Model Output Discussion - Colder spell ending, what's to follow?

[Valleyboy]

This Is the reason I don’t look beyond 5 days, it’s pointless.  These super computer generated models are no more accurate than a 5 year old scribbling on paper.  In fact I believe the long range forecasts have not improved greatly over the last 40 years.  Best to stick to 3 - 4 days out, as blocking type weather throws up easterlies at short notice.  The charts beyond 5 days are just for fun, last nights and today’s models prove that.

[mountain shadow]

Fantastic Northern Hemisphere view. Let's see where it all goes wrong now!

[Paul_1978]

For me, one of the biggest problems with all the runs in recent days is not so much the stationary blocking over Russia, but all the lows getting spun up around Hudson Bay that are being carried towards us. Yes obviously we want these to be sent on more of a southern trajectory, but if they weren't being flung across the Atlantic towards us then that would be better overall. I am not sure if that is a too simplistic view of things? 

[That ECM]

Winter was off at 4 o’clock this morning but looks like it’s back on again at 10.00

[Day 10]

For what it's worth, much better run than this morning. Better ridging in the Atlantic as the low clears east a little further and elongates, stronger heights southern tip of Greenland and nearly into a north to north easterly wind, getting colder!

[mountain shadow]

Atlantic going under, this might be a doosra of a run here..

[Cold Winter]

Just now, That ECM said:

Winter was off at 4 o’clock this morning but looks like it’s back on again at 10.00

I have a feeling we might still be saying this with T72-96 to go!

[frosty ground]

With the Jet still doing this it is going to be hard dragging cold from the north and north east. 

[Nick F]

5 minutes ago, Cold Winter said:

6z looking interesting to me around the T204 mark... northeasterly imminent? 
 

In all seriousness, think we’re going to see a lot of model flip flopping over the next few days while they try to get to grips with the Arctic high.

It's all very well looking north and seeing good things happen with heights and high pressure in the arctic, but, if the jet stream remains flat across the Atlantic, the deep cold remains bottled up there. Really need to see some amplification working downstream, the 06z GFS op does show this happening late next week with a northerly developing weekend of 19/20th. But just out of the reliable for now.

 

[Tim Bland]

What do Greenland wedges make?  

[mountain shadow]

2 minutes ago, Nick F said:

It's all very well looking north and seeing good things happen with heights and high pressure in the arctic, but, if the jet stream remains flat across the Atlantic, the deep cold remains bottled up there. Really need to see some amplification working downstream, the 06z GFS op does show this happening late next week with a northerly developing weekend of 19/20th. But just out of the reliable for now.

 

At least the jet is further south though, and if we can pull in some Arctic air, we have the potential for frontal snow as the Atlantic disrupts against like the 6z GFS? And yes, i am grasping at straws.

[Methuselah]

Could we be looking at a big pattern change, come Day 10?

    

It's coming lads, it's coming. I know it is; I saw my first seagull, of the season, only yesterday!

We might need one or two more 'bites of the cherry' before this comes off... A Cristmas Eve 1968 redux?

    

Edited December 10, 2020 by General Cluster

[danm]

For those of us who have been watching the models for 15 years or more, all of this flip flopping is completely normal and to be expected. We have not yet seen a cold spell modelled within the reliable time frame, so there is no need for any hand wringing or melodrama. If we had something modelled within 5 days that then fell apart, it would be understandable. However, "all" we have so far are increasingly reassuring and interesting background signals and a northern hemispheric pattern developing that increases (although does not guarantee) our chances of a cold spell as we head through the month. As this is a developing situation, the models will continue to struggle to get a handle on it and we will continue to see variations run to run and between ensemble sets. 

I think we all need to be patient and see how this develops. The cards are more stacked in our favour than they have been since Feb 2018 and in any December since 2010. 

Edited December 10, 2020 by danm

[Skullzrulerz]

11 minutes ago, frosty ground said:

With the Jet still doing this it is going to be hard dragging cold from the north and north east. 

And there's the lack of any cold air as well to take issue with 

 

[Ali1977]

The BBC mentioned POSs colder around Xmas, and this chart could be about to show that , we need the low around Labrador to swing our way and that WAA behind it might have a bit more strength , blocking the W-E train, and sending the jet North!! 

Edited December 10, 2020 by Ali1977

[Matt H]

 

5 minutes ago, Skullzrulerz said:

And there's the lack of any cold air as well to take issue with 

 

Do the uppers matter when it’s on a phantom chart 246 hours away? Surely the trends matter more than anything at that range, be it positive or negative.

Edited December 10, 2020 by Frosty Winter

[BLAST FROM THE PAST]

27 minutes ago, weirpig said:

Why anyone Takes charts after 144  serious is beyond me .  Trends  maybe  but OP runs?.

Compare 6z  0z   

      

Correct, it was the same yesterday and the same reactions.....the the timing is still aimed at last 3rd to week of Dec for a ‘chance’ of a direct hit.  

 

BFTP

[frosty ground]

5 minutes ago, Skullzrulerz said:

And there's the lack of any cold air as well to take issue with 

 

Cold is not the issue its the location of the Jet, Thou I am sure there could be a rather large snow fall if that actually came off along the boundary. 

[mountain shadow]

5 minutes ago, Ali1977 said:

The BBC mentioned POSs colder around Xmas, and this chart could be about to show that , we need the low around Labrador to swing our way and that WAA behind it might have a bit more strength , blocking the W-E train, and sending the jet North!! 

Did they! That is very strange for them to say that with two weeks to go.

[Dimie10]

2 hours ago, AvidWinterSpectator said:

Morning - same as yourself (it’s literally in my name). The trick (and what everyone is doing with FL charts) is to spot trends amongst all the available runs

Yes, they maybe unlikely but;

a) fun to look at
b) the more that come onboard with a certain trend, (in theory) a higher rate of verifying.

I find it fun to look at but also infuriating as the cold signals always seem to dissipate  

[Nick F]

15 minutes ago, mountain shadow said:

At least the jet is further south though, and if we can pull in some Arctic air, we have the potential for frontal snow as the Atlantic disrupts against like the 6z GFS? And yes, i am grasping at straws.

If we can get both low pressure to move east over Scandinavia and the jet to dig south towards the Azores and SW Europe to allow height rises around Iceland and Greenland ( better -NAO signal for us) then things will suddenly start to get more interesting for cold/snow lovers, as it will allow the deep cold moving west into the Barents Sea / Svalbard to get pulled further southwest towards NW Europe.

[frosty ground]

That's why we need the Jet to be swinging north to south over the UK not West to East.

This was the same issue with the 18Z last night

[alexisj9]

3 hours ago, DavidS said:

So what is the ECM serving us up this morning. Well for the next 5 days we’ll have some milder weather with rain, followed by a cooler 5 day period with you’ve guessed it folks, rain.

I'm not looking in FL, and would expect all models to find it difficult at the min. We'll see if the low heads South East again or not later, fl is probably moving forward again though. Give it a few days or so.

[mb018538]

I'm....dreaming....of a mild....Christmas?

[BLAST FROM THE PAST]

4 minutes ago, frosty ground said:

That's why we need the Jet to be swinging north to south over the UK not West to East.

This was the same issue with the 18Z last night

And with a jetstream being so meridional that is very plausible outcome too.  I’d still rather see the jetstream like that than flat....loads to develop from here...it’ll be good model watching over the next week or so if it stays meridional

 

BFTP