Model output discussion - Winter has arrived

[That ECM]

11 minutes ago, chionomaniac said:

I don’t know about anyone else, but I am content with the slow building blocks put in place so far - in fact far happier that no Armageddon type scenarios are shown at day 10 which unduly raise up hopes. The critical issue here is how strong any trop wave 2 activity is. The stronger and more it penetrates towards the middle strat, the better. Just not seeing the strength quite yet, hence the stalling and dissipating Atlantic troughs without the undercut. 

When do you think we will really start to see the output pick up on the possible strength? TIA

[swfc]

6 minutes ago, CreweCold said:

Yep!

Perfectly happy with the ECM day 10. Signs of the TPV starting to split bang on cue tbh. Anything showing before day 10 is pie in the sky stuff.

OK. Have you the lotto numbersI hope your correct and the PV is demolished going forwards

[chionomaniac]

2 minutes ago, That ECM said:

When do you think we will really start to see the output pick up on the possible strength? TIA

This may seem like an obvious answer - but when it does  

otherwise keep an eye on the MJO - which hopefully will move towards a stronger phase 5 in the week before Christmas. If, and a big if here, it does then some time soon after that

[That ECM]

5 minutes ago, swfc said:

OK. Have you the lotto numbersI hope your correct and the PV is demolished going forwards

I understand the scepticism but for those of us who have been on here for many years will recall that chiono talked about the potential in 2009/10 and the BFTE well before it showed on what we understood. I think we need to sit and watch with interest.

Edited December 7, 2020 by That ECM

[blizzard81]

12 minutes ago, D.V.R said:

The Euro high extends North to join the Arctic high? 

We can hope lol. Will look different come day 10 anyway. 

[MATTWOLVES 3]

I'm gerrin more and more confused the more posts I read.. Will it or won't it!! Is he or isn't he! Who cares what the ECM and UKMO show.... Its what the GFS control shows that really matters. It could be onto something... Or couldn't it!! Stay tuned for the next big episode here on Netweather... Cue the drum role from Eastenders..

[LRD]

Just a tip to less experienced members/model-watchers and I hope this doesn't sound patronising because I really don't mean it to.

Don't get too hung up on each op run every day. Nothing cold is going to happen for at least 12 days (if it does at all) so don't worry about that just yet (if things keep getting pushed back that can be a bad sign but we're nowhere near that stage at this point in time). It's the longer term trends that are getting folk hopeful at the moment

Ensembles, clusters, strat data, twitter experts, some posters on here (won't embarrass them by naming them but you'll know who they are) and the extended Met Office outlooks are good indicators for trends. It may still come to naught but don't get too grumpy with a 384hr GFS chart that is showing blowtorch SW'lies when it was previously showing frigid NE'lies

As I say I don't want this to sound condescending but I'm just thinking back to when I was new to this hobby and how I was!

Edited December 7, 2020 by LRD

[Methuselah]

36 minutes ago, Steve Murr said:

Close but no cigar on this run > we need more heights over the top like UKMO 144!

So it's just another fag-end then, Steve?

[Anthony Burden]

ECM tonight very messy and uninspiring,but gfs well out into fantasy island showing 

the high pressure in the right place to bring what most on this forum wants.

Sure to disappear but keep an eye on appearances over a period of time,then

if that happens time to take notice if it drops into 144hrs or less.

[swfc]

14 minutes ago, That ECM said:

I understand the scepticism but for those of us who have been on here for many years will recall that chiono talked about the potential in 2009/10 and the BFTE well before it showed on what we understood. I think we need to sit and watch with interest.

I've been on here 17 years and we'll awair of chinos and gp experience. My point was tongue in cheek for them that know. Hopefully some of the touted outcomes and hopes land with avengence. Chill out its only weather after all

Edited December 7, 2020 by swfc

[Scott Ingham]

54 minutes ago, IDO said:

I am still unsure why the T144 chart is exciting, one low undercuts but this is halted as a plumb climbs the eastern edge of the trough:

ecm t144> gem> 

On all models this warms out the undercutting replacing it with heights! I am not sure how we can get further undercutting from this. To me, the models have made their mind up? This will mean only one direction the cut-off low can move to?

They can't move any further east due to the invisible block chio mentions. It will fill over the UK nearer to time 100%. 

[stodge]

Evening all

A thoroughly cold and bleak day here in downtown East London though the early mist lifted up more than I had anticipated. The journey to a milder evolution seemed set in the short to medium term yesterday - longer term signs of a rise of pressure in the vicinity of the British Isles but lots of options as to location and orientation from traditional Bartlett to mid-latitude to even some promoting high latitude blocking.

The models may not like Mondays, those who discuss them may be more ambivalent - let's go..

12Z GEM: - the opening salvo proceeds with the incoming Atlantic LP again shifting SE as it comes up against the weight of the Eurasian block but by the weekend (T+120) the trough and the Azores HP are aligning more positively suggesting a milder regime on the horizon. Indeed, that's what happens as the invigorated LP spins round for a while but by T+192 it has split and started to fill. Heights remain over Europe with the hint of a new storm coming off North America. However, we're not in a typical zonal environment by any means - there is no strong jet and PV to propel the storm across the Atlantic flattening every thing in its path. Instead, the LP starts to shift ESE and it meanders towards us by T+240 and heights are showing to the north of the British Isles and we end with an E'ly over the north of Britain and the evolution far from clear.

12Z GFS OP - while the GEM has given us a bit of a poser with its evolution, can we rely on GFS to play the old zonal game? by T+120 not too different from GEM as you'd expect - the second LP is developing nicely and set to re-invigorate the first to the south of Iceland and re-align the trough positively. I also note the Azores HP is weaker and further south than GEM with the lower heights over Europe more pronounced. By T+192 it's starting to get interesting - heights far to the north are holding the LP just to the west of the British Isles where it is going nowhere slowly. A mild SW'ly flow for most but we're not talking a long fetch draw from the Caribbean by any stretch - also unsettled with rain and showers. On then to the T+258 chart for the end of next week and the heights are over Greenland but also building from the south west - the Atlantic isn't anything like as strong as you'd expect with weak systems moving erratically across the British Isles. By T+336m HP is in charge with a cut-off LP in the Atlantic and a new HP developing between Iceland and Greenland albeit with signs of renewed PV activity. Instead, and this becomes apparent by T+384, the jet is forced far to the south. It looks as though the core of the PV is moving from Greenland to Scandinavia - I'm not sure what to make of it in all honesty.

Both GEM and GFS have dished up some fascinating midwinter evolutions this evening and while neither guarantee cold for the UK, both would offer much more likelihood for cold than we've seen at this stage of winter for several years. Can ECM be the showstopper or will it be as dull as today's weather? Let's see. By T+120 it makes more of the elongated trough across the UK and into Europe with heights over Scandinavia but the second LP is in mid-Atlantic and you'd think would re-align the trough positively as the Azores HP pushes into Europe. That's pretty much what it happens and by T+240 it's a fairly familiar winter chart though the evolution from there would be interesting.

Looking elsewhere, 12Z GFS Control is superb for cold weather fans so I won't bother posting any of those as I expect it's been analysed to death already. This morning's 00Z GFS Parallel was also worth a look.

It seems very likely we will have a milder interlude next week but the stress seems to be on the "interlude" - plenty of evolutions suggesting nothing more than a 3-5 day break before the possibility of more amplification.  GFS OP doesn't quite get there but Control does in some style. GEM is the pick of the medium term output once again while ECM keeps it mild to T+240 but we'd expect that. The truth is the next amplification is still just over the hill and it may not happen but the PV looks much weaker and less organised than normal and if the decrease in zonal winds forecast comes to pass the opportunity for amplification increases. All in all, a highly interesting few days of model watching ahead - the next fortnight may not inspire but there's a chance we'll be in a better position for some colder and perhaps snowier conditions as wr approach Christmas - we'll see.

 

[Scott Ingham]

The ECM day 10 chart is a good chart. You need to look at the Northern Hemisphere. The trough will dig further south and push heights North connecting with the arctic high and pull blocking further west. The warm up is inevitable as it pushes waa up through the great British isles. As chio said to John and I said yesterday the skill is in seeing what the models are not showing yet. Knowing how it will evolve due to both background signals and known bias. No panic needed. Its a slow builder to wintry nirvana

[IDO]

1 minute ago, Scott Ingham said:

They can't move any further east due to the invisible block chio mentions. It will fill over the UK nearer to time 100%. 

Indeed, a possibility, and highlighted in the gefs. I was just stating that the undercut scenario seems a lost cause, due to the plume, and mentioned that the only direction the low could spill was NE if it chooses to.

Assuming it does warm-out over the UK, that will just leave us a repeating pattern of a Russian block -v Atlantic, a Mexican standoff that trends to nothing suitably cold? I am just uncertain why that is something we want? I think last year the Russian high again stopped the UK cold in nov and early Dec, and by the time it relented, the trop and strat linked, and we had 8-weeks of Atlantic weather! I do understand that the Russian high in the long game is good but I only get excited about strat warming when it arrives before Spring and impacts our arena. 

[Bricriu]

4 minutes ago, Anthony Burden said:

ECM tonight very messy and uninspiring,but gfs well out into fantasy island showing 

the high pressure in the right place to bring what most on this forum wants.

Sure to disappear but keep an eye on appearances over a period of time,then

if that happens time to take notice if it drops into 144hrs or less.

The time to really take note- ala Februrary 2018- is when all the models are following the same script and don't have wild swings. If the GFS pub run shows mild south westerlies tonight no doubt some folks will be saying it's all over. This is a mistake, If the 10-12  days period is really the focal point, then most models won't be firming up on this for a few days yet. Let's hope by this time next week they are.

[Scott Ingham]

Just now, IDO said:

Indeed, a possibility, and highlighted in the gefs. I was just stating that the undercut scenario seems a lost cause, due to the plume, and mentioned that the only direction the low could spill was NE if it chooses to.

Assuming it does warm-out over the UK, that will just leave us a repeating pattern of a Russian block -v Atlantic, a Mexican standoff that trends to nothing suitably cold? I am just uncertain why that is something we want? I think last year the Russian high again stopped the UK cold in nov and early Dec, and by the time it relented, the trop and strat linked, and we had 8-weeks of Atlantic weather! I do understand that the Russian high in the long game is good but I only get excited about strat warming when it arrives before Spring and impacts our arena. 

We want this stand off as its going to create the second warming in the strat. The MJO is also going to move into phase 5 and signs of phase 6 which will aid this block into moving further north at a time when the tpv is splitting due north of us. From there I would expect Greenland heights last week in December to the first week in January 

[IDO]

3 minutes ago, Scott Ingham said:

We want this stand off as its going to create the second warming in the strat. The MJO is also going to move into phase 5 and signs of phase 6 which will aid this block into moving further north at a time when the tpv is splitting due north of us. From there I would expect Greenland heights last week in December to the first week in January 

I understand that and fair enough, just not keen on wasting a prime NH profile, even though we will need the trop to drive any cold. Hopefully this slow warming, not an SSW as I understand, leads somewhere this time?

The ecm mean falling in line with the general consensus as to post-d5:

 

[Mike Poole]

You learn something new on here every year, last year it was the Indian Ocean Dipole (and that did no-one any favours!), this year it’s the Invisible Block!

Genuinely interested in this as you can kind of see it in the GEFS ensemble members of ‘something’ causing a N/S connect of heights across the arctic, and on the other side, but it’s way above my pay grade!!  

This thread is at its absolute best this year, with great input from so many people.  

And if it properly snows at the end of it, it will be a roller coaster worth the ride

Edited December 7, 2020 by Mike Poole

[Scott Ingham]

Just now, IDO said:

I understand that and fair enough, just not keen on wasting a prime NH profile, even though we will need the trop to drive any cold. Hopefully this slow warming, not an SSW as I understand, leads somewhere this time?

The ecm mean falling in line with the general consensus as to post-d5:

 

Im confident very confident it will. Again that mean isn't bad we want to see heights rise through the UK and connect with the Arctic High. MJO events don't even filter into the models until the 17th which is when that mean ends. Its post the 17th we need to be looking. As it is. We need this stand off to keep sending warming into the Strat

[Scott Ingham]

11 minutes ago, Mike Poole said:

You learn something new on here every year, last year it was the Indian Ocean Dipole (and that did no-one any favours!), this year it’s the invisible block!

Genuinely interested in this as you can kind off see it in the GEFS ensemble members of ‘something’ causing a N/S connect of heights across the arctic, and on the other side, but it’s way above my pay grade!!  

This thread is at its absolute best this year, with great input from so many people.  

And if it properly snows at the end of it, it will be a roller coaster worth the ride

Its just a split stretching from the troposphere to the lowest ends of the stratosphere. It shows if the top of the strat isn't filtering down to lower levels we only need the lower levels to split to cause some blocking and slowing of the jet 

Obviously if we didn't have this disconnect between the top of the strat and troposphere we wouldn't be able to get into this position and if we didn't have the weather patterns driving all this waa and wave breaking we would have more chance of them connecting. And if we didn't have the mjo and the nino esque atmosphere creating all this forcing we wouldn't have the patterns. Its all finely linked 

Edited December 7, 2020 by Scott Ingham

[mulzy]

I know it’s like a broken record but the outer reaches of the extended EPS broadly as before. Significant heights to the northwest, north and northeast.  Low heights over southwest Europe.

[Methuselah]

How many more feeble excuses can there be? Every year (bar about three?) something 'scuppers' Snowmageddon: moon filaments, invisible walls, other miscellaneous bugbears... Could it possibly be that possibly, just possibly, nobody knows how to forecast the upcoming season's weather???

[Griff]

Might want to check out the latest ecmwf zonal chart over on the strat thread

Sod it, here it is (at least it's not a tweet) 

 

Edited December 7, 2020 by Griff

[Geordiesnow]

I thought the ECM looked promising early doors but went downhill afterwards although it shows how small differences can potentially make a huge differences longer term. 

Really do think we need the Arctic high to come into play enough to drop the PV into Scandinavia otherwise we will just continue to feed onto scraps in terms of true cold air. So I'm hoping for heights developing north of Shetland like the UKMO shows and we go from there. 

[Mike Poole]

1 minute ago, General Cluster said:

How many more feeble excuses can there be? Every year (bar about three?) something 'scuppers' Snowmageddon: moon filaments, invisible walls, other miscellaneous bugbears... Could it possibly be that possibly, just possibly, nobody knows how to forecast the upcoming season's weather???

I think the invisible block might be working in our favour, Pete!