Model Output Discussion - Into the new year

[Snowman.]

18z mean vs 0z

Incredible upgrade!

[Cheshire Freeze]

Those heights into SE Europe are an actual thorn in our side. They need to do one pronto.

[Scott Ingham]

Some extreme cold weather heading in to scandi and north west europe on the GFS 0Z at the end of its run

The next round of amplification will definitely not be marginal!!!!

[Rollo]

You night owls are surely sniffing the coffee!

[Snowman.]

5 minutes ago, Rollo said:

You night owls are surely sniffing the coffee!

Just whiskey here my friend!

[feb1991blizzard]

G

17 minutes ago, Rollo said:

You night owls are surely sniffing the coffee!

GEFS 0z are certainly a snorter!

[northwestsnow]

UKMO...144

[PiscesStar]

1 hour ago, Connor Bailey Degnan said:

I was originally sceptical about this winter, I thought it would be a case of deja-vu. However, the last 2 weeks of watching the models has really interested me.

We are at solar minimum, Nao and Ao going pretty negative along with an Average December which is always a good sign

The coming week will be slightly colder than average, along with a showery theme of weather. Snow surprises could just about pop up anywhere, so now casting is definitely key. 

 

However, for me, the main core of proper cold weather, ie from the east, with substantial falls of snow, will be from the second week of January.  !

I think for a lot of us now. Second week looks primed provided the output stays cold 

[Daniel*]

From an ens mean this is outstanding hugely strong signal for wind to veer from east late this weekend. Increasingly cold.

Edited December 28, 2020 by Daniel*

[Cheshire Freeze]

Look at this for an ensemble mean out at that lead time-

[KTtom]

50 minutes ago, CreweCold said:

Those heights into SE Europe are an actual thorn in our side. They need to do one pronto.

Solid agreement for the high to be aligned perfectly for an easterly feed, now were back into the 850 game! The Ruski high which seems to have been present all winter is preventing a real artic blast into scandinavia and as such the cold is pretty much home grown, like you say the heights in the south east are a pain and have fed less cold uppers into southern areas for the last 2 gfs runs. The alignment of the flow looms crucial as to wheather we get a memorable easterly or a t-shirt easterly!

[northwestsnow]

GEM looks good too..

[That ECM]

T72 on ECM.

[SLEETY]

gem is nuts for the amount of blocking at the end.Never seen a chart like it since 1947 lol

[That ECM]

T144 all 3. GFS is a bit quicker but a lovely sight for coldie.

[Kentspur]

Lovely ECM at 168 that will be a little chilly with a Northeasterly flow across the country and widespread -7c to -6c 850 Hpa

Edited December 28, 2020 by Kentspur

[That ECM]

2 minutes ago, Kentspur said:

Lovely ECM at 168 that will be a little chilly with a Northeasterly flow across the country

Yes.  Lovely.

[tight isobar]

Great chart @168 but we DO need to keep an eye on those by then eastern euro heights.. could be friend... could be foe... as we progress.

[Battleground Snow]

Feels good to not wake up to one bad run this morning.

ECM 192

 

[tight isobar]

Wow @worry not.. full swirl of heights link.. and it only goes 1 way from here... cracking @ecm ooz 

[That ECM]

T192 not much point going past T168. Imo

[Nick F]

Intetesting low pressure system on 00z EC moving east across the south on Wednesday. GFS has the low, but tracks it SE much further south into France.

I suspect, then, that EC maybe too far north track, as is usually the case it seems, but one to watch of many disturbances over the coming days that could bring snow. Another disturbance dropping south New Year's Eve too.

Feel like I need to pinch myself that this not all a dream that we could actually be looking down the barrel of a long protracted cold spell, in January, that gets colder and colder. And we've not even seen the effects of the SSW yet! 

 

[tight isobar]

Sit bk ponder .. and admire.. ec ooz.. 216! 

[Ols500]

5 minutes ago, Nick F said:

Intetesting low pressure system on 00z EC moving east across the south on Wednesday. GFS has the low, but tracks it SE much further south into France.

I suspect, then, that EC maybe too far north track, as is usually the case it seems, but one to watch of many disturbances over the coming days that could bring snow. Another disturbance dropping south New Year's Eve too.

Feel like I need to pinch myself that this not all a dream that we could actually be looking down the barrel of a long protracted cold spell, in January, that gets colder and colder. And we've not even seen the effects of the SSW yet! 

 

For all of west london i think we like the look of that gfs chart lol

[West is Best]

27 minutes ago, KTtom said:

Solid agreement for the high to be aligned perfectly for an easterly feed, 

There might come an easterly out of this but words about 'solid agreement for a perfect alignment' make me nervous. The progression of the high pressure cell towards Iceland is a precarious synoptic setup at the best of times. A small shift and we find ourselves under a high pressure not an easterly and many, many, many times easterlies have been promised even at short notice only to come to nothing (John Kettley's infamous beast from the east being the classic example).

The models have generally trended more cold over the past 24 hours but only by a notch. My concern is that there remains a lack of 1. robust upstream blocking and 2. significant cold pooling to our east, although this has improved slightly. It should also be noted that later on in the run  0z GFS has a south-easterly veering southerly: in fact what Steve Murr used to call the backdoor exit from a cold spell. This is because it has the hp evaporating. That also needs to be watched as it's a relatively new development with the GFS which has continued to be all over the place past T168 - another reason to be cautious. In addition we should note that in FI models are continuing to show Atlantic low pressure cells and without robust upstream blocking this should be a cause for concern. It can, of course, be the prelude to proper snow: when a low pressure collides with cold pooling and the undercut leads to real snow. We are a long way from that scenario at the moment. The 0z ECM indeed has the hp cell eventually moving so far north that the cold uppers over the UK lift from the south: we lose the cold source. 

These setups are precarious. I can only really remember one perfect alignment for an easterly and that was February 1986 - one of the three coldest months of the C20th I believe but one hardly anyone remembers as it was simply cold. No snow. Just bone chilling boring dry cold.

At the moment I see evidence to stick with the Met Office that we're in for a week of cold weather, with rain, sleet and snow but also a lot of dry weather. Temps below average but nothing seismic or significant. Pretty much in line with the kind of below average conditions we experienced in July and October. Beyond T144 at the moment is unclear and uncertain. Caution should be the watchword not over-enthusiasm. At least for now.