Model output discussion - January cold spell ending, what next?

[sheikhy]

8 minutes ago, Jason H said:

I think you might be on the hype train too soon again my friend and it will only lead to disappointment. It's one operational run. The interesting part for cold weather fans lies 5+ days away. Definitely overall in the model world, it's trending in the right direction though. 

Defo mate but i did mention only IF the ukmo is correct!!!

[Djdazzle]

23 minutes ago, sheikhy said:

Let me mention something to my model peeps on here right now!!im glad i have taken a break from the model thread for a few days as nothing was really happening until now!!!!BUT IF THE UKMO IS RIGHT what we are about to witness is an upgrade of epic proportion between 96 and 144 hours largely thanks to the warming!!i have not seen short term upgrades for a very long time but this has all the hallmarks of january 2013!!!again i say IF the ukmo is correct!!

I love your posts mate but this is a bit OTT. Even if UKMO is right, there would still be quite a few obstacles before we can even talk about it being “epic.”

[Battleground Snow]

Can we get a double ensemble boom from @feb1991blizzard

ECM v GFS 240. ECM looks just as good to me

 

[Matt H]

Fairly good ECM 12z mean this evening, looks like there’s a decent amount of support for the op at day 10.

Op:

Mean:

 

 

Edited January 8, 2021 by Frosty Winter

[Tim Bland]

ECM showing some Compensation for the snow starved south east...

[I remember Atlantic 252]

7 minutes ago, Djdazzle said:

I love your posts mate but this is a bit OTT. Even if UKMO is right, there would still be quite a few obstacles before we can even talk about it being “epic.”

Aye sheikhy cool, but maybe a bit excited!

[Mike Poole]

51 minutes ago, chris55 said:

You haven’t got to be technical. Just let me know why the UKMO 144 is notoriously unreliable?

This idea has been floating around here for years.   When I started model watching the UKMO resolution dropped after 3 days I think I am correct in saying, which meant by day 6 it could be pretty poor.  But just checked and now it is 17km to T168, so if this was true once it definitely isn’t now.  

[swfc]

So I've had a terrible day. My brother is in hospital with covid. Anyway I've missed all the model output since early today. Are the models and synoptics looking OK today. Sheffield missed the snow today but are things looking  good

Edited January 8, 2021 by swfc

[sheikhy]

5 minutes ago, Mike Poole said:

This idea has been floating around here for years.   When I started model watching the UKMO resolution dropped after 3 days I think I am correct in saying, which meant by day 6 it could be pretty poor.  But just checked and now it is 17km to T168, so if this was true once it definitely isn’t now.  

Whats ecm up to 168 hours mate?

[Matt H]

1 minute ago, swfc said:

So I've had a terrible day. My brother is in hospital with covid. Anyway I've missed all the model output since early today. Are the models and synoptics looking OK today. Sheffield missed the snow today but are things looking god good 

Really sorry to hear that news, wishing your brother all the best and a speedy recovery from the virus.

[Mike Poole]

50 minutes ago, Steve Murr said:

Eve -

Not often I give favourite here but UKMO solution ( similar to its all conquering 2013 run ) its as high in my eyes as 75%

JMA 144 very similar & extends to 192 = 2013 nirvana ( who remembers March 2013 !!)

Thanks Steve, I can also see big parallels with 2013 in this setup.  I believe JMA uses a Met office based model similar to the UKMO, so it is always worth keeping an eye.  Now that we’ve had the SSW, I will also check the strat charts for similarities if Meteociel has them and report back.  

However, no situation is the same, and if the wedge scenario plays out, it does definitely not mean that the rest of winter will follow 2013 i.e. nothing more re cold until March - and the booster warmings in the strat to come may be a part of that, and i still expect a more severe cold spell to follow end of Jan into Feb

[Mike Poole]

6 minutes ago, sheikhy said:

Whats ecm up to 168 hours mate?

9km 137 vertical layers out to T240.  That’s one reason why it is the best.  

Just to add I think the GFS is 13km throughout.  But resolution isn’t the only issue.  The data at T0 is vital and both ECM and UKMO have a vastly superior algorithm for establishing this (4DVar) than GFS.  Hope that helps.

Edited January 8, 2021 by Mike Poole

[Griff]

32 minutes ago, Griff said:

A side by side of the 144s

Unless it's blindingly obvious I'm not experienced or educated enough to analyse upstream / downstream features that will grace or scupper our prospects for snow. Didn't need this much knowledge for my cpl met ground school exam (it was multiple choice with a question bank you could easily memorise ). 

I'm far more comfortable with general synoptics / charts and their relative comparison to each other via shapes, areas covered and intensity (if that makes sense), etc. 

That said, I can see fairly clearly why the UKMO comes out on top for the majority today. 

However, just passing the time, I have to say, and unlikely as I appreciate that it sounds, the JMA would be perfectly satisfactory for me at 192... Yes I'm being serious, and no, I'm not trolling! 

 

5 minutes ago, Mike Poole said:

Thanks Steve, I can also see big parallels with 2013 in this setup.  I believe JMA uses a Met office based model similar to the UKMO, so it is always worth keeping an eye.  Now that we’ve had the SSW, I will also check the strat charts for similarities if Meteociel has them and report back.  

However, no situation is the same, and if the wedge scenario plays out, it does definitely not mean that the rest of winter will follow 2013 i.e. nothing more re cold until March - and the booster warmings in the strat to come may be a part of that, and i still expect a more severe cold spell to follow end of Jan into Feb

 

59 minutes ago, Steve Murr said:

Eve -

Not often I give favourite here but UKMO solution ( similar to its all conquering 2013 run ) its as high in my eyes as 75%

JMA 144 very similar & extends to 192 = 2013 nirvana ( who remembers March 2013 !!)

Ha! I knew I must have been inspired by something to have a look!

I wish I could say it was my own original thinking but clearly inspired (possibly subconsciously through mental osmosis).

 

[TSNWK]

15 minutes ago, Mike Poole said:

This idea has been floating around here for years.   When I started model watching the UKMO resolution dropped after 3 days I think I am correct in saying, which meant by day 6 it could be pretty poor.  But just checked and now it is 17km to T168, so if this was true once it definitely isn’t now.  

Agree. UKm did have form for unreliable at 144 but even then I felt it was solid at 120

These past couple of winters ive not had that feeling that UKM has struggled. All a bit subjective I accept...but I do find that UKM is the sensible, strong silent type now.

Anyway it owes us.  It lead the way around new year in not having it when there was a chance of deeper cold.

[Man With Beard]

ECM individual ensembles D10 - no clear pattern. As many Atlantic highs as Euro highs. Can't make a forecast on that. 

Wrt D5 snow potential, it's clear the UKMO route is not in the main spread. It has won out a couple of times from this position over the years, but even so, smart money still has to favour other models, which brush aside the wedge quite easily.

[northwestsnow]

26 minutes ago, swfc said:

So I've had a terrible day. My brother is in hospital with covid. Anyway I've missed all the model output since early today. Are the models and synoptics looking OK today. Sheffield missed the snow today but are things looking  good

I'm sorry mate.

I hope he recovers soon ...

[northwestsnow]

The mean looks decent but clearly there are still a number of members keeping heights across Europe ...

Would like to see a bit of momentum towards a block to the NW tomorrow...

Still feeling this is a slow burner to where we want to be ....

[BARRY]

Just now, northwestsnow said:

The mean looks decent but clearly there are still a number of members keeping heights across Europe ...

Would like to see a bit of momentum towards a block to the NW tomorrow...

Still feeling this is a slow burner to where we want to be ....

what the models look like in 2 days time will be any ones guess.

 

[stodge]

Evening all

Another cold day in lowland East London and tomorrow will mark two weeks of below average temperatures since Storm Bella - another sharp frost overnight as well. Yes, it's not feet of snow and -20 uppers but in the context of recent times, not too bad.

An evolution to something less cold or even mild is assured but some signs last evening of that not lasting while GFS went off not just on one but on a series of ones as the prevailing stratospheric happenings continue to play out in the atmosphere.

On then to tonight's plateaux du jour from the models - will it be a sensual delight or a one way trip to the bathroom? Let's see..

12Z GEM: T+120 takes us to next Wednesday. There are significant changes from the modelling of last evening at this time.  The LP currently developing over to the west of Iceland, which on some earlier output was going to come south across the British Isles, then was going to stay to the north or north-east is now moving east before sinking south over western Scandinavia and quickly forming a trough south-east into the Ukraine. The HP to the south remains over Iberia but a nose of LP has split the ridge to new heights to the east of Iceland. Frigid air sits over Scandinavia (-16 850s anyone?). Over the British Isles, the initial push of milder air is replaced with a new plunge of colder air on Monday and Tuesday especially over northern and eastern parts with milder air trying to return from the west by T+120. It's a complex situation with a lot happening. From there, it doesn't get any simpler - basically, heights build to the west of the British Isles aligning north-south while weak heights sit to the north and north-east and the troughs sit over Poland and southern France respectively. A weak N'ly flow covers much of the British Isles with -4 to -8 uppers back in charge with the milder air pushed away to the south. From there, the HP slowly topples across the British isles and into north-western Europe with a weak Atlantic flow coming in although heights persist to the north.  Milder air has reached almost all parts of the British Isles by T+240.

12Z GFS OP - that was an interesting run from GEM which was the most bullish for mild a couple of days ago. The American OP was quite bullish about a mild evolution yesterday but let's see what it offers this chill Friday evening - big differences from GEM as early as T+120. A more straightforward Atlantic-based evolution with HP over or just to the north-west of Iberia and a run of WSW'ly winds with a complex upstream Atlantic trough and the residual Scandinavian trough over the Baltic States. Again, a brief push of colder air back south but GFS pushes this away quicker than GEM and by T+120 most of the British Isles is in a milder airflow. From T+120 it's the GFS OP's turn to go complex. The Atlantic LP goes nowhere slowly and heights rise through the British Isles to Scandinavia but a small lobe of the trough develops into a secondary LP and crosses the British Isles being in the southern North Sea by T+180. 850s are zero to -4 over much of the British isles but with milder air again encroaching from the west. Oddly enough, it gets even messier from there with the Atlantic LP cut off by a new wedge of heights extending south-east from Greenland to Iberia with a new Atlantic LP diving SE. The trough over the British Isles extends from eastern Iceland through the British Isles (with a secondary feature over East Anglia) and further south-east to the Balkans. Weak heights are now over Scandinavia. Colder air has extended back through the British Isles by T+240 with uppers of zero to -4 generally.

12Z Parallel - another significant upgrade for cold from GFS OP and the chart a million miles from GEM at the same time. On then to Parallel which was more bullish for cold yesterday. Once again, differences as early as T+120 with Parallel positing a more robust Atlantic with more defined heights to the north and a weaker HP to the south. Milder air is back across the whole British Isles by this time. From there, heights develop over Scandinavia and points further north and west and this deflects the Atlantic LP SE down the North Sea. By T+180 a shallow LP is off the north west coast of Scotland with heights persisting to the south. Milder in the south but colder air persists in the north. From there, the Scandinavian heights dissipate but heights build over Greenland and these start to push the jet and the LP further south so by T+240 the LP are crossing the British Isles but the divide between a mild south and west and a colder north and east persists as do heights over Iberia.

12Z ECM - Parallel is intriguing as well albeit mild for many and especially in the south. Finally, ECM and with the huge uncertainty in the other models, I expect something completely different.  By T+120, ECM has a more progressive Atlantic profile but otherwise nothing too dramatic. Milder air covers all parts of the British isles by this time. By T+192, a wedge of heights has tried to build into Scandinavia but a new Atlantic LP over Iceland has thrown a trough over the British Isles even as heights rise upstream. It's still on the mild side at this time. The heights manage to split the trough by T+240 with a new wedge of heights running from west of Iberia north-north-west to Greenland leaving the British Isles on the cold side of the trough with a series of weak LP to the north and east. It's colder too with -4 uppers generally and -8 uppers approaching the east coast. 

It's a fascinating split - ECM and GFS OP take us back cold, Parallel is heading the same way as T+240 and only GEM has a milder solution. I note 12Z JMA is cold by T+192 while UKMO teases at T+144.

Looking further ahead, the usual "far FI" charts (no, not T+144) from GFS OP and Parallel at T+312 and T+384 respectively.

After nights of real divergence, some notable similarities in OP and Parallel this evening. Both show strong Greenland heights - neither shows a raging PV in its usual place, both show a jet tracking south and both show real cold cores to the east. 

Looking further afield, 12Z Control has plenty of cold as well. As for the 10 HPA charts, Control keeps the vortex under pressure with a series of strong warmings through FI. Similar evolution on OP and Parallel.

Confusion: - yep, that's still in charge tonight. Apart from GEM, which offers something colder around T+180, there's a general move towards something milder early next week despite a brief final push of colder air from the north. From T+180 GEM makes less of any Greenland heights and brings back a milder evolution. GFS OP and ECM have the ridge SE from Greenland to Iberia which keeps the British isles under the cold trough while Parallel is nearly there but keeps the door open to the Atlantic albeit with the jet being pushed south. Further into FI, the story is one of a southerly jet and LP moving over the British Isles so potentially a lot of weather as we move further into January with milder spells and colder spells aplenty. The south always perhaps on the milder and wetter die but a lot of snow opportunities further north with the PV settling over or close to Scandinavia helping to steer Atlantic systems south and east.

All I'll say is there's a lot of weather forecast - what, when and for whom is up for grabs.  

[Tim Bland]

13 minutes ago, Man Without Beard said:

ECM individual ensembles D10 - no clear pattern. As many Atlantic highs as Euro highs. Can't make a forecast on that. 

Wrt D5 snow potential, it's clear the UKMO route is not in the main spread. It has won out a couple of times from this position over the years, but even so, smart money still has to favour other models, which brush aside the wedge quite easily.

I’m a bit confused where the day 5 snow potential is on the UKMO ?

[Singularity]

Look past the fluctuations to the details and there's an important adjustment to be seen in the mid-range.

For a week today, an amplified ridge has become increasingly well supported by the ensembles. This feature splits the low heights in the North Atlantic from those over eastern North America, preventing that cold, unstable air from surging out across the ocean and fuelling deep Atlantic storms.

As a result, the emerging high latitude blocking has a much easier time gaining some direct influence over the UK's weather. We're seeing model runs that manage to get there despite taking complicated routes full of small lows attempting to be spanners (in the works).

This sort of relatively small but highly important feature is a classic example of what tends to be missed in the extended range, especially by GFS but as we see here, by even the more impressively verifying models too.

[Cheshire Freeze]

21 minutes ago, northwestsnow said:

The mean looks decent but clearly there are still a number of members keeping heights across Europe ...

Would like to see a bit of momentum towards a block to the NW tomorrow...

Still feeling this is a slow burner to where we want to be ....

Remember my date of the 20th from the other day? Still think that'll be the landing point.

[phil nw.]

Two promising looking 240 means tonight with that surge of heights towards Greenland.

If we are to get a favourable response to the ssw then this is about the time scale many watchers have looked to for the real cold interest to start following the ssw.-allowing for the lag effect.

It will be interesting now to see if this next step can be counted down now and more importantly we see any block close enough to keep the uk in the cold.

Edited January 8, 2021 by phil nw.

[Griff]

10 minutes ago, Singularity said:

Look past the fluctuations to the details and there's an important adjustment to be seen in the mid-range.

For a week today, an amplified ridge has become increasingly well supported by the ensembles. This feature splits the low heights in the North Atlantic from those over eastern North America, preventing that cold, unstable air from surging out across the ocean and fuelling deep Atlantic storms.

As a result, the emerging high latitude blocking has a much easier time gaining some direct influence over the UK's weather. We're seeing model runs that manage to get there despite taking complicated routes full of small lows attempting to be spanners (in the works).

This sort of relatively small but highly important feature is a classic example of what tends to be missed in the extended range, especially by GFS but as we see here, by even the more impressively verifying models too.

I was about to post your tweet on this to the twitter thread 

Much appreciated, ta.

[northwestsnow]

Just now, CreweCold said:

Remember my date of the 20th from the other day? Still think that'll be the landing point.

I'm inclined to agree...

Its looking good for another cold episode, the extent and duration is anyones guess.