Model Output Discussion - Spring Has Sprung

[feb1991blizzard]

 Met4Cast

That's what i always thought, but there has been times before where it has died into COD and re-emerged in a phase not far away from where it died.

[bluearmy]

 Jacob but where do the pieces fall ??  Not well for us and the 06z looks similar thus far 

recovers late on to make a better split than the 00z and the trop profile reflects that with a building Atlantic upper ridge 

Edited February 8 by bluearmy

[Blessed Weather]

10 minutes ago, Met4Cast said:

The MJO runs on a cycle of roughly 60-90 days, it won’t be back into favourable cycles again until April (ish). 

AAM tendency likely won’t return in any meaningful way until late March (assuming a coherent MJO cycle). 

So in a word.. no. 

Whilst certain phases of the MJO are known to assist with 'bringing on' a SSW (and the MJO has recently been in phases 6 and 7 which do), there is also research suggesting that - acting in the reverse direction - the SSW then impacts the MJO. So maybe it's 'all bets off' with regard a continuance of the normally expected MJO and AAM cycles? Extracts from a 2020 paper:

Influence of stratospheric sudden warming on the tropical intraseasonal convection

.....analysis reveals that SSWs also exert considerable influence on tropical intraseasonal convection. The occurrences of MJO phases 6 and 7 significantly increase during around 20 d after the onset of SSWs...

Full paper: https://iopscience.iop.org/article/10.1088/1748-9326/ab98b5

[Ali1977]

There are 6/7 decent ensembles at day 9 a bit like these, but I think people are just fed up so not seeing the possibilities here. I think some rapid swings to better Synoptics are really quite probable. 

[StretfordEnd1996]

There are one or two promising charts I can see around D9-10 this morning from the GEM and ECMWF but these are more "if they ran a couple of days further beyond D10 type charts" (which equivalates to straw clutching in a way  )

The GEM towards the end of its time frame has a huge bulk of HP moving slightly towards the W/NW of us which may suggest something of a colder note thereafter



ECMWF somewhat similar but less pronounced - but interesting to see some sort of cross-model similarities 

GFS nothing like the above though




ENS across the board are all a tad disappointing, although the very back end of the mean for the GFS doesn't look all that gloomy to be honest

The ECMWF clusters appear to have lost the signal for more general northern blocking - it's still there on some but they have all gone a bit everywhere to be honest (may not necessarily be a bad thing?)

Agree with others - not waving a white flag yet. I often feel mid-Feb to mid-March can bring some notable cold spells if things add up. I feel like this period on the law of averages has better potential than December. As a kid growing up through the 00s - 2004, 2005, 2006, 2008 all favoured the colder conditions post mid-Feb and for me as I was getting into climatology at the time this mid Feb- mid March period has just kind of stuck in my own personal experience of a period I look out for for colder weather, I fully acknowledge it doesn't happen every year.

Some picks of model output from the above aforementioned years just so the above comment is somewhat still on topic with the thread



Just because the outlook at the moment is a tad frustrating - and indeed its been a frustrating model thread a good deal of the time this Winter - it doesn't mean that this reduces the chances of a colder spell as we head further forward - it's not as though the weather and the charts have a memory and are playing some sort of game with us here in this thread - they'll just do what they do - not much cold of note in the next 10 days but beyond that and until mid-March we can still quite easily get something of note, no question. 

GFS 6z op tries its best to get something of interest or eye candy in deep FI, doesn't quite come off but interesting to see nonetheless 

[Met4Cast]

 Blessed Weather

Interesting, thanks for the link I'll give it a read later this afternoon! 

The SSW seems to be triggered (assuming we do indeed see one, here) by the MJO but also (perhaps more likely) by the recent strong +EAMT event increasing heatflux right up into the stratosphere.

There certainly seems far more evidence supporting a SSW this time around compared with the previous attempts this winter but without a QTR (this is another uncertainty) we'd be looking towards late February/early March for any potential impacts. I'm not seeing anything within extended NWP modelling to suggest an overly exciting QTR, usually you'd expect to see at least a couple of outrageous runs from GEFS ensembles but they've been relatively muted, the same is true for the EPS. 

MJO forecasts are currently quite uniform across. modelling, slow meander through phase 7 before a low amplitude phase 8 follows, albeit these are of course not factoring in any potential impacts from the (again, assuming here) possible SSW. 

Certainly quite a complicated picture unfolding but in any case, I'm not sure many would be happy with winter finally arriving in March just when some much needed warmth is wanted..

[johncam]

 northwestsnow and we all know what that Elephant is. It must be interfering with all the great signals we have had for cold. Can only see this getting worse as tge climate heats up even more 

[TEITS]

I haven't posted much recently not just because the output is so poor but i'm unconvinced by the model output and what they are predicting. Plus the performance has been poor even the likes of the UKMO/ECM.

The part of the modelling which I find rather suspect is actually between +72 to +120 and how they model the low pressure which is currently sat to the W of Ireland.

Now i'm making any promises or trying to clutch at straws but I believe changes could still occur at this timeframe which could have more significant changes later on. We understandably always expect downgrades at relatively short timeframes and rarely get upgrades. However in my opinion the chance of a sudden change to what is being predicted around mid Feb i.e+168, +192 could occur because of the change in how the models handle the low between +72 to +120.

[Airedalejoe]

Lol. Anyone here remember a certain Ian Brown, early this century vintage? He sounded like a few on here, winter in the UK is finished etc. From memory something called the Gin corridor. Never going to see snow again....

Then along came 2009/10/11/13/18 etc.

I suspect that in the next few years, when it's due, we will get another real wintery spell.

The charts are hinting at an easterly flow in the not to distant future and we could get another snowfall which would be the 3rd here. Deepest snow I ever saw here was second half of March, 1977 I think.

Trying to snow currently.

[MJB]

44 minutes ago, Ali1977 said:

There are 6/7 decent ensembles at day 9 a bit like these, but I think people are just fed up so not seeing the possibilities here. I think some rapid swings to better Synoptics are really quite probable. 

Totally agree, just gone through them all, no need to write anything off yet. 

[Severe Siberian icy blast]

 TEITS But the thing is even when we have full spreads showing northern blocking etc we always seem to miss out and it becomes a fleeting visit.

This year has been a joke in all honesty. It's all well and good removing posts when they don't read what you want but the reality is as a model output discussion, then airing frustration on hear surely is relevant particularly when it relates directly to the forcing drivers we've all obsessed over in depth then it's completely relevant.

Every single time we enter into an opportunity whether it's a wave break, trop led, strat led, etc it implodes infront of our very eyes.

I think there's a lack of ownership on hear when things turn out different. 

Be humble when it comes to the weather its the best way and understand that we dont know everything and its a constant learning curv but loud drums all winter has been pounded about cold on hear yet it's becoming the opposite this year and i think different angles need to be took moving forward and look at other drivers because the we rely so heavily on forecasts which hasn't actually happened yet.

And even when they do fall into place we still manage to go wrong.

We can have all the drivers in place and be left with a limpet low hanging around for days removing all cold from Europe with ease,

Yet we can have trop led events in zonal dominated pattern and still receive snow.

I think too much weight has been placed on drivers. When in reality It means very little. 

[MJB]

2 minutes ago, Severe Siberian icy blast said:

. It's all well and good removing posts when they don't read what you want but the reality is as a model output discussion

It is, so what is wrong with posting charts? So let people discuss the charts that are posted ???

[Tamara]

 Met4Cast

Based on a likely spontaneous tropospheric response to what looks like a very robust SSW reversal of -ve zonal winds upcoming, the timing of tropospheric switch to a falling angular momentum regime implies that returning polar jet energy faces a roadblock across higher latitudes and result in actually perpetuating blocking effects across the NH.

I say this from a purely diagnostic viewpoint of a macro scale synoptic response & objectively as to how such a blocked regime may play out - without regard to surface weather responses at any given geographical location. 

So protracted +AAM transport c/o +EAMT and tropical convection rossby wave driving has been incipient in initiating stratospheric diminution, and it could be that falling momentum heading into late winter & early Spring wavelengths augments  -ve AO/NAO synoptic responses.

The same was said in January of course & the nature of the briefest of reversals underwent a reflective u-turn which allowed the polar jet to return unencumbered as angular momentum fell back The circumstances this time are quite different & the sheer scale of the stratospheric diminution heading towards the start of Spring puts at least a preliminary question mark over the return of the vortex as a final warming event.

In turn it suggests a relatively lengthy period of fractured jet flow betwixt & between blocking structures

[Rain All Night]

15 hours ago, Rain All Night said:

12z deterministic runs, Thu 8th to Wed 14th (day 7)

We were due a reprieve, and at least in terms of "dry" and "potential", these runs are that. There is still room for doubt, since it is only in the last two frames that pressure really starts to build properly, and there's no guarantee that it will build in the way that the ensemble means below suggest that it will, but it's at least showing fairly uniformly across all five models shown here, though the UKMO leaving some of that low lingering to our east is an interesting variation.

12z ensemble means, Thu 8th to Sat 17th (day 10)

Since the full ECM ensemble is still loading more slowly than usual and I need an early night, I'll just take us up to day 10 this evening. It's a little odd seeing ECM as the least supportive model for a strong Scandi high tonight, given it has generally been the most enthusiastic about high pressure (be that to the northeast, northwest, or over the UK) for the past few days. At day 10, the mean surface pressure contours are just about coming from the Atlantic side. Still, it's just one run, and the GEM ensemble is looking very shiny indeed (albeit not stonkingly cold, for those that way inclined).

0z/6z deterministic runs, Thu 8th to Thu 15th (day 7)

It's the battle of the bulge with those southerly surface contours over the UK at day 7. I want to see them curving to the west to indicate resilience against the Atlantic influence, but only ECM and maybe GEM are really obliging with this.

0z/6z ensemble means, Thu 8th to Fri 23rd (day 15)

The ensembles still suggest that height rises will prevail against the Atlantic mid-month, but the signal for these heights to go on to become a significant presence to our northeast or northwest has weakened. From about 20th Feb onwards, the mean heights recede, and we begin to see frames showing the mean surface pressure contours tracing from the Atlantic to the British Isles once more.

Edited February 8 by Rain All Night

[StretfordEnd1996]

The GEFS 6z doesn't look horrendous in the latter stages - plenty of members flirting with -5 uppers including the control





The operational was one of the more milder in the run. I keep seeing this recently - the op just consistently seems one of the mildest members vs its ensembles - not sure why this is, it just seems to consistent recently. 

[Severe Siberian icy blast]

 MJB nothing at all, you're twisting my words.

Im allowed to vent i speak truth only. When ones obsess it misleads many into thinking this particular path is the outcome yet in reality a+b doesn't make 3. 

And if it can go wrong it will.

Many haven't seen a fake this winter

[IDO]

The GFS Control shows the cluster that gets the Alaskan ridge>Alaskan high>Arctic high direction of travel in the post D8 period:

This is our best hope based on the current NH pattern of getting some cold. But even then we have to wait until post-D14. The GFS op shows what happens with an Alaskan ridge>Alaskan high>Pacific wedge>Arctic high passage:

This has been cluster of late. Leading to a delay of several days with a UK high then retrogression post D16. That would take us close to March.

[Downburst]

 Daniel* It's interesting you think the position of these transient anomalies have such a linear response. It may be as simple as measuring wind flows from a particular direction. It is much more complex than that. In any case I was responding to the fact that there is a north and south Atlantic and trying to remove some doubt on a simple geographical fact.

[raz.org.rain]

This, of course, is very much cherry picked. It's going in the "will not happen" pile, but the fact that the models are suggesting it as a possibly in February is quite frankly ludicrous. It's reminiscent of those 15° isotherms we saw back in September. Something that was once laughable now growing closer to reality.

Probably the last thing we want to see, but evidence that spring is indeed on its way. In my opinion, it suggests a trend for the weather ahead.

 

[Blessed Weather]

3 hours ago, Severe Siberian icy blast said:

This year has been a joke in all honesty. It's all well and good removing posts when they don't read what you want but the reality is as a model output discussion, then airing frustration on hear surely is relevant particularly when it relates directly to the forcing drivers we've all obsessed over in depth then it's completely relevant.

Just a quick comment on this, assuming it's a comment about the moderation of the forum.

It's not a case of "removing posts that don't read what you want". The team fully understand the frustration for many of trying to get some proper wintry weather into the UK and have no problem with folk discussing those frustrations and the causes. But what we, the team, are trying to do is encourage that to happen in the appropriate thread and not in the Model Output Discussion thread. From comments, messages and reported posts we know there are many members that prefer to keep the Model thread 'clean' and to read about the latest output. And there are some members who aren't of a cold persuasion and are quite happy with this winter. We try to strike a balance for the benefit of the majority.

We therefore have the Model Banter and Emotions thread as well as the more general Moans, Ramps & Banter thread in the Winter Discussion area for folk who aren't happy with this winter and wish to sound off.

The Model thread guidelines - the link is at the top of every page - give clear guidance about posting in this thread.

I hope everyone understands.
Thanks.

[topo]

Isn't it extremely interesting that we are having the same weather set up that brought more than 1m of snow in the south of Norway, just one month later?

 This is 1st of January

 This is on Sunday

Is this something driven by global patterns or just pure luck?

[Lukesluckybunch]

Looking likely we will settle on a UK high..looking at the icon 

[Nick2373]

06z shows the road we are taking but there is so much scatter from the 18th i think anything goes, what the long range shows well they haven't been spot on really this winter to be honest.

i think we'll see a pattern change soon.

[Ali1977]

 Lukesluckybunch looking likely, and icon in the same sentence??  I’d wait for the rest of the runs first!! 

[Lukesluckybunch]

5 minutes ago, Ali1977 said:

looking likely, and icon in the same sentence??  I’d wait for the rest of the runs first!! 

Sorry ali..I was commenting on the icon alone..and yes better models on the way!