Model output discussion - The run up to Christmas

[Griff]

7 minutes ago, Battleground Snow said:

Very quiet this morning considering the output, GFS is very close to something special, won't take much adjustment east of that "true Greenland high"

I have been impressed with the consistency of the GFS, can't remember so many runs where it churns out similar output past 192.

Ukmo looks decent too, will be interested to see the ECM at 192, I suspect it will move to the GFS again.

Next blitz of excitement here will either be stunning charts in the reliable or a catastrophe... 

I'm not sure that many of us know what to do with non zonal winter synoptics? 

Pretty sure it's going to feel colder, regardless of precipitation. 

[Griff]

1 minute ago, swfc said:

Just as a quick side note the oz control on gfs looks a belter way in fi. Great 850s heading in and plenty on offer

GFSP daily run (latest available is yesterday's still) seems to be consistent too. 

[Battleground Snow]

4 minutes ago, Griff said:

Next blitz of excitement here will either be stunning charts in the reliable or a catastrophe... 

I'm not sure that many of us know what to do with non zonal winter synoptics? 

Pretty sure it's going to feel colder, regardless of precipitation. 

It's the fun of the chase, look at this chart for new years day, would have killed to have this last year.

[Sky Full]

The GFS overnight has continued its prediction of cold for the first week of January....and then redoubled it!   Just look at this evolution from the 30th December to the 7th January....

  

The Atlantic ridge extends up to Greenland and traps the cold air over the UK, then draws down even colder air from the Arctic.  
Fab-U-lous!  

Now all we need is to see these charts move into the +72h range and we can start talking about the Winter of 2020/21 in historical terms.....

Edited December 22, 2020 by Sky Full

[That ECM]

T144 of all 3. 

[dallas]

3 minutes ago, That ECM said:

T144 of all 3. 

Nice to see the alignment

[Sky Full]

^^^ Ha Ha - that ECM.....snap!  ^^^

A comparison of the main models at +144h (28th December) this morning shows agreement on the placement of the Atlantic ridge and the trough over the UK:

UKMO   

ECM       

GFS        

GEM.     

The UKMO has wound up the low GFS-style but they are all keen to have that ridge rise into Greenland.  Charts at +144 are still not entirely reliable especially given the differences between the models following these frames but, given the overall agreement between them, presumably we can at least expect the charts to continue showing this set-up in the days after Christmas.  It’s not showing mild weather, that’s for sure.

Edited December 22, 2020 by Sky Full

[V for Very Cold]

Hmmm, surface temps t 72 onwards not as low as modelled a few days ago and again, ppl are starting to focus on the mythical t240, even when a cold/cool snap/spell was forecast for 24th onwards, are we subtley downgrading our cold expectations over time? 

Edited December 22, 2020 by V for Very Cold

[Cheshire Freeze]

1 minute ago, V for Very Cold said:

Hmmm, surface temps t 72 onwards not as low as modelled a few days ago and again, ppl are starting to focus on the mythical t240, even when a cold/cool snap/spell was forecast for 24th onwards, are we subtley downgrading our cold expectations over time? 

ECM is showing a fairly widespread snow event at D8.

[Battleground Snow]

Much improved ECM at 216 compared to the 12z, Greenland high incoming?

 

[That ECM]

10 minutes ago, dallas said:

Nice to see the alignment

T144 is where there starts to be some differences towards the nw. ECM is much improved imo. Awaits SM to tell me it’s not

[V for Very Cold]

3 minutes ago, CreweCold said:

ECM is showing a fairly widespread snow event at D8.

Don’t get me wrong, I would love deep cold and snow events.... I was merely wondering should we water down our expectations for the next week?

[Battleground Snow]

Would have loved to see a ECM day 11, it's definitely following the GFS path from earlier

 

[That ECM]

Differences of course but is this the 1st time that both have shown a Greenland high is on the table?

[Chesil View]

1 minute ago, That ECM said:

Differences of course but is this the 1st time that both have shown a Greenland high is on the table?

Indeed so TE.  Subtle improvements across GFS and ECM this morning.

[bluearmy]

1 minute ago, That ECM said:

Differences of course but is this the 1st time that both have shown a Greenland high is on the table?

Gfs op is definitely a greeny upper ridge ....ec op is not - it’s just the amplification of the mid Atlantic ridge as it ebbs and flows with repeated bouts of WAA off the eastern seaboard dragging it up before it goes through another cycle. What comes later week 2 and certainly beyond that could be different .........

[Stu_London]

Still bags of potential beyond day 7 - getting that into the reliable timeframe remains problematic as anyone who has any experience of watching model output will be able to testify to. 

Looks like the 27-29Dec period will only deliver to the minority now and there is now a strongish signal for the trough to remain close to us, which will probably create too much mixing. We really needed things to be that bit colder to start with - it's still relatively early in the season and we will always have to overcome the fact we are an island with relatively warm waters around us.

That said, as others have noted, there is still genuine potential down the line - we just need to get dealt the right cards. For the last two years, we have been stuck outside the casino in the mild rain!

 

[swfc]

Ec looks on the up to me. Fi but day 10 is most excellent on the nhp. Good start to the day long may it continue

[sheikhy]

Brilliant output this morning!!we seemed to have stopped that rut of flattening everything to the north of greenland as well!!i think quite a few people going to be surprised in the next week or so!!ukmo still more amplified across greenland at 144 hours by the way

[That ECM]

2 minutes ago, bluearmy said:

Gfs op is definitely a greeny upper ridge ....ec op is not - it’s just the amplification of the mid Atlantic ridge as it ebbs and flows with repeated bouts of WAA off the eastern seaboard dragging it up before it goes through another cycle. What comes later week 2 and certainly beyond that could be different .........

I appreciate we are talking about a t240 chart but wouldn’t the low coming out of the states go under the high thus keeping it in place?

[Stu_London]

It's only brilliant output if you like looking at projections at D9, D10, D11 onwards etc.

There is a shorter interlude of below average temps, which as ever at this time of year, has potential to deliver a few transient snow events in favoured places.

At present there is no evidence to suggest any sustained cold spell.

[Chesil View]

2 minutes ago, Stu_London said:

It's only brilliant output if you like looking at projections at D9, D10, D11 onwards etc.

There is a shorter interlude of below average temps, which as ever at this time of year, has potential to deliver a few transient snow events in favoured places.

At present there is no evidence to suggest any sustained cold spell.

Apart from the fact that there is no zonality on any output .

[bluearmy]

5 minutes ago, That ECM said:

I appreciate we are talking about a t240 chart but wouldn’t the low coming out of the states go under the high thus keeping it in place?

not necessarily- it looks to be headed n to me although I accept we cannot know for sure if it would extend enough split ese  to undercut the ridge 

[swfc]

3 minutes ago, Stu_London said:

It's only brilliant output if you like looking at projections at D9, D10, D11 onwards etc.

There is a shorter interlude of below average temps, which as ever at this time of year, has potential to deliver a few transient snow events in favoured places.

At present there is no evidence to suggest any sustained cold spell.

I think that's a given tbh. Looking forward is part of the thread tho altho nothing is certain it's interesting nonetheless

[Polar Maritime]

Snow chances for some into the early hours of Wednesday..