are still on the table.

However....I make no bones about it, I am looking for the straws to clutch.  I look with a large amount of hope, but at the same time i do keep a healthy dose of realism close by.  Yes I hope something develops for February and even for March.  And though it doesn't show in the models at the moment perhaps, it was there not long ago so I retain the hope it will come back

But.......but......for example I see comments about what March could be and it does make me think that maybe recent experience has led to  expectations being a little too high.

The March of the 2012-13 winter (and for the purposes of this post I will include March as being part of winter) was the coldest since 1962 and first one to come in with a mean CET of 3.5C or under since 1969.  Indeed there's only been one other, in 1955 since the end of the FIRST world War. So they are far and few between which suggests to anticipate one might be aiming to high.

In terms of all winter months (again including March), the five winters from 2008/9 to 2012/13 probably spoiled us. In those twenty months, nine were at or below a mean CET of 3.5C..... so practically half!  But only one other month in a winter that started in this century - Jan 2001 -  has been that cold!!  So that's only ten months in 62 months this century (assuming this month doesn't make it).

Again, assuming this month doesn't make it, that will be wait of 10 months.  That's not by any means a long wait in relative terms.  Dec 2008 ended a wait of 30 winter months with CETs greater than 3.5C.  Indeed it was down to the March of 1916 to bring an end to 25 consecutive such winter months.  It did so in spectacular fashion leading to the winter of 1916/17 ...the only winter since 1900 where none of the four months exceeded 3.5C.

So I'd say the chances are slim. but they exist.   And even if it doesn't happen, next winter could be 1916/7, or 1947 or 1955 or 1962/63.  There will always be hope!!! 
 

[bluearmy]

1 hour ago, Dancerwithwings said:

 Next week.....Well look where we were suppose to be 7 days ago....big differences! so again who knows

Todays Chart

7 days ago for today

perhaps look at the ecm anomoly ens mean for today from 10 days ago. the ens mean and anomolys are again leading the way, especially ecm.  the issue we have over the next couple weeks is not a lack of HLB but the euro heights. without the euro heights, we could see a split jet at the very least.  no low euro heights = no CAA.  we wait for the euro heights to be tempted west by a mid atlantic ridge at some point. lets hope it isnt april!

[Just Below Zero]

25 minutes ago, Timmytour said:

Going through the GFS ensembles, the encouragement I take out of them is not that any are showing any particularly stella charts at T180, but that there is a degree of disagreement between then.   Maybe similar themes but enough disagreement to suggest that there are still options both being modelled and not being modelled that are still on the table.
 

Nice history lesson TT just goes to show how difficult it is to get those real winter experiences here. Most on here enjoy the chart possibilities but atm not much doing.

By the way TT Who is this Stella Charts who should be giving us all encouragement?

[fergieweather]

Do bear in mind the very different evolution into medium range touted by 12z GFS-P. It's not wholly without support elsewhere, albeit a minority probability presently.

[Grimsby Snow Lover]

2 minutes ago, fergieweather said:

Do bear in mind the very different evolution into medium range touted by 12z GFS-P. It's not wholly without support elsewhere, albeit a minority probability presently.

Hi Ian, as a novice what in simple terms do you mean? Many thanks

[bluearmy]

1 minute ago, fergieweather said:

Do bear in mind the very different evolution into medium range touted by 12z GFS-P. It's not wholly without support elsewhere, albeit a minority probability presently.

I noticed that before I posted Ian. It does keep  cropping up on ops from time to time. Judging by Tomas' 10pm forecast last evening, it must have had some MOGREPS support too.  However, the ECM ens uppers spread has drifted away from it in the 10 day period.  As I said in my post, without any drop off in euro heights, there is no catalyst to advect the cold this way.  The gfsp waits nearly two weeks to get there but the signal for sceuro heights to sustain is significant so we only need to get that med trough initiated and the blue touch paper is lit.  

[mulzy]

FWIW the ECM extended ensemble mean (days 11-15) follows on from the morning suite in showing lower than normal heights around the SE Greenland/Iceland vicinity and higher than normal heights over mainland Europe - looks a fairly zonal pattern to me.  It does seem that the negative height anomalies are travelling slowly from west to east though the Atlantic sector though at this range usual caveats apply.

Edited January 19, 2016 by mulzy

[fergieweather]

1 minute ago, Grimsby Snow Lover said:

Hi Ian, as a novice what in simple terms do you mean? Many thanks

resurrection of colder continental flow in further reaches of run.... this always remains a latent prospect whilst the very cold pool remains out east

[bluearmy]

9 minutes ago, fergieweather said:

 

 http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=0&runpara=1

[BLAST FROM THE PAST]

Quote

Time instead for looking at the best case scenario, which still remains - but with further evidence to hand, as just stated above, its one that demands caution and probably has to be adjusted back further into the new month

Is this a reason for 'not forecasting' Tamara and a backtrack on 'expectations, strat allowing' ?   Is this an end of the rainbow scenario?  For me the most important part of your indepth post...

 

BFTP

Edited January 19, 2016 by BLAST FROM THE PAST

[Ali1977]

No sign of the pub run following the GFSP,  where as the GFS12z kind of did for a while.

Let's see what tomorrow brings, I'm hoping nicks optimism rating jumps from 2/10 to at least 5/10.

[nick sussex]

1 minute ago, Ali1977 said:

No sign of the pub run following the GFSP,  where as the GFS12z kind of did for a while.

Let's see what tomorrow brings, I'm hoping nicks optimism rating jumps from 2/10 to at least 5/10.

Its crashed to 1/10. The GFS 18hrs run so far is even more underwhelming than the ECM and that's saying something!

 

[Jason M]

The pub run is making me feel nostalgic. Ah, 1988 what a year 

if anyone wonders what a classic Bartlett set up looks like this is a prime example. It's going to be very very difficult to shift these Iberian heights. 

Edited January 19, 2016 by Jason M

[Timmytour]

GFS 18z T186   v GFS parallel  12z T192

         v      

 

Looks to me as if GFS is squeezing the Azores high eastwards and pushing the cold further away while the Parallel run was more readily finding a way for heights to get up into Scandinavia instead and keep the cold pool available for tapping into at a later date....

Hopefully, and who's to say it won't happen as it seems to have done every other day since late December, future runs will give us back the hope we crave! 

[tight isobar]

5 hours ago, tight isobar said:

Well its the iberian heights for me scuppering things! .. its a case of she's going she's going. ..oh no shes not ...

Id like to ring the neck of that thing...However still potential and things are perhaps knife edge for the craved beast.

@easterly incursion. 

 

[booferking]

So as it stands going by the last GFS run Ireland will be seeing rain everyday from this Thursday right through to the end of the Month that's just great suppose we had two dry day's this week that will make up for next 11 rainy days..

 

Edited January 19, 2016 by booferking

[nick sussex]

The best thing about this GFS 18hrs run is that thankfully it will be over soon! lol

A horrid set of charts with the PV going into overdrive.

[blizzard81]

Well, this is the model output discussion and to be totally honest, the operational runs of the major players for the last couple of days have been consistently appalling for cold lovers. I could not paint a worse picture than the ones shown on the ops. I really do hope that GP and Tamara are onto something here but the fact that GP's negative nao torpedo forecast has now been put back by at least a week sets off alarm bells imo. If he is a week to 10 days out and his predictions still come true, then all will be well and good as no one cares about a week here or there. If on the other hand it keeps getting put back, I for one will be bracing myself for the third crappy mild/borefest winter on the bounce.

[Catacol]

36 minutes ago, BLAST FROM THE PAST said:

Is this a reason for 'not forecasting' Tamara and a backtrack on 'expectations, strat allowing' ?   Is this an end of the rainbow scenario?  For me the most important part of your indepth post...

 

BFTP

Odd post Blast. What exactly are you trying to say?

[blizzard81]

4 minutes ago, booferking said:

So as it stands going by the last GFS run Ireland will be seeing rain everyday from this Thursday right through to the end of the Month that's just great suppose we had two dry today's this week that will make up for next 11 rainy days..

 

If this winter doesn't get it's act together soon, it will be dumped into the class of 88/89.

[nick sussex]

9 minutes ago, booferking said:

So as it stands going by the last GFS run Ireland will be seeing rain everyday from this Thursday right through to the end of the Month that's just great suppose we had two dry today's this week that will make up for next 11 rainy days..

 

That made me laugh so much!  You have to have a sense of humour to cope with these wretched outputs! Brilliant post Booferking, keep them coming! I think it was the emoticon that sent me over the edge.

Edited January 19, 2016 by nick sussex

[snowray]

1st February, not long to go now. Hope this don't verify.

[tight isobar]

Mad as it seems to say...

I think vast amount of operationals' gfs; ecm; gem ukmo...are going into hyper overdrive here!!!! (Mobility madness)!!!

Perhaps I've just gone mad in saying so...but I can certainly mind things may not look so dire within 48hrs!!! 

 

[mountain shadow]

2 minutes ago, snowray said:

1st February, not long to go now. Hope this don't verify.

Well,  our only remaining hope is that the ramping up of the PV is its dieing swansong as the Strat led warming start to work. 

I do believe it will be mid February before the change to much colder conditions occur.