Model output discussion 25th Jan - The final third of winter beckons..

[Summer Sun]

ECM and UMKO extended (t168) look pretty close

 

[Rocheydub]

1 minute ago, Summer Sun said:

ECM and UMKO extended (t168) look pretty close

 

I'm sorry, but no they don't. Upstream they are miles apart!!! Even just off shore here they are vastly different.

[Frosty.]

I can see good potential for a battleground scenario developing over the uk during next week into week 2 as the atlantic and cold scandi block lock horns, hopefully leading to snowfalls in parts of the uk..really hope February delivers the snow most of us crave and deserve!

[TEITS]

As excellent as the models runs are the models will not have the correct solution because the main period of interest is +96 to +144. I know from experience that the positioning, orientation of the high is subject to change and the direction of the associated cold pool. We shall also see changes with regards to how the Atlantic interacts with the blocking to the NE with changes to the track of the shortwaves splitting off from the main low pressure system.

When we get towards Sunday we should have a better idea because in these situations the models are much more accurate at +48/+72 than +96/+120. If this was a bog standard W,ly spell then the difference is much less.

If I was going to have a punt then in my opinion we are seeing the typical scenario of the models having too much eastward momentum for the period at +120 to +144. I would expect corrections W for this period by Sunday.

Finally my favourite subject the ensembles. A few days back the Berlin ensembles only had 1 cold member. Now look at the increase of colder runs!

[Man With Beard]

To be fair I think SS was focusing on the trend to stall the Atlantic in front of the Scandi High, not the whole chart.

Some yesterday expressing surprise at the fading away of the Atlantic next week - is this linked to the stratosphere - I'm not an expert but I believe that on this chart anything in blue at 10hpa / 60N equates to a technical SSW - so have we just about got there by the skin of our teeth, and is that part of the magic dust evaporating the Atlantic chart?

(note - this will change later today)

[bluearmy]

I was going to say that there must be quite a few clusters in the eps and then saw Matt has confirmed  this.

whilst my thoughts are drifting towards the chances of a proper wintry spell looking more likely, the uncertainty in that mid term period un nerves me. Were we two weeks behind then I would be confident that we would get there in the end but it could turn out that the end becomes the last week of Feb and that is going to be tough to get lasting snowcover in the south of the uk

anyway, those wanting the Azores ridge not to play a big part may well need to prepare for a bumpy ride. The 00z suites look like they want to build pressure across from the sw towards scandi post day 10 and don't think this can be as far nw as Iceland as steve would like. I believe the key to getting a decent wintry period here will lie with the Euro troughing. The trend has been to grow this as time has ticked by and without it, I think the block will end up too far south for us. get enough split flow se and we should be ok - however, as we saw a few weeks ago, promising charts petered out in the end as the trough lost its supply line and sank into the med failing to support the scandi ridge at a high enough latitude 

all in all, brilliant output to be looking at - again. Coldies really deserve some luck this winter. 

[Cheshire Freeze]

1 minute ago, Man With Beard said:

To be fair I think SS was focusing on the trend to stall the Atlantic in front of the Scandi High, not the whole chart.

Some yesterday expressing surprise at the fading away of the Atlantic next week - is this linked to the stratosphere - I'm not an expert but I believe that on this chart anything in blue at 10hpa / 60N equates to a technical SSW - so have we just about got there by the skin of our teeth, and is that part of the magic dust evaporating the Atlantic chart?

(note - this will change later today)

Yes, read on the other side that we achieved a technical SSW by the very slightest of margins!

[Cheshire Freeze]

3 minutes ago, bluearmy said:

I was going to say that there must be quite a few clusters in the eps and then saw Matt has confirmed  this.

whilst my thoughts are drifting towards the chances of a proper wintry spell looking more likely, the uncertainty in that mid term period un nerves me. Were we two weeks behind then I would be confident that we would get there in the end but it could turn out that the end becomes the last week of Feb and that is going to be tough to get lasting snowcover in the south of the uk

anyway, those wanting the Azores ridge not to play a big part may well need to prepare for a bumpy ride. The 00z suites look like they want to build pressure across from the sw towards scandi post day 10 and don't think this can be as far nw as Iceland as steve would like. I believe the key to getting a decent wintry period here will lie with the Euro troughing. The trend has been to grow this as time has ticked by and without it, I think the block will end up too far south for us. get enough split flow se and we should be ok - however, as we saw a few weeks ago, promising charts petered out in the end as the trough lost its supply line and sank into the med failing to support the scandi ridge at a high enough latitude 

all in all, brilliant output to be looking at - again. Coldies really deserve some luck this winter. 

I wouldn't bring that one up again...I already went there yesterday 

I cannot disagree with anything you have said there. I've already noted the influence of the Azores HP in that day 10 ECM mean...it is a concern.

Edited February 2, 2017 by CreweCold

[Ravelin]

I know the ECM is the 'bell of the ball' this morning but I've been keeping an eye on the GFS Ensemble graphs for my local. Normally you'd be concerned if the OP was an outlier, but if the OP and the Control are consistently the coldest of the runs, in the medium term, during the last 24hrs ? 

Going to be interesting to see if the OP/Control are right.

 

[Ali1977]

We may not know till the weekend how this pans out however we aren't in the far reaches of FI, so each run now does have a fair bit of reality to how mid next week will pan out.  We need some correction West of the Scandy high to hold back the progression of the initial Atlantic flow, and hopefully something like the ECMs HP over Scandy on it's latest run.  Over to the 06z.

[TEITS]

Compare yesterdays +96 fax with the latest +84. Note the block is slightly further W as is the low over Iceland.

The +84 is on the left.

Edited February 2, 2017 by TEITS

[Ali1977]

2 minutes ago, TEITS said:

Compare yesterdays +96 fax with the latest +84. Note the block is slightly further W as is the low over Iceland.

The +84 is on the left.

Even by T60 on the GFS you can see it has slightly moved West, and the Jet is digging slightly more South to our SW.  

[snowfish1]

34 minutes ago, TEITS said:

As excellent as the models runs are the models will not have the correct solution because the main period of interest is +96 to +144. I know from experience that the positioning, orientation of the high is subject to change and the direction of the associated cold pool. We shall also see changes with regards to how the Atlantic interacts with the blocking to the NE with changes to the track of the shortwaves splitting off from the main low pressure system.

When we get towards Sunday we should have a better idea because in these situations the models are much more accurate at +48/+72 than +96/+120. If this was a bog standard W,ly spell then the difference is much less.

If I was going to have a punt then in my opinion we are seeing the typical scenario of the models having too much eastward momentum for the period at +120 to +144. I would expect corrections W for this period by Sunday.

Finally my favourite subject the ensembles. A few days back the Berlin ensembles only had 1 cold member. Now look at the increase of colder runs!

So are u suggesting less Atlantic energy against the block and a more prolific easterly for the UK with a westward movement I still learning. Thanks TEITS

[NorthYorksWeather]

6 minutes ago, Ali1977 said:

Even by T60 on the GFS you can see it has slightly moved West, and the Jet is digging slightly more South to our SW.  

Yes more noticeable now at t72, hopefully we can continue the westward trend over the coming days.

[Nouska]

Comparing the latest ensembles for SW Holland to the 12Zrun I posted last night.

 

There is still the 'shadow' of the previous run but much of the scatter afterwards has been resolved. There may be six clusters but a good percentage of them go easterly as early as the 7th.

Looking at the extended EPS means - cold 850 temperatures right the way to the end of the run.

eg. 

 

Edit to say - loving the up to the top button!

 

Edited February 2, 2017 by Nouska

[snowice]

06z is going to be  fantastic  at 96hrs the high is 200miles west already!

Edited February 2, 2017 by snowice

[SMU]

Big upgrade coming on 06z

trigger low diving south @ 96- indicitive of one of the Cold debilt clusters ( control )

S

[Ali1977]

16 minutes ago, snowice said:

06z is going to be a fantastic  at 96hrs the high is 200miles west already!

Still tricky but defo looks better, the front coming in from the Atlantic has a sharper front as it's being held back by the block - it may give us a better chance of a stalling rain to snow event mid/late next week - still unsure if it will be a Stella type run but certainly an improvement and a better looking run (hopefully don't speak to soon)

 

Edit - Early improvement haven't really led to ones by T120 - quite similar to the 00z although maybe slightly weaker initial Atlantic blast and colder 850s associated with E flow around southern Scandy.  By 144 things are looking better

Edited February 2, 2017 by Ali1977

[The Beast From The East]

1 hour ago, Steve Murr said:

Yes we are closer

t120-144-168 is the transition

Scandi high is 99% a dead cert now - just the flow allignment towards the UK very unclear however ECM mean is excellent now all the way out to T240

 

expect the 10 - 15 debilt ENS to be the best yet...

S

Thank you both Steve murr and Matthew Wilson for your replies .

[Ravelin]

That cold pool to the East is trying to get here....

Will it make it?

Edited February 2, 2017 by Ravelin

[Ali1977]

3 minutes ago, Ravelin said:

That cold pool to the East is trying to get here....

Will it make it?

YES - its looking good - for the East especially.  This is only mid next week too - helped by heights in Scandy being more NW too.

Edited February 2, 2017 by Ali1977

[Weathizard]

The Atlantic low is disrupting and stopping the Azores high linking up too much with the scandi high which is nice to see, not too much difference overall to the 0z at 120 more a variation on the theme

[Man With Beard]

17 minutes ago, Steve Murr said:

Big upgrade coming on 06z

trigger low diving south @ 96- indicitive of one of the Cold debilt clusters ( control )

S

I'm thinking this is going to be a close one, actually, what with the Azores High that tiny bit stronger...

[Weathizard]

Signs of attempted retrogression to greenland? We appear stuck a little bit in no mans land at 132, complex situation unfolding.

[Ravelin]

Clawing it's way West inch by inch...

Compared to the 0Z...

 

Edit:

Kind of makes it by t180, but not convincingly so...

Edited February 2, 2017 by Ravelin