Model Output Discussion - 30th November onwards

[cobbett]

Just out of interest - there was a post about a week ago which looked at the current similar synoptic pattern (albeit one week ago now) as against how 62/63 panned out. Anyone have any idea as to how this still currently looks or was that just a blink and you'll miss it similarity - Thanks

[pdiddy]

Just out of interest - there was a post about a week ago which looked at the current similar synoptic pattern (albeit one week ago now) as against how 62/63 panned out. Anyone have any idea as to how this still currently looks or was that just a blink and you'll miss it similarity - Thanks

 

Definitely some similarities, though quite how important these are is anyone's guess...

Edited December 3, 2013 by pdiddy

[Troubleatmill]

Just out of interest - there was a post about a week ago which looked at the current similar synoptic pattern (albeit one week ago now) as against how 62/63 panned out. Anyone have any idea as to how this still currently looks or was that just a blink and you'll miss it similarity - Thanks

 

Blink and you will miss it i think Cobbett, it may of been to show that cold can eventually come from even the worst current synoptics, rather than were heading for a 62/63, be nice though wouldnt it if everyone/thing is looked after and safe   

Edited December 3, 2013 by Arron B

[Gavin Hannah]

If anyonevwanted to, they culd do animated gifs of dec 62 and this dec.

Would be the best way to do an anomolie comparrison.

I aint as im at uni and on my phone and have study to do rather than get caught up chasing the dragon.... Oops, t o late lol

Edited December 3, 2013 by IBTHToThoseShortwaves

[iamgazza]

http://forum.netweather.tv/topic/35386-winter-1962-63/

Interesting similarities...

[Gael_Force]

Just out of interest - there was a post about a week ago which looked at the current similar synoptic pattern (albeit one week ago now) as against how 62/63 panned out. Anyone have any idea as to how this still currently looks or was that just a blink and you'll miss it similarity - Thanks

 

It is still near top of the analog table - you need to look at the date as the synoptic development may be more applicable to the following month. Some nice cold months in the CET table for the years featured.

 

[cobbett]

Cheers Pdiddyb for the chart - must admit having a quick look at GFS 06z for today, they look quite similar but I'm definitely no expert !

[Yarmy]

Just out of interest - there was a post about a week ago which looked at the current similar synoptic pattern (albeit one week ago now) as against how 62/63 panned out. Anyone have any idea as to how this still currently looks or was that just a blink and you'll miss it similarity - Thanks

 

I flagged this up in the Winter thread yesterday.

 

 

 

But really the point is not that 62/63 will happen (it's extremely unlikely), but that even a synoptic outlook where it's hard to see where the cold is coming from can be deceiving.

[Frosty.]

A trip back in time to Dec 3rd 1986.......what a horrible pattern...........run it forward to mid January 1987...dream charts, even from a yuck set up things change when you least expect it.

[Troubleatmill]

At T240 on the 06z i count 11 ensembles picking up a continental flow due to HP building and drifting north / NE, think Nick F had 9 on the 00z, so more improvements overall 

Edited December 3, 2013 by Arron B

[Gael_Force]

For anybody interested in looking at analog analysis, there is a lot of information on the CIPS site - it is US orientated but we often look at what the upstream patterns are.

 

http://www.eas.slu.edu/CIPS/ANALOG/analog.php

 

00Z GFS  east coast analysis for example.

 

 

[legritter]

Yes it would be nice for a block to set up to our north or n /east ,and just going by current Model output and Data we are in with a shout .but let us not get our hopes up too high as its always a big fall if the pattern sets up wrong .many more runs needed and plenty of patience ,but very comforting that its still only early days yet .lets hope tonights ECM firms up and Gfs becomes more consistent ,No STella  runs just consistent day by day ,oh that would be nice ,STELLAS all round .

[Catacol]

I'm still waiting for the Greenland blocking it showed for over a month about this time last year...

 

A anti-cyclonic outlook this morning and although we see energy taken South into the Azores by the NWP, going forward this is not a set-up that will lend itself to high enough latitude blocking to bring a 'proper' easterly to the UK. The cold uppers will remain for E and SE Europe until there is another pattern change.

 

Let's look at this with some data because your analysis there is simplistic. I have just spent an interesting 30mins scanning strat signals this morning and am feeling quite optimistic.

 

At the root of my interest today is this chart showing renewed wave 2 warming - good news especially, as the the current wave 1 event that is helping promote pressure rises to our NE is scheduled to fade quite fast. Here is the predicted wave 2 warming at day 9

 

 

It is a moderate event - we need to see values 2 or 3 times as high as this to attack the vortex with any great power, but look at the focus of the warming - from 10hPa down to about 50hPa just north of 60N. This means less far for the impact to propagate downwards so a quicker response time and perhaps less requirement for it to be a major attack.

 

Compare this then with another very interesting chart - this time temperatures in the strat at 20hPa to try and locate where in the NH this warming is forecast to occur:

 

 

Notice here the warming still ongoing over Europe, helping to promote the height rises over Scandy that were spotted a few days ago - but also now a warm sector over the US.

 

This Meteo chart from GFS at 10hPa - a little higher up in the atmosphere - shows the same location for the warming, so we have cross model support for a warming and consequent disruption of the vortex centred over the US

 

 

 

What is the forecast impact? Another interesting 9 day chart, this time highlighting global mean zonal winds from ECM:

 

 

2 points of interest here. We have mean zonal reversal from about 83N to the pole suggesting to me ridging through the arctic blocking off those zonal winds from 300hPa downwards. We also then have a very interesting signal at 60N for a near reversal of the same zonal winds from 300hPa downwards and another tiny stagnant signal at around 50N on the surface.

 

What does all this mean? Well - interpreting this is the interesting bit, but I'll give it a try. The warming over Europe is clearly helping promote a Scandy height rise, something that is very clear indeed from this strat 100hPa forecast at 9 days once again

 

 

But in all likelihood it will not gain enough high latitude to do any more than create yet more stagnant weather for us, though the NW may have a mild flow as picked up by the MetO update suggesting a NW/SE split.

 

But the forecast wave 2 attack analysed above is without doubt going to try and shove the core of the vortex away from the Canadian sector and promote another ridge over the mid atlantic or possibly even up through Greenland. Time scale for this? Day 9 when the warming is underway is Dec 12. Allow a few days for a trop reponse and I would guess anywhere around Dec 15/16. Now then... there is an outside chance of the holy grail scenario from here... namely that ridging out of Canada or the North Atlantic helps suck scandy heights NW with energy from the relocating vortex dropping underneath creating a greenland block with low pressure undercutting. The sharp meridional pattern we have been having possibly makes this more likely - but in opposition to this is the fact that the warming is currently forecast to be only moderate and therefore there is a strong chance that, as the vortex moves away from the Canadian sector, it will simply flatten the atlantic pattern as it moves east leaving pressure to rise in behind and a resultant NW flow.

 

The second scenario is the more likely and the wise money would not be on a link up between scandy heights and a new greenland ridge at this stage. However... I will be keeping a close eye on this forecast from here, because the warming is far enough west to make me think that energy might easily be forced sharply SE out of Canada as pressure starts to build - and the overall undercut scenario is not a million miles away. In addition if the relocating vortex was flattening out the pattern I would not expect to see that mean zonal average of around 0 for 60N - bar the most almighty high pressure sitting over most of Russia that mean zonal wind flow would be in positive numbers if low pressure was firing through the north atlantic. 

 

So a very interesting mid to late December brewing up here. Chance of mid to high lat blocking with easterly undercut; also chance of an active atlantic followed by NW and N artic air feeing in afterwards. Euro high and warm southerly feed for any length of time? Not on the charts as published today I think.

 

Did I read earlier that both Met and EC32 had a tentative greenland signal showing up? Not at all surprising given the above - it is possible you wont have long to wait Ian.

Edited December 3, 2013 by Catacol_Highlander

[SW Saltire]

The operationals this morning have not shown agreement regarding a future easterly (shock horror). This was to be expected and is simply part and parcel of the run variability that will definitely take place. The update by Ian F is very encouraging but obviously a long way from coming to fruition. It is also good that 11 GFS ensemble members develop some kind of easterly flow as add 2/3rds more amplification and.... if only it were that simple. This is of course the easy part, watching the Scandi high tentatively be brought into nearer FI. Once it reaches high res the real drama will start. If i was living on the east coast it would certainly seem like winter was upon me with temperatures seeming suppressed with the propensity for them to continue to lower, although the magical white stuff looks like a while off for the time being

Edited December 3, 2013 by SW Saltire

[Nick L]

Let's look at this with some data because your analysis there is simplistic. I have just spent an interesting 30mins scanning strat signals this morning and am feeling quite optimistic.

 

At the root of my interest today is this chart showing renewed wave 2 warming - good news especially, as the the current wave 1 event that is helping promote pressure rises to our NE is scheduled to fade quite fast. Here is the predicted wave 2 warming at day 9

 

 

It is a moderate event - we need to see values 2 or 3 times as high as this to attack the vortex with any great power, but look at the focus of the warming - from 10hPa down to about 50hPa just north of 60N. This means less far for the impact to propagate downwards so a quicker response time and perhaps less requirement for it to be a major attack.

 

Compare this then with another very interesting chart - this time temperatures in the strat at 20hPa to try and locate where in the NH this warming is forecast to occur:

 

 

Notice here the warming still ongoing over Europe, helping to promote the height rises over Scandy that were spotted a few days ago - but also now a warm sector over the US.

 

This Meteo chart from GFS at 10hPa - a little higher up in the atmosphere - shows the same location for the warming, so we have cross model support for a warming and consequent disruption of the vortex centred over the US

 

 

 

What is the forecast impact? Another interesting 9 day chart, this time highlighting global mean zonal winds from ECM:

 

 

2 points of interest here. We have mean zonal reversal from about 83N to the pole suggesting to me ridging through the arctic blocking off those zonal winds from 300hPa downwards. We also then have a very interesting signal at 60N for a near reversal of the same zonal winds from 300hPa downwards and another tiny stagnant signal at around 50N on the surface.

 

What does all this mean? Well - interpreting this is the interesting bit, but I'll give it a try. The warming over Europe is clearly helping promote a Scandy height rise, something that is very clear indeed from this strat 100hPa forecast at 9 days once again

 

 

But in all likelihood it will not gain enough high latitude to do any more than create yet more stagnant weather for us, though the NW may have a mild flow as picked up by the MetO update suggesting a NW/SE split.

 

But the forecast wave 2 attack analysed above is without doubt going to try and shove the core of the vortex away from the Canadian sector and promote another ridge over the mid atlantic or possibly even up through Greenland. Time scale for this? Day 9 when the warming is underway is Dec 12. Allow a few days for a trop reponse and I would guess anywhere around Dec 15/16. Now then... there is an outside chance of the holy grail scenario from here... namely that ridging out of Canada or the North Atlantic helps suck scandy heights NW with energy from the relocating vortex dropping underneath creating a greenland block with low pressure undercutting. The sharp meridional pattern we have been having possibly makes this more likely - but in opposition to this is the fact that the warming is currently forecast to be only moderate and therefore there is a strong chance that, as the vortex moves away from the Canadian sector, it will simply flatten the atlantic pattern as it moves east leaving pressure to rise in behind and a resultant NW flow.

 

The second scenario is the more likely and the wise money would not be on a link up between scandy heights and a new greenland ridge at this stage. However... I will be keeping a close eye on this forecast from here, because the warming is far enough west to make me think that energy might easily be forced sharply SE out of Canada as pressure starts to build - and the overall undercut scenario is not a million miles away. In addition if the relocating vortex was flattening out the pattern I would not expect to see that mean zonal average of around 0 for 60N - bar the most almighty high pressure sitting over most of Russia that mean zonal wind flow would be in positive numbers if low pressure was firing through the north atlantic. 

 

So a very interesting mid to late December brewing up here. Chance of mid to high lat blocking with easterly undercut; also chance of an active atlantic followed by NW and N artic air feeing in afterwards. Euro high and warm southerly feed for any length of time? Not on the charts as published today I think.

 

Did I read earlier that both Met and EC32 had a tentative greenland signal showing up? Not at all surprising given the above - it is possible you wont have long to wait Ian.

 

What a fantastic post. But a question...where do you get most of those charts from?

[ARNOTT ad]

Highlander what a fantastic post and interesting read! Good work.

[Severe Siberian icy blast]

The ECM has gone from this :

 

 

To this....in the space of 3 days.

 

 

There has been a very significant downgrade in terms of the severity, potential snowfall, longevity and extent of area at risk.

absolutely bang on. Charts dont lie . The northerly was over amplified so much by all the models. In particular the ecm , I no the annalysis steve gave last night was very good , and in the main it got the profile in the northern hemisphere right . But small corrections have major implications on the UK. Mainly in the over amplification of the ridge to our west. Along with been to far west. But I think we are all aware of that when it comes to northerlies !

Great to see the met o in favour of a battleground type scenario . I know it's a genuine threat when ian and john h talks of it. Interesting times

[Robbie Garrett]

In terms of a longer-term output, I can see things calming down for Christmas and something abit more warmer than what we have at the moment.  A firm Scandinavian ridge till the New Year I believe is the more expected output.  

 

 

[Frosty.]

Well, the Gfs 00z op run and some of the GEFS 00z perturbations showed it, and the met office update is hinting at changes by around mid month onward...here is a snippet :-   However, there is the potential for colder conditions to spread in from the southeast towards the end of the period (6-15 day range)..........further on...there is the potential for colder than average temperatures across the south and east during the start of the period..........which is the festive period. So, there is potential for a cold and wintry easterly  / southeasterly pattern during the second half of the month, probably unsettled, windier and relatively milder for the northwestern corner of the BI.. Looking forward to seeing this pattern as it evolves.

Edited December 3, 2013 by Frosty.

[gottolovethisweather]

In terms of a longer-term output, I can see things calming down for Christmas and something abit more warmer than what we have at the moment.  A firm Scandinavian ridge till the New Year I believe is the more expected output.  

 

 

 

I maybe wrong but I believe this was relating to Robbie's observations on the implications on the stratosphere given the attached charts and the only warming up Robbie would be talking about is presumably from within the stratosphere profile.   Please somebody correct me of I'm wrong.

Edited December 3, 2013 by gottolovethisweather

[Catacol]

What a fantastic post. But a question...where do you get most of those charts from?

 

All from the excellent Berlin centre here:

 

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/

[Frosty.]

God i hope so, sounded like roger's post yesterday with warm spell later in december.

[bluearmy]

far too much to speculate on today. good post catcol though the strat charts post day 7/8 are liable to change (not as much as trop ones). everything going as per expected re last evenings posts. i would say that the far fi modelling from both naefs and ecm is beginning to look very interesting indeed. (there is a spread from naefs that introduces zonality - lets hope that disappears quickly). patience is required and plenty of pitfalls on the way (note Kriss' recent post about energy being left behind whent the vortex vacates nw siberia - recent gefs fi's show energy being transferred back from canada to siberia but hopefully further north so the blocking doesnt come under too much attack.) i'm dreaming ................................post later after the 12z ens are out

[Catacol]

In terms of a longer-term output, I can see things calming down for Christmas and something abit more warmer than what we have at the moment.  A firm Scandinavian ridge till the New Year I believe is the more expected output.  

 

 

 

The key to that 360h mean chart is what happens over Canada. Fingers crossed the wave 2 warming picked up today at day 9 - 10 might build to be a bit more significant - if it does then expect to see height rises forcing their way through the mean low pressure swathe forcing a change in the pattern and the possibility of what i posted above.

 

I would add at this stage that if the warming itself fades fast then northerly blocking seems unlikely. No way at this stage to be sure of the level of warming, but the 10 hPa strat charts are available on the less than impressive GFS via meteo, and they are suggesting a fading of the US warming by 360 but a significant rise in warming, this time over Russia. How this will tie in to the position of the vortex - should it come true - on 19 December is anyone's guess at this stage... but it will certainly create more interest.

 

[Frosty.]

The GEFS 06z mean @ T+240 hours is heading in the right direction, as time goes on, growing ensemble support will make the mean look more wintry.