Model output discussion - 5th December 2016 - Into Winter we go

[chris55]

6 minutes ago, Mucka said:

A Christmas miracle?

Ensembles definitely show a little interest but I'm not buying. (Wouldn't want to jinx it anyway)

Thats the first ensemble I've seen that actually takes the initial Low under the block.....! Trendsetter haha

[IDO]

2 minutes ago, karlos1983 said:

It flattens out pretty quickly after that, but I expected that. 

Hi

The weak Scandi heights at D5 have no chance of being undercut if we look at the last 3-5 days GFS runs as by D7 there is a wave of heights incoming from the Azores, so any undercut (cold pool) will be in the Med rather than UK bound. That has IMO been nailed for days so that "window" is probably closed. I am surprised it is still up for debate!

[karlos1983]

3 minutes ago, IDO said:

Hi

The weak Scandi heights at D5 have no chance of being undercut if we look at the last 3-5 days GFS runs as by D7 there is a wave of heights incoming from the Azores, so any undercut (cold pool) will be in the Med rather than UK bound. That has IMO been nailed for days so that "window" is probably closed. I am surprised it is still up for debate!

Well that's your opinion. You may well be right, but what I've said is that the low is further south and more negatively tilted than this morning, so something to watch. I don't think you can 100% write it off.  That's why it's still up for debate.

Edited December 10, 2016 by karlos1983

[Cheshire Freeze]

6 minutes ago, IDO said:

Hi

The weak Scandi heights at D5 have no chance of being undercut if we look at the last 3-5 days GFS runs as by D7 there is a wave of heights incoming from the Azores, so any undercut (cold pool) will be in the Med rather than UK bound. That has IMO been nailed for days so that "window" is probably closed. I am surprised it is still up for debate!

It isn't up for debate as far as I've seen IDO.

However what is up for debate is the latitude the high can gain traction to, the orientation of advection on its western limb and how much falling of heights we can get across Europe. What may seem like minute, insignificant vagaries within these parameters will have large ramifications going forward towards Christmas (seeing as we're still being trop led). Given your vast expertise on all things meteorological, I'm surprised that you cannot see this?

Edited December 10, 2016 by CreweCold

[bobbydog]

26 minutes ago, Bullseye said:

Confused by the posts in past 30 mins. We have went from UKMO looking good/interesting post 144hr to next post saying no blocking possible in next 16 days to good cold pool of -4 around east England then to round it off next post saying "awful charts, worse than 2015". Onto ECM it is... which won't be much help I would imagine.

It is confusing, problem is, the charts are not looking great at face value, what you have is opinions on where the situation could evolve to at any given point. When you look at the GEFS for example, there are a huge range of options on the table. The operational run is virtually just another perturbation in the ensembles and until we get a good fix on where we are heading,  it will stay that way. There are still a good few points during the runs where things could take a different turn, even quite early on. Until the models can agree, you won't see any agreement from the members in here. Mind you, you probably won't see much even when they (the models) do!

[Singularity]

  

Just took a moment to look at how the trough disruption next Wed has evolved. Seems the model saw that it could happen from a good distance out, but way underestimated the southward turn of the jet. Interesting that we've seen that trough sharpen up despite the Atlantic jet being adjusted to something flatter and stronger. 

The ridge to the NE has improved markedly - not a bad example of the usual model bias it would seem. I say seem because the ECM 00z still lacked much of a high there and UKMO falls short as well due to the different handling of the shortwave +72 to +96 hours. If the high was further west and we had a quick easterly import on the cards I imagine a fair few of us would be going a bit berserk 

[Seasonality]

30 minutes ago, CreweCold said:

OK- so that isn't a particularly impressive block but I ask you...was the Jan 2013 block impressive in terms of absolutes? No.

Also I'm highlighting it because such a scenario (with much more impressive MSLP numbers) has been floating around the GEFS for a couple of days. 

I genuinely do not know whether your aim on this forum is to act as forum WUM but you do sometimes convey a strong sense of wanting to be so.

You're saying what many people are thinking crewe. Have just now checked out the 12z and this is a pretty good ending! I should think there is plenty to be positive about this evening. Although for balance a miserable ending on 06z gfsp. Chin up people, onwards and upwards.

 

[SMU]

58 minutes ago, doghouse said:

Yeh, Steve snap out of it man. Why not join with GP and find a route to cold instead of sounding like IDO. Come on, ye know ye want to

Hi Doghouse-

I think in a nutshell Id love to sound like usual self- however theres got to be 'some' reality- when the chance arises I will be the first one singing its praises, however as it stands you have a total dome of warmth over NW Europe with & the jet continues unabated over the top.

Id rather just post the reality than hopecast a cold spell just to safisfy everyone.

All things considered the next opportunity comes around day 11- ( other than the slim chance at day 7 ) why?

Everytime theres a wave of energy exiting the states or developing across the atlantic then theres the chance for change for NW europe - however the backdrop to that is a deep area of vortex setting up shop over canada so theres not likely to be to much window for change when theres so much energy exiting eastwards our way-

The route to cold ( as I think ive tried to highlight a few times ) is the scandi one as that high pressure can remain in situ in a strongly positive AO scenario - so most of the mid lats are mild apart from the area in the immediate SE vicinity of that Scandi High-

Talking of AO & realism - the medium term mean has trended towards +2 on the scale - that is significant in terms of that index-

 

 

very difficult to protract cold out of that- but as said not impossible.

With a little bit of luck that xmas is at day 16 theres time to have a run at a festive cold spell - we would need continuity from the 22nd ish....

S

PS - UKMO is poor tonight, just not as poor as the GFS, the amplitude of the high is way to low to promote undercutting- you need a high pressure central point around Norway as a minimum to get that -See the 2 charts below 1 is good, one is UKMO 

 

If we take the day 1991 started 4th & 5th the AO was positive...! Before dropping out when the high migrated west

Edited December 10, 2016 by Steve Murr

[Summer Sun]

The beebs longer range forecast shows 2 options beyond the 16th

One is for reasonably mild south westerlies and cloud the other is for colder south easterlies bringing the risk of frog and fog

The GFS ens seems to be going with option A so far                                                                                                                                                                                                                                  

 

[Banbury]

28 minutes ago, Summer Sun said:

The beebs longer range forecast shows 2 options beyond the 16th

One is for reasonably mild south westerlies and cloud the other is for colder south easterlies bringing the risk of frog and fog

The GFS ens seems to be going with option A so far                                                                                                                                                                                                                                  

 

Something like this

or this

This even

Edited December 10, 2016 by Banbury

[phil nw.]

Let's keep it sensible and friendly please guys.

I know the charts are underwhelming currently but please keep on topic and hold back on personal digs.

Thanks all.

[chris55]

Take a look at the 00z vs the 12z GFS. Lets imagine we all lived around the Croatia area or thereabouts...... within 12 hours at T150ish we have lost some very cold 850s which have been replaced by a markedly less cold flow and to be frank nothing that exciting! The longwave pattern and overall theme is similar but the details make all the difference. This just highlights how fickle the Op runs (and associated ens" for each run can be at this range without a clear and consistent trend) Calling anything past 144 without a solid signal is futile IMO.

 

00z

12z

[booferking]

So which model is right @96hrs quite a difference and only 4 days out weres your money.

[Ravelin]

Also quite a difference from yesterday's ECM 12z for 16th and today's... 

 

With changes that big within a suite at day 6 it seems daft to obsess about outcomes at longer ranges. 

[Banbury]

Plenty of blocking in the ENS varying positions some good for us some indifferent , one can see why its a flip of a coin job

[SMU]

This is what I mean by minimal window of opportunity between bouts of energy-

leads to a collapse of any heights ridging North - 

WARM -

 

Edited December 10, 2016 by Steve Murr

[chris55]

24 minutes ago, chris55 said:

Take a look at the 00z vs the 12z GFS. Lets imagine we all lived around the Croatia area or thereabouts...... within 12 hours at T150ish we have lost some very cold 850s which have been replaced by a markedly less cold flow and to be frank nothing that exciting! The longwave pattern and overall theme is similar but the details make all the difference. This just highlights how fickle the Op runs (and associated ens" for each run can be at this range without a clear and consistent trend) Calling anything past 144 without a solid signal is futile IMO.

 

00z

12z

Im going to quote myself here lol!! Just imagine if those cold 850s down towards Greece/Croatia were set to hit the UK on yesterdays Ops... think of all the posts in here that would have been firing on all cylinders! Now look at the latest ECM option for that area...just makes you take note yea. Without consistency in the mid term its best to absorb the data without expectation and be open to changes.

 

 

[phil nw.]

We would struggle to get any surface cold off the continent on this ECM run next week end with the high too far south.

I was looking to see if the second pulse from the Azores high around T168hrs would do enough such as the GFS mean

and looking at the gefs 2m temps for C.England

would give max's around 4-6C ,some night frosts and some brighter conditions for a few days.Where the main high settles makes the difference between something reasonably seasonal or maybe a rather mild and more cloudy south westerly.

The former is only crumbs when many of us are looking for the whole loaf but probably preferable to most of us given the alternative.

 

 

Edited December 10, 2016 by phil nw.

[Summer Sun]

ECM following GFS ens by going for a southwesterly to return so we're likely to see quite a bit of cloud keeping temps mild towards the end we could well see more in the way of frost as pressure builds over the UK and cutting off the milder flow

Edited December 10, 2016 by Summer Sun

[northwestsnow]

At least ecm looks mainly dry under the influence of that euro high on steroids!Granted for high lat blocks its as bad as it gets but id rather dry and mild than this drizzle ...in any event we are literally as far away from cold uppers as we could possibly be.

[Scandinavian High.]

I don't think this done yet more changes to come im not giving up yet lets see what the pub run comes up with.

Edited December 10, 2016 by abbie123

[Stuie]

I think this ECM run should make us realise that FI is FI. When was the last time you saw a 1040HP over the SE of England? ...... and in winter?...

Models are obviously struggling somewhere, if this verifies then... well..

 

[karlos1983]

Ok I think I'm ready to give up on the first scandi heights after seeing the ECM. Onto the next 

[Stuie]

14 minutes ago, karlos1983 said:

Ok I think I'm ready to give up on the first scandi heights after seeing the ECM. Onto the next 

Karlos, think we are looking at T96 at the min, no further.

Edited December 10, 2016 by Stuie W
Name

[blizzard81]

Very confusing that the ecm switched to the scandi high potential yesterday after having none of it and has now ditched it again completely! Quite bizarre. I will wait for the ensembles and see what they show.