[Model Output Discussion - Into Winter]

3 hours ago, Nick123 said:

So confused. 4 posts one after the other. 2 says good start to the day, 2 say poor!! 

If you are looking at the bigger picture it's a great start to the today.  If you are looking at the medium term outlook,  and hoping for cold to come back quickly,  it's not a great start to the day. The few  dry days we had could  soon be cancelled  out by slow moving systems  that decay close by 

[Model Output Discussion - Into Winter]

4 minutes ago, Dennis said:

are you kidding? 

No I am not.  Some of the more knowledgeable posters were indicating a period of less cold weather until around Mid December.

 We don't do well in terms of snow from an Easterly, but cold and dry with gin skies is the second best thing to snow. So bring on the Easterly soon,Dennis!

[Model Output Discussion - Into Winter]

After reading some posts I thought for sure it is game over for a couple of weeks , then along comes the ECM tease. It's encouraging that these kind of runs keep appearing even if they don't have solid support across the models.

[Model Output Discussion - Into Winter]

I hope this ECM run isn't a huge outlier and that it  is backed by the GFS pub run later. If it is a lot of people will be scratching their heads wondering how the models came to show this.

[Model Output Discussion - Into Winter]

34 minutes ago, blizzard81 said:

That could end up excruciatingly frustrating afterwards lol. 

That would be my fear. A case of close but no cigar. I hope I am wrong. Let's just say  the coldest upper air did some how make it all the way across to England, what would the uppers be after modification from  travelling over the warmer sea? Did -20 upper air clip the south east of England in Janaury 1987?

[Model Output Discussion - Into Winter]

1 hour ago, Met4Cast said:

Looks like my expectation for an unsettled start to December is going to come to fruition after all, just with a bonus cold spell before hand. 

Quite a few turn their noses up at background drivers/teleconnections in this thread, I suspect due to a lack of understanding them but I think that’s a shame, they are an incredibly useful tool and add a lot of context to NWP outputs. 

 

The MJO continues it’s progression eastwards is a rather amplified state, this wave has been a little faster than modelled and is expected to reach the central Pacific sometime around mid December, meanwhile we should see overall GLAAM rising via frictional & mountain torque processes thanks to this MJO wave with WWB’s returning. 

i.e I don’t expect we’ll see an Atlantic onslaught for weeks on end, it’s very possible we see a switch to more blocked/colder conditions over the Christmas period > into early January. 

Just a thought on this, given background drivers are always in a state of flux, it would seem that on very rare occasions  the background signals can be overridden. Look at the winter of 1962/63, I presume the MJO and AAM weren't  conducive to blocking through that extremely long lasting  spell,but the intense blocking must have overriden them. Perhaps if we had an omega block this time with the cold well entrenched the same thing might have happened this time. I take your point though that they generally have a huge bearing on what type of weather we are likely to have .

[Model Output Discussion - Into Winter]

Our - Meteorological service- Met Eireann in its long range forecast is saying it will be mild and unsettled  for the rest of December. The only crumb of comfort for me is the EC46 didn't  go for this cold  spell and it can often flip in fi. I just hope we are not going to be stuck under slow moving systems for weeks on end due to heights to the North East.  We had enough rain over the last six weeks.

3 minutes ago, LRD said:

Very mild in a week or so

I could live with that if the high then migrated  north or north eastwards a few days later.  I know I am straw clutching 

[Model Output Discussion - Into Winter]

34 minutes ago, Met4Cast said:

Becoming rather difficult to keep up the rhetoric for a continuation of cold beyond the first week of December now, MOGREPS showing a clear trend towards less cold air moving in across the UK, in agreement with the GEFS & EPS.

Hopefully we can squeeze as much snow out of this week as we can!

Less cold for a few days seems inevitable now, but whether it becomes a lot milder, and for how long it lasts,  is far from certain. There is not much sign of raging zonality for weeks on end as of yet

[Model Output Discussion - Into Winter]

14 minutes ago, TSNWK said:

Thanks.. I was going to pose the question where to now after next weeks currently progged breakdown…which has broad support across the operations/ with the same trend showing in the clusters now…probably leading to a couple of weeks at least of mobility?

I’ve read thecteleconnections are postive for late December? Why should we believe them when they were wrong in summer and were not aligned to this current high pressure dominant chilly spell.

The say a day is long time politics.. Jeeze it’s a lifetime in model viewing

 

The teleconnections  give us a chance  of blocking but like you say they don't  guarantee it. This blocking was always on borrowed  time  due to those background factors not being in our favour.  I really hope, as I am sure most here do, it's only a temporary return of the Atlantic. A cold spell for Christmas week would be brilliant. 

[Model Output Discussion - Into Winter]

3 minutes ago, Kasim Awan said:

You can't deny the fact that the models have such strong momentum to keep us in cold, we are seeing unusually low momentum towards a breakdown.

It's starting reminds me of February 2012 or was it 2013?. The cold breakdown kept being pushed back.

[Model Output Discussion - Into Winter]

1 minute ago, MJB said:

Stunning chart

 

Slider gate? Could Roger J Smith be right about this winter having this kind of pattern?

[Model Output Discussion - Into Winter]

2 minutes ago, mountain shadow said:

Any moisture with it? Otherwise dry as a bone.

It might not suit you if it turns out like that, but dry and cold will do me after six weeks of wet weather.

[Model Output Discussion - Into Winter]

Come on let's gets that -12 air to the north down over us!

[Model Output Discussion - mid Autumn]

1 minute ago, MattStoke said:

Makes a nice change from mild late autumn/winter weather when the only questions are over when the rain will end whether we’ll ever see the sun again.

Indeed it does after six weeks of wet weather . I will be more than happy with come crisp days and frosty nights. Snow would be a bonus. 

[Model Output Discussion - mid Autumn]

11 minutes ago, Tim Bland said:

How Long would it be until the next shot at a ridge though…

Hopefully just in time for Christmas week the high migrates north westwards! I don't like the look  of the pv there but at least the bulk of it is away from Greenland. 

[Model Output Discussion - mid Autumn]

48 minutes ago, joggs said:

Tamara's informative post a few days ago did mention sliding lows coming into play.

Roger J Smith did speak about this too. He thinks the theme for much of this winter could be battleground scenarios. If that is the case let the boundary  be to the south of Ireland  and Cornwall!

[Model Output Discussion - mid Autumn]

51 minutes ago, blizzard81 said:

Yep. I'm not a huge fan of the 06z gfs but the favourable changes happen relatively early on so it is quite promising. 

Why is  that. Do you think its less accurate than the other GFS runs?

[Model Output Discussion - mid Autumn]

1 minute ago, northwestsnow said:

4th to 11th

ties in with BBC tweet..

So  is it milder the following week?  

[Model Output Discussion - mid Autumn]

21 minutes ago, Met4Cast said:

EPS still broadly cold out to day 10 but no denying the shift towards a more Atlantic influence in the extended now.

Does seem the blocking might be numbered, but perhaps not a surprise given the MJO is cycling through 2/3 at the moment. Unless we can somehow get very lucky with a secondary wave break then a period of Atlantic activity is probably inevitable as we go through the first week of December.

Considering what's happening now in spite of the atmospheric drivers,It would be ironic if the background signals, like the MJO ,  when they are in a favourable phase for blocking fail to deliver. The weakening in heights over Greenland  is never a good sign. We just have to hope any Atlantic  influence is not a full on return to zonal for weeks on end, but of course  it could be.

[Model Output Discussion - mid Autumn]

3 minutes ago, BLAST FROM THE PAST said:

As an ‘overall’ pattern the Gfs is beautiful.   If we get a SSW on top of this hemispheric forcing….could be a very interesting winter indeed.

 

BFTP

Is there any danger a ssw could end up shaking up the tropospheric pattern for the  worse.  Has this ever happened before while the troposphere  had a blocking pattern?

[Model Output Discussion - mid Autumn]

37 minutes ago, Met4Cast said:

Another perfectly timed wave-break to throw up another block.. surely we're not going to get quite that lucky!

The GFS were right when they led the way with this cold spell. So therefore they must be right about the Easterly;)  When they are showing a breakdown or relaxation of cold we can discount it as the usual GFS rubbish. This is why I was dismissing it as crud until I saw the Easterly:)

 

But seriously after six weeks of rain,  cold and dry will do nicely , if we can't have snow. A  heavy rime frost like last year  would be  a bonus as it took on the appearance of snow after a few days.

[Model Output Discussion - mid Autumn]

Fantastic  ECM!!. That could lead to a sustained  cold spell! If only it was at t24. 

[Model Output Discussion - mid Autumn]

1 hour ago, Met4Cast said:

One question I have is how sustained can this blocking become? We know the teleconnective drivers aren't in favour of this but through what appears to be pure chance we've seen a wave-breaking event at the exact right time to throw up this high-latitude blocking.

Now.. with the likely return of an active jet into early December on the back of -AAM tendency & MJO transitioning phases 1/2/3. if blocking is somehow able to take a quasi-stationary residence to our north this may south shift the more active jet stream, we then see the Canadian warming kicking in which helps to reinforce any blocking. 

By mid December MJO should be cycling into more favourable blocking areas with a switch to +AAM tendency.. very, very interesting times.

If we are to get a breakdown/ return to Westerlies ,I wouldn't  mind if it's between  the 11th the 20th, then let the lag of effect of the mjo show its influence and deliver  a snowy nirvana just in time for Christmas. 

[Model Output Discussion - mid Autumn]

16 minutes ago, MattStoke said:

Or it'll miss and we'll stay dry, which many ironically seem happier with.

To be honest from an imby perspective I would be one of those happier people. I would much rather cold and dry than cold and wet.  Although  I appreciate others who could be on the right  side of the cold boundary in a marginal setup will see it alot differently! 

[Model Output Discussion - mid Autumn]

12 minutes ago, bluearmy said:

that’s rather a glass half empty view …… pretty confident that elevation will see 

It could well be cold rain for many places though,especially,  Cork, where he is from. In FI on the ECM it looks like the heights are moving away from Greenland too. I would be much happier if it wasn't all so marginal. Still its better to have the chance  of something decent than be looking at weeks of zonality,which was the favoured outlook for December a few weeks back