Model Output Discussion - Winter arrives

[IDO]

Variation on the theme from the GFS 06z. Compared to the two ECM runs from yesterday we are not seeing the ridge split the low from the main NW vortex, which is what we really need:

GFS 06z>  ECM 0z (Dec 1)>

So the 06z at D9 similar to the 0z:

06z>  0z> 

With ECM killing that ridge it does seem less likely that we will revert back to that outcome?

[johnholmes]

20 minutes ago, Yarmy said:

Well we'd better hope it corrects southwards and becomes shallower because otherwise that's a catastrophic storm for Ireland and the southwest.

That chart cannot have the low in the correct position; why?

It has deepened a lot, if that is correct then it must turn NE!

The laws of physics and meteorology cannot be ignored, well not in my view

[PiscesStar]

11 minutes ago, johnholmes said:

That chart cannot have the low in the correct position; why?

It has deepened a lot, if that is correct then it must turn NE!

The laws of physics and meteorology cannot be ignored, well not in my view

Yes but it kind of revolves around John. Admittedly 06z looks better for. Cold, but only slightly... To my eye the charts scream wind and rain and slightly below temps.... 

Edited December 2, 2021 by PiscesStar

[Bradley in Kent]

Anything to stop that Azores High migrating eastwards towards the Med. If that happens you can kiss goodbye to anything seasonal for a good few weeks. As others have mentioned, we now know a lively low will be in this part of the world middle of next week with weak heights to the east. IMO this'll be one of those month deciders: if it goes south we'll continue the cooler conditions seen of late with possible heights nosing in from the east while heights remain in the Mid-Atlantic. If the low goes and joins its friend east of Iceland allowing heights to slip east into the Med, (not to mention a strong Canadian PV) then we might as well call the rest of December off!

It's not happened yet of course, so all eye on that low!

[mb018538]

A chart from most modern winters...Europe again devoid of any cold air with a turbo charged PV parked up to our NW. Hopefully tropical forcing is enough so that this pattern doesn't get bedded in and is disrupted after mid month.

Look at that huge swathe of the USA with 850 temps above 10c too....in the middle of December. That just shouldn't be happening. 

Edited December 2, 2021 by mb018538

[sheikhy]

2 minutes ago, mb018538 said:

A chart from most modern winters...Europe again devoid of any cold air with a turbo charged PV parked up to our NW. Hopefully tropical forcing is enough so that this pattern doesn't get bedded in and is disrupted after mid month.

Look at that huge swathe of the USA with 50 temps above 10c too....in the middle of December. That just shouldn't be happening. 

At least they are not stealing all the cold and snow!!makes me feel a lot better!!

[mountain shadow]

A think we have passed the tipping point today. The Winter killer is going to return to Greenland..

No more MJO phase 7 nonsense.

 

[carinthian]

21 minutes ago, sheikhy said:

Gona have to keep an eye out on that low in the atlantic!!its one of those that could just vanish just like that!!its relying on the interaction of the main vortex across greenland!!very uncertain times!dont even think the 12zs might get this one done and dusted!!

Yes, sheikhy ,uncertain as it has yet to form. Think period 96-120 h is going to get very interesting in the model evolutions. 

C

 

[Ali1977]

Interesting that quite a few ENS are showing this at 144 - like the ECM a few days ago 

Edited December 2, 2021 by Ali1977

[DavidS]

12 minutes ago, mb018538 said:

A chart from most modern winters...Europe again devoid of any cold air with a turbo charged PV parked up to our NW. Hopefully tropical forcing is enough so that this pattern doesn't get bedded in and is disrupted after mid month.

Look at that huge swathe of the USA with 850 temps above 10c too....in the middle of December. That just shouldn't be happening. 

There is no ‘should’ with regard to weather.

[MP-R]

On 02/12/2021 at 10:40, johnholmes said:

That chart cannot have the low in the correct position; why?

It has deepened a lot, if that is correct then it must turn NE!

The laws of physics and meteorology cannot be ignored, well not in my view

On this run it does gradually move NE and weaken as it does so, opening the door to traditional Atlantic guff behind it. The track does look a bit odd for a low of that strength though.

[Yarmy]

20 minutes ago, johnholmes said:

That chart cannot have the low in the correct position; why?

It has deepened a lot, if that is correct then it must turn NE!

The laws of physics and meteorology cannot be ignored, well not in my view

Well yes, and that's exactly what it does. The cyclogenesis starts here:

...and then it tracks NE through the UK. Of course, it's too far out to determine exact details of the track, position, and depth of a storm, so it's extremely unlikely to pan out like that. But I'm not seeing anything particularly unphysical aside from the GFS tendency to deepen  depressions too much.

[LetItSnow!]

13 minutes ago, mountain shadow said:

A think we have passed the tipping point today. The Winter killer is going to return to Greenland..

No more MJO phase 7 nonsense.

 

12 days away... that's all I will say

[mb018538]

16 minutes ago, mountain shadow said:

A think we have passed the tipping point today. The Winter killer is going to return to Greenland..

No more MJO phase 7 nonsense.

 

The lower heights do start to fill out a bit at the end of the run - see the purples almost all gone. Always a good sign. GFS looks quite bullish about this at the moment!

[tight isobar]

Clear drop lining in the ens also, and as b4 we will have to start somewhere! The mean now begins to look to drop line also. Great  stuff if ya like being kept on ya toes!- the nxt 3/5 days are also starting to look interesting, for wintery surprises!!..

Edited December 2, 2021 by tight isobar

[Methuselah]

9 minutes ago, tight isobar said:

Clear drop lining in the ens also, and as b4 we will have to start somewhere! The mean now begins to look to drop line also. Great  stuff if ya like being kept on ya toes!- the nxt 3/5 days are also starting to look interesting, for wintery surprises!!..

IMO, the forecast is currently very fragile: If I remember correctly (always a tough call!), the doom and gloom generated by yesterday's 'overnight' runs was banished by the wonders produced by the 12Z and 18Z? I'm half-expecting (given Exeter's current take on things) that the same thing might happen today?

[tight isobar]

On 02/12/2021 at 11:32, Ed Stone said:

IMO, the forecast is currently very fragile: If I remember correctly (always a tough call!), the doom and gloom generated by yesterday's 'overnight' runs was banished by the wonders produced by the 12Z and 18Z? I'm half-expecting (given Exeter's current take on things) that the same thing might happen today?

Fully expecting their genarated forecast to change today/tomorrow...notably colder!

Edited December 2, 2021 by tight isobar

[SqueakheartLW]

Here's one for Christmas from the GFS Extended run today

Also the 12z CFS run too

I know I don't rate the CFS very much but it has very much been calling this winter as mild and zonal more or less throughout December to February really right from around mid October on it's 9 monthly runs and with the way the AO and NAO look to be heading positive then rather annoyingly it would seem both the CFS and most of the seasonal models look to have called this winter correctly.

You occasionally get these sudden freaky cold runs on the CFS but in the last few weeks they have become so rare and all I see on most of them are reruns of December 2015.

I feel we missed our golden opportunity last winter to be fair with the patterns we had that didn't quite line up favourably and as we know in the UK if we miss any cold chances it can often be a long time before we get another one.

Cold snaps at best most likely and if we'll be lucky if we get anything more than a 2 day wonder at any stage

[MattStoke]

UKV shows a risk of some sleet/snow on Monday. Something that the Met Office regional written forecasts also mention.

Before then, some of the showers over the weekend may be wintry and there is the risk of some transient snow late tonight/early tomorrow as a front crosses the UK from west to east.

Not exactly Narnia for most, but a 'seasonal' start to winter after a snowy end to Autumn for some of us. Not the raging mildness that some comments would lead one to believe we are in for!

[blizzard81]

A big signal from the gfs to build a substantial Siberian high as we approach the middle of December. A big signal when you consider this is the mean. The 00z run was the same. 

[blizzard81]

2 hours ago, sundog said:

I'd say it looks like a good bet that the coming more mobile pattern won't last too long and likely be replaced by a more HP dominated pattern in the run up to xmas. 

Backed up by the EC46 (last update), now increasing from the gfs as we approach that time and also the cfs. 

[Cold Winter Night]

3 hours ago, blizzard81 said:

Ok so the short term disappoints aside, looking at the extended ecm debilt ens compared to last night's, interesting to note some colder runs in the extended compared to basically none on last night's. I wonder if these runs are showing the influence of the block backing west and pressure rising in our locale as alluded to by knocker in his post above? A crisp, seasonal Christmas would be nice. 

Yes, this is interesting.

It's visible in the clusters and regimes.

The 192h-240h clusters this morning have moved to a NAO+ dominated picture. The accompanying big jump away from cold stands out in the De Bilt 2m temperature plume.

That move at 192h is visible in the regime chart (that only goes as far as 192h) as well.

However, interestingly, the clusters in the extended are dominated by BLO+ (Scandi blocking) regimes.
A 31 member majority goes for BLO+ against 20 for a NAO+ regime.
So that Ural High moving West is a serious option in the extended period.

That there are only a few members showing real cold in the De Bilt plume has to to with the alignment of the block. If it's positioned too far South, we get Southerlies and Southeasterlies from Greece instead of Easterlies and Northeasterlies from Siberia.

Anyway, all this FI depends heavily on what is going to happen before 120h, so it's way too early to put confidence in any outcome.

[Ruzzi]

1 hour ago, SqueakheartLW said:

Here's one for Christmas from the GFS Extended run today

Also the 12z CFS run too

I know I don't rate the CFS very much but it has very much been calling this winter as mild and zonal more or less throughout December to February really right from around mid October on it's 9 monthly runs and with the way the AO and NAO look to be heading positive then rather annoyingly it would seem both the CFS and most of the seasonal models look to have called this winter correctly.

You occasionally get these sudden freaky cold runs on the CFS but in the last few weeks they have become so rare and all I see on most of them are reruns of December 2015.

I feel we missed our golden opportunity last winter to be fair with the patterns we had that didn't quite line up favourably and as we know in the UK if we miss any cold chances it can often be a long time before we get another one.

Cold snaps at best most likely and if we'll be lucky if we get anything more than a 2 day wonder at any stage

Looked to have called this winter correctly? It's the 2nd of December.... THE 2ND OF DECEMBER!! The models can't call beyond 4 or 5 days correctly the now, how on earth can they have called the next 3-4 months correctly?!

If you haven't done so already, read the netweather winter forecast, really great insight to what can happen. 

With regards to the CFS, it's a complete waste of time looking at it as is looking at any one model that tries to tell you what the weather will be like months in advance! 

There's a reason that human input is put into the MetO fax charts and that's only at a couple of days out, so an automated forecast from a model months in advance is utterly pointless. Whatever time you are spending viewing the CFS, instead dive into the depths of each different teleconnection and how they can impact our weather and winters etc and watch your perception change. There's stacks to be learned, loads of helpful threads on here too with great explanations. It'll dismantle any creedance you hold for a 3-4 month in advance nonsense automated weather model like CFS. 

[jules216]

56 minutes ago, blizzard81 said:

Backed up by the EC46 (last update), now increasing from the gfs as we approach that time and also the cfs. 

Cansip seasonal heading that way overal,with this anomaly i Can expect  brutal inversion cold spells alike winters 2003/04 or 2007/08.

[Battleground Snow]

2 hours ago, mountain shadow said:

A think we have passed the tipping point today. The Winter killer is going to return to Greenland..

No more MJO phase 7 nonsense.

 

It's not really nonsense is it?

It's a statistically proven phenomenon that has direct evidence of affecting the UK's climate in winter.

Granted, it's not sole influence, and not at a very high amplitude, but it can't be discounted either.

 

What is the Madden-Julian Oscillation?

WWW.METOFFICE.GOV.UK

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The Madden-Julian Oscillation is characterised by an eastward spread of large regions of enhanced and suppressed tropical rainfall, mainly observed over the Indian and Pacific...