Model output discussion - proper cold spell inbound?

[karlos1983]

7 minutes ago, Ed Stone said:

IMO, it's rather like deciding to kick someone in the goolies. And easy enough decision...What's more difficult, however, is assessing their likely response!

Running round like a headless chicken trying to figure out what do and shouting a lot..... I’d say thats a fair representation right now in here  

Edited February 9, 2018 by karlos1983

[london-snow]

Just now, Chevron12345 said:

Comment related to 6z output. Thats what it showed. Maybe should of added: 'going by the 6z output...' Lots of panicing and jumping on posts again it seems.

With all due respect posts like yours create the jumping and start the bickering off..

Not many members have a great deal of knowledge but are ‘ weather enthusiasts ‘ and whilst trying to learn rely on more seasoned and knowledgeable posters for pointers or predictions of which way our weather is heading. When you post one gfs that shows day 10 mildish weather and don’t take into effect what impacts a ssw may have it kind of rubs people that have took hours to write a well balanced and thought out post backed up by charts the wrong way. 

Not saying your theory might be right or wrong but try and take everything into consideration and not just view one run and think ‘ that’ll hack them off ‘.

[bobbydog]

Just now, Chevron12345 said:

Comment related to 6z output. Thats what it showed. Maybe should of added: 'going by the 6z output...' Lots of panicing and jumping on posts again it seems.

no it wasn't. i'm sure you are knowledgeable enough not to write off february on the basis of one run from one model, in the midst of huge ensemble scatter and operational variation. therefore by adding "going by the 6z output", your comment would make even less sense.

[chionomaniac]

Right, there are a lot of borderline off topic posts and bickering starting to creep in. Please make sure that your post is on topic or in the right place.

Mods haven't got all day to remove/transfer posts - it will be easier to remove posting ability so please keep that in mind.

Using Mark Twains example

'It is better to post nothing and be thought a fool rather than post something and remove all doubt'

Patience is needed when awaiting a SSW and perhaps a little bit of following Mark Twains example.

[TEITS]

16 minutes ago, Chevron12345 said:

Comment related to 6z output. Thats what it showed. Maybe should of added: 'going by the 6z output...' Lots of panicing and jumping on posts again it seems.

No panicing from me. After nearly dying from Pneumonia/Sepsis and being in intensive care two weeks ago, I find snow and cold spells to be the least of my worries. Obviously I would like to see a decent cold spell but it isn't the end of the world for me should it not occur. This is why I can view the model output objectively without emotion.

[ZK099]

2 minutes ago, TEITS said:

No panicing from me. After nearly dying from Pneumonia/Sepsis and being in intensive care two weeks ago, I find snow and cold spells to be the least of my worries. Obviously I would like to see a decent cold spell but it isn't the end of the world for me should it not occur. This is why I can view the model output objectively without emotion.

Hard to beat pneumonia and sepsis as I've witnessed from personal experience. Respect. 

[TEITS]

I see a sub -15C ensemble member has appeared. Anyone know which perb this is as my eyesight isn't what it used to be.

 

Edited February 9, 2018 by TEITS

[Man With Beard]

EC clusters - Two potential options for the D11-D15 period:

Cluster 1 (30 out of 51) - heights to the north, trough stuck towards Europe. Tasty! Britain certainly on the cold side of the flow there

Cluster 2 (21 out of 51) - Atlantic quiet but heights stuck over Europe. Toasty! Spring comes early.

 

[Fozfoster]

8 minutes ago, Man With Beard said:

EC clusters - Two potential options for the D11-D15 period:

Cluster 1 (30 out of 51) - heights to the north, trough stuck towards Europe. Tasty! Britain certainly on the cold side of the flow there

Cluster 2 (21 out of 51) - Atlantic quiet but heights stuck over Europe. Toasty! Spring comes early.

 

Well i think most know which will verify!! LOL

[karlos1983]

10 minutes ago, TEITS said:

I see a sub -15C ensemble member has appeared. Anyone know which perb this is as my eyesight isn't what it used to be.

 

15 TEITS 

hope your feeling better 

It’s a peach!

Edited February 9, 2018 by karlos1983

[Polar Maritime]

Many posts belong to the moan/banter thread, Please think before posting as off topic posts may start to go missing.

Thanks, And please continue discussion on what the model outputs are showing.

[Summer Sun]

11 minutes ago, TEITS said:

I see a sub -15C ensemble member has appeared. Anyone know which perb this is as my eyesight isn't what it used to be.

 

P15

[Frosty.]

19 minutes ago, TEITS said:

I see a sub -15C ensemble member has appeared. Anyone know which perb this is as my eyesight isn't what it used to be.

 

What a BEAUTY!!..and there are quite a few other very cold GEFS 6z perturbations ???

Edited February 9, 2018 by Frosty.

[Daniel*]

5 minutes ago, karlos1983 said:

15 TEITS 

hope your feeling better 

It’s a peach!

If that materialised it would be the coldest spell of weather since 1991? Very heavy snow to for Southern England with a wave moving from east to west off near continent, also frequent heavy snow showers along east coast going well inland. P15 will do nicely the ENS look better than they did when I last checked..  

 

[karlos1983]

Just now, Daniel* said:

If that materialised it would be the coldest spell of weather since 1991? Very heavy snow to for Southern England with a wave moving from east to west off near continent, also frequent heavy snow showers along east coast going well inland. P15 will do nicely the ENS look better than they did when I last checked..  

 

Yup, my view (rightly or wrongly) is that until this SSW has happened, (this weekend), then the operationals are going to show everything but the kitchen sink! Which is why I’ve taken a bit of a step back recently, seems futile commenting on individual runs at the moment.ENS should start to give us a clearer picture of the overall theme in terms of how cold we may or may not get and roughly when it’s like to happen following the impending SSW. Exciting model watching ahead that’s for sure.  

[TEITS]

Thanks for highlighting which perb. The country would come a grinding halt if that occurred.

Look at this for a GEFS mean at +384. Simply amazing.

[alexisj9]

1 hour ago, Daniel Smith said:

There's a bit of negativity with regards to the models this morning so lets try and clear a few things up. 

The SSW is currently underway, the first signs of warming are appearing over Canada

By Tuesday, we're at this point. SSW reached.

Until the SSW has fully happened, the models are effectively "guessing" what the effect of the warming will be. When the warming is in full motion they'll start to get real time data about it fed into them and this should snowball into more consistent runs, at the moment Shannon Entropy is high and we're seeing a lot of run to run variations. The good news is that despite these variations, there's a lot of suggestions of blocked weather, albeit the details with where the blocks set up is up for grabs. The ensembles show this quite well

 

There's a massive amount of scatter in the mid-term but if you look at the very end of the run, more of the ENS members are on the colder side.

The control run of the GFS seems to be the most consistent at the moment out of it and the OP, continuing to show blocked weather to our North.

The ECM this morning was also a very good run

The EPS whilst not the coldest in the world, also show more clustering towards the colder solutions with the mean ever so slightly dropping away towards the end of the run. Note the overnight GFS was on the warmer side

So for those saying "the ensembles aren't improving" or that "the GFS has dropped the blocking", I'm not entirely sure what models/ENS suites you're looking at, but the ones I'm looking at are very much trending towards a blocked scenario.

Whether that means cold for the UK and snow IMBY I don't know. At this stage it's about looking at trends, seeing just how warm the stratosphere gets and in turn how quickly we see a trop response to that. At this early stage I'd put a 50% chance of the UK becoming cold, 30% chance of deep cold and a 20% chance of no cold at all. 

We're in a good place. Trends are going our way. Sit back and relax, don't take ANY output literally, it's going to be volatile and all over the place. Look for broad consistency, i.e is there blocking somewhere to the North of us, and the answer over the last 10-15 runs or so has been yes.

 

Also considering the warming is over Canada, I find it very difficult to believe the vortex will, stay strong like is been shown by the GFS today so far.

 

[ICE COLD]

Just went through the 6z GEFS for days 9,10,11 and 12 to see how many back up the ECM op from this morning and there is quite a few that go for similar evolution to the ECM . Sorry there not in order but you get my drift .

EDIT -obviously Purb 15 is the trend setter ?

Edited February 9, 2018 by ICE COLD

[Frosty.]

20 minutes ago, alexisj9 said:

Also considering the warming is over Canada, I find it very difficult to believe the vortex will, stay strong like is been shown by the GFS today so far.

 

No change to the longer term trend, still pointing towards increasingly cold and blocked late feb lasting well into march..the models are still getting to grips with the pattern change although the Ecm looks to have latched onto it and some of the GEFS too..it's  very exciting watching this unfold.

[bluearmy]

To the question about why the models shouldn’t be trusted post SSW, seeing as they are modelling it in the first place - I tend to agree with this. But the big thing is that this is a variable being thrown into the mix. And it’s a huge variable. So the further out that the modelling sees the SSW the worse place it would be at this point re verification anyway. It has little chance of getting what follows right. 

We should be in a much better place now to see some consistency - gfs ops are clearly inconsistent re any blocking and he eps are fairly binary in their assessment through week 2 of how any blocking will affect nw Europe

i would be looking for Sunday’s noon runs to have pinned down the likely route of any qtr.

 

[mb018538]

Just a note on those ensembles....at day five one member is down at -10, another is at +5! Just shows there is a lot to be resolved. Just ignore anything from a week onwards, it’s going to be completely different to what’s modelled.

Edited February 9, 2018 by mb018538

[Mike Poole]

27 minutes ago, bluearmy said:

To the question about why the models shouldn’t be trusted post SSW, seeing as they are modelling it in the first place - I tend to agree with this. But the big thing is that this is a variable being thrown into the mix. And it’s a huge variable. So the further out that the modelling sees the SSW the worse place it would be at this point re verification anyway. It has little chance of getting what follows right. 

We should be in a much better place now to see some consistency - gfs ops are clearly inconsistent re any blocking and he eps are fairly binary in their assessment through week 2 of how any blocking will affect nw Europe

i would be looking for Sunday’s noon runs to have pinned down the likely route of any qtr.

 

I had been wondering about this too.  The models picked up the SSW ages ago, GFS from well beyond T+300, and the details of the evolution of the stratospheric warming have appeared to me to remain consistent from run to run for some while now.  But I guess we need to remember that the stratosphere verifies much better than the weather down here in the troposphere in the models, where we know anything beyond T+96 is suspect. 

So while there is now little uncertainty about the  stratospheric evolution in the model output, what has been very uncertain to the models over the last week is the state of the troposphere at the moment that the warming occurs - that's still subject to normal modeling errors that we see on the model output day to day (FI beyond T+96 say), and which are only now reducing into the reliable. 

[comet]

1 hour ago, ICE COLD said:

I know it's right at the end and unlikely but that's impressive -17 850s hitting the uk ?. Let's have some of that . 

I think some posters and people just viewing the thread  should realise that this run is very much a distinct possibility in a couple of weeks time. Virtually on par with Jan 87.

[bluearmy]

3 hours ago, Singularity said:

So let's see... all 00z runs had Arctic height rises by day 5 but ECM and GFS keep a trail of low heights through Svalbard that prevents a linkup to the W. Asia height rises and leaves us waiting for the Atlantic zonal winds to tumble before we can get that continental flow set up (with only ECM delivering in this regard).

Given the forcing from above I would have though the models in general would be more keen to break down that trail of low heights but as it is, UKMO is the only one doing this within the next 5 days while GEM takes two days longer and the others even longer than that.

 

 

I will admit that this reluctance is surprising me; I was anticipating a stronger, clearer model response to the first phase of warming that's focused a little NE of the UK. 

Obviously I have overestimated either the model's ability to handle the process prior to the SSW date (Sunday) or the SSW's ability to force strong blocking high development in the face of pre-existing troughs. Hopefully the former of the two as otherwise it's much harder to establish a long-fetch easterly that has the right alignment of flow to bring deep cold air from the likes of Siberia.

I think you will find that the problem is the smaller daughter vortice which splits on the Asian side. One chunk rotates clockwise around the polar block and instead of heading towards Europe (which was originally modelled on gfs fi - remember the consistent ops showing HLB)  it heads closer to the pole in the mid strat (and obviously lower down too) and phases with the Canadian vortex extension. hence, no room for high heights over the pole within 7/8 days and possibly a few after that. 

 

[Mucka]

GFS 06z was a little more encouraging as it at least picked up the potential for an Atlantic ridge.

It does seem that if we get substantial blocking this is currently the route the models are looking at rather than undercutting a block to our East.

GFS's recent wobbles may just be a case of it moving across no-mans land - moving away from one blocking scenario and moving toward another.

If so we can look forward to a stronger Atlantic ridge on future runs more in line with ECM.

Any potential ridge is now just  getting into range of UKMO so the next few runs may at least give us a general idea of how blocking may take hold.

If past experience is anything to go by though, the tribulations only really begin once we have model agreement on a cold spell - so save some energy!