model discussion Model output discussion 11th July onwards

[Cambrian]

12z ECM operational run at 240h

 

Google dictionary definition of “kibosh”

- decisively end or reject (something).

"the presence of a submarine would kibosh the operation"

[Frosty.]

Of course I would love a very early  potent arctic blast like some of those GEFS 12z members but looking at the ECMWF 12z operational day 10..it’s heights to the south in the ascendancy which is clear when you flick between days 9 and 10…however, it’s hypothetical in that range isn’t it?  …my cold dream hasn’t been shattered on the basis of this unhappy ending!

 

Edited October 10, 2021 by jon snow

[Frosty.]

Here’s the day 10 ECMWF 12z operational / Ensemble mean comparison…. …erm, erm, yeah, I’ll take the mean thanks! 

 

[Allseasons-Si]

I present you the 18z control run....

...although it is at the bottom end of the pack....

but there does seem to be a growing confidence of heights building to our NW,but as with the NWP'S past days 6-7 the reliability drops considerably WATCH THIS SPACE.

later's.

[Cheshire Freeze]

On 10/10/2021 at 19:06, jon snow said:

P14 is a cracker, just waiting for Exeter to jump on-board the polar express now?!  …. If I had a wishbone  

  

Noticed some posts in other threads saying cold pooling doesn't get going until January. That's wrong, but an excusable assumption given the past few years we've seen Europe remain mild until fairly late (cold pooling trapped on the other side of the hemisphere). 

November is a perfectly viable month to catch winter in- it's just historically weather patterns do not play ball to allow cold air advection to our shores (Atlantic too energetic).

[Methuselah]

5 hours ago, CreweCold said:

Noticed some posts in other threads saying cold pooling doesn't get going until January. That's wrong, but an excusable assumption given the past few years we've seen Europe remain mild until fairly late (cold pooling trapped on the other side of the hemisphere). 

November is a perfectly viable month to catch winter in- it's just historically weather patterns do not play ball to allow cold air advection to our shores (Atlantic too energetic).

Aye, Aaron, I did initially fear that an Eastern European HP might pump warm Mediterranean air into Scandinavia and scupper our chances of early cold (much as it did last year); but that no-longer looks likely. GFS 00Z:

    

    

    

On the contrary, there's (touch wood!) plenty of cold pooling where we want it, and not even a hint of a Mediterranean 'heat pump'!

[mb018538]

1 hour ago, Ed Stone said:

Aye, Aaron, I did initially fear that an Eastern European HP might pump warm Mediterranean air into Scandinavia and scupper our chances of early cold (much as it did last year); but that no-longer looks likely. GFS 00Z:

    

    

    

On the contrary, there's (touch wood!) plenty of cold pooling where we want it, and not even a hint of a Mediterranean 'heat pump'!

Yep - plenty of cold there in November. Just as you can see 25c plus in April, there is heat available early in the year too.
It’s there, you just need the right setup to get it. As November is more often than not a zonal and typically autumnal month, it rarely materialises.

[damianslaw]

3 hours ago, mb018538 said:

Yep - plenty of cold there in November. Just as you can see 25c plus in April, there is heat available early in the year too.
It’s there, you just need the right setup to get it. As November is more often than not a zonal and typically autumnal month, it rarely materialises.

November is possibly the most difficult time to tap into any notable cold for sustained periods. Really need a easterly or north easterly deep seated such as happened in 2010. Northerlies usually bring fleeting episodes before toppled by heights unless associated with Greenland heights which are extremely difficult to achieve in November. Scandi highs tend to more likely but still fairly elusive.

I tend to associate cold in November with anticyclonic spell with high directly overhead. Night time minima can drop markedly and the weak sun struggles to raise daytime temps. 

[Man With Beard]

Long time no see. Work busy! First time in weeks I've had a chance to check the clusters. My view: an unsettled, windy, but reasonably mild final third of October beckons, with a small chance of a ridge building sufficiently across Europe to allow warmer air to push up from Iberia at times:

 

[MP-R]

On 11/10/2021 at 14:22, damianslaw said:

November is possibly the most difficult time to tap into any notable cold for sustained periods. Really need a easterly or north easterly deep seated such as happened in 2010. Northerlies usually bring fleeting episodes before toppled by heights unless associated with Greenland heights which are extremely difficult to achieve in November. Scandi highs tend to more likely but still fairly elusive.

I tend to associate cold in November with anticyclonic spell with high directly overhead. Night time minima can drop markedly and the weak sun struggles to raise daytime temps. 

That's why we struck gold in November 2005! Pretty much every type of weather condition was experienced that month - we can only dream for a repeat. To a lesser degree 2010 too, although there was no prolonged settled weather that month, just more severe cold at the end.

[Cambrian]

Wow, the 12z GFS op  at 192h is much more progressive than the 6z op run in deepening the low and bringing the UK and Ireland well and truly into the fray. That’s a better set up for a deeper more sustained feed from the northwest.

6z / 12z

 
 

Keeps the main centre of the low further south with no secondary low formation in the subsequent day or two as well, here at 216h

6z / 12z

 

[bluearmy]

Week 6/7 of the latest ec46 presents some potential …….

someone will no doubt find the detail on freely available data to show - whilst the back end of the 46 is not something to hang your hat on, it’s not a completely surprising set up it’s beginning to sniff 

[damianslaw]

Quiet in here this evening.. probably because the models are showing very standard fayre for the time of year.. which generally means nothing overly mild or cold.. becoming more unsettled. All a bit humdrum and uninspiring. 

[Ali1977]

16 minutes ago, bluearmy said:

Week 6/7 of the latest ec46 presents some potential …….

someone will no doubt find the detail on freely available data to show - whilst the back end of the 46 is not something to hang your hat on, it’s not a completely surprising set up it’s beginning to sniff 

Well the back end of Nov would be a nice place to start for proper winter type weather, if that’s what it’s showing!! I don’t think any prolonged “big freeze” can start much before then, albeit 2010s last week of Nov was pretty epic (even though I missed that, and all of the following Dec due to being overseas with work ).

I thought I’d check the latest CFS for the last week of Nov , just for fun, and it ain’t too bad a few charts for the week below!! 

 

 

Edited October 11, 2021 by Ali1977

[andymcpool]

2010?

[Tamara]

On 11/10/2021 at 22:30, bluearmy said:

Week 6/7 of the latest ec46 presents some potential …….

someone will no doubt find the detail on freely available data to show - whilst the back end of the 46 is not something to hang your hat on, it’s not a completely surprising set up it’s beginning to sniff 

This is a general response and not a personal one. Its simply based on responding to numerical modelling forecast extrapolations for very long distances ahead that trigger expectancy.

I  am sure that Week 6/7 will not be anything  exactly the same even down here where the now villainous Azores High (in the UK) still lurks close by to its natural home.

The stratospheric forecasts at x or y range simply echo these standard Autumn rossby wavelengths under a given forecasted tropical > extratropical propagation regime and attempt to give lagged and timeline related responses -  but all numerical models predictions are subject to large error on the basis that tropical convergence patterns and poleward momentum flux feedbacks between the troposphere and stratosphere cannot be predicted with any degree of accuracy several weeks/months  ahead.

Edited October 12, 2021 by Paul
Removed un-needed and unnecessary sniping.

[Frosty.]

I like the direction of travel from the longer term Gem 0z, becoming increasingly unsettled..and colder…veering towards meridional! 

 

 

Edited October 12, 2021 by jon snow

[Northwest NI]

On 12/10/2021 at 06:43, jon snow said:

I like the direction of travel from the longer term Gem 0z, becoming increasingly unsettled..and colder! 

 

 

The absolute (polar?) opposite of the direction of travel we’ve wanted for the last 6 months

Its that time of year.

Edited October 12, 2021 by Northwest NI

[Ali1977]

ECM is definitely pumping more WAA up into the Arctic at day 6 so imagine a more blocked outcome here, the GFS seems to be diluting that slightly over the last few runs. 

 

By day 7 the ECM is still pumping the warm air up into the Arctic, displacing the PV to the East. Possibly leading to a pretty potent Northerly later down the line!! 

Edited October 12, 2021 by Ali1977

[bluearmy]

I think @Tamara is attempting to put a lid on unjustified expectations which can quickly grow if a brake isn’t applied. as I wrote in my post, week 6/7 model output is not something to hang your hat on but simply to monitor as each subsequent ec46 run appears. What was of interest to me was that it reflected what some of the seasonals have been showing with higher than average mid Atlantic (possibly) greeny  anomolys and a lack of euro high anoms in tandem. 

Edited October 12, 2021 by Paul
Removed quote from post as the original post has been removed.

[Neil Harris]

Not for me, I like proper seasons, and for me that means winter starts in December.
It is October 12th, any late warmth, golden sunsets, cool misty mornings and opportunities for long walks is what I want the models to show me, weather like we had yesterday and is forecast for the rest of the week is perfect thanks.
Looking for this to last a few weeks yet.

Edited October 12, 2021 by Paul
Removed the quote from your post as it has been edited.

[mb018538]

Let's look at the models instead eh?

Sunday looks to be the last 'quiet' day before the Atlantic really starts to show it's teeth for the first time in quite a while!




Into next week and we start to see strong Atlantic lows with their associated wind and rain giving everywhere a good soaking:





As is normal for westerly based weather - western areas (higher ground especially) bearing the brunt of the wettest weather, with eastern areas seeing lower totals.






 

[damianslaw]

29 minutes ago, mb018538 said:

Let's look at the models instead eh?

Sunday looks to be the last 'quiet' day before the Atlantic really starts to show it's teeth for the first time in quite a while!




Into next week and we start to see strong Atlantic lows with their associated wind and rain giving everywhere a good soaking:





As is normal for westerly based weather - western areas (higher ground especially) bearing the brunt of the wettest weather, with eastern areas seeing lower totals.






 

Yes a return to more typical mid Autumn fayre into the new week. Atlantic comes back, wind and rain. The chart above for 20th shows a deep trough anchoring down into the UK, once it moves through we remain exposed to colder polar air with a strong ridge behind.

In the meantime generally very quiet and little going on.

[Cambrian]

The change to trough-influenced weather is bedded in at day 7 now on the ECM and GFS ops.

168h ECM / GFS

 

 

At 192h, the ECM elongates the trough, with a deep dig of cold air down its western flank, and plunges it all the way down to 40 degrees North, while the GFS does what it can often do and blows it up a bit more into a big round somewhat deeper low. 

 

 

As a result, by 216h, the ECM is maintaining good prospects for a sustained northerly behind the trough once it passes through, with high pressure trying to build into the gap between Greenland and Iceland.

 

 

I just wanted to say, I know that this time of year isn’t perhaps as much of a thrill as some other times, but there is nothing dull about this chart, nor the one at 240h, or the weather they would bring, with some good chilly air entrained down through the back end of what is now setting up as a Scandinavian trough. Very interesting Autumn weather.

240h / 240h T850

 

 

With the GFS at 216h, on the other hand, the low fills rapidly, high pressure pushes up from Spain over southern France and we’re into a mundane looking westerly with occasional frontal systems passing through. Big differences between the models by then. 
 

 

[Kentspur]

1 hour ago, Ali1977 said:

ECM is definitely pumping more WAA up into the Arctic at day 6 so imagine a more blocked outcome here, the GFS seems to be diluting that slightly over the last few runs. 

 

By day 7 the ECM is still pumping the warm air up into the Arctic, displacing the PV to the East. Possibly leading to a pretty potent Northerly later down the line!! 

The trouble is all that early relatively cold air that Eastern Europe has built up is now going to be blasted away if this occurs its not a good sign. +16 850HPA in late October is tragic for the Baltics/Poland etc. Goodbye cold pool. Tell me ECM day 10 was an outlier?