Model Output Discussion - Christmas and New Year

[Day_9]

1 hour ago, AmershamMike said:

Why is the Met office app forecast so....”meh”? Told the kids we would have snow in the chilterns next week. 

Shortwave incoming.

[SLEETY]

How can the pattern be getting flatter when none of it actually exists yet, lol, usual overreaction to fantasy land charts, that never verify, for the umpteen time. 

[Mike Poole]

1 minute ago, swfc said:

Isn't that day 10 and in fi

It was the 10 day ECM that was being discussed but it has been like it for weeks, meridional jet upstream, illustrated by GFS at T96:

It is a rinse and repeat pattern.  My point is in winter (different for summer) it is much better to look at the output on the NH plots because the upstream pattern is so important.  

[Reversal]

4 minutes ago, Broadmayne blizzard said:

Did objective opinion not consider the reamplifying process of the pattern.

But yesterday, and for a few days before that we were seeing successful amplification into Greenland. Now we're seeing potential of reamplification at the far reaches if FI. The output has become less amplified with every run since yesterday evening. That's not saying it's a totally flat pattern, but the trend is the wrong way today.

[Osbourne One-Nil]

Can we just discuss nicely. One errant comment and it all goes off topic and I can’t be bothered tonight so please...no point scoring, no bickering, no wind ups, just nice discussion please!

[Eskimo]

Just now, SLEETY said:

How can the pattern be getting flatter when none of it actually exists yet, lol, usual overreaction to fantasy land charts, that never verify, for the umpteen time. 

Because this is the model output discussion. 

[bluearmy]

Last two eps suites around day 10 run to run change in heights around greeny - a swing back is needed to restore the level of anomoly we saw yesterday .......

  

[kold weather]

Still as per most of my updates looking at the 28-29th period as the best shot for snow.

The ECM still remains the most bullish of the models, it maybe a little overdoing it but the possibility is there for sure.

The GFS and its ensembles are still shifting around but this 12z suite is probably the best agreement seen so far with a path broadly similar to the 12z ECM, though some are too far south and a few are definitely still further north, but not drastically so. I'd guess we are zeroing in on an area within a 100 miles either side of where the ECM is, so still scope for change, but maybe not huge change from here.

[swfc]

2 minutes ago, MATTWOLVES said:

I've seen nothing in the output,either myself or from the top guys on here,or from the pros further afield to back this up mate..

I think his point is over the last 7-9days things have leveled off in the amplification. There were epic runs showing huge Heighths and total splits in the PV. It has trended to more to just an Atlantic based high and has dropped the epic blocking. All fair comment imo

[Eagle Eye]

Cold air feeding through from the Arctic. 

Cold Uppers could bring Snowfall with flimsy High's causing it to be balanced and create a Ridge meaning that even though the Low will weaken over Time the constant feeding through from Polar Regions will cause it to Strengthen again making it feel like for 2 Weeks it's oonn and off Snow for different Rehions however it is just the refueling of the Low with Polar Region's Cold with a Jet Stream that constantly feeds it around. 

The constant recycling off Cold Air will allow points where the Snow is piling up to Windows and Points where it's nearly all melted. With this Jet Stream if it is Weak it will create Slow moving Low's however as you can see it is a Pretty Strong one and will keep an almost constant feeding of Cold air. 

These further Charts Show Just that. 

Edited December 25, 2020 by Sheldon Cooper

[Howie]

2 minutes ago, bluearmy said:

Last two eps suites around day 10 run to run change in heights around greeny - a swing back is needed to restore the level of anomoly we saw yesterday .......

  

Oof

[Kasim Awan]

10 minutes ago, Eskimo said:

Agreed. Always tends to be some bitterness/tribalism in here when someone goes against the grain, and unfortunately when someone does, there's usually an element of childish mocking that follows and its embarrassing when you consider most people in here are likely to be adults.

You are right though, I've noticed an element of the pattern to flatten too, but more particularly in the ECM rather than all the models. However, I'll reserve my own judgement about further developments until the weekend. 

 

Whilst I must agree the cold at this period is not 100%, I feel you are both failing to see the bigger picture which is that any zonal energy is highly likely to add to the colder picture. This is because of the sharp NNW-SSE alignnent of the jet that we currently have. Lows become immobilized to the SE due to the merodinial 500mb flow. Look at the jet for Monday and the jet for 3rd Jan. 

Therefore the low heights will likely be shunted SE in a somewhat similar mannor to the new few day. This can not be described as zonal, Imo, as the upper waves are still heading away from climatology.

Hope this helps. K.

 

Edited December 25, 2020 by Kasim Awan

[northwestsnow]

Well I have to confess , I did overtime today much to my eternal shame.

I've read through the discussions today and they have been truly fabulous reading so thanks to all my net weather buddies for this.

WRT the models...

1. Its going to be cold.

2.Some will get snow,others won't.

3.Most important of all, perspective.We live on the edge of a warm ocean , in a warming world, we don't reside in Canada!

We almost certainly have 5 days of cold locked in, plenty of frost, and some snow.

Enjoy...

[bluearmy]

4 minutes ago, Howie said:

Oof

for perspective this is what’s left .....

hardly shabby !   Just not quite the traction we saw on yesterday’s runs

Edited December 25, 2020 by bluearmy

[Methuselah]

18 minutes ago, swfc said:

Indeed the output has become less amplified  esp in fi. You only have to go back and take a look over the last 7 days. 

I agree, swfc... first the GFS 06Z and, even more so, the 12Z. But, we are still talking of 12 days' hence? And, as we all know (unless there's a suggestion of a BFTE) taking such long-range charts as Gospel -- or daring to mention them -- is almost universally frowned upon!

Edited December 25, 2020 by General Cluster

[seabreeze86]

4 minutes ago, swfc said:

I think his point is over the last 7-9days things have leveled off in the amplification. There were epic runs showing huge Heighths and total splits in the PV. It has trended to more to just an Atlantic based high and has dropped the epic blocking. All fair comment imo

I don’t think that correct to be honest the pattern is still amplified the models are just playing around as to where the ridges will end up. This is anything but zonal. Great position going forward does that guarantee proper cold for the UK of course not 

[sheikhy]

1 minute ago, bluearmy said:

for perspective this is what’s left .....

hardly shabby I guess !   Just not suite the traction we saw on yesterday’s runs

Is  the above the newly updated chart blue?

[MATTWOLVES 3]

4 minutes ago, swfc said:

I think his point is over the last 7-9days things have leveled off in the amplification. There were epic runs showing huge Heighths and total splits in the PV. It has trended to more to just an Atlantic based high and has dropped the epic blocking. All fair comment imo

Yes fair comment mate...but until I see it going that way on numerous runs and ensembles, I will reserve judgement on it..I still think things are going in the right direction,and we are obviously going to be seeing minor tweaks,for better or worse,over the coming days

[swfc]

3 minutes ago, seabreeze86 said:

I don’t think that correct to be honest the pattern is still amplified the models are just playing around as to where the ridges will end up. This is anything but zonal. Great position going forward does that guarantee proper cold for the UK of course not 

I was looking earlier in various runs than that but the Atlantic high is or has not been as robust as it was over recent days imo. Also who mentioned zonal weather, its obv not

Edited December 25, 2020 by swfc

[Kasim Awan]

The 12z output remains highly blocked and cold going forward, and whilst not at the level the gfs had a few days ago, is still enough for cold& snowy conditions. Plus an inversion is highly likely to develop reducing upper requirements for surface cold. So those bfte charts are not the end all.

 

Edited December 25, 2020 by Kasim Awan

[seabreeze86]

Just now, swfc said:

I was looking earlier in various runs than that but the Atlantic high is or has not been as robust as it was over recent days imo. 

Yeah fair enough the Atlantic high not as strong as it was in the midterm but the blocking signals are still there as strong as ever. Think January could be a month for the archives if we get a bit of luck

[northwestsnow]

3 minutes ago, Kasim Awan said:

The 12z output remains highly blocked and cold going forward, and whilst not at the level the gfs had a few days ago, is still enough for cold& snowy conditions. Plus an inversion is highly likely to develop reducing upper requirements for surface cold. So those bfte charts are not the end all.

 

Love this post..

So very true...

Next week is going to be very cold at the surface despite the mediocre uppers...

A bit of snow-cover and clear skies will see temps plummet , Scotland in particular could see some double digit minima, IMO..

Edited December 25, 2020 by northwestsnow

[bluearmy]

8 minutes ago, sheikhy said:

Is  the above the newly updated chart blue?

Yep 

[Griff]

Excellent news everyone, in a week or so we should know which way it's trending and I'm sure we'll all be magnanimous, with the victors no doubt humble in their success, whilst gladly accepting an apology, most likely in the form of a case of beer or wine (just none for Sheldon, please drink responsibly, age aware etc). 

Model watching is subjective... Be nice. 

[sheikhy]

Ecm mean looks lovely all the way thorugh!!cold trough across the uk and looks like heights in the atlantic and ridging into greenland between 216 and 240 hours!