model discussion Model output discussion - the final third of Autumn

[Met4Cast]

The current flatter pattern appearing on the models is no surprise to anyone who has been looking at the bigger picture & not following every GFS Deterministic run. 

The Det has been consistently in the cold outlier camp and was for several days on the trot, there was never much support from the GEFS or the EPS, it was clear from the start that the GFS Det was on it's own, possibly over-reacting to the emerging MJO phase 4-5-6 signal, although latest MJO forecasts show that signal is pretty much dead now which I suspect is why the GFS Det has also dropped the idea of significant blocking. 

Uncertainty now lies in where exactly high pressure will setup, a wave break NEwards across the UK suggests a period of settled weather for a time, but perhaps turning more unsettled/zonal later on in the forecast period. This puts up a ridge into the Uruals/Russia putting pressure on the vortex, but probably not enough to do much damage to the rapidly strengthening SPV.

My hope is that any zonal/Atlantic progression will be limited, wettest in the N driest in the S type affair, forecasts suggest a continued disconnect between the Strat/Trop for the time being, but if this doesn't last and we see a connection going into December then it might be a pretty big nail into winters coffin.

In short, no notable cold spell in the second half of November, there never was unless you were only looking at the GFS Det.

[carinthian]

Morning all, 12 c uppers today at 850mb level in the Eastern Alps and it feels it ! Precious snow melting away just like those cold winter charts shown only 48 hour ago. The latest chart below from UKMO does show some much colder air moving into Eastern Europe and encroaching closer to Austrian Alps early next week. Those in Blighty may at least begin to feel some late Autumn chill for a couple of days or so.

C

[Kirkcaldy Weather]

Much better set of ensembles from the 00Z GEFS toward the possible easterly I’d been focusing on (these are just some showing there’s others that have a similar pattern)  and I got flashbacks to the setup of the 2018 beast *note I’m referencing how it developed not that we are headed for anything of that severity

If you check the archive charts you’ll see what I’m meaning

 

[bluearmy]

1 minute ago, Kirkcaldy Weather said:

Much better set of ensembles from the 00Z GEFS toward the possible easterly I’d been focusing on (these are just some showing there’s others that have a similar pattern)  and I got flashbacks to the setup of the 2018 beast *note I’m referencing how it developed not that we are headed for anything of that severity

If you check the archive charts you’ll see what I’m meaning

 

The gefs late on are quite different to previous suites and have limited support from the eps and geps. Caution!! 

[Anthony Burden]

Morning all,GFS 06z rolling out still playing with options in guess what’s next.as mentioned yesterday

keep to max 144 hrs..Their take high pressure Scandinavia drifting slowly east keeping U.K. under its

influence with low pressure to southeast wind flow from easterly direction.Temperatures very uncertain 

my take on the cold side next week we shall see.

[Froze were the Days]

ECM looks woeful...goes flat as the proverbial witches at D9-10, little of anything of note other than a brief easterly (for a change) but that's mildish.

Edited November 10, 2021 by Froze were the Days

[Frosty.]

The longer term ECMWF 0z ensemble mean looks pretty flat with a north / south split…broad brush of course as it’s the mean!  

[carinthian]

21 minutes ago, Anthony Burden said:

Morning all,GFS 06z rolling out still playing with options in guess what’s next.as mentioned yesterday

keep to max 144 hrs..Their take high pressure Scandinavia drifting slowly east keeping U.K. under its

influence with low pressure to southeast wind flow from easterly direction.Temperatures very uncertain 

my take on the cold side next week we shall see.

Think you may be right. Already , latest GFS starting to show some resistance to activity in the Eastern Atlantic in the upper air pattern .

C

[Methuselah]

So, following a few days' excitement, things appear to have returned closer to what one expects for November? That said, mild weather with a few frosty/foggy nights can be most exhilarating. It's a matter of taste!

    

    

    

It would keep a lid on fuel bills too. And that's something!

PS: I forgot to add that mid-November's weather has no influence (or, at any rate, we can't see one!) on the upcoming winter?

Edited November 10, 2021 by Ed Stone

[booferking]

2 hours ago, Met4Cast said:

The current flatter pattern appearing on the models is no surprise to anyone who has been looking at the bigger picture & not following every GFS Deterministic run. 

The Det has been consistently in the cold outlier camp and was for several days on the trot, there was never much support from the GEFS or the EPS, it was clear from the start that the GFS Det was on it's own, possibly over-reacting to the emerging MJO phase 4-5-6 signal, although latest MJO forecasts show that signal is pretty much dead now which I suspect is why the GFS Det has also dropped the idea of significant blocking. 

Uncertainty now lies in where exactly high pressure will setup, a wave break NEwards across the UK suggests a period of settled weather for a time, but perhaps turning more unsettled/zonal later on in the forecast period. This puts up a ridge into the Uruals/Russia putting pressure on the vortex, but probably not enough to do much damage to the rapidly strengthening SPV.

My hope is that any zonal/Atlantic progression will be limited, wettest in the N driest in the S type affair, forecasts suggest a continued disconnect between the Strat/Trop for the time being, but if this doesn't last and we see a connection going into December then it might be a pretty big nail into winters coffin.

In short, no notable cold spell in the second half of November, there never was unless you were only looking at the GFS Det.

Very bullish but fair play of right,  im definitely not rulling out anything for second half of Novemeber and still favour a cold spell in some shape or form Mjo only one player in the cog. 

[sebastiaan1973]

1 minute ago, booferking said:

Very bullish but fair play of right,  im definitely not rulling out anything for second half of Novemeber and still favour a cold spell in some shape or form Mjo only one player in the cog. 

There is some support from EC46 for a cold 3 decade of november.

[booferking]

1 minute ago, sebastiaan1973 said:

There is some support from EC46 for a cold 3 decade of november.

And the last gefs looking more blocked again along with metoffice i wouldnt rule it out.

[Met4Cast]

On 10/11/2021 at 11:49, sebastiaan1973 said:

There is some support from EC46 for a cold 3 decade of november.

Perhaps, although looking at the forecast for the current period from two weeks ago

vs the very latest forecast for the current period

It's clear 2 weeks out the model isn't particularly accurate, and from what I can remember of last year tends to have a bias towards Mid Atlantic/Greenland blocking. 

[Cold Winter Night]

The reality of this moment is that nothing special is going on, and that doesn't have to be a bad thing.

We don't have very strong forcings in any direction, other than common seasonal changes.
MJO is quiet, no ongoing SSW, no real Strat-Trop coupling etc.
The Troposhere is free to do what it wants for now, so to speak, and there is lots for us to learn about the atmosphere's behaviour.

In think this is reflected in this morning's EPS clusters 8-10 days out:

Cluster 1 is more meridional and blocked (although not where we would like it).

Cluster 2 is more zonal/Euro High-ish in our part of the world, although it has more blocking in the Arctic near Alaska.

If the atmosphere moves towards a meridional pattern, there is not much in the way for that, but if it moves towards a seasonal zonal pattern, there is not much hindering that either.
Although I personally think that the calm situation will allow more meandering of the jet streams, perhaps leading to a blocking episode in a few weeks time.

We'll just have to wait and see and practice patience (and that's always a tough one for winter fans).

[Ali1977]

So with all the signals moving away from a colder mid- late Nov will the METO long range revert today, or monitor for a few days do you think!! Or are they correct

Edited November 10, 2021 by Ali1977

[sheikhy]

I mean for the ec46 to be incorrect at just a week or two out would be a shambles!i get it if it was just the odd ec46 run that was goin for height rises but its been showing these blocky forecasts for quite a number of runs now!!!always better off looking at the normal gfs ecm and ukmo!!the only positive i can take right now is this big norwegian/scandi high!hopefully we can get an upgrade and push heights further west or keep the atlantic away for as long as possible!!!apart from that it is looking very bleak!!!

[SqueakheartLW]

Some nice BOOM charts from the GFS extended run today. All cold. Ordered from least cold by 850hpa temps to coldest

P13     +534 hours     850hpa temp -10.5C

BOOM !!!

P13 again     +834 hours     850hpa temp -11.0C

BOOM BOOM !!!

P29     +828 hours     850hpa temp -11.0C

NICE !!!

P16     +560 hours     850hpa temp -11.3C

BOOM !!!!!

P22     +534 hours     850hpa temp -12.7C

This one is a good BOOM !!! chart but the last one is my favourite one

P07     +744 hours     850hpa temp -15.8C

BOOM !!! BOOM !!! BOOM !!! I'm BANKING this one right now, BOOM !!!

[Met4Cast]

The MJO isn't providing any forcing and currently neither is the stratosphere, although the 06z GFS is slightly more keen for a connection between the strat/trop than recent runs, but we'll see how that develops in the coming days, at the moment the strat/trop is de-coupled. 

Maybe the AAM can give us some guidance?

We've recently seen a brief spike in AAM off the back of a +FT event, although not particularly strong, the up-coming HP event across the UK and into Scandi is likely a result of the brief +AAM spike coupled with a well timed atmospheric wave break in the Atlantic, the HP looks likely to end up over Scandi/Russia temporary putting pressure on the SPV, we see this with increased wave 2 activity in the models, albeit unlikely to see much in the way of disruption, a few more of these events could well do the trick.

For the UK, a rather dry outlook with high pressure pushing over the UK > NE towards Scandinavia, scope for a brief easterly early next week albeit unlikely to be particularly cold, we could see some fairly foggy/frosty nights. 

Going forward into the later part of the month, declining AAM could mean we see a period of westerlies, Atlantic driven weather albeit probably rather weak given lack of Strat/Trop coupling combined with above average SST's across the entire basin putting a bit of a limiter on any explosive cyclogenesis potential. 

Rather boring all in all in terms of our weather for probably much of the month. 

 

Edited November 10, 2021 by Met4Cast

[IDO]

Looking familiar to Nov 2020 with the NH pattern (mid-Nov forecasts):

2020> 2021>

This has been a recurring theme so no reason to think anything will change soon with no strat>trop linkage and MJO remaining quiet, as it was much of last winter. Without tropical forcing, we saw last winter a quiet Pacific, we do not get those standing waves and have to rely on wedges from the Azores/Pacific, combined with the troughing to our south, to make something interesting, with the odd Atlantic plume. 

Interesting to see how long this underlying pattern maintains and why it is prevalent?

[Cambrian]

There are some colder looking charts knocking about beyond the edge of the reliable timeframe in days 7-10. 

The 0z GEM operational run takes this at 144h, pretty much the same as the other models, with the UK and Ireland at the meeting point of high pressure to our southwest and east….

To this at 240h, with a deep low in the northern North Sea and an unsettled northwesterly incoming on a good track down from Iceland. Plenty of scope for further southward movement from there too. 

 

The GEM day 7-10 evolution is every bit as credible as that shown in the other models, such as the 0z ECM op, shown here at 144h and 240h.

 

The main difference between the two, is that the GEM, like the JMA from yesterday for 264h, develops a deeper Aleutian low and keeps it to the south of the archipelago, whereas the ECM (and GFS at 6z) build a high directly to the south of Alaska. Like I intimated last night, it’s not all one-way traffic with the models at the moment, and these are fine margins, just beyond the more secure timeframe. The main models could quite easily readjust and it wouldn’t surprise me one bit if it turns out cold and changeable by the end of next week.

[swfc]

Ive been cooling my powder and at the same time been posting fi charts. Tbh looking at all the factors eqbo, la Nina, sun spot activity, sst, soi, and the enso I can't see anything giving the UK a cold late novber 

Front loaded winter is still my choice but I think Novber is done. Enjoy your day  and remember "were all Wednesday arnt we wi",,

 

 

 

 

 

[Methuselah]

And, here (just to bring us all back down to Earth) is the Met Office's take on the models:

 

[Ali1977]

No comments on this op run, maybe the above video had diminished the small chance of it happening . Wait for the GEFS, the last 3 runs have increased FI blocking opportunities so let’s see if that goes to 4!! 

[Cambrian]

Voila! Or as my French mate who plays in the orchestra would say - Viola!

GFS 12z operational run for day 12 (288h)

 

Alright, I know it’s day 12, two days later than the 0z GEM, but it has similar evolution and even better amplification into southern Greenland. I’ll be looking for support in the ensemble (sorry).

[Cold Winter Night]

In the reliable timeframe GFS 12z Op has little to offer.

In deep FI, it keeps toying with (transient) Atlantic ridging and lowering heights in Europe.

Also interesting to see a cross-model Arctic High from +120h onward, in contrast to last year, as shown in @IDO's post.
Something to keep an eye on.

3 hours ago, IDO said:

Looking familiar to Nov 2020 with the NH pattern (mid-Nov forecasts):

2020> 2021>