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

[Ali1977]

Just now, Summer Sun said:

An easterly to southerly in 3 days

Get that Easterly in place and anything could happen, certainly will be very cold for a 5/6 days anyway.

[A Frayed Knot]

[Stuie]

1 minute ago, Summer Sun said:

An easterly to southerly in 3 days

That`s OK summer, it will marry the super Scandi high and then we will get a blast back from the NW ;-)

[Smiler1709]

A different set up to 6z but after seeing the 12z a change to colder condition is likely, how cold and how long it lasts for is the question. 

[Catacol]

8 minutes ago, blizzard81 said:

What do you think to the ukmo BA?

B81  - perhaps a look at the Wetter UK 144 chart will keep you smiling. Clear sign of squeezed undercut still, though we will hope that future runs see the heights push a tad further north for perfection.As a run its fine  - not awful.

Edited December 29, 2016 by Catacol

[Weathizard]

I actually think this run is a good thing... Shows us there is more than one option on the table that leads to cold, which is always a positive in this country where it's like pulling teeth to get a cold spell.

[Dominic Carey]

Is this a case of get the cold in then see what happens?

[Mucka]

Of GFS 21 ensembles around 6 go for something closer to UKMO than the Op by 144, so a little less than a 3rd which makes it quite possible but still the outsider.

I will take look if any of those runs are salavageable,

[northwestsnow]

1 minute ago, Catacol said:

B81  - perhaps a look at the Wetter UK 144 chart will keep you smiling. Clear sign of squeezed undercut still, though we will hope that future runs see the heights push a tad further north for perfection.As a run its fine  - not awful.

Thats the 120- the 144 shows the ridge sinking/sunk.

[bluearmy]

6 minutes ago, blizzard81 said:

What do you think to the ukmo BA?

I think it's not a million miles away from the 00z ECM op and given its upstream profile, it's not as dreadful as some are saying. clearly presents more hurdles to get to cold than the easy solution of the 06z GFS. Imo, the two things to be looking for on ECM 12z are the day 7/8/9 profile in the west Atlantic re split flow and whether the sceuro troughing remains keen to back wsw. of course this assumes it doesn't go verticus breastus pre day 6!

[doctor32]

Control run looks better going forward, more robust high in atlantic and lower hights to east drawing down more cold...

[Banbury]

Control so far

[SMU]

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

[PersianPaladin]

13 minutes ago, Catacol said:

Ummm - are you grinning right now?? Even the most die hard Amis are fully aware that their model leaves a lot to be desired when compared to their Euro rivals....

Having said that - GFS has a habit in my opinion of picking up on trends at the extended range when the other models struggle. The specifics will never be the same when T+0 comes around... but be careful not to ignore GFS trends at 240 - 300h and from this perspective your respect for GFS has some weight. 

Will be very interested to see the clusters later on. Would also very much like to see a UK +192 chart because I suspect those wringing their hands right now about that 144 chart might feel a bit better...

 

Those of you who have been following the Model Diagnostics Discussions on NOAA for several days and weeks now - will realise that there isn't really a preference for the Euros within the short time-frame of T90. As far as the extended time-frame is concerned, its really too close to call. Though a model blend is usually preferred.

Edited December 29, 2016 by PersianPaladin

[Methuselah]

1 minute ago, Weathizard said:

I actually think this run is a good thing... Shows us there is more than one option on the table that leads to cold, which is always a positive in this country where it's like pulling teeth to get a cold spell.

I would respectfully disagree with you there, W...There is but one 'option on the table': the actual weather...And, IMO, no one individual model-run has ever yet predicted it 100% correctly?

[Catacol]

Just now, Weathizard said:

I actually think this run is a good thing... Shows us there is more than one option on the table that leads to cold, which is always a positive in this country where it's like pulling teeth to get a cold spell.

Agreed. The key is that both models are seeing lower pressure running under the block created by the second surge. We are never going to be able to predict exactly where that block will sit in 7 days time - but the signal is for a block supported by lower pressure to the south. Thinking back a week or so most must surely want to jump for joy at this overall prognosis. Personally I didnt think it would happen and that instead the jet would run over the blocks quashing each surge to the south in classic Nina style. But the MJO does not seem to want to leave phase 8 and so we are getting modification of that Nina imprint.

Very exciting. If ECM can also give us an undercut of a block - wherever the block sits in terms of latitude at this stage - then we are in business. Go and run Jan 1963 on the archives. We are not at that level of extreme... but the overall pattern in the N Atlantic looked like the models are suggesting now... and all against a backdrop of a significantly -PNA as we also have now.

If this comes off - and let's all remember the misery of Dec 2012 (nothing is ever set in stone) - then hats off once again to GP for calling this pattern first of all even when the Met and extended models began to talk of a more zonal January.

[snowice]

4 minutes ago, Mucka said:

Of GFS 21 ensembles around 6 go for something closer to UKMO than the Op by 144, so a little less than a 3rd which makes it quite possible but still the outsider.

I will take look if any of those runs are salavageable,

28% that's poor odds for UKmo hopefully Gfs right. 

[Ali1977]

The mean (top)is better than the op at 192 which is v good, WAA into Greenland still.

Mean temp on ENS will be better than 06z

Edited December 29, 2016 by Ali1977

[Catacol]

11 minutes ago, northwestsnow said:

Thats the 120- the 144 shows the ridge sinking/sunk.

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?

Edited December 29, 2016 by Catacol

[Dominic Carey]

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

[radiohead]

It's no surprise to see the 12Z GFS downgrade the coldie-heaven that was the 06Z GFS FI (it's called Fantasy Island for a reason!). Those runs only come along very rarely outside of individual ENS members or the CFS. Only downgrades were possible from that.

Looking at the ENS, a second cold spell/snap is still very much on the cards. It just may not be as epic as the 06Z operational. 

Hopefully a good ECM this evening!

 

[karlos1983]

Strat looks a little troubled to say the least at 10hpa

[northwestsnow]

2 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 the same time span. Which do you prefer??? 12z or 0z?

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

Edited December 29, 2016 by northwestsnow

[blizzard81]

12 minutes ago, Catacol said:

B81  - perhaps a look at the Wetter UK 144 chart will keep you smiling. Clear sign of squeezed undercut still, though we will hope that future runs see the heights push a tad further north for perfection.As a run its fine  - not awful.

Thank you for the reply but I was referring to the 144 chart.

[radiohead]

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.