Model Output Discussions 06z 04/11/16

[bluearmy]

looks like  cold/chilly and blocked remains most likely although the chances of the Atlantic making inroads (especially into N Britain) currently more likely than seemed the case 24 hours ago. the GEFS messing about with taking the vortex segment further east to Arctic Canada (perhaps strat influence at play here) which would allow height rises to get further north our part of the NH through week 2. 

The date from the 46 is 18 December and the sudden draining away of the euro high anomoly at that timescale seems quite strange on a 51 member ens. but it's been fairly consistent around that timescale so we'll run with it as a broad background signal for the high anomoly over Europe to be gone by the 20th. Anything sooner is a bonus !  More specific micro patterns coming along could well elicit this bonus and the background pattern could easily establish earlier. or it might not verify at all! 

anyway, the GEFS contnue to migrate the high anomoly in the right direction late on so onto the eps to see if they are interested in any acceleration. 

[knocker]

The ecm also develops the upper feature on Monday without it becoming enclosed on the surface. Thereafter it treats the HP slightly differently to the GFS by tracking it more south east with a negative tilt which keeps the trough to the west at bay Thus remaining dry under the HP umbrella with the wind in a southerly quadrant.

[knocker]

10 minutes ago, bluearmy said:

l

 

anyway, the GEFS contnue to migrate the high anomoly in the right direction late on so onto the eps to see if they are interested in any acceleration. 

I notice that at the same time it rapidly loses the Aleutian ridge.

[Frosty.]

Tonight looks very frosty in the south with freezing fog forming and minimum temperatures of minus 7 to minus 9 celsius..a Bitterly cold night followed by a crisp, cold sunny day tomorrow..hopefully a taste of things to come during the winter.

The Gfs is pretty woeful at minimum temps in this set up with -1 / -2c..BBC maps indicate widespread severe frost across the south tonight!

Edited November 29, 2016 by Frosty.

[Man With Beard]

GEFS clustering this morning almost unanimous on a return to something mild by D10 with a very strong Iberia height anomaly.

By the end of the run, though, a very different story. Around half of the runs push heights a lot further north allowing something more wintry around the side. They would tie in with the mid-December predictions we've been hearing about. But very, very messy.

[Banbury]

8 minutes ago, Frosty. said:

Tonight looks very frosty in the south with freezing fog forming and minimum temperatures of minus 7 to minus 9 celsius..a Bitterly cold night followed by a crisp, cold sunny day tomorrow..hopefully a taste of things to come during the winter.

The Gfs is pretty woeful at minimum temps in this set up with -1 / -2c..BBC maps indicate widespread severe frost across the south tonight!

-6.8c in my garden last night .  Looks like a cold day to come with another bitter night, these are true Winter days . Like you Im hoping for much more of the same , just need the HP to hang and find the right home....so to speak

[northwestsnow]

Have..to...say...this...ecm..day10..looks...poor.insofar...as..any..retrogressive...signal..is...concerned..-

That..Euro-high...is...HUGE!!!!-...I'm...aware...things..can..and...do..change...quickly...but..i'm..struggling...to...see..how..we...would...rid...ourselves..of...that..Euro-high,and..that's..the..9thDecember...

On...the..plus...side...its...dry....and...cold...generally...

Edited November 29, 2016 by northwestsnow

[carinthian]

Morning all, all 3 main models same at 120 hours. High pressure centre over Southern North Sea and fall of pressure over Iberia. There after , GFS in particular packs the high pressure SE wards and open up a SW flow into NW Europe. ECM heading that way but dragging its feet. The UKMO models looks the most robust, so will be interesting later this morning to view its extended charts. I still think ECM and GFS have not got the pressure pattern nailed yet over the Med as I still expect a circulation to form here in the 7-10 day span and if that does form there will be no fast sinking of the high pressure. So still time for changes from 144 hours for pressure pattern changes. Meanwhile , here in the Eastern Alps we have a wedge of very cold air over us. Went down to -14c in the back garden last min and DP of -20c. Sunny start, uppers will rise a bit today but temps well below freezing at most levels. Nice to see extensive low temps recorded this morning across most of Europe  including England and Wales, certainly better than this time last year.

C

 

 

[Paul_1978]

2 hours ago, IDO said:

Just a word of warning that this could all be the models over doing the signal, background or not. I am still not seeing a consistent signal for forcing either in the Pacific or Atlantic. On this morning runs the mid-latitude block (UK HP) sinks and we get a zonal milder flow with an abundance of rain. 

GEM going that way, with the PV getting a bit more energy. This being a continuation of the 18z mean that was distinctly insipid.. The current output in FI remains poor for cold on the GEFS, not a great purview for upcoming cold and if anything the trend has been away from the current cold spell to a milder more unsettled outlook. Obviously stuff happening but I would be less than optimistic based on the last few runs and the wait for a consistent cold pattern remains illusive.

Show me the last 240 chart that verified and you might have something. 

[MattH]

As mentioned on Twitter what is quite remarkable is the consistency within the EC monthly to maintain this signal for northern blocking the further we progress into December, obviously we've not even started December yet mind. What could well be the 'crucial point' is where we go from after this prolonged anticyclonic spell through the rest of this week, this weekend and into early next week. As been discussed this morning the ECM remains more bullish about keeping the block in place. However, the EC monthly seems to show this initial blocking drifting northwards, with time, but that could well be the crucial point as, overall, the most likely scenario would be for the block to decline into the near Continent to allow for the SW'ly flow, as per GFS. If that set's up then it is a difficult pattern to break. If the signal is maintained over the next week, once we actually get into December, then it's going to either be one hell of a catastrophic failure in terms of model output and guidance, or the likes of EC monthly, our NetWx's winter forecast, the output from the UKMO et al will all come to fruition. A 'make or break' point may well arrive towards the early to middle part of December, if the evolution follows what has been forecast and what is being signaled then it could well be a very interesting December. 

Ignoring the MSLP isobars, for now, note the signal for higher than average pressure anoms to the north of the UK on the below chart for week 4, this is, essentially the EC monthly for 19th to the 25th Dec with also a signal for -ve MSLP anoms over Iberia which, in theory, would equate to a potential E or NE'ly flow.

Regards, Matt.

[fergieweather]

16 minutes ago, northwestsnow said:

Have..to...say...this...ecm..day10..looks...poor.insofar...as..any..retrogressive...signal..is...concerned..-

That..Euro-high...is...HUGE!!!!-...I'm...aware...things..can..and...do..change...quickly...but..i'm..struggling...to...see..how..we...would...rid...ourselves..of...that..Euro-high,and..that's..the..9thDecember...

Looks generally in keeping with the script of last 2 days however. Whilst there's been fine balance over what degree of mobility asserts into early Dec, the currently favoured outcome remains for the high to slip SE; some degree of mobility taking over initially, into especially NW/N (possibly more rapidly nationwide: but 30% chance high remains dominant more widely for a while)... This followed by a more concerted period of limited mobility, with greater W-E frontal progression, but this phase looking temporary before blocked patterns re-establish around mid-month onwards. That remains the broad UKMO sequence into medium range.

EDIT ie in keeping with Matt's explanation above

Edited November 29, 2016 by fergieweather

[northwestsnow]

12 minutes ago, MattHugo said:

As mentioned on Twitter what is quite remarkable is the consistency within the EC monthly to maintain this signal for northern blocking the further we progress into December, obviously we've not even started December yet mind. What could well be the 'crucial point' is where we go from after this prolonged anticyclonic spell through the rest of this week, this weekend and into early next week. As been discussed this morning the ECM remains more bullish about keeping the block in place. However, the EC monthly seems to show this initial blocking drifting northwards, with time, but that could well be the crucial point as, overall, the most likely scenario would be for the block to decline into the near Continent to allow for the SW'ly flow, as per GFS. If that set's up then it is a difficult pattern to break. If the signal is maintained over the next week, once we actually get into December, then it's going to either be one hell of a catastrophic failure in terms of model output and guidance, or the likes of EC monthly, our NetWx's winter forecast, the output from the UKMO et al will all come to fruition. A 'make or break' point may well arrive towards the early to middle part of December, if the evolution follows what has been forecast and what is being signaled then it could well be a very interesting December. 

Ignoring the MSLP isobars, for now, note the signal for higher than average pressure anoms to the north of the UK on the below chart for week 4, this is, essentially the EC monthly for 19th to the 25th Dec with also a signal for -ve MSLP anoms over Iberia which, in theory, would equate to a potential E or NE'ly flow.

Regards, Matt.

Fascinating,if we don't see this high drift north it could put a lot of LRF's on very dodgy ground...eeeeeeeeek. Hope to see signs of that sharpish.

Edited November 29, 2016 by Osbourne One-Nil
To make it easier to read for everyone

[Banbury]

17 minutes ago, northwestsnow said:

Have..to...say...this...ecm..day10..looks...poor.insofar...as..any..retrogressive...signal..is...concerned..-

That..Euro-high...is...HUGE!!!!-...I'm...aware...things..can..and...do..change...quickly...but..i'm..struggling...to...see..how..we...would...rid...ourselves..of...that..Euro-high,and..that's..the..9thDecember...

On...the..plus...side...its...dry....and...cold...generally...

Day 10...............................nuff said

[northwestsnow]

2 minutes ago, fergieweather said:

Looks generally in keeping with the script of last 2 days however. Whilst there's been fine balance over what degree of mobility asserts into early Dec, the currently favoured outcome remains for the high to slip SE; some degree of mobility taking over initially, into especially NW/N (possibly more rapidly nationwide: but 30% chance high remains dominant more widely for a while)... This followed by a more concerted period of limited mobility, with greater W-E frontal progression, but this phase looking temporary before blocked patterns re-establish around mid-month onwards. That remains the broad UKMO sequence into medium range.

Thanks..Ian..Matts..post..(above)suggests..EC..monthly..favouring..the..high..drifting..north...

[northwestsnow]

1 minute ago, Banbury said:

Day 10...............................nuff said

For..sure..but..ECM..monthly..suggests.High..drifting..north...I'm..intrigued..;D

[Frosty.]

4 minutes ago, fergieweather said:

Looks generally in keeping with the script of last 2 days however. Whilst there's been fine balance over what degree of mobility asserts into early Dec, the currently favoured outcome remains for the high to slip SE; some degree of mobility taking over initially, into especially NW/N (possibly more rapidly nationwide: but 30% chance high remains dominant more widely for a while)... This followed by a more concerted period of limited mobility, with greater W-E frontal progression, but this phase looking temporary before blocked patterns re-establish around mid-month onwards. That remains the broad UKMO sequence into medium range.

EDIT ie in keeping with Matt's explanation above

Great to have superb input from you and Matt, it's a case of coldies putting faith in the seasonal models cold / blocked signal and keeping fingers crossed.

[Methuselah]

13 minutes ago, Paul_1978 said:

Show me the last 240 chart that verified and you might have something. 

Good point. Even though at T+240 the ECM marginally outperforms the GFS, it's not too reliable at that range, either...And, given the current 'impasse', the noise probably overwhelms the signal even sooner than usual? The building blocks are in place, but more runs needed!

[Snowyowl9]

Looking cold with those surface easterlies.

 

[nick sussex]

In typical model style the GFS goes from most promising in terms of cold to pretty ghastly in the space of 12hrs.

The ECM although continuing with the bloated high is likely to keep the colder conditions for longer even as the upper temps warm up. The best solution today at T144hrs is the UKMO and on the Atlantic region we can see on the T168hrs that crucially has lower heights into Iberia, these differences are mainly due to shortwave energy either phasing or not with the upstream troughing. You can see on that UKMO below the separation of the troughing from that area of lower heights across Iberia and associated precip.

The ECM is an improvement on yesterdays 12hrs run because for the UK the flow remains from more central Europe rather than coming from north Africa in the latter stages.

 

 

Edited November 29, 2016 by nick sussex

[Summer Sun]

16 minutes ago, northwestsnow said:

For..sure..but..ECM..monthly..suggests.High..drifting..north...I'm..intrigued..;D

Could I make a polite request that you don't put .... after every word it makes it hard to read

Thanks

[bluearmy]

Just to say that our particular high could drift se and another Azores pulse could ridge North thereafter - infact I would say that is the more likely scenario, especially if we get some limited zonality.

 

[northwestsnow]

Just now, Summer Sun said:

Could I make a polite request that you don't put .... after every word it makes it hard to read

Thanks

My...spacebar...is..goosed.;(.......buying..new..laptop..)

[I remember Atlantic 252]

NW snow, looks like your full stop button knackered too!

[knocker]

3 minutes ago, bluearmy said:

Just to say that our particular high could drift se and another Azores pulse could ridge North thereafter - infact I would say that is the more likely scenario, especially if we get some limited zonality.

 

I was just thinking the same and it makes next week interesting regarding what inroads the Atlantic makes as already alluded to by the pros. Reputations could be hanging by a thread.

Edited November 29, 2016 by knocker

[jvenge]

2 minutes ago, northwestsnow said:

My...spacebar...is..goosed.;(.......buying..new..laptop..)

Hold down your alt key and press 0160, which should create a space for you. Or, use the tab key and then delete what you don't need ;-)