Model output discussion - winter proper underway

[Scandinavian High.]

Very cold air to east gfs still trending the way I see a shot of cold coming from east end of December in to January  .

[Daniel*]

4 minutes ago, feb1991blizzard said:

We nearly did and indeed might well have gone on to, in fact we did get an E'ly just with no cold uppers.

Fair play cold south east flow pretty consistent to extreme FI of 06z ! 

 

[northwestsnow]

I actually prefer ukmo 144 to gfs!!

Looks slightly more amplified upstream up the west coast of Greenland.

either way as nick has posted its moving in the right direction...

Edited December 14, 2017 by northwestsnow

[Snowjokes92]

Ukmo improving run to run. I dont think it will be long before the odd model to go off tangent and produce something tasty before are eyes to be honest. Gfs more likely. Probably build some kind of strong ridge into the new week up to greenland from the atlantic, where potential will be screaming.ECM is so stubborn this season! 

Edited December 14, 2017 by Snowjokes92

[northwestsnow]

Pretty big swing to cold on the 12z GEFS ens...23rd-25th cold members gathering momentum...

Edited December 14, 2017 by northwestsnow

[Decemberof2010]

Yes and some very odd looking charts. I say odd, as they show a very strange NH. Hopefully it will gain momentum over the coming days 

[northwestsnow]

3 minutes ago, ShortWaveHell said:

To be fair the ecm has a bloody nose this autumn / winter off the gfs slapping it about , gfs has done well in my opinion even the ukmo followed it two weeks ago ! 

I agree- although the stats probably disagree with us both!!

Really good trends developing with GFS/GEFS today..

[Daniel*]

Looking at the London ENS a pretty good cluster going cold growing by the run.  

[tight isobar]

2 minutes ago, Daniel* said:

Looking at the London ENS a pretty good cluster going cold growing by the run.  

Yep...trend gathering pace.

[Snowjokes92]

8 minutes ago, ShortWaveHell said:

To be fair the ecm has a bloody nose this autumn / winter off the gfs slapping it about , gfs has done well in my opinion even the ukmo followed it two weeks ago ! 

I agree with this. Not to say ecm is wrong on most runs, but i think this season we have seen it been pulled kicking and screaming to be in line with other models.

[Snowy L]

1 minute ago, Snowjokes92 said:

I agree with this. Not to say ecm is wrong on most runs, but i think this season we have seen it been pulled kicking and screaming to be in line with other models.

Its a weird one because the last few winters it was always too amplified and now so far this winter it has been too progressive (and hopefully that continues to be true for the weeks ahead).

[mulzy]

11 minutes ago, ShortWaveHell said:

To be fair the ecm has a bloody nose this autumn / winter off the gfs slapping it about , gfs has done well in my opinion even the ukmo followed it two weeks ago ! 

Is this just conjecture or do you have any evidence?  I would doubt your assertions.

[Snowmadsam]

Well what a period of model watching! More exciting than the Eastenders Christmas special! 

I fondly remember the GFS picking up on the December to remember back in 2010 (I used the excuse to go to the loo in school, whilst waiting till the end of the model run to go and see what it had churned out on the computer!)

It is still too early to call the (cold) shots, but I think we may have to accept that a pattern change based on model output and more professional posts on here is likely around Christmas/post Christmas - New year. The question is when, and how quickly this takes place?

Join us again for a future episode of more tantalising questions that we don’t yet have the answers too....

[bluearmy]

A re writing of history in favour of gfs ......

if this day 7/8 amplification verifies then it is the first time the ecm has been consistently wrong thus far 

gfs has been less bad than previous years but to say its wiped the floor with the ecm really isn’t correct

Most of the ops post day 7/8 haven’t been good

The gefs suite splits the vortex Asia across to Alaska at the end. The height rise to our north/northeast gathering pace for the new year 

[northwestsnow]

1 minute ago, bluearmy said:

A re writing of history in favour of gfs ......

if this day 7/8 amplification verifies then it is the first time the ecm has been consistently wrong thus far 

gfs has been less bad than previous years but to say its wiped the floor with the ecm really isn’t correct

Most of the ops post day 7/8 haven’t been good

The gefs suite splits the vortex Asia across to Alaska at the end. The height rise to our north/northeast gathering pace for the new year 

Agreed Blue.

No doubt EC will be another flat solution- it seems to be the polar opposite of last year!

[bluearmy]

1 minute ago, ShortWaveHell said:

Which part? the ‘in my opinion’ bit ? If you read the previous thread to this , it was noted frequently that the ecm was being a Scrooge and wouldn’t come into line with the GFS ..low and behold it did , and the southern half of the country got a snowload ! 

Now you have really confused me

gfs never showed snow in the south apart from its original undercut slider runs which generally went past the sw of the country and were just sypnotically wrong  

[Snowjokes92]

I know we have been use to the models trending cold and then resulting in absolutly nothing, e.g december 2016 showed much potential. In fact most of the winter had signifanct cold trends in place, but came to nothing of noteworthy. This year it feels different and also with teleconnections favourable. But since november, the models seem to pick up the trends slowly and they end upgrading closer to timeframe and earlier than modelled! Thats just my opinion, it feels like any mild/typical weather is downgraded less and less. E.g the gfs looked horrendous a few days ago from next week to the end of the run. Now a trend has been interepreted in the model and mild weather next week has been downgraded for a smaller timescale and  also watered down. Based on my own opinion or it maybe wishful thinking, but i can imagine, the models upgrading the ridging/amplification in future runs, which can only be a good thing moving forward.

[bluearmy]

Just now, northwestsnow said:

Agreed Blue.

No doubt EC will be another flat solution- it seems to be the polar opposite of last year!

whilst we have seen amplifications this season, they have generally been short and flattened fairly quickly - ecm is the model picking this up before the other models which sustain for too long 

however, this flatter pattern off the esb has also meant it has failed to amplify enough, especially  in the 8/10 day range 

[Methuselah]

2 minutes ago, Snowjokes92 said:

I know we have been use to the models trending cold and then resulting in absolutly nothing, e.g december 2016 showed much potential. In fact most of the winter had signifanct cold trends in place, but came to nothing of noteworthy. This year it feels different and also with teleconnections favourable. But since november, the models seem to pick up the trends slowly and they end upgrading closer to timeframe and earlier than modelled! Thats just my opinion, it feels like any mild/typical weather is downgraded less and less. E.g the gfs looked horrendous a few days ago from next week to the end of the run. Now a trend has been interepreted in the model and mild weather next week has been downgraded for a smaller timescale and  also watered down. Based on my own opinion or it maybe wishful thinking, but i can imagine, the models upgrading the ridging/amplification in future runs, which can only be a good thing moving forward.

Seeing as none of us really knows, I guess a bit of wishful thinking is commonplace...Whatever, we ought to be beware of getting 'snowed under' with potential?

[Snowjokes92]

1 minute ago, Ed Stone said:

Seeing as none of us really knows, I guess a bit of wishful thinking is commonplace...Whatever, we ought to be beware of getting 'snowed under' with potential?

I think its another good way of trying to understand what the weather may do lol.

[tight isobar]

One things a-cert' ec12z finding much better height alignment...@scandi

In 'compare' 00z run

Going steady.@120..

Edit: for compare..and a' frame- on ec 00z 144

 

12z 120

00z -144

Then starts to flatten'via' migration east canadian lobe...

Nevertheless' baby steps!!

Edited December 14, 2017 by tight isobar

[ACCOUNT DELETED]

GFS has high pressure well and truly in charge next week bringing a lot of mild weather especially in southern & western areas with any cold air being very brief here, early indications are for a mild Christmas Eve in the SW of the UK, colder elsewhere particularly in the north & east. 

Edited December 14, 2017 by Draig Goch

[tight isobar]

You have to feel that the ecm is lagging way behind the gfs of late!?

It almost has the mood of a teenager!!!

I will -i won't!!!

 

[bluearmy]

ecm should be much more amplified ne of the uk T168/T192 as per the 00z eps spreads

sorry - should be day 8/9, not 7/8

Edited December 14, 2017 by bluearmy

[Guest]

A BRILLIANT GFS 12Z RUN TODAY

Following my cross-model analysis this afternoon, I was going to take a break until tomorrow (and finally start writing some Christmas cards) but today's GFS 12z run has really grabbed my attention. This is one of the most sensible and far more logical routes to cold that I've seen by any of the models with an easterly evolution over the next 2 weeks (probably around D17/18 as it's still evolving at D16). Let's examine how this happens:

                            T+120                                                              T+174                                                             T+222

                                            

At 120 we have a +PNA with HP ridging across the pole with a vast belt of HP across central Asia. The HP over the UK is taking on a nice south-west to north-east orientation. There are lower heights in north-east Europe. By 174  the +PNA is strengthening further and now pushing HP across the Arctic. Meanwhile a north/south double cell lobe of LP has intensified over the eastern Arctic, through Svalbard and down through the Norwegian Sea with a straight northerly to its west.  The HP close to the UK is ridging north-westwards towards Greenland. There is now slack pressure over much of Europe.(great for stagnating the modest amount of cold air there at that time). By 222 the LP extends from the Arctic right down through Scandinavia to reach southern/central Europe. At this stage this is much better than the UK receiving yet another briefer northerly shot as loads of colder air is moving into Europe to help develop a decent cold pool there (for later use!).  

                                T+300                                                              T+360                                                             T+384

                                           

By 300 the +PNA has strengthened even more and a strong ridge of HP is thrown right across the Pole linking with further HP cells over Siberia and through to central Asia. The long lobe of LP is breaking away from the Arctic with the northern cell weakening over eastern Scandinavia (it has done its job of dropping some colder air into Europe) with the main cell now being cut off over central to south-eastern Europe. Meanwhile the UK HP stretches all the way from western Norway down to north Africa. You can see how powerful this block is by how all those LP cells in the western Atlantic are prevented from making any eastward progress (no time for showing the jet stream now). All these changes are  the building blocks for our easterly. By 360 the upstream pattern is similar but our HP has intensified and is taking up residence towards Scandinavia with low heights maintained over central and southern Europe. By 384 the HP is producing a cold (perhaps very cold) but dry south-easterly flow over the UK. Now, please do not be disappointed with no snow at this stage - looks what's happening to our north and north-east. HP is intensifying over the Arctic as well as Siberia with some deep cold building there. The remaining LP to the north-east is weakening over north-west Russia and our HP is developing a second cell. We often see these HPs swept away eastward but NOT this time - it will be our friend. I see the HPs from Siberia and the Arctic merging into our one in Scandinavia and a huge cell developing to our north and north-east. By 384 (see below) a decent cold pool is developing over much of Europe with much of the same area below zero at the surface. Without anything to move it away, this pool will deepen in situ and in time should be topped up from the north-east. Then the UK will import and tap into this cold (around the New Year):  

                   T+384 850 temps                                         T+384 2m Surface Temps

                         

 

If I'm reading this correctly and if GFS are getting this anywhere near right, this is the set-up that delivers many of our prolonged cold spells and is very much in line with the background signals. It takes quite some time to evolve but the rewards usually make the wait worth it as it tends to stick around for many days or even weeks. January looks really interesting to me.

CAUTION:  One run and a post from an excited coldie.

 

Edited December 14, 2017 by Guest
Correct typos and check charts