Model Output Discussion - 31/10/2014 and Beyond

[Ali1977]

06Z proves that FI is by no means sorted, the 18z and 00z both showed a slightly more intensive PV, where as the 06z shows a very broken one. Not sure things will change but I think the best shot we have for early cold is the Siberian high moves NW, then we get an undercut.  Well thats what I hope as really I'm not sure that is possible in this set up.

[Purga]

The 06z is well summed up by one chart from the GFS-P

 

Wet, very windy and mild as a dominant theme across most model output at the moment.

[summer blizzard]

The ECM gives with one hand and takes away with the other..

 

We finally get enough of an undercut to form a low in the right place to just about completely undercut but the primary low is too far north to throw anything but an Atlantic front at us.

 

[Polar Maritime]

I would't call Mild Purga, The charts you posted show a pretty chilly N/W flow, And adding in the Wind Chill..

 

Edited November 6, 2014 by Polar Maritime

[Ali1977]

GEFS Control run is awesome in FI. Still not that cold though but good set up.

Edited November 6, 2014 by Ali1977

[Polar Maritime]

GEFS Control run is awesome in FI.

 

Yes plenty of blocking over Greenland showing by the GEFS Control out in the run, Drawing an E/N/E flow. 

 

Edited November 6, 2014 by Polar Maritime

[captaincroc]

I would SO prefer this 'mild'....

 

 

 

 

 

 

 

...than this mild...

 

 

 

 

 

The key word is potential. There is blocking all over the place, it wouldn't take much of a shift for us to be in a totally different airmass. 

 

Exciting times.

[SMU]

Good Morning All-

 

Stayed away for a couple of days - I see no change in what I presented 2 days ago despite some saying that it was just a hopecast.

 

The NH pattern from the long range GFS ensembles have got it wrong trying to overun the whole pattern & exit the -AO pattern very quickly. This is standard fair for the GFS & why myself & generally the NOAA / CPC generally discount it....

 

For the UK whilst the flow may appear from the atlantic the surface temps will remain supressed with generally lower heights & polar air catching up the stalled fronts.

 

Post that ECM still the best fit-

http://www.meteociel.fr/modeles/ecmwf/runs/2014110600/EDH1-168.GIF?06-12

 

Remember up to 2 /3 days ago people still posting the GFS ensemble mean showing the whole pattern not shifting for 2 weeks -

 

The GFS control feels out a best fit ( relative to what I presented so have a browse....)

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=6&carte=1&mode=0

 

Higher heights being sucked towards Greenland from the lower central part Scandi the Warm air gradually being sucked out.

 

If we look where the residual heights are left they support a block somewhere close to Svalbard - maybe a tadge further west for an east based NAO or a tadge east feeding in very cold air to Europe.

 

At no point have I said the UK will get very cold, however the general pattern ( earmarked to change around the 14th-16th) will start sucking the warmth out of Europe.

 

Watch out for some possible snow for Scotland Monday......

 

S

Edited November 6, 2014 by Steve Murr

[SMU]

Just adding to my post why the GFS is so bad- People think I ignore it for fun-

 

March 10 2013 - the ACTUAL CHART

http://modeles.meteociel.fr/modeles/reana/2013/archivesnh-2013-3-10-0-0.png

 

Notice the nice high pressure cell over Iceland-

 

if we look on the 7th the Pressure being sucked through WAA north west out of the central continent

http://modeles.meteociel.fr/modeles/reana/2013/archivesnh-2013-3-7-12-0.png

 

So the GFS on the 1st - just 168 out

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013030100-0-168.png?0   has no clue whats going on for the 7th.

even on the 12z that day for the 7th 144 its struggling

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013030112-0-144.png?12

 

The ECM was a lot closer

http://www.meteociel.fr/modeles/ecmwf.php?jour=1&mois=3&annee=2013&heure=12&archive=1&mode=1&ech=72&map=1&type=0

& by the next day it nailed it.

http://www.meteociel.fr/modeles/ecmwf.php?jour=2&mois=3&annee=2013&heure=12&archive=1&mode=1&ech=72&map=1&type=0

 

 

The forthcoming pattern with that 'suck' of high pressure towards Greenland is highly unusual - expect some poor modelling from ALL models- especially the GFS.............

 

S

[Gibby]

Gibby - your excellent summary closely replicates latest UKMO discussion of 10-15d trend period.

Thanks Ian. I'm sure some people here and on the other channel think I am a mild ranper but this is totally untrue as I like cold weather and a good blizzard like most but as yet I see no real excitement on that front on the horizon yet.

Edited November 6, 2014 by Gibby

[Winter Frost]

Good Morning All-

 

Stayed away for a couple of days - I see no change in what I presented 2 days ago despite some saying that it was just a hopecast.

 

The NH pattern from the long range GFS ensembles have got it wrong trying to overun the whole pattern & exit the -AO pattern very quickly. This is standard fair for the GFS & why myself & generally the NOAA / CPC generally discount it....

 

For the UK whilst the flow may appear from the atlantic the surface temps will remain supressed with generally lower heights & polar air catching up the stalled fronts.

 

Post that ECM still the best fit-

http://www.meteociel.fr/modeles/ecmwf/runs/2014110600/EDH1-168.GIF?06-12

 

Remember up to 2 /3 days ago people still posting the GFS ensemble mean showing the whole pattern not shifting for 2 weeks -

 

The GFS control feels out a best fit ( relative to what I presented so have a browse....)

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=6&carte=1&mode=0

 

Higher heights being sucked towards Greenland from the lower central part Scandi the Warm air gradually being sucked out.

 

If we look where the residual heights are left they support a block somewhere close to Svalbard - maybe a tadge further west for an east based NAO or a tadge east feeding in very cold air to Europe.

 

At no point have I said the UK will get very cold, however the general pattern ( earmarked to change around the 14th-16th) will start sucking the warmth out of Europe.

 

Watch out for some possible snow for Scotland Monday......

 

S

Snow on high ground?? Can't see where. 

 

 

Snow in NI to lowish levels the other day but was forecast. 

Edited November 6, 2014 by Owen Cummins

[mushymanrob]

Just adding to my post why the GFS is so bad- People think I ignore it for fun-

 

March 10 2013 - the ACTUAL CHART

http://modeles.meteociel.fr/modeles/reana/2013/archivesnh-2013-3-10-0-0.png

 

Notice the nice high pressure cell over Iceland-

 

if we look on the 7th the Pressure being sucked through WAA north west out of the central continent

http://modeles.meteociel.fr/modeles/reana/2013/archivesnh-2013-3-7-12-0.png

 

So the GFS on the 1st - just 168 out

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013030100-0-168.png?0   has no clue whats going on for the 7th.

even on the 12z that day for the 7th 144 its struggling

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2013030112-0-144.png?12

 

The ECM was a lot closer

http://www.meteociel.fr/modeles/ecmwf.php?jour=1&mois=3&annee=2013&heure=12&archive=1&mode=1&ech=72&map=1&type=0

& by the next day it nailed it.

http://www.meteociel.fr/modeles/ecmwf.php?jour=2&mois=3&annee=2013&heure=12&archive=1&mode=1&ech=72&map=1&type=0

 

 

The forthcoming pattern with that 'suck' of high pressure towards Greenland is highly unusual - expect some poor modelling from ALL models- especially the GFS.............

 

S

 

i think thats unfair, you can  cherry pick over the last few years charts off the ecm to 'prove' it gets it wrong.

ill counter the 'bad gfs' theory by pointing out that it was the gfs that predicted the breakdown of the cold in december 2010, long before the ecm or ukmo.

statistically the ecm might be more  accurate then the gfs, but the gfs isnt that far behind and is a credible resource which is why the professional met men have it in their armoury. NO model is always right, but ignoring any one of the big 3 is imho foolish.

 

Snow on high ground?? Can't see where. 

 

 

 

 

to be fair owen, the post said possible snow on high ground.

Edited November 6, 2014 by mushymanrob

[nick sussex]

Typical Autumn patterns are much easier to forecast, so lows moving quickly ne past Scotland are synoptics NWP like however slow moving situations with troughing near the UK and pressure building nw towards Greenland are certainly going to lead to quite a lot of model variability.

 

 

You can see how this becomes a difficult juggling act for NWP.

 

It has to decide how much undercutting and trough disruption occurs and how much forcing is placed on this troughing by any build of pressure towards eastern Greenland and the Svalbard region.

 

Models are generally useless at undercutting scenarios, we've seen countless times how they desperately try and push everything too far ne.

 

So for the timebeing I'd keep an open mind about output past 168hrs, remembering here that if the model has got the wrong view of the undercut then anything past this point is going to be completely wrong.

 

 

 

[IDO]

As others have said November will not likely bring cold to the UK. There has been no signal for this from the models, just normal seasonal weather.

 

The question has always been how long this current pattern will maintain? There remains a large spread on the GEFS for the NH at D16 and the only trend is that a slight majority show a less disrupted PV. Only one member has an Arctic PV.

 

So there is no clear signal how the late high latitude will develop as we enter the last week of November, but interestingly for our sector, despite the variations in the NH profile, the members strongly agree on some sort of negative heights with average temps. There are exceptions but these look to be no more than background chatter.

 

Looking at the latest JMA, this ties in with the GEFS. Week 3-4 anomaly: 

 

Anomalous positive heights to the NE and a trough centred just to the west of the UK, with temps average or above.

 

So JMA suggests this current setup will continue till at least week one of December. So let the strat. warming continue, and just wait for its repercussions, and if as a bonus the PV remains relatively disrupted, then mid latitude cold looks inevitable, and the UK then just needs a bit of luck to benefit from it.

 

Although the 06z Control was promising, at the moment its an outlier: 

[bluearmy]

the strength of the mid month -AO is gradually moderating on ecm ensemble (and GEFS). will be interesting to see if the period around the 20th begins to drop once it ticks down a few days.

[Ali1977]

I'm not sure if Ian Ferguson still posts on here, last Winter it was great to have the opinion and outlooks striaght from the METO. EC32 updates were always appreciated, even though last years were dire for cold lovers. It would be interesting to know if the Strat and Opi have been discussed when looking at the charts being churned out at the minute.

[Yarmy]

I'm not sure if Ian Ferguson still posts on here, last Winter it was great to have the opinion and outlooks striaght from the METO. EC32 updates were always appreciated, even though last years were dire for cold lovers. It would be interesting to know if the Strat and Opi have been discussed when looking at the charts being churned out at the minute.

 

He posted this morning:

 

https://forum.netweather.tv/topic/81718-model-output-discussion-31102014-and-beyond/page-16#entry3064853

[Winter Frost]

Well lets hope that this winter is nothing like the disaster that we received last year. It would appear that the cold in North America has started up again as evident from the snow storm in Maine.. which to me is quite worrying. I'm not sure if it will impact the British Isles but if it were to I would not be surprised. There are only a few winters that I know of which were cold on both sides of the Atlantic - 2010 and 1963. 

 

People keep talking about the cold coming at the end of the month but i've looked at the GFS Parallel and while there is massive change in each run they all seem to show the mild over us. In saying that we could get some snow from the cold in Canada as last year Scotland and Ireland did receive some snow around February from that. (I received 3/4 inches one night) I would disagree with the person who said that the cold air will moderate too much, yes it will moderate but if it keeps coming over and cooling the ocean moderation will be reduced. (like last year)

Edited November 6, 2014 by Winter Frost

[Ali1977]

He posted this morning:

 

https://forum.netweather.tv/topic/81718-model-output-discussion-31102014-and-beyond/page-16#entry3064853

Apologies for not seeing that, thats good he's still on here.  And to Ian, sorry for spelling your surname incorrectly.

Edited November 6, 2014 by Ali1977

[Mucka]

Since we are looking right to the edge of model output for possible developments I think it is probably best to stick to the 7/10 anomaly charts for now although run to run variance is interesting and give clues which way the output is going.

 

  

 

 

We still see there are big differences between the longwave patterns. For newbies look to the far right of each image and the blue shading which represents below mean average heights (trough) and look at the angle of the trough ( "U" shape rotated 90 degrees anticlockwise GFS but 135 degrees ECM)

I did draw up a basic diagram with arrows to point it out but don't know how to upload images from my PC. (Not a problem any other forum but seems a mysteriously obscure process here)

We can see that ECM is going for a trough with some undercutting and attempting to retrogress heights from scandinavia to Greenland while GFS is staying with the shallower trough and little to no undercutting.

 

We should look for subtle changes to see if either model is moving toward the other.

Edited November 6, 2014 by Mucka

[SnowBallz]

I'm not sure if Ian Ferguson still posts on here, last Winter it was great to have the opinion and outlooks striaght from the METO. EC32 updates were always appreciated, even though last years were dire for cold lovers. It would be interesting to know if the Strat and Opi have been discussed when looking at the charts being churned out at the minute.

 

Hi Ali,

 

Strat f/c is continually fed into discussion, albeit rather cautiously.  With regards to OPI, I would say that that falls into the many correlative theories which probably need to be refined a little bit further, before it's used deterministically.  That said, the micro correlation appears to present an interesting relationship though.

 

No discernable pattern yet established for the coming season, by the way; that's not to say it'll be as relatively benign (in terms of cold weather, at least) as last year, just nothing of note jumping out.  But, it is only early November, and so that's hardly surprising.  To that end, I'd suggest that any forecast og unseasonable, near-term cold to be a little optimistic; upstream, whilst anomalously cold air exits the eastern CONUS, the form horse is an accelerated jet stream, feeding cyclogenesis, with a resulting unsettled and stormy pattern closer to our shores.

 

SB

[BlueHedgehog074]

I would SO prefer this 'mild'....

 

 

 

 

 

 

 

...than this mild...

 

 

 

 

 

The key word is potential. There is blocking all over the place, it wouldn't take much of a shift for us to be in a totally different airmass. 

 

Exciting times.

Certainly quite a difference between those two charts with quite a vicious looking Vortex to the North on the second chart. I personally know which one I would prefer as well. While it's not certain when the first proper cold spell could arrive (or even if it's just a Northerly toppler to start with), I think this does go to illustrate how things seem to be in a better position for cold Winter potential this year.

 

Looking at the European and Canadian view of the models, they do generally show some kind of shallow(ish) Vortex to the North-West near and around the Canada area (an example used at 240 hours from the 00Z GEM, 06Z GFS, 06Z GFS (P), and 00Z ECMWF and ECMWF ensemble mean 'Sea Level Pressure and 500 hPa' charts):

 

 

I think again, though, it doesn't seem too menacing (but perhaps may try to bring a bit more of an Atlantic influence from the West at times). The weather does also look 'blocked' to the East and North-East of us. So still quite a contrast when compared to some of the charts from around this time last year. 

 

Although the blocking to the North-East may not be enough to provide the cold and snow fans with the first 'bite of the cherry' (though at the time-frame, things could clearly still change a fair bit), then there's certainly other opportunities further down the line. I think as Snowking mentioned, it would probably be a lot better to see favourable conditions for UK cold and snow to develop later down the line, with better cold pooling to the North-West/North/North-East (and perhaps East) to tap into.

 

For now, though, it does look like one of those patterns of Low Pressure systems sliding Eastwards or South-Eastwards towards the UK against blocking High Pressure to the East/North-East, but chances of the Lows stalling to the South/South-West, West, or over, the UK at times. (Won't go into anymore detail as others have covered it well).

[Barry12]

GFS 12Z looking much better than the 6z, much less stormy a swell.

 

[Man With Beard]

re: Mushyman's post above - I too agree the GFS has merit but in 2010, just like in recent weeks, I do feel it falls into the trap of 'predict the same thing and it will be right eventually'. In 2010, it kept predicting a breakdown, and it came many days late IIRC - right now, as I have been mentioning, it keeps building a strong vortex in FI (just occasionally it doesn't) and we're still waiting for it. So I can well see why people are backing the ECM in the next 2 weeks over GFS.

[Mucka]

Run to run variance and all that but interesting to note GFS 12z jet profile is more in line with ECM anomaly forecast than its own.

 

 

Certainly we will need the jet to relent upstream somewhat if we do get some undercut so that we can get an Atlantic ridge to support any retrogression of heights from Scandinavia to the Geenland area. 

 

The form  horse is always the Atlantic, particularly in November but at least we do have some interest in the charts in early November which often is not the case.

Edited November 6, 2014 by Mucka