Model Output Discussion. 3/12/2022. How cold will it get?

[Derecho]

Just now, damianslaw said:

Its a saying I seem to repeat year in year out, but many people can't seem to refrain from looking at 10 day plus range on every run and jumping to conclusions far far far too quickly.. it comes with age and experience..

There is large uncertainty surrounding the Azores Low granted but in all my time as a forecaster and weather enthusiast I know that when the EC and UKMO operational are on the same page it's a warning.

We need the Azores low to stay out west but if it is developing tropical characteristics the uncertainty is still very high.

[swfc]

Just now, jam said:

Muker in Swaledale will have cold air sinking into the valley bowl. -18 in 2010.. breath freezing on your face 

What

[ItNeverSnowsInWindsor]

Makes a rather refreshing change to the past countless mild Decembers!

[Catacol]

I think I’m becoming a GEM junkie. 12z evolution in the medium once again hits the spot with regards to broad evolution.

 

ECM now following suit, kicking and screaming a bit

 

And the EPS and GEFS are also on the same page

 

Where is this coming from? Torques are in their way up signalling an atmosphere predisposed to amplification, the lower stratospheric and tropospheric vortex are not provided downwelling westerlies to flatten the pattern and here comes the MJO cycling back towards the maritimes quite quickly. 

 

Note MJO Phase 7 composite.

Conclusion? All good on the Polar Express. Cold to start, chances of snow, more chances of snow as the channel runner enters stage left, relaxation of the cold at that point likely (though that is relative = from cold to fairly cold perhaps) before we approach Xmas week and get the second dig. As I said this morning, keep your eye on all that Siberian cold being bottled up on the GEM as the vortex shifts to Asia….and no better way of pulling that in than a Scandy High.

But remember - these setups often go wrong. Don’t shoot the messenger if the ball rattles in the jaw of the pocket. Nothing ever certain in this hobby.

 

[MATTWOLVES 3]

4 minutes ago, damianslaw said:

Its a saying I seem to repeat year in year out, but many people can't seem to refrain from looking at 10 day plus range on every run and jumping to conclusions far far far too quickly.. it comes with age and experience..

You know why that is Damian?? All the best looking charts are always at the 10 day plus

[damianslaw]

2 minutes ago, LRD said:

Oh dear

Got to be a warm outlier. Right?

Not wanting to speculate or indeed say this will verify, but it does show significant WAA again on the eastern side of the jet, could go from a southerly to a significant block to the NE very quickly in the days ahead.. the jet remains highly buckled, and amplification order of the day. Rinse and repeat epsiode in the run up to christmas after a very mini milder breakdown more so in the south. This is not a pattern that would return us to a default mild zonal flow, far from it.

[swfc]

1 minute ago, Catacol said:

I think I’m becoming a GEM junkie. 12z evolution in the medium once again hits the spot with regards to broad evolution.

 

ECM now following suit, kicking and screaming a bit

 

And the EPS and GEFS are also on the same page

 

Where is this coming from? Torques are in their way up signalling an atmosphere predisposed to amplification, the lower stratospheric and tropospheric vortex are not provided downwelling westerlies to flatten the pattern and here comes the MJO cycling back towards the maritimes quite quickly. 

 

Note MJO Phase 7 composite.

Conclusion? All good on the Polar Express. Cold to start, chances of snow, more chances of snow as the channel runner enters stage left, relaxation of the cold at that point likely (though that is relative = from cold to fairly cold perhaps) before we approach Xmas week and get the second dig. As I said this morning, keep your eye on all that Siberian cold being bottled up on the GEM as the vortex shifts to Asia….and no better way of pulling that in than a Scandy High.

But remember - these setups often go wrong. Don’t shoot the messenger if the ball rattles in the jaw of the pocket. Nothing ever certain in this hobby.

 

Thanks catacol, hanging on in here bye eyelashes decent output for December even if its not "the day after Tom"

[damianslaw]

3 minutes ago, Catacol said:

I think I’m becoming a GEM junkie. 12z evolution in the medium once again hits the spot with regards to broad evolution.

 

ECM now following suit, kicking and screaming a bit

 

And the EPS and GEFS are also on the same page

 

Where is this coming from? Torques are in their way up signalling an atmosphere predisposed to amplification, the lower stratospheric and tropospheric vortex are not provided downwelling westerlies to flatten the pattern and here comes the MJO cycling back towards the maritimes quite quickly. 

 

Note MJO Phase 7 composite.

Conclusion? All good on the Polar Express. Cold to start, chances of snow, more chances of snow as the channel runner enters stage left, relaxation of the cold at that point likely (though that is relative = from cold to fairly cold perhaps) before we approach Xmas week and get the second dig. As I said this morning, keep your eye on all that Siberian cold being bottled up on the GEM as the vortex shifts to Asia….and no better way of pulling that in than a Scandy High.

But remember - these setups often go wrong. Don’t shoot the messenger if the ball rattles in the jaw of the pocket. Nothing ever certain in this hobby.

 

I'm with you on this, a very temporary return to something less cold, note not especially mild - brief indeed before we see a return of scandi heights before christmas.

[Methuselah]

9 minutes ago, MATTWOLVES said:

You know why that is Damian?? All the best looking charts are always at the 10 day plus

I'm glad my grandchildren will always be able remember the great day-10 winter of of '22-23! Eeee, when ar were a lud, Day-10s were nowt like these nambi-pambi Day-10s we get today...

Edited December 4, 2022 by Ed Stone

[LRD]

4 minutes ago, damianslaw said:

Not wanting to speculate or indeed say this will verify, but it does show significant WAA again on the eastern side of the jet, could go from a southerly to a significant block to the NE very quickly in the days ahead.. the jet remains highly buckled, and amplification order of the day. Rinse and repeat epsiode in the run up to christmas after a very mini milder breakdown more so in the south. This is not a pattern that would return us to a default mild zonal flow, far from it.

I think you're right. There are also signs of amplification in the Atlantic again too

It won't look like that, of course, but, on the negative side, the Iberian heights look strong on that chart. That's what I'd be concerned with there

[Derecho]

2 minutes ago, LRD said:

I think you're right. There are also signs of amplification in the Atlantic again too

It won't look like that, of course, but, on the negative side, the Iberian heights look strong on that chart. That's what I'd be concerned with there

Exactly no hope of a cold spell with a strong high pressure cell over Spain / Italy.

It took so much for things to fall into place for this cold spell, it would be a shame to have those building blocks taken down so rapidly. It may just be a wobble, we could still easily see a turn to the colder members of the GFS but I'm anticipating a mild flip tomorrow morning on all the models if the trend this evening continues. Then alarm bells would really be ringing.

Hope I am wrong.

[Eagle Eye]

This is what forms into our disruptive low (stronger low in the upper part of the image), the initial tropical wave getting forced up with a moisture stream lifting up from the south and becoming a more natural December low but with extra moisture input. I think the main problem for the models is that we're still in a +VE AAM state and how they handle the -VE EAMT is probably going to end up in quite a messy solution, as we have seen already. I don't think we'll see an evolution that seems a bit more natural until closer to time. We could see a few runs show the more natural evolution over the coming days but it's clear that the models are mostly struggling on how to evolve this low.

[weatherguy]

As "bad" as things are looking compared to past output, I think it's important to keep some perspective.  

ECM 12z uppers shown for +48h to +120h, with the +120h NH profile for reference.  We have some pretty deep cold entrenching itself, with associated snow risk, and this is only modelled to recede by +216h.

This is, of course, way out in FI at this stage as it's very unlikely to have nailed exactly how the "Atlantic Hurricane" will interact with the cold air mass.  It's a high-risk potential setup, but not worth getting stressed over at this stage.  

In any case, the 240h charts for the ECM/GFS (shown below) are wildly different from each other, and both still have plenty to interest us with the NH profile as a whole - there will be further bites of the cherry in all likelihood. 

[BLAST FROM THE PAST]

ECM….zero problem.  Look at movements from t192 to t240.  Cold wane….but wax to follow.  Folks, we aren’t in a Dec 2010 episode ….this is a winter episode, not a December one.  I’m comfortable with what’s potentially ahead.  Nothing is of longterm concern imo.  INDEED I’m finding this potential deep tropical storm of real interest

 

BFTP

[Day_9]

32 minutes ago, LRD said:

Very poor (for cold) ECM days 8 and 9

Day 9. -NAO becoming west-based

As far as the European mainland is concerned, it shows something similar to the UKMO at 168 except we get an extra day's grace on ECM

Having said that there are no certainties that this is right. Just feel that things might be trending away from longer term cold. It could trend back of course

One run doth not a trend make.

[damianslaw]

2 minutes ago, Day_9 said:

One run doth not a trend make.

Yes Friday evening repeating itself tonight no doubt..

[LRD]

1 minute ago, Day_9 said:

One run doth not a trend make.

I'm not talking about exactly how the 12z ECM FI run looks specifically. I'm talking in general terms that things seem to be trending less and less away from longer term cold. Not a clear trend as yet but things are slowly moving in a less cold direction I feel.

[nick sussex]

Not sure why the UKMO is seen as supporting the ECM solution . It’s overall pattern is better at day 7 .

Theres already more forcing on the Atlantic low which is further south and it’s possible a wedge of heights will develop ahead  of that shortwave dropping south from Greenland .

 

[Vikos]

Just now, LRD said:

I'm not talking about exactly how the 12z ECM FI run looks specifically. I'm talking in general terms that things seem to be trending less and less away from longer term cold. Not a clear trend as yet but things are slowly moving in a less cold direction I feel.

 

but what are your expectations? Narnia open end? unfortunately we all live too close to a sea that is too warm for that...

[LRD]

11 minutes ago, damianslaw said:

Yes Friday evening repeating itself tonight no doubt..

Sorry not sure if that's aimed at me. I didn't post on Friday night. Didn't even look at any runs on Friday

But the fact it, apparently, showed similar on Friday would suggest that things might be just moving a little bit away from sustained cold. 2 12z ECM's in 3 showing a poor FI for cold? Too early to say it's a defined trend but it's something that needs to be noted

As it happens. I think this ECM 12z will be a massive outlier

Edited December 4, 2022 by LRD

[IanT]

It is always fascinating to see posters queueing up to say that the “…models are struggling…”. I assume this comment is based on the lack of consistency in model output. Whilst there will be only one resolution, at this point multiple evolutions are possible - as reflected by model output..!

Don’t be too quick to conclude that models are struggling because their output is inconsistent. It may be better to recognise that there is still significant uncertainty given the set of starting conditions.

[LRD]

2 minutes ago, Vikos said:

 

but what are your expectations? Narnia open end? unfortunately we all live too close to a sea that is too warm for that...

I haven't got any. I've no skin in the game. If it turns significantly cold, great. If it doesn't, I ain't going to lose sleep over it

I'm just interpreting what I'm seeing. I hadn't looked at models from Thursday night until this morning. It feels to me that longer term prospects have deteriorated in terms of cold since Thursday. You are allowed to disagree with me. It's fine

[Day_9]

3 minutes ago, LRD said:

I'm not talking about exactly how the 12z ECM FI run looks specifically. I'm talking in general terms that things seem to be trending less and less away from longer term cold. Not a clear trend as yet but things are slowly moving in a less cold direction I feel.

No, there has been consistent output now forecasting a week/10 day long snap.

 Look at the ensembles.  Absolute consensus.  Anything after that timeframe is always spaghetti whatever the model…….. enjoy the next week or so if cold is your thing.  It is entirely conceivable that it becomes entrenched.  

[Guest]

3 minutes ago, nick sussex said:

Not sure why the UKMO is seen as supporting the ECM solution . It’s overall pattern is better at day 7 .

Theres already more forcing on the Atlantic low which is further south and it’s possible a wedge of heights will develop ahead  of that shortwave dropping south from Greenland .

 

There is definitely a leap being made by some to attach the UKMO 12z to this ECM to strengthen a case for the 'mild breakdown'. Always odd to see that narrative when we haven't even seen the cold spell start.

I think we need to wait for the ECM ensembles before we put any extra weighting behind the run.

[Robbie Garrett]

By the way, in the real world; what happens when the lows start heading our way with a Greenland block and cold air firmly established

 

 

 Quick look at the models, and they are already doing just that vs yesterday.   For how erratic things are;

+120HRS on the 06z

+120HRS on the current run

 

Then look to 180hrs how much divergence between the runs for the same time.   Photoshop overlay of the Current (C)  centre of the Atlantic LOW and 06z of the centre of the Atlantic LOW.

 

 

Fantasy Island is currently +48HRS on the GFS!

Edited December 4, 2022 by Robbie Garrett