Model output discussion - into the start of Winter

[Drifter]

If we get to this point at 1 week out I would call it promising. No point looking further than this. 

[SMU]

T180 & 06z starting to look like last nights 18z..

Thats 3 runs with no atlantic intrusion..

[Ice Day]

Ignoring details for our little part of the world, this NH profile brings one word to mind from a 'coldies' perspective.......  Ripe!

[SMU]

Look at the jet on the normally zonal GFS

 

[IDO]

With the loss of the potential Atlantic ridge and the more blocked HL pattern we see GFS give us the best case scenario from that. The UK on the cold side of the jet with a NW to SE sliding Atlantic in a gentle flow with an initial pulse of cold providing a starting cold pool for the sliders and fronts to interact with:

Of course, an easterly or northerly would be a preference, but better than a lot of other options including the rest of the models!

That broken Atlantic sees the 06z slow down further (viz 0z) allowing a better mini-ridge in the flow:

So at d8 we see another injection of colder uppers into our region. Hopefully that wedge of heights will maintain the undercutting and keep the general pattern. Certainly if GFS is right a very interesting pattern setting up for early December!

[ALL ABOARD]

The old saying wedges make sledges looks like it may be making a December special soon. 

06z is a good example of how small pockets of heights across Iceland can allow sliders.

Slack airflow and heavy percipation and you cant rule out a snowflake falling anywhere. 

[Snow lover 2020]

Ok it’s all well it showing cold and snow for higher ground but I want some in the south! I where are those charts?

[ALL ABOARD]

216 here comes the next one. 

Heights building towards Iceland. 

You can see the low disrupting already. 

 

[swfc]

Can sense slider gate cropping up again not a bad start to the day. Wintry weather possibly on high ground next week

[I remember Atlantic 252]

Just now, Snow lover 2020 said:

Ok it’s all well it showing cold and snow for higher ground but I want some in the south! I where are those charts?

where's your location for a start, GFS not great for low levels, snowy for hills wraparound type feature

[Ali1977]

If the heights to our NW can join the ones over in NE Russia it would be proper game on Easterly feed. These sliders would be epic by late Dec, not quite cold enough to produce much away from hills on this current run. Great chart watching though.

 

Edited November 28, 2020 by Ali1977

[SMU]

11 minutes ago, Snow lover 2020 said:

Ok it’s all well it showing cold and snow for higher ground but I want some in the south! I where are those charts?

Day 11

[bluearmy]

7 minutes ago, swfc said:

Can sense slider gate cropping up again not a bad start to the day. Wintry weather possibly on high ground next week

Slider gate is currently a cluster in week 2 .... as long as we get enough surface cold and below zero uppers to our south and southeast we could be in business .....Atlantic systems (traversing a mid Atlantic high which ebbs and throws up wedges) headed into a broad w euro trough wouldn’t be a bad way to head towards mid dec ..... 

[Dancerwithwings]

7 minutes ago, I remember Atlantic 252 said:

where's your location for a start, GFS not great for low levels, snowy for hills wraparound type feature

Not necessarily, anything could happen with heights, there are possibilities that low levels could see snow with what’s on offer.... won’t be long before the Hi res NMM’s will be showing it’s hand

[BLAST FROM THE PAST]

19 minutes ago, Steve Murr said:

T180 & 06z starting to look like last nights 18z..

Thats 3 runs with no atlantic intrusion..

Steve, this for me is when the nervousness starts when we start seeing successive cold runs and improvements still outside reliable timeframe.  Although I have had and wintry front end in mind for sometime.  Still not there yet and the Nov model flip is fresh in my mind.  

Still we aren’t seeing a model rush to cold nirvana of -12 easterly gales which is a good thing as the evolution showing does look pretty feasible.

 BFTP

 

 

[Scandinavian High.]

4 minutes ago, Steve Murr said:

Day 11

It looks like right old dumbing for southern England..

[swfc]

6 minutes ago, bluearmy said:

Slider gate is currently a cluster in week 2 .... as long as we get enough surface cold and below zero uppers to our south and southeast we could be in business .....Atlantic systems (traversing a mid Atlantic high which ebbs and throws up wedges) headed into a broad w euro trough wouldn’t be a bad way to head towards mid dec ..... 

You may be correct on the 6z output

[bluearmy]

1 minute ago, abbie123 said:

It looks like right old dumbing for southern England..

Sadly it won’t pan out like that but it is certainly on the table given the current output ....

[bluearmy]

Just now, swfc said:

You may be correct on the 6z output

Not just the 06z output .....it’s a  cluster on most ens 

[damianslaw]

Models continue theme of recent runs, longwave trough dropping through the UK, unusual pattern. At this range difficult to say how and where exactly, but the indications currently are for a direct hit, with the trough splitting in situ becoming a shallow slack feature. 

There is the possibility of a significant wintry surprise for some, but all depends on amount of cold air, thicknesses and dew points crucial in such situations. Intensity of precipitation also, evaporative cooling effect. At this stage if models verify as shown, safest to say anywhere with bit of height in the north most prone.

Still we are talking 6 days away, so all conjecture right now.

Beyond the reliable, no sign of polar front jet returning northwards, indeed NW-SE trajectory, which suggests some build of heights to our north behind the trough which makes sense. This would be slider territory, very Dec 2017.

[Atmogenic]

Tbh I don't get all this excitement from models that keep getting pushed back further and further, the 20 previous pages people were getting excited about the outputs from 4-5th december and now after page 20 they're now talking about the 8th and 11th december like it is every year with snow and keeps getting pushed back. I would only get excited if its within the 5 day range and i'm not even a cold lover but snow is something that makes winter bearable and interesting. Now people are talking about interest on the 4-5th again but only on the hill tops and how many members here live on the hills i bet very few and not only that but its mainly confined in the North, it's another North/south split again like you get in the Summer with heat. Until a confident percentage of the outputs are shown giving a more widespread chance of snow, I wouldn't really be that excited.

I know this is a moan but i'm not seeing a moan thread or i'm just blind.  

[Singularity]

I think we may ‘feel’ climate change in first third Dec as we struggle to draw in cold enough air for low level snow even with decent patterns in place.

Larger-scale progress has my interest though - good steps made toward assaulting the polar vortex. Whether we can manage the elusive wave-2 or even rarer well-aligned wave-1 SSW (Usually orientates poorly for us) remains to be seen.

GFS still making much more of the MJO as it crosses the Pacific this week into next, compared to ECM. Professional consensus favours GFS when MJO is starting out where it is now, over Indonesia. This is encouraging - stronger MJO passage, bigger wave assault on polar vortex 2-3 weeks later.

[ALL ABOARD]

Have we had a SSW?

What a pattern to start winter with. 

One run and not to be taken in isolation. 

Hopefully these charts can continue. 

[Methuselah]

Well, it would be marginal:

    

But it could be time to get out those NW dancing shoes: BOOM!

 

[damianslaw]

1 minute ago, Atmogenic said:

Tbh I don't get all this excitement from models that keep getting pushed back further and further, the 20 previous pages people were getting excited about the outputs from 4-5th december and now after page 20 they're now talking about the 8th and 11th december like it is every year with snow and keeps getting pushed back. I would only get excited if its within the 5 day range and i'm not even a cold lover but snow is something that makes winter bearable and interesting. Now people are talking about interest on the 4-5th again but only on the hill tops and how many members here live on the hills i bet very few and not only that but its mainly confined in the North, it's another North/south split again like you get in the Summer with heat. Until a confident percentage of the outputs are shown giving a more widespread chance of snow, I wouldn't really be that excited.

I know this is a moan but i'm not seeing a moan thread or i'm just blind.  

People are just speculating, and when it comes to snow in UK it's always tricky to pinpoint where and when it may occur. Expect such postings and musings all winter, if you dont like them, you'll find this forum hard going for next 4 months!