Model output discussion 11/12/21

[Battleground Snow]

2 minutes ago, Ed Stone said:

What keeps getting pushed back?

The high to move north away from the UK

[Ali1977]

Scandy high inbound 

[SLEETY]

Another 06zrun fit for the bin,good luck if you think it will verify like that,utter garbage.

[Ali1977]

Mean better at 150 

[mbrothers]

6 minutes ago, Lukesluckybunch said:

im going to call that a boring run,but with so much potential,quite dissapointing really.

So to clear things up it’s boring , full of potential and disappointing too.

[Lukesluckybunch]

1 minute ago, mbrothers said:

So to clear things up it’s boring , full of potential and disappointing too.

haha im only commenting on the output

[Catacol]

19 minutes ago, blizzard81 said:

I wonder why the MJO is always seemingly prone to being delayed? Seems to happen every year.

A very good question. Tropical convection sits at the heart of the global pattern, doing so much to create the peaks and troughs of the jet stream at our latitude….but it is seemingly extremely hard to predict. The very slow progress of the MJO this season must be throwing some seasonal projections into doubt, though in the near term it is doing much to help sustain the forecast of a UK block over Christmas.

Referencing Eric Webb again - over on Twitter he has flagged a recent paper that shows how an eQBO serves to magnify the impacts of the MJO. Add into this the fact that we know we have a Nina that is supportive of convection getting as Far East as phases 7/8 and we have an extremely good background context for ongoing amplification. The forecasts at the moment are a bit meh because we are staring at a dirty high and cold sitting just out of reach - but it is early in winter still and plenty of time to try and get a block in the right place.

If we take to heart the theory that an eQBO magnifies the MJO’s impacts and that we know NWP has a devil of a time forecasting the MJO correctly then it follows logically that NWP output will consistently under model MJO impacts this winter. It gives me pause for thought….because it suggests that even if we don’t get an SSW this year we could yet get a phase of amplification anchored on strong MJO forcing that could bring in an easterly, especially if the vortex has been weakened enough to ensure a strat/trop disconnect.

Does this suggest that the attack on the vortex that is being lined up for the Xmas period could combine with an undermodelled MJO forcing to push a block up to our north and bring in a cold period at New Year? Yes it does. 

Edited December 12, 2021 by Catacol

[northwestsnow]

9pm Xmas Eve ...

santa bring a scarf

[IDO]

Looking at the WAA up to D11 we can see that it rolls over the top of the UK high (yellows):

The warmer air is mobile so I would say that the mini ridges over the high have little chance of sustaining any momentum at ridging into Scandi or Greenland. I noticed after D12 on the 0z run we got another burst of WAA that was more a standing wave so that is the next fledgling of hope for more sustained HLB'ing. WAA at T312 on 06z:

[Methuselah]

13 minutes ago, Battleground Snow said:

The high to move north away from the UK

Ah, that? I can't say as I've ever been convinced. Not until the UK Met start seeing it, anyway? Crap Internet connection these past couple of days. So, if I'm missing anything. . ?

[northwestsnow]

6z has temps struggling to get much above freezing Xmas day...

By sunset  its back to a frosty landscape.

Basically 6z is cold for the festive period ,and dry.

Of course I'd love snow but it's very unlikely for Xmas 2021.

This is a good second best, and it beats wind and rain every single time for me.

[Notty]

32 minutes ago, Ali1977 said:

Eastern Europe is proper cold 

Cold maybe off to Greece (again)

[IDO]

Another run and another possibility in FI on the 06z:

The WAA just restocks the UK high and by D13 a familiar scene over the UK. This is very different to the 0z as the 06z kills the Pacific forcing (wedge instead) which will knock on downstream in our quadrant with less amplification compared to the 0z:

So again, we have uncertainty as to the MJO Pacific forcing highlighted in these two runs, no forcing and maybe Groundhog Day (06z), a clearer MJO standing Pac ridge and better potential (0z) after D12...

[PiscesStar]

6 minutes ago, Notty said:

Cold maybe off to Greece (again)

High Needs to shift west couple hundred miles or so should do it...  

[Ali1977]

Some great GEFS even by day 8, snow is still a poss by Xmas 

[Catacol]

Don’t often see these charts chucked out on the model thread…..but I’m doing my best at the moment to grow an understanding of the tropospheric precursors for +EAMT, thereby adding further amplification to the pattern.

I posted one of these before at longer range, and while +EAMT has been gently positive for a while we didn’t see a spike. We now have this for the end of the week, shorter range than my previous effort

Note the semi-permanent low to the east of the Himalayas but note also high pressure to the west and the descending nature of a high pressure cell NW to SE through China. If this chart verifies (and like all NWP it has to verify first before brining impacts!) then it would suggest a +EAMT event at the end of the week, extending the pacific jet and bringing more amplification. Add lag impacts into the equation, and this may be perfectly timed to force the UK high up to Iceland at Xmas and the days after.

Definite reasons to be optimistic today.

[Chesil View]

Yet another gfs run that tempts and teases with getting the high North but just ends up being all mouth and trousers and goes all meh in the latter stages.

At the very least we need the jet to split and send some energy south towards continental europe otherwise the high will continue to flatter to deceive before sinking back.

Preferable would be the jet dives south completely  so the high has nowhere to go but north.

Edited December 12, 2021 by Broadmayne blizzard

[MATTWOLVES 3]

10 hours ago, blizzard81 said:

That's the most 'glass half empty' post I have seen you post lol . However, its good to have some realism to balance things out. Something I always believe in. After all, its a fine line between positivity and fantasy. Lets hope your post acts as a reverse psychology mechanism and we see some big upgrades tomorrow

Yes mate,it's perhaps a tad negative from somebody like me who loves a ramp. I will be chasing long and hard probably through til end of March....I think  the main point was some posters put all there eggs in one basket regarding SSW events! Yes they can be game changers,but they can also ruin a favourable sypnotic pattern. But I suppose many will take the 66% chance of wintry conditions that can follow.

The post was very much a sitting on the fence type,without all my usual hype,but I remain confident that we can get some rewards moving forward....its going to take many many poor operational runs before I lose my mojo.

And just a little reminder its rarely this side of Xmas we ever see significant cold,a major cool down across Europe will be one of the main things we need to see right now,if things still look muted come late January....it could spell trouble for obvious reasons.

So I'm not dreaming of a white Xmas....but most definitely dreaming of a white New Year....in all fairness I'm becoming sick to death of the green landscape.

[ANYWEATHER]

Looks like an increasingly settled and dry outlook to the run up to Chrimbo ,good news for travelling and getting about at least. The usual Caveats for fog and frost with high pressure over us, but I've got a feeling we will be chasing cloud as generally pressure building from the south retains a lot of moisture as it moves north....Anyway lots of time post Christmas for ice and snow ,when winter really begins....☺

[That ECM]

It gave up.

[AFCBSNOW]

1 minute ago, Catacol said:

Don’t often see these charts chucked out on the model thread…..but I’m doing my best at the moment to grow an understanding of the tropospheric precursors for +EAMT, thereby adding further amplification to the pattern.

I posted one of these before at longer range, and while +EAMT has been gently positive for a while we didn’t see a spike. We now have this for the end of the week, shorter range than my previous effort

Note the semi-permanent low to the east of the Himalayas but note also high pressure to the west and the descending nature of a high pressure cell NW to SE through China. If this chart verifies (and like all NWP it has to verify first before brining impacts!) then it would suggest a +EAMT event at the end of the week, extending the pacific jet and bringing more amplification. Add lag impacts into the equation, and this may be perfectly timed to force the UK high up to Iceland at Xmas and the days after.

Definite reasons to be optimistic today.

Thank you for the explaination. I find your posts, and others on here, the ones i look for when looking at the direction we are heading. There seems to be too much personal bias, both ways with interpretation and personal preference, which can deflect from what the charts are actually saying. The trend is your friend! It, to my untrained eye points to a colder period of seasonal weather, snow or not, that to me is enough to have some xmas cheer. Keep the posts coming!!

[northwestsnow]

Well, 6Z sumed up is dry from mid month to the end of the month ...

Increasingly colder as we hit Christmas..

Fascinating weather with an inversion in play , could be foggy at times ,freezing fog even ...

But the main thing for me ,dry , I hope we get light winds and breaks in the cloud ,I'm sure we will intermittently - that's when temps should plummet ...

 

[Cold Winter Night]

EPS regime chart now gathering pace towards BLO+ and NAO- at the 192h mark.
Good to see. This hints at retrogression.

Leaving the clusters for now, they're still decent, but the fact that yesterday we had a million clusters 264h-360h and today just two shows there is much to be resolved.

All is still good, no worrying trends right now IMO.

[sheikhy]

On some good news.....gfs mean and control massive improvement!!!

[blizzard81]

8 minutes ago, MATTWOLVES said:

Yes mate,it's perhaps a tad negative from somebody like me who loves a ramp. I will be chasing long and hard probably through til end of March....I think  the main point was some posters put all there eggs in one basket regarding SSW events! Yes they can be game changers,but they can also ruin a favourable sypnotic pattern. But I suppose many will take the 66% chance of wintry conditions that can follow.

The post was very much a sitting on the fence type,without all my usual hype,but I remain confident that we can get some rewards moving forward....its going to take many many poor operational runs before I lose my mojo.

And just a little reminder its rarely this side of Xmas we ever see significant cold,a major cool down across Europe will be one of the main things we need to see right now,if things still look muted come late January....it could spell trouble for obvious reasons.

So I'm not dreaming of a white Xmas....but most definitely dreaming of a white New Year....in all fairness I'm becoming sick to death of the green landscape.

Nice one matey . Don't rule out a sneaky pre-xmas easterly. Ok, its the 06z control but it has some similarities to this morning's ecm op .