Model Output Discussions 12z 01/09/2016

[Ali1977]

4 minutes ago, fergieweather said:

You'll have seen the 2m temp and PPN anomalies from EC Monthly posted above (via Hungarian Met Service). The temperature anomalies weaken substantially after week 2 and are thus of limited significance thereafter, whilst conversely, 500hPa GPH anomalies continue leaning towards +ve heights to the NW of the UK throughout November. However, bear in mind that nearer-term, forecast confidence is low on outcomes beyond circa 4th November, with a widening synoptic spread having emerged in the 00z EC ENS beyond 1st week or so of the month (albeit underpinning a continued theme of temperatures a bit below normal). Glosea favours those -ve temp anomalies to generally remain this month, with -ve AO/NAO considered by UKMO the more likely outcome onwards into early winter. But as repeatedly stressed, respective high-low centre(s) positioning remains very low confidence (& ditto re possible strat-related matters late Nov and/or early Dec) and consequently so do the weather outcomes for the UK. So in short, no confidence can really be expressed for now beyond week 1 of November.

Great post Ian, stops plenty of speculation out in FI Atleast. Still looks ok for coldies though, compared to the last few years wash outs - I imagine those who have been flooded lately will be particularly happy with the current set up.

[knocker]

And to add to the above

As Sidney said this morning, "bring it on!!"

 

Edited October 28, 2016 by knocker

[karlos1983]

To add to the above....

" However, bear in mind that nearer-term, forecast confidence is low on outcomes beyond circa 4th November" 

[Ali1977]

4 minutes ago, karlos1983 said:

To add to the above....

" However, bear in mind that nearer-term, forecast confidence is low on outcomes beyond circa 4th November" 

Yeah this bit is important, I wonder where and why that is - the low spinning out of Greenland maybe, and to which way it travels. 

I mean, this could still be possible !! 

Edited October 28, 2016 by Ali1977

[Frosty.]

20 minutes ago, knocker said:

And to add to the above

 

As Sidney said this morning, "bring it on!!"

 

Not according to the GEFS 6z mean, it looks like becoming progressively colder with ppn turning more wintry, especially on hills and night frosts becoming widespread out to mid Nov and beyond..poles apart from the mild atlantic driven dross this time last year.

Edited October 28, 2016 by Frosty.

[karlos1983]

Many options on the table at the turn of mid month. None of which seem to indicate a return to Atlantic LP systems sweeping in.

 

Edited October 28, 2016 by karlos1983

[fergieweather]

39 minutes ago, knocker said:

And to add to the above

As Sidney said this morning, "bring it on!!"

 

Just a note about interpretation of the anomaly fields in EC Monthly. When these (eg 2m temp fields) resort to nil/clear areal signal, this should be taken to mean there's 'no useful signal' that departs from the model climatology. It does *not* mean, de facto, that a signal reflects no potential for milder/colder than average conditions; merely that we should read it as the signals having weakened to such an extent as to no longer offer any useful steer away from climatology. Some people seem to read these 'nil' signals - such as when emerging after an earlier phase showing -ve temp anomalies - as thus meaning it turning 'milder'. Whilst that could of course be the ultimate outcome (especially if other model parameters are suggestive of that), it does not mean that result is being actually shown by the anomaly itself.

[Ali1977]

3 minutes ago, karlos1983 said:

 

This looks nice and seasonal but nothing really cold. I guess maybe 9-11c down south and 7-9 up North,  but temps nearer freezing in sheltered spots away from towns on a night if sky's clear. Would be happy with that, Atleast the cold will be in place in Europe and the North ready for us if the set up falls favourable. 

[Frosty.]

3 minutes ago, Ali1977 said:

This looks nice and seasonal but nothing really cold. I guess maybe 9-11c down south and 7-9 up North,  but temps nearer freezing in sheltered spots away from towns on a night if sky's clear. Would be happy with that, Atleast the cold will be in place in Europe and the North ready for us if the set up falls favourable. 

Yes Ali it's the November trend which has got my interest and I'm sure all the coldies with temperatures expected to be below average for most of the time..I'm expecting plenty of cold eye candy charts in the days and weeks ahead.

[Glacier Point]

14 minutes ago, fergieweather said:

Just a note about interpretation of the anomaly fields in EC Monthly. When these (eg 2m temp fields) resort to nil/clear areal signal, this should be taken to mean there's 'no useful signal' that departs from the model climatology. It does *not* mean, de facto, that a signal reflects no potential for milder/colder than average conditions; merely that we should read it as the signals having weakened to such an extent as to no longer offer any useful steer away from climatology. Some people seem to read these 'nil' signals - such as when emerging after an earlier phase showing -ve temp anomalies - as thus meaning it turning 'milder'. Whilst that could of course be the ultimate outcome (especially if other model parameters are suggestive of that), it does not mean that result is being actually shown by the anomaly itself.

I'd echo that. 

The week 3 500z anomaly pattern remains similar to the week 2 and 4 pattern, so interpretation of a mean 2m temp value should be based on this and not model-based projection. I would not suggest that the week 3 value is average as suggested in the tweet, particularly as we've seen models begin to drop systems underneath the block, increasing a NW-SE tilt to the upper flow.

Worth also noting that the EC extended run intensifies the -NAO / -AO at the end of November / start of December.

Edited October 28, 2016 by Glacier Point

[fergieweather]

1 minute ago, Glacier Point said:

Worth also noting that the EC extended run intensifies the NAO / AO at the end of November / start of December.

Yes, quite so - we were just discussing that at work. It'll be interesting to see if that tentative signal and associated 'dip' in 850 temps late month is bolstered in further output.

[Hocus Pocus]

Fascinating stuff readiing how the pros are looking at this going forward and the insight into the inner workings of the MetO. Sorry just realised I'm off topic.

[phil nw.]

There has been some recent interesting and informative posts unfortunately interspersed by some rather silly and off topic ones which have been removed.

Please keep to model discussion so to keep this thread useful reading for everyone.

Many thanks.

[Frosty.]

9 minutes ago, fergieweather said:

Yes, quite so - we were just discussing that at work. It'll be interesting to see if that tentative signal and associated 'dip' in 850 temps late month is bolstered in further output.

That would be a huge contrast to late autumn / early winter last last year which was a nightmare for coldies, fingers crossed! Anyway, one step at a time, the models show a gradual change next week to colder air from the north which is a good start.

Ps.great to see GP posting, welcome back

Edited October 28, 2016 by Frosty.

[Paul_1978]

15 minutes ago, Glacier Point said:

 

Worth also noting that the EC extended run intensifies the -NAO / -AO at the end of November / start of December.

Right when it starts to matter... 

[Matthew.]

13 minutes ago, Frosty. said:

That would be a huge contrast to late autumn / early winter last last year which was a nightmare for coldies, fingers crossed! Anyway, one step at a time, the models show a gradual change next week to colder air from the north which is a good start.

Agree Frosty. If the ECM 0z is to be taken for next Friday that keen NW wind will be a real shock to the system with temps close to high single figures, wind-feel maybe only 4c

Edited October 28, 2016 by Matthew Wilson

[fergieweather]

26 minutes ago, Paul_1978 said:

Right when it starts to matter... 

....but do bear in mind the inevitably low confidence at that sort of lead time. There's enough 'issues' to unravel in the nearer-term medium range... albeit the broad sort of blocky/slowly-progressive pattern anticipated through first 2 weeks of November is favoured to *probably* persist thereafter. Key word 'probably'.... :-)

[Ali1977]

12z looks pretty similar to the last run on bonfire night , another decent looking Greeny block forming - lets see how it plays out. 

[Ali1977]

Great chart, -12c 850s in towards Oslo 

[Barry12]

Very cold air not too far away...

Edited October 28, 2016 by Barry95

[winterof79]

10 hours ago, winterof79 said:

The big finger of heights across the pole nearly splitting it,how refreshing to see these synoptics remaining.Only a matter of time before the cold entrenches somewhere in Europe I feel

GFS 12z says it's us for for the cold on this run.

[northwestsnow]

GFS keen on a very cold first 10 days of November- i can almost feel the blue crayon itching to make an apperance

[SMU]

Good agreement on the 06z v 12z GFS & UKMO raw ( to 144 ) now where the cold uppers develop over Northern Europe & deepen in situ-

One cold attempt over the UK circa 96-120 followed by a developing signal of perhaps more substantial cold trying to edge west out of Scandi at day 8-10....

interesting to see the extended ECM picking up further blocking signals with a   -AO/NAO base framework -

Its nothing short of what was has been touted in the autumn / winter threads all ready based on the Oct AO, Zonal wind anomaly etc....

 

S

[knocker]

There is no basic change with the pattern evolution on this GFS run in the nearer time frame merely adjustments to the precise tracks of the troughs as they dive SE. The first one is just slightly further east so has little negative impact and does allow brief ridging subsequently but the next is much further west and introduces some quite cold air.next weekend. That is of course how it currently looks but 8 days is a very long time in meteorology.

[northwestsnow]

1 minute ago, Steve Murr said:

Good agreement on the 06z v 12z GFS & UKMO raw ( to 144 ) now where the cold uppers develop over Northern Europe & deepen in situ-

One cold attempt over the UK circa 96-120 followed by a developing signal of perhaps more substantial cold trying to edge west out of Scandi at day 8-10....

interesting to see the extended ECM picking up further blocking signals with a   -AO/NAO base framework -

Its nothing short of what was has been touted in the autumn / winter threads all ready based on the Oct AO, Zonal wind anomaly etc....

 

S

I got my eye on the core of the cold (vortex) switching to the Siberian sector longer term steve, in the meantime plenty of cold frosty weather should be on offer during the 1st week of November.