Model Output Discussion 29th December - Into mid-Winter.

[Mucka]

11 minutes ago, Steve Murr said:

GFS mean @ 138 is totally at the opposite end of the scale to the UKMO which is good-

however as much as excitement that can generate - we have to temper it with the fact that UKMO has been the correct spoiler before- 

People saying there's a huge difference between 06z & 12z when in reality they are very similar up to 168 - post that the angle of the wave & jet off the NE seaboard is more 45 degrees hence a tad flatter-

45 degrees is about the very MAX we can have to still achieve a cold undercut at day 10 because you can still achieve your wedge of high over Scandinavia & the CAA can head in to England- NB Scotland not as cold on this run because the block is further SE..

The mean @ 174 is near identical to the OP - so do we go with the progressive trait of the 12z or the slightly weaker data in the 06z 

no one can say at this stage - just prey the ECM doesn't look like the UKMO come 18:25...

S

I expect the 192 mean will be excellent too. Of the GFS ensemble member that go for something closer UKMO they are split between recovering the amplification, it all depends on the timing of the phasing of Azores low and upper trough. The more delayed, the further East the phasing, and the better the outcome. 

Assuming ECM doesn't throw a curved ball this evening I am about as confident as a traumatised coldie can be we will get through the first phase and see the necessary Atlantic amplification from there to bring at least a cold spell.

With regard to the bigger picture it looks like the pattern has been backed West by GFS through today which has allowed for colder upper air and improved snow prospects. It would be great to see ECM go back to that kind of pattern tonight rather than having the ridge build too far West - cold but less exciting.

Thereafter it is all about how amplified upstream is and whether it allows for undercut and maintaining MLB.HLB and an Easterly type flow 2nd week of Jan - but UKMO could be right and the pattern go TU from there. If so this forum will not be a good place to be.

I'm going to say UKMO comes around tomorrow and it's all happyclappy though. 

Edited December 29, 2016 by Mucka

[Ali1977]

On 29/12/2016 at 17:22, radiohead said:

Less pronounced ridging on the 12Z GFS Day 10 mean compared to the 06Z. Tilted more to the east than the west too. Not what we wanted to see.

 

Some awesome runs in there though, but yes not as good as earlier, mean may improve further on as the beasts get modelled in

Edited December 29, 2016 by Ali1977

[Catacol]

5 minutes ago, northwestsnow said:

Neither ukmo runs today im afraid.Compared to ecm0z and all 3 gfs runs today,its poor.

Really? The most recent UK chart has low pressure undercutting towards Iberia with a better aligned trough over Russia than on the 0z to advect the cold westwards including a more developed low pressure over northern Italy.

Good grief - if this doesnt float your boat in the reliable time frame (given that I am talking only 120h out) then nothing will.

Edited December 29, 2016 by Catacol

[Jason M]

Plenty of easterly options in GEFS at day 10. Half go with some sort of easterly and its the biggest cluster. Still plenty of rubbish in there as well for balance!!!!

 

[Summer Sun]

 

Edited December 29, 2016 by Summer Sun

[northwestsnow]

4 minutes ago, Catacol said:

Really? The most recent UK chart has low pressure undercutting towards Iberia with a better aligned trough over Russia than on the 0z to advect the cold westwards including a more developed low pressure over northern Italy.

Good grief - if this doesnt float your boat in the reliable time frame (given that I am talking only 120h out) then nothing will.

Well its all about opinions so no probs.

Ps im talking about the 144 im not sure why you keep refering to 120..

Edited December 29, 2016 by northwestsnow

[Seasonality]

7 minutes ago, Dominic Carey said:

From what I can see from gfs temp charts we have potentially twelve days of below average temperatures. That's not bad for us.

Exactly. Decent cold spell by UK standards on the more realistic 12z following the mad 06z and some lovely synoptics in there too. 

[karlos1983]

Control having a good old go at scandi height rises

 

[bluearmy]

2 minutes ago, Mucka said:

I expect the 192 mean will be excellent too. Of the GFS ensemble member that go for something closer UKMO they are split between recovering the amplification, it all depends on the timing of the phasing of Azores low and upper trough. The more delayed, the further East the phasing, and the better the outcome. 

Assuming ECM doesn't throw a curved ball this evening I am about as confident as a traumatised coldie can be we will get through the first phase and see the necessary Atlantic amplification from there to bring at least a cold spell.

With regard to the bigger picture it looks like the pattern has been backed West by GFS through today which has allowed for colder upper air and improved snow prospects. It would be great to see ECM go back to that kind of pattern tonight rather than having the ridge build too far West - cold but less exciting.

Thereafter it is all about how amplified upstream is and whether it allows for undercut and maintaining MLB.HLB and an Easterly type flow 2nd week of Jan - but UKMO could be right and the pattern go TU from there. If so this forum will not be a good place to be.

I'm going to say UKMO comes around tomorrow and it's all happyclappy though. 

ECM should be further east with the ridge and the sceuro trough (than GFS)  if  it follows continuity. 

If it backs it west then a nice surprise. given the general direction of travel, the back end of the run with the undercutting to our west is whatever I will be looking for. 

[Banbury]

ENS are good

2 , 4, , 6 , 7 , 9 ( bloody hell ) , 10 ( wow ) , 12 , 13 ,16 , 17 , 19

[blizzard81]

13 minutes ago, Catacol said:

My apologies - I meant to include the 144 from 0z as direct comparison. Here it is now

Look for trends. This is for as close a time span as is possible with UKMO - 12 hours apart. Which do you prefer??? 12z or 0z?

Ok, I am not a big fan of comparing charts 12 hours apart but I sort of understand where you are coming from. I have just compared yesterday's 12z 144hr chart to today's 12z 120hr chart and todays is much improved. Now why couldn't you have posted these to put my mind at ease lol

[Singularity]

I've been out for most of the day, did I miss much? 

*Catches up, falls of chair several times*

Okay. Well let's start from the bottom shall we - UKMO is perhaps not quite as concerning as the 00z, but there's no escaping just how differently everything is orientated still on the 12z. Peculiar indeed, but which models are actually being wacky here? 

If instead we can get to day 6 with a similar setup to the GFS 06z or 12z then it appears we have the ingredients for producing a decent easterly spell even if a huge and intense trough develops off N. America, which is encouraging. If the upstream pattern behaves supportively instead - which seems plausible given the ongoing tropical Pacific-sourced 'nudging' toward amplification in that sector - then... we could find ourselves in a spot of bother, but in a different way to usual . The GFS 06z is up there with some of those of Nov-Dec 2010, but toward the end seemed to vault into some other realm of cold unlike anything I can recall witnessing. Cutting of a wedge of high pressure to the NW can work absolute wonders when combined with a Euro trough - we can dream of such things, sure we can, but that's as far as it should go until such charts are at around +144 hours range.

 

Anyway - I reckon it's still possible to rebuild heights in the mid-Atlantic going forward from a UKMO-like outcome, but only if there wasn't an intense low looking to try and flatten things; a fledgling block may struggle to put up such a good fight, although the jet could still in theory be split sufficiently... I guess then you're looking at something akin to the ECM 00z which was actually pretty similar at days 5-6.

The ECM 00z had a very 'I might, you know!' look about it so it will be of great interest what it gets up to this evening. If it rearranges those lows near the Azores to be more like the GFS 06z or 12z then eyebrows will be raising very high indeed.

[Mucka]

6 minutes ago, bluearmy said:

ECM should be further east with the ridge and the sceuro trough (than GFS)  if  it follows continuity. 

If it backs it west then a nice surprise. given the general direction of travel, the back end of the run with the undercutting to our west is whatever I will be looking for. 

In reality there hasn't been that much continuity though Blue.

ECM showed this just last night.

So I see the more East based solution of this morning as more of run to run variation rather than a trend or continuity for now. 

TBH I will just be glad to secure the amplification of the ridge into the polar regions but my gut tells me that if we do get it then it will be a bit further West than this mornings run - hope so anyway.

Edited December 29, 2016 by Mucka

[Singularity]

14 minutes ago, radiohead said:

Less pronounced ridging on the 12Z GFS Day 10 mean compared to the 06Z. Tilted more to the east than the west too. Not what we wanted to see.

 

That 06z mean is extraordinary - usually at that range the natural variability produces enough runs looking to power a low out of N. America to produce a more subdued wave pattern, such as we see with the 12z.

As long as we retain a mean trough signal right down to Italy from S/C Scandinavia, the scope is there for the toppling Atlantic ridge to stretch out to our NE and bring about an at least brief (b)easterly. Signs are there will be plenty of deep cold to tap into, for a change...!

[Captain Shortwave]

Well GEFs

       

 

Well the positive here is that we get low heights into Europe which is something we could not manage in the past month. Couple that with above average heights to our north then easterly/north easterly solutions are certainly viable. 

[Day 10]

Even if the ECM is a cracker and the GFS 18z is a doozy I won't get too excited until the UKMO comes on board. So if we get to the UKMO unscathed by the morning it will be nervous viewing. In these bloody cold setups the one out of kilter always ends up being right when it's showing what we don't want.

GFS UKMO ECM???

 

[Catacol]

2 minutes ago, Mucka said:

 

Thereafter it is all about how amplified upstream is and whether it allows for undercut and maintaining MLB.HLB and an Easterly type flow 2nd week of Jan - but UKMO could be right and the pattern go TU from there. If so this forum will not be a good place to be.

I'm going to say UKMO comes around tomorrow and it's all happyclappy though. 

Time to climb off my perch and attempts to bolster the UK output that others see as poor. ** Shakes head. I think the difference between snowmageddon fantasy and UK reality is not well understood. The UK 120 chart is a good one. Less good at 144.

Agreed - if it goes TU time to run and hide. But very interesting supporting teleconnections coming into line now:

Profile at the bottom of the strat strongly supportive of ridging to our NW

and when one factors in the squeeze on the vortex higher up being brought about by a moderate wave 1 assault the westwards shunt of cold through Europe looks well supported also though this will take time to come into line - maybe 10 - 14 days

As far out as 12 January Ventrice is still producing graphs supporting of am 8/1 phase to the MJO

 

 

 and bear in mind that the last UK ensemble MJO run has it moving to phase 3. If we assume that human interpretation rather than model run might hold sway here, then the phase 3 composite is interesting:

Note the agreed signal for low heights to the south, but less of a signal for pumped up heights to the north than the compositve I posted last night. End result? UKMO may be undercooking the northward extend of the heights in its current modelling.

Finally worth reposting what GP showed the other day - big reduction in wind velocity at the equator continues to be forecast, and if I understand frictional torques at all (been doing a lot of reading about these recently...) this should provide the amplification we want to get a block in the right place.

Yes - its all good. Quite prepared to go "happy clappy." A good ECM tonight will send me on my family day trip tomorrow perfectly cheerful. :-)

 

 

 

 

[Jason M]

Overall a good day. I personally won't be too bothered by ECM as we only see the opp and at day ten its not much better than looking at one GEFS ptrb.

[Catacol]

9 minutes ago, blizzard81 said:

Ok, I am not a big fan of comparing charts 12 hours apart but I sort of understand where you are coming from. I have just compared yesterday's 12z 144hr chart to today's 12z 120hr chart and todays is much improved. Now why couldn't you have posted these to put my mind at ease lol

Hehe - tried to do that... but clumsy at the keyboard sometimes... :-)

It's all good today - it really is. Not had it this good for 4 years at least.

[bluearmy]

7 minutes ago, Mucka said:

In reality there hasn't been that much continuity though Blue.

.

need to know which op runs to discard late on mucka! 

There still seems to be a propensity to over amplify late on in the op ECM runs. The 00z day 10 was thus although that run had a strange end with the Siberian ridge looking to bridge over to the Atlantic (cutting off a chunk of vortex to our east which would be just as 'mental' as the 06z GFS op. If that set up repeated on the 12z then jeez! 

i expect to see a less amplified version of the 00z run by late on but as I said earlier, the undercutting of the ridge is vital and also enough draining of the Euro heights to ensure a west based -NAO doesn't come into play. 

[Spikey M]

when does the ECM come out?

[joggs]

1 minute ago, Spikey M said:

when does the ECM come out?

6pm onwards

[Banbury]

Cant grumble with that

[booferking]

1 minute ago, Spikey M said:

when does the ECM come out?

Starts in 12 Mins.

[northwestsnow]

3 minutes ago, Banbury said:

Cant grumble with that

Excellent GEFS banbury! Sure to be some cold easterlies in there..