Model Output Discussion - Deeper into Autumn

[Anthony Burden]

Morning all,ECM/GFS crucially all about 120 hrs /144 hrs showing the high pressure building from the south and transferring to the east holding it’s ground and then bingo Huge Scandinavian/Russian high taking over.Low pressure will try and push up to effect southern parts at times,over time with temperatures dropping this could set up possibly some of the white stuff,all of course if all goes to plan.Long time since I have seen such a promising winter set up for December.

[Mike Poole]

Pages and pages to get through this morning!  Glad I didn’t watch the pub run yesterday!

ECM perfect this morning, and well backed up by ensembles.  Here’s op and mean anomalies T240:

I have to say, given the ensembles are 51 runs, and the anomaly plot is therefore diluted by virtue of different individual runs having the block in slightly different places (hence it is more pink and less red than the op anomaly chart), it is a very strong signal and there looks now a high chance of the block being situated and orientated in a way to bring in a really decent, prolonged easterly.  So if it isn’t cold to start with, it will soon get colder.

Just a word on the op runs.  At the timescales we are interested in at the moment, the op runs will be churning out runs within a large envelope of uncertainty.  You can see roughly what that is from the ensembles, clusters etc.  So just because the 18z was a bad one doesn’t mean GFS has flipped or anything, it could be any of the other models that roll bad dice next time.  So while it is interesting to watch the individual runs come out, it is best done with an idea in the head of what that envelope of uncertainty currently is.  If an op run throws up a solution way outside that envelope, then take note, otherwise just expect a few good ones, a few bad ones and the occasional peach like the ECM op this morning - until the uncertainty reduces and we can see the way forward.

Edited November 24, 2022 by Mike Poole

[Mike Poole]

ECM clusters T192-T240:

Well, a full house of red borders = blocked, well = very blocked!  This illustrates what I said in the last post about the block being in slightly different places, you can see that on the 5 clusters, but very much variations on a strong theme now.  T264+

In the extended timescale, a couple of other options come into play, on clusters 2 and 4 retrogression, cluster 5 (7 members) brings in the Atlantic, unlikely, I would suggest.

[Liam Burge]

14 minutes ago, Mike Poole said:

Pages and pages to get through this morning!  Glad I didn’t watch the pub run yesterday!

ECM perfect this morning, and well backed up by ensembles.  Here’s op and mean anomalies T240:

I have to say, given the ensembles are 51 runs, and the anomaly plot is therefore diluted by virtue of different individual runs having the block in slightly different places (hence it is more pink and less red than the op anomaly chart), it is a very strong signal and there looks now a high chance of the block being situated and orientated in a way to bring in a really decent, prolonged easterly.  So if it isn’t cold to start with, it will soon get colder.

Just a word on the op runs.  At the timescales we are interested in at the moment, the op runs will be churning out runs within a large envelope of uncertainty.  You can see roughly what that is from the ensembles, clusters etc.  So just because the 18z was a bad one doesn’t mean GFS has flipped or anything, it could be any of the other models that roll bad dice next time.  So while it is interesting to watch the individual runs come out, it is best done with an idea in the head of what that envelope of uncertainty currently is.  If an op run throws up a solution way outside that envelope, then take note, otherwise just expect a few good ones, a few bad ones and the occasional peach like the ECM op this morning - until the uncertainty reduces and we can see the way forward.

It's not just a small or weak block either. GFS showing a 1060mb high with very cold air just to our west and even getting into the country by the end of the run. Not sure what would shift that high to be honest. Definitely an interesting time to be model watching! I think we'll see a change in the Met's outlook presto.

[Ice Day]

Some great posts this morning following the overnight runs.  As @CreweCold and others have said, this potential set up really does scream longevity and the positive on this occasion is that the transition looks fairly smooth and isn't overly complicated and reliant on shortwaves all over the place.  That said, the UKMO does show a different route, and whilst I don't think that will be the final outcome, it cannot be discounted.

I like to keep an eye on the GFS Ensemble graph when a possible cold spell is on the way to see if the cold rows are increasing, so this is from the 0z this morning.

Nothing overly severe showing yet but a definite trend for something colder from 240.  Let's see if that increases as the days tick by!  Superb model viewing whatever happens.

[Singularity]

The important first step is now at a weeks lead time - the one that determines whether we start out with an easterly drift or westerlies prior to whatever advances north/west the high makes down the line.

For what it’s worth I believe even the UKM 00z is just about slowing the polar jet sufficiently for the continental drift, judging by the low dangling down west of the Azores. The deep one west of Iceland therefore looks to be a stalling, amplifying feature rather than the sort that steamrollers the downstream pattern.

Past experience tells me to wait a couple more days before calling it for the first step.

Regardless of how that turns out, longer-term possibilities should keep us on our toes as the blocking high looks well placed to drive strong wave breaking on the polar vortex. I’ve yet to see enough of a wave-2 imprint in the stratosphere to really raise my interest on that aspect yet, but that *may* start to show up in due course for sometime 2nd half Dec. Much water to pass under the bridge yet.

[Kentish Snowman in Yorks]

13 minutes ago, Ice Day said:

Some great posts this morning following the overnight runs.  As @CreweCold and others have said, this potential set up really does scream longevity and the positive on this occasion is that the transition looks fairly smooth and isn't overly complicated and reliant on shortwaves all over the place.  That said, the UKMO does show a different route, and whilst I don't think that will be the final outcome, it cannot be discounted.

I like to keep an eye on the GFS Ensemble graph when a possible cold spell is on the way to see if the cold rows are increasing, so this is from the 0z this morning.

Nothing overly severe showing yet but a definite trend for something colder from 240.  Let's see if that increases as the days tick by!  Superb model viewing whatever happens.

I think I may have asked this before but do you have a link for these graphs?  I assume you can adjust them for your own location?

Thanks

[Ice Day]

6 minutes ago, Kentish Snowman in Yorks said:

I think I may have asked this before but do you have a link for these graphs?  I assume you can adjust them for your own location?

Thanks

I think you ask me this question annually Kentish 

No problem, I get them from Meteociel.  If you go to the GEFS Ensemble page, there's an option called 'paintings'.  Just select your location, then voila!

[Frosty.]

The day 10 ECMWF 0z ensemble mean is the best I’ve seen so far in recent days?!…increasingly blocked and colder sums up the mid / longer term outlook I think! …anyone agree?

 

 

[Nick F]

3 minutes ago, jon snow said:

The day 10 ECMWF 0z ensemble mean is the best I’ve seen so far in recent days?!…increasingly blocked and colder sums up the mid / longer term outlook I think! …anyone agree?

 

 

Yep, think coldies should be fairly happy with the outlook this morning as we head into early December. A look at the GEFS mean days 12-16 shows widespread cold over northern Europe including the U.K. the 500mb and MSLP mean supports this too, looks like a pattern that could lock in for while, as hinted in my winter forecast.

No doubt we will have more wobbles over the next few days from the operationals, after day 10 we can expect this, taunting us with  a quick return to Atlantic mild SW'erlies as the models try to break down the blocking too quick, but the overall theme of the way the patterns are progressing from ensemble guidance are on the right track, but patience required, don't expect a quick route to deep cold and snow potential from the east - it could take a while for the pattern to evolve towards this potential.

[GSP]

Well the models are certainly playing with emotions at the moment, and can see more of that coming.

Everything is still too far out however, but something’s up what with all the changes going on.

As we stay indoors more this time of year, love it when there is so much interest and here’s to a decent 6z.

 

[sheikhy]

Beware the icon!!!much flatter at 120 hours in the atlantic!!it has spoiled the party before just saying!!!

[booferking]

4 minutes ago, sheikhy said:

Beware the icon!!!much flatter at 120 hours in the atlantic!!it has spoiled the party before just saying!!!

Absolutely not very little change?

[bluearmy]

2 hours ago, CreweCold said:

The angrier the PV gets over that side of the hemisphere the more violent its ultimate disintegration will be. We could be looking at late Dec for part deux.

Think of a bike wheel spinning faster and faster and then think of what happens when you put a stick in it. Bits of stick go flying everywhere…in this case bits of PV would be the thing flying everywhere. Hopefully in a way that ultimately benefits us.

Come on- you know that one chunk would end up just sw of Greenland …….but if the leviathan of a siberian ridge sets up as it looks like it might then even that may not be a bad thing! 

59 minutes ago, Mike Poole said:

ECM clusters T192-T240:

Well, a full house of red borders = blocked, well = very blocked!  This illustrates what I said in the last post about the block being in slightly different places, you can see that on the 5 clusters, but very much variations on a strong theme now.  T264+

In the extended timescale, a couple of other options come into play, on clusters 2 and 4 retrogression, cluster 5 (7 members) brings in the Atlantic, unlikely, I would suggest.

Yes, too many clusters to bother too much with analysing that suite 

One thing nagging at me currently is the thought that the euro trough will end up too far west and leave nw europe in a flow without E european air source involvement 

[TSNWK]

2 minutes ago, bluearmy said:

Come on- you know that one chunk would end up just sw of Greenland …….but if the leviathan of a siberian ridge sets up as it looks like it might then even that may not be a bad thing! 

Yes, too many clusters to bother too much with analysing that suite 

One thing nagging at me currently is the thought that the euro trough will end up too far west and leave nw europe in a flow without E european air source involvement 

Morning.  How are the pressure trend charts you shared yesterday looking?

And yes to your point on  euro trough there is annoying less cold air being scooped up by the back door.. 

[feb1991blizzard]

2 hours ago, CreweCold said:

The angrier the PV gets over that side of the hemisphere the more violent its ultimate disintegration will be. We could be looking at late Dec for part deux.

Think of a bike wheel spinning faster and faster and then think of what happens when you put a stick in it. Bits of stick go flying everywhere…in this case bits of PV would be the thing flying everywhere. Hopefully in a way that ultimately benefits us.

was thinking of this analogy the other day.

[Methuselah]

Good morning, folks... if the 00z ensembles are anything to go by, we're in for another day of mixed emotions:

    

[bluearmy]

18 minutes ago, TSNWK said:

Morning.  How are the pressure trend charts you shared yesterday looking?

And yes to your point on  euro trough there is annoying less cold air being scooped up by the back door.. 

comparing todays 00z with yesterdays 06z shows little change (mean charts here) - yesterdays 00z with it’s notable griceland  mean upper ridge hasn’t returned 

    

Edited November 24, 2022 by bluearmy

[northwestsnow]

De Bilt..

[Ali1977]

1 minute ago, northwestsnow said:

De Bilt..

Looks good to me, as does this.

[northwestsnow]

Just now, Ali1977 said:

Looks good to me, as does this.

Yesterday's mate but yeas ,I saw that chart and thought yes please..

[Row w]

If that doesn't say chilly  I don't know what does, it'll be interesting to see what the gfs 06z has in store...

[sheikhy]

Gfs 06z still not quite there at 168 hours like ecm!!should get there in the end!!

[Metwatch]

Still some decent looking means this morning from the 00z suites.

SIngle runs will obviously flip between different solutions but in the broad scheme of things, a decent amount of blocking looks to be developing later next week.

Need to look out for the Atlantic, and not underestimate its power in flattening things out.

Edited November 24, 2022 by Metwatch

[TSNWK]

06z Gfs very consistent at 168 compares with 00z 

Could be OK:)