Model Output Discussion - Into Winter

[LRD]

The start of the next chase?

2 weeks away but we've gotta start somewhere

[Catacol]

25 minutes ago, Ali1977 said:

I like the last line of the METO long range , a chance of a longer cold spell later into Dec!! Guessing that’s MJO related!!

anyway, cmon ECM

Most significant development of the day, especially for those of us that have championed a cold but not spectacular spell at the start of the month leading to a IO driven relaxation for 10 days or so followed by shift back to deeper and more impactive cold. The MetO have all the computer power hidden up their sleeve. Yesterday there wasn't a hint of a colder shift in the text - and today that cryptic little dangler at the end. That suggests to me they are seeing cold holding on over Scandy as many have predicted and then a renewed surge of heights backing that cold W and SW at Xmas time. I don't pay a huge amount of attention to MetO updates because they can swing around....but they rarely risk a cold statement especially at range. The fact they have come out and risked it today I think is huge.

Best keep this relevant before Mods stab me. Note again this chart, same sort of period as yesterday. That high anomaly over Kara is beginning to back west....

Edited December 1, 2023 by Catacol

[MidnightSnow]

I know it's been said many times before, but given the fact that lows historically end up further south... why not just assume the same thing will happen again? Would it not be a safe bet to assume the low on Sunday/Monday will be 50-100 miles further south than what the models are currently showing?

[alexisj9]

7 hours ago, offerman said:

So far, it looks like the cold gets pushed out the way by Atlantic low pressure systems towards the middle part of next week.

One thing the GFS charts are good at seems to be highly accurate with forecasting mild wet and windy and low pressure systems, but it struggles with cold SynOptics and often Waters them down in longevity of cold snaps.

at the moment, it doesn’t look like we will get locked into any prolonged cold periods, judging by the charts, but there has been a lot of talk recently of a cold Christmas period leading up to New Year. 

Looking better than yesterday's 00z then, as it was Sunday/Monday for most at that point.

[LRD]

They're a minority but some members of the GFS ensemble suite see the 850s plunging towards mid-December. Not the full set...

[Mike Poole]

11 minutes ago, Catacol said:

Most significant development of the day, especially for those of us that have championed a cold but not spectacular spell at the start of the month leading to a IO driven relaxation for 10 days or so followed by shift back to deeper and more impactive cold. The MetO have all the computer power hidden up their sleeve. Yesterday there wasn't a hint of a colder shift in the text - and today that cryptic little dangler at the end. That suggests to me they are seeing cold holding on over Scandy as many have predicted and then a renewed surge of heights backing that cold W and SW at Xmas time. I don't pay a huge amount of attention to MetO updates because they can swing around....but they rarely risk a cold statement especially at range. The fact they have come out and risked it today I think is huge.

Yes, agreed, but the bit in bold will be crucial if, as looks likely, the Atlantic does start to make inroads.  If the cold does not hang on over Scandi (putting the UK to one side for a minute), then my optimism for the late December cold spell will massively diminish.  If everything has gone back to normal zonal fayre by that point, then how many of us would trust supposedly favourable phases of the MJO to actually deliver from scratch?  

This puts the onus back on the current model uncertainty resolving itself in a way that, even if the UK warms for a while, doesn’t produce a complete zonal reset.  Damage limitation will become the watchword of the next couple of weeks modelling, unless, of course the Scandi high and easterly option (which is still in the mix, by the way) verifies.  

Edited December 1, 2023 by Mike Poole

[feb1991blizzard]

1 minute ago, LRD said:

They're a minority but some members of the GFS ensemble suite see the 850s plunging towards mid-December. Not the full set...

yes - nice - probably best graph yet in terms of no of severely cold members.

[Catacol]

10 minutes ago, Mike Poole said:

Yes, agreed, but the bit in bold will be crucial if, as looks likely, the Atlantic does start to make inroads.  If the cold does not hang on over Scandi (putting the UK to one side for a minute), then my optimism for the late December cold spell will massively diminish.  If everything has gone back to normal zonal fayre by that point, then how many of us would trust supposedly favourable phases of the MJO to actually deliver from scratch?  

This puts the onus back on the current model uncertainty resolving itself in a way that, even if the UK warms for a while, doesn’t produce a completer zonal reset.  Damage limitation will become the watchword of the next couple of weeks modelling, unless, of course the Scandi high and easterly option (which is still in the mix) verifies.  

Momentum elastic ping-back has already peaked and settling. We have the jet firing up in response as MJO is in 2/3/4 but I think here the brakes will be applied because that momentum surge is not record breaking and the cold will hold to our E and NE. CPC charts to me say the same. So.... cold pushed away from the UK mid week - which at the very start of this spell was the form call - but the trough to stall. That might mean some wet days for us and general damp grimness - especially as the residual heights over Greenland that I have mentioned before should ensure the trough stays chilly with plenty of arctic rather than tropical air being fed into it. But Scandy to stay cold and lack of Euro High to allow central Europe also to stay pretty cold.

Watch then for 7/8/1 MJO phases and renewed momentum surge mid month. Phase 7 around Dec 9....allow for lag - one week? - so signs of heights rebuilding as we approach the final third.

One of the best tweeters still tweeting since Masiello disappeared is Eric Webb. Some very detailed discussion from him yesterday. He sees -NAO digging in for the long term and a hemispheric wave patttern conducive to strat disruption. It is good to read real pros coming up with the same arguments at this point.

Most exciting winter in years continues. Snow chances this weekend. MJO playing ball. Strat pressure well forecast. I can see a cold Xmas week followed by a Jan SSW and given Aleutian Low activity I'm willing to gamble on a split. This winter has a chance of being a cracker.

Edited December 1, 2023 by Catacol

[Dennis]

wait a bit....please not to fast in the wishes of new cold 

the MJO 7 is not now at start of dec23 but more after15th

Edited December 1, 2023 by Dennis

[Anthony Burden]

Evening al,most charts ie UKMO/ICON and to some extent GFS going for the Atlantic advance at 144hrs this coming breakdown still looks very interesting to me,as MattH said erratic breakdown likely before the less cold air reach all parts of UK.Still single figure temperatures could remain in a large part of the UK for some time even with the Atlantic influence.Not going to speculate further regarding future cold until I see this very cold air anchored to our north east displaced if at all.

[Catacol]

2 minutes ago, Dennis said:

wait a bit....

the MJO 7 is not now at start of dec23 but more after15th

I'm still in love with BOMM Dennis

but seriously - yes. Timing will not be definite. Might take longer. Still see the changes final third. However NWP charts will hove into view in advance....so the chase will resume before too long. I'm giving it 10 days of westerly before we see jammy doughnuts in NWP again.

Edited December 1, 2023 by Catacol

[alexisj9]

6 hours ago, Jackski4 said:

I’m gonna go for a 17% chance just so I look more knowledgeable than you if it happens

 

6 hours ago, Kasim Awan said:

They'll laugh in my face when I say a frosty morning can overpower a 250mph low pressure system holding 100 billion trillion tonnes of water.

True, but I'm not one hundred percent sure that's what's been said.

[sheikhy]

Well done gfs again!!ecm lost at only 48 hours out!low is further north unfortunately!!

[Chesil View]

24 minutes ago, Catacol said:

Momentum elastic ping-back has already peaked and settling. We have the jet firing up in response as MJO is in 2/3/4 but I think here the brakes will be applied because that momentum surge is not record breaking and the cold will hold to our E and NE. CPC charts to me say the same. So.... cold pushed away from the UK mid week - which at the very start of this spell was the form call - but the trough to stall. That might mean some wet days for us and general damp grimness - especially as the residual heights over Greenland that I have mentioned before should ensure the trough stays chilly with plenty of arctic rather than tropical air being fed into it. But Scandy to stay cold and lack of Euro High to allow central Europe also to stay pretty cold.

Watch then for 7/8/1 MJO phases and renewed momentum surge mid month. Phase 7 around Dec 9....allow for lag - one week? - so signs of heights rebuilding as we approach the final third.

One of the best tweeters still tweeting since Masiello disappeared is Eric Webb. Some very detailed discussion from him yesterday. He sees -NAO digging in for the long term and a hemispheric wave patttern conducive to strat disruption. It is good to read real pros coming up with the same arguments at this point.

Most exciting winter in years continues. Snow chances this weekend. MJO playing ball. Strat pressure well forecast. I can see a cold Xmas week followed by a Jan SSW and given Aleutian Low activity I'm willing to gamble on a split. This winter has a chance of being a cracker.

Excellent post Catacol and similar to how I would see things panning out through December. The loss of our current cold pattern does look inevitable and the form horse would be for the lows not really to advance in any real form past dear old blighty.

The global drivers much as Eric Webb points out, favour continued and extended negative NAO conditions after the coming week's relaxation.

The cards do appear to falling in our favour with the general background of Central el nino and easterly qbo providing a very favourable and helpful background upon which others like mjo etc can imprint itself. 

As you say the winter season starting today has a good chance of being a real cracker.

 

 

Edited December 1, 2023 by Chesil View

[Ali1977]

1st low too far south , miss out on snow. 2nd chance is too far north

2 minutes ago, Ali1977 said:

1st low too far south , miss out on snow. 2nd chance is too far north

Mondays ok though for midlands north anyway  

Edited December 1, 2023 by Ali1977

[northwestsnow]

EC is decent Midlands northwards 

[Ali1977]

1 minute ago, northwestsnow said:

EC is decent Midlands northwards 

Much more by midday Monday

[nick sussex]

The ECM develops the shortwave near Iberia and has a more favourable upstream low positioning at T96 hrs .

[TSNWK]

Just now, nick sussex said:

The ECM develops the shortwave near Iberia and has a more favourable upstream low positioning at T96 hrs .

Let's hope it continues with the icon route then

[Jason M]

50 minutes ago, feb1991blizzard said:

yes - nice - probably best graph yet in terms of no of severely cold members.

Notice how control and opp run together though. Expect the GEFS to start dropping the cold runs over the next couple of suites. We see this so many times every winter. 

[Allseasons-Si]

Squeaky bum time,will the trough disrupt?

EC at 144.

[LRD]

1 minute ago, Allseasons-Si said:

Squeaky bum time,will the trough disrupt?

EC at 144.

I'm reckon that'll barrel through. Midweek will see the cold ease

[KTtom]

1 hour ago, Catacol said:

Most significant development of the day, especially for those of us that have championed a cold but not spectacular spell at the start of the month leading to a IO driven relaxation for 10 days or so followed by shift back to deeper and more impactive cold. The MetO have all the computer power hidden up their sleeve. Yesterday there wasn't a hint of a colder shift in the text - and today that cryptic little dangler at the end. That suggests to me they are seeing cold holding on over Scandy as many have predicted and then a renewed surge of heights backing that cold W and SW at Xmas time. I don't pay a huge amount of attention to MetO updates because they can swing around....but they rarely risk a cold statement especially at range. The fact they have come out and risked it today I think is huge.

Best keep this relevant before Mods stab me. Note again this chart, same sort of period as yesterday. That high anomaly over Kara is beginning to back west....

Call me sceptical,  actually best not someone else has that name, cant be doing with a law suit, but in relation to the Mets wording, arent the chances of a more prolonged cold spell always greater as we head into late December and Jan compared to early December? Bit like at the start of May saying chances of a warm settled spell increasing late in the month?

Edited December 1, 2023 by KTtom

[Allseasons-Si]

1 minute ago, LRD said:

I'm reckon that'll barrel through. Midweek will see the cold ease

Putting up a good fight that block to the east

12z 168 v's 00z 192.

[LRD]

Look at this polar profile

And the Atlantic still swans in with little resistance