Model Output Discussion - early October

[jules216]

2 minutes ago, Catacol said:

Every chart tells a story but you are going to struggle to depress people on here with that 16 day mean. There is clearly no euro high, there is a strong Scandy anomaly which will aid with any wave 2 action keeping the strat vortex from descending too effectively, and that is hardly a raging low pressure anomaly off the tip of Greenland. In addition there is a suggestion of a cross polar ridge. Arguing about air source from a 16 day mean run is pointless...but I’d also suggest much more of an easterly air source over much of Europe than you are seeing. That is NOT a poor chart for winter if the long game is the one being played, and if it comes to pass like that then I’d suggest some long range seasonal forecasts are in trouble before the season even starts.

But as said already, details will be different when mid November actually arrives. Personally my optimism has grown over recent days.

Good for you, give me some of that optimism,no offense . I think the main differences are that for UK perspective is all about the huge build up to a possible 2 week cold snap if all teleconnections hold steady. As for us in continental Europe Novembers not long time ago were like winter months, see temperature anomalies for Novembers in 90s. What we are facing now is unprecedented spell of above average months, not only here in Slovakia but most of other countries as well nearby. November 2019 will not be an exception, as I have alluded to the fact that any reasonable cold source will most likely be close to USA/Canada then Scandi/Western Russia for example. I am missing that trigger low somewhere in central/eastern Europe to drag colder air. Without that we can hope for surface cold under -4 T850. Not saying GEFS will verify as they may not, but the trend is for warmer Europe, even ECMWF 46d agreed. Only average temperature departures were week 4 yesterday and weeks 2 and 3 were way above average for most of Europe. For me one month wasted aready, maybe for UK no worry at all as Novembe is rarely month where you get lying snow. 

[Catacol]

3 minutes ago, jules216 said:

Good for you, give me some of that optimism,no offense . I think the main differences are that for UK perspective is all about the huge build up to a possible 2 week cold snap if all teleconnections hold steady. As for us in continental Europe Novembers not long time ago were like winter months, see temperature anomalies for Novembers in 90s. What we are facing now is unprecedented spell of above average months, not only here in Slovakia but most of other countries as well nearby. November 2019 will not be an exception, as I have alluded to the fact that any reasonable cold source will most likely be close to USA/Canada then Scandi/Western Russia for example. I am missing that trigger low somewhere in central/eastern Europe to drag colder air. Without that we can hope for surface cold under -4 T850. Not saying GEFS will verify as they may not, but the trend is for warmer Europe, even ECMWF 46d agreed. Only average temperature departures were week 4 yesterday and weeks 2 and 3 were way above average for most of Europe. For me one month wasted aready, maybe for UK no worry at all as Novembe is rarely month where you get lying snow. 

Hehe certainly looks like November was a good month in Slovakia in the 90s! Early days to right off Euro cold for the coming November - maybe that Scandy anomaly can align usefully for you!

[knocker]

Well above average rainfall here. as well as elsewhere of course, for this month and the continuation of the frontal rain for the next 18 hours or so is not going to help matters, albeit it may become a bit patchy

http://www.met.reading.ac.uk/~brugge/CURR.html

 

Edited October 30, 2019 by knocker

[johnholmes]

38 minutes ago, jules216 said:

I disagree, its not a long fetch easterly anomaly at all where you drag Siberian air. Its more like southerly,south easterly where winds are being dragged from vicinity of Turkey! With polar vortex deciding to park in usual spot Greenland/Hudson Bay, Europe is left with limped Sceuro high and totally devoid of any reasonable cold. I think this couldn't be worse than GEFS 6Z output, but entirely plausible by recent winters standards. I know its a forecast for middle of November, but why we can't have an early visit from winter if Americans get in whenever with no issues in November. Another above average month beckons for most of continental Europe apart from UK or IE.

A word of caution using anomaly charts. They do NOT necessarily show any wind direction.

[shaky]

Nice cold north easterly setting in on ukmo 12z and gfs around 120 hours!!seems to be some consistency in regards to this northerly!!would rather take this than mild south westerlies in november anyday!! 

[Mike Poole]

Early 12z runs, at T144, ICON, UKMO and GFS:

UKMO and GFS more amplified and here T850s with GFS at T144, some cold air encroaching from the north:

Edited October 30, 2019 by Mike Poole

[knocker]

25 minutes ago, shaky said:

Nice cold north easterly setting in on ukmo 12z and gfs around 120 hours!!seems to be some consistency in regards to this northerly!!would rather take this than mild south westerlies in november anyday!! 

Bu all of this is transitory as this weekends trough tracks east and another arrives from the west in the fluid pattern

Edited October 30, 2019 by knocker

[SMU]

Enjoyable afternoon runs- 

Pretty cold relative to the time of year mid autumn. Still not quite cold enough  for widespread snow but its pretty on the eye.

GFS 12z goes from a Northerly then transitions via a slider to an Easterly although there could be many variations there ranging from mild to cold-

Lets get the Northerly 100% nailed first

UKMO looks the coldest in the 144-168 window-

Edited October 30, 2019 by Steve Murr

[booferking]

2 minutes ago, knocker said:

Bu all of his transitory as this weekends trough tracks east and another arrives from the west in the fluid pattern

Yea and hopefully that becomes more elongated and slides further south as time goes on.

[Mucka]

 

[knocker]

18 minutes ago, booferking said:

Yea and hopefully that becomes more elongated and slides further south as time goes on.

 

 

But the moral of the story is that it's a dangerous practice to select odd days in a mobile pattern, unless of course you deliberately want to misrepresent the output, and I'm well aware that nobody posting on here would stoop to this.

And Upstream developments appear to be having a knock on effect downstream

Edited October 30, 2019 by knocker

[Tim Bland]

Not bad for November ! Could be some wintry showers in Eastern areas... 

[LRD]

2 minutes ago, Mucka said:

 

I have to say I'm not a fan of anomaly charts unless they are looking at precipitation or temperature. Or both. Those pressure anomaly charts can be really misleading

[johnholmes]

2 minutes ago, LRD said:

I have to say I'm not a fan of anomaly charts unless they are looking at precipitation or temperature. Or both. Those pressure anomaly charts can be really misleading

Yes very true. They have to used very carefully.

[Methuselah]

Very close to being a November stonker:

[nick sussex]

I’m back from my hibernation! 

The time just flies , can’t believe we’re back to chasing those winter nirvana charts already .

So anyway a warm welcome to newer members who have joined and hello again to the old timers ! 

Just perusing the outputs , agreements of sorts on the overall pattern . 

A wedge of higher pressure is maintained to the north and ne, so this takes the jet track se through the UK .

Pressure looks like building further to the east later on with hints of a Scandi high.

One trend we have seen over the last few days , originally the outputs were reluctant to clear low pressure sufficiently se and had it slow moving over the UK . Now this gets further se allowing a colder shot from the north .

Also interesting is where the PV might end up in the medium term.

The purple blob of doom seems reluctant to set up shop over Greenland but staying further to the west .

 

 

Edited October 30, 2019 by nick sussex

[Mike Poole]

^ Welcome back nick!!

Just taking a look at the NH profile of the GEFS 12z, here at T240 (no point going further than this at the mo, given uncertainty) here's the postage stamps:

No consistently organised trop vortex, but what is consistent is lower heights on a WSW-ENE axis with uncertainty to the north and south.  

At same timescale strat is organised (stratobserve.com plot is for 0z though) 

Vortex consistently oriented NW-SE (blue) with pressure from the SW (red), key thing is how long we can keep these trop and strat vortices apart, this is a key issue for me as we go into November in what is already a season of big interest, and while the long range models may think they have it nailed, I think with so many variables in play a much wider range of possibilities including for a memorable winter is entirely possible, but like everyone else at this stage, I imagine, I'm struggling to pick a winner.  Look forward to the winter forecasts for those brave enough to make them...

Edited October 30, 2019 by Mike Poole

[Jordan S]

The longer term does look very interesting but the short term also has a lot to keep an eye on if ukmo is to be believed then very wet for southern England for Sunday and Monday with very strong winds for northern France basing it off the midnight run.. 

these southern sliders are difficult to forecast and have in the past given damaging wind gusts to France which is notable as these areas are far less prone to Atlantic storms I think it demonstrates quite well the jet perhaps behaving in an untypical way we all know that on here anyway.. one things for sure we are going to be very wet at times this weekend and next week but how wet is uncertain the GFS for example in its recent updates have taken the two deep lows further south with Sundays system only giving rain for the far south and the next system on Monday effecting France and staying to the south and keeping southern parts mostly dry.

 

The further northeast you are the drier it will tend to be in the next few days.. in the coming days I suspect the models will have an agreement on the tracks of the lows to the south by Friday.. Atleast we hope so. Most areas are obviously going to be very unsettled in the coming days. Sorry the ukmo charts are the midnight ones but tells the story nevertheless. 

Edited October 30, 2019 by jordan smith

[Tim Bland]

Better news from the CFS re the PV / strat winds.  I know it’s the CFS but it’s usually less volatile and more reliable when modeling the stratosphere.  All CFS members are now showing a reduction in wind speeds in the strat late Nov/early Dec with some indicating an SSW. Can’t recall a SSW this early, does anyone know when it last occurred late Autumn? 

[Mike Poole]

No comment re the ECM yet, it follows other models in the early part, but then this at T216:

With some minor latitude on anatomy, looks like a rabbit that has been given an enema! 

Edited October 30, 2019 by Mike Poole

[shaky]

3 minutes ago, Mike Poole said:

No comment re the ECM yet, it follows other models in the early part, but then this at T216:

With some latitude on anatomy, looks like a rabbit that has been given an enema! 

A cold ecm tonight from 96 hours onwards!!looking really forward to this seasonal feel!!a bit of frost and cold crisp days!!

[knocker]

Regarding the detail Sat > Mon the ecm is different to the gfs which merely emphasizes the uncertainty, albeit wet and windy will cover it in general

 

Edited October 30, 2019 by knocker

[Methuselah]

Nothing extreme in tonight's GEF 12Z ensembles; but, there seems to be a very weak warming signal, late on...? More likely to be random scatter...hopefully!

   

   

All in all, a bit ?

[Mapantz]

18 minutes ago, Tim Bland said:

Better news from the CFS re the PV / strat winds.  I know it’s the CFS but it’s usually less volatile and more reliable when modeling the stratosphere.  All CFS members are now showing a reduction in wind speeds in the strat late Nov/early Dec with some indicating an SSW. Can’t recall a SSW this early, does anyone know when it last occurred late Autumn? 

I'll look for the post when I'm home. Interitus made a post last year regarding the CFS and strat winds. It's not particularly good.

[SMU]

9 minutes ago, Mapantz said:

I'll look for the post when I'm home. Interitus made a post last year regarding the CFS and strat winds. It's not particularly good.

I replied to Matt Hugo on twitter who posted it as well

This is the 00z & last weeks CFS mean

So in isolation that purple CFS run is a bit rogue- however in my notes from last year the CFS always had stark warmings however the lead time was 4-6 weeks & eventually verified about 2 months down the chain-

The only thing noteworthy here is the lead time is shorter circa 4 weeks so at this stage its work making a mental note to self-

( There have been minor warmings forecast but that one is a major SSW )

Heading back to the models I think we still need to better describe the meaning of when people post Zonal & mobile - the reality is its always going to be mobile somewhere it should be relating to the UK, so the upcoming weather for the next 10 days I guess would be classed Cold zonal on a NW > SE axis - even that could be misleading though because post the weekend if you live in the NE the atlantic may not get close again for post 8-10 days...

@Tim Bland 2009/2010 was a good example of November warming downwelling - Also 1981

 

S

Edited October 30, 2019 by Steve Murr