Model Output Discussion - 12th December Onward

[Daniel Miller]

Oh the infamous CFS charts!

You'd be better off reading the tea leaves, even if they were more accurate the problem is with them that they simply reflect what the overall month ends up to be, this can mask lots of variation within that month.

Personally I think they're a load of rubbish and I said the same thing last winter even when they progged below average temps down here in sw France for January and February, what we ended up having was the complete opposite!

Haha, it's quite mad that people who disregard what the models show in 2 weeks time can actually what that nonsense shows for 3 months time!

As you said, it's only an average. We could have a heatwave the first half of January and then the deepest cold on record for the second half and it would come out like that.

[beng]

Can't really see much evidence of an arctic high this side of the North Pole on 00z ECM, though it does show the Polar Vortex spliting at the end of the run, with two seperate cold domes across Nern Canada and the other over NW Russia. 06z GFS elongates the polar vortex to spread right across higher latitudes from Nern Canada across Greenland to NW Russia going into FI, though a proper split would be better to allow the jet to amplify to our west.

With regards to the Jan 1985 analogue, Dec 1984 had a very strong west Russian high but also a deep vortex to the NW of the UK, the Russian high then sank SW and merged with the Azores high to form a large Euro High, but at the same time the Polar Vortex was splitting to allow a dome of cold air to sink south over Nern Russia, which then eventually moved west and southwest towards the UK during Jan 1985 giving the very cold wintry spell that month. Can't really see any great similarities yet, as there's no strong high over Wern Russia right now and the PV shows no realistic signs of splitting yet - certainly no signs of stratospheric/upper tropospheric warming to split and sink cold vortex either.

It's a brave call to see something similar to Jan 1985 in Jan 2012 to develop from the current pattern.

http://meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=1&archive=0

1040mb high more or less smack bang over the pole by day 10 - of course it may not happen but this is what the model shows - and it's been consistent the last few runs in developing the feature. If you look at the archive charts for end of Dec 84 - hemispheric view, there are similarities there - and yes there are differences - I'd be amazed if there wasn't.

http://meteociel.fr/modeles/archives/archives.php?day=27&month=12&year=1984&hour=0&map=0&mode=0

Please read what I actually wrote - rather than just making comments about something I didn't actually say. The message I was trying to get over was that IF the ECM model was correct with the arctic high, then I would expect to see a less flat jet stream than it currently shows. I then pointed out how in the 85 spell, it started with an arctic high, which then amplified the jet, drove warm air into the arctic and then intensified the heights there.

[karyo]

Interesting to note that April for once is average, and that June is above average (for once). I do wonder what Summer will bring for the Olympics let alone this Winter.

Looking at this, we've gone through our cold winter cycle then?

I wouldn't bother looking at April onwards. I only look up to 2 months, at this range it is reasonably reliable.

February still has a chance to come below average but I'd want to see this starting to show soon on the CFS charts.

Karyo

[Frosty.]

Isn't a lot of this pure conjecture? That's not really the point of this thread.

Not really OO-N, it's based on what the latest ensembles are showing and not pure guesswork, the ensemble mean indicates fairly cold zonal at times in the north but nearer average further south and a few milder days next week and some colder days later.

[karyo]

Oh the infamous CFS charts!

You'd be better off reading the tea leaves, even if they were more accurate the problem is with them that they simply reflect what the overall month ends up to be, this can mask lots of variation within that month.

Personally I think they're a load of rubbish and I said the same thing last winter even when they progged below average temps down here in sw France for January and February, what we ended up having was the complete opposite!

You keep saying that Nick just because the CFS got your location wrong last winter. That doesn't mean that the model is rubbish, just that it got it wrong on that occassion. At the same time, it was pretty good for the UK for the last 2 winters.

I am not taking those charts as a gospel, I just look at them as trends.

Karyo

[Nick F]

Please read what I actually wrote - rather than just making comments about something I didn't actually say. The message I was trying to get over was that IF the ECM model was correct with the arctic high, then I would expect to see a less flat jet stream than it currently shows. I then pointed out how in the 85 spell, it started with an arctic high, which then amplified the jet, drove warm air into the arctic and then intensified the heights there.

Ok, I'll get my coat. Maybe I'm in the wrong thread if we are discussing what may happen beyond a t+240 chart, rather than what the charts are showing! Though all I can see, without any strato warming, is a continuation of the zonal flow we have next week to the end of Dec, kind of what the models show atm. What happens thereafter is pure conjecture.

[nick sussex]

You keep saying that Nick just because the CFS got your location wrong last winter. That doesn't mean that the model is rubbish, just that it got it wrong on that occassion. At the same time, it was pretty good for the UK for the last 2 winters.

I am not taking those charts as a gospel, I just look at them as trends.

Karyo

Are there actual verification stats for the CFS?

It would be interesting to see just how well it does, but i have been consistent regarding the CFS, even if it showed icebergs floating down the Channel I'd still criticize it.

Even those charts you put up show close to average for the UK so that could mean basically anything in terms of synoptics, looking at Russia even if those temps were that above average thats still very cold, what the CFS doesn't show then is a mild sw/w dominated pattern as that would certainly produce well above average for the UK and not just for Russia.

Unless you can find some verification stats then I won't be convinced of the CFS, maybe I'll have a trawl around the net to see what I can find, but I would have thought if the CFS was that good they'd be happy to advertise its worth with some concrete stats.

Edited December 17, 2011 by nick sussex

[shedhead]

You keep saying that Nick just because the CFS got your location wrong last winter. That doesn't mean that the model is rubbish, just that it got it wrong on that occassion. At the same time, it was pretty good for the UK for the last 2 winters.

I am not taking those charts as a gospel, I just look at them as trends.

Karyo

Have to agree. Easy to diss them when they got it wrong, but if that's the case they should be praised when they get it right and without question they nailed Nov and are a long way to nailing Dec too. CFS's high confidence call of an anomolously warm Scandi has been the most striking, but even they looked to have underplayed it. I don't view their refusal to drop the above ave temps up there thru Jan as a major concern quite yet, but it they don't begin to reduce them before close of play this month I may well start too.

Edited December 17, 2011 by shedhead

[Frosty.]

I wonder if the CFS factors in the likely effects of the upcoming strat warming event when it churns out charts for months ahead or not? I have more faith in what GP says with his expert teleconnections knowledge rather than what the CFS shows although it would be nice if it began to show some blocking as we had last december..would be a nice xmas present. :smiliz34:

Edited December 17, 2011 by Polar_ Low

[nick sussex]

Have to agree. Easy to diss them when they got it wrong, but if that's the case they should be praised when they get it right and without question they nailed Nov and are a long way to nailing Dec too. CFS's high confidence call of an anomolously warm Scandi has been the most striking, but even they looked to have underplayed it. I don't view their refusal to drop the above ave temps up there thru Jan as a major concern quite yet, but it they don't begin to reduce them before close of play this month I may well start too.

For a model to prove worthwhile it needs to show that its results are not just down to pure chance, and that its forecast statistically correlates with the observed results.

I did manage to find this site but I don't think I've got months to go through it all!

http://www.cpc.ncep....erif/verif.html

If you want to see some epic failures of this model then they are discussing it here:

http://www.easternus...s-verification/

Not just a bit out but basically the opposite to what occured in the USA!

I will have a go after about 15 espressos to go through those verification stats!

Edited December 17, 2011 by nick sussex

[karyo]

I'll look forward to your analysis Nick! lol

It's easy to pick on the failure of a model that goes so far in advance, that's why is best not to go more than 2 months.

Karyo

[tinybill]

what can i say looks to me mild weather is chucked in the bin for xmas day could make things interesting if the gfs is right!!

[nick sussex]

I'll look forward to your analysis Nick! lol

It's easy to pick on the failure of a model that goes so far in advance, that's why is best not to go more than 2 months.

Karyo

Lol!

That link gave me a headache, talk about information overload!

I will report back what i find at some point and will do my best to uncover the sinister truth behind the CFS!!!

[stewfox]

what can i say looks to me mild weather is chucked in the bin for xmas day could make things interesting if the gfs is right!!

Before people jump on the 'its only one run' is does suggest the christmas period is not 'nailed'

[johnny1972]

Latest Ski Blog with usual Synoptic patterns now out.

Jackone

Would really appreciate inclusion of Italy in your forecasts. Heading to sauze d'oulx in January

Cheers

[Pixel]

I've found this site quite interesting.

Pick an airfield near where you live here:

http://wxweb.meteost...ed_Kingdom.html

eg:

http://wxweb.meteost...html?text=EGTH/

the underlined values open a new window to view

I've been watching the "pink" (sub 528dam) come and go - even the models blush sometimes (-:

Italy is here:

http://wxweb.meteostar.com/sample/country/Italy.html

Edited December 17, 2011 by shadowcat

[Summer Sun]

Run up to christmas

http://www.wetterzen...s/Rtavn1501.png

http://www.wetterzen...s/Rtavn1741.png

http://www.wetterzen...s/Rtavn1921.png

Some very high pressure developing in FI 1050mb

http://www.wetterzen...s/Rtavn2881.png

End of FI as you were high pressure firmly in charge

http://www.wetterzentrale.de/pics/Rtavn3841.png

Edited December 17, 2011 by Gavin D

[Grimsby Snow Lover]

Run up to christmas

http://www.wetterzen...s/Rtavn1501.png

http://www.wetterzen...s/Rtavn1741.png

http://www.wetterzen...s/Rtavn1921.png

Some very high pressure developing in FI 1050mb

http://www.wetterzen...s/Rtavn2881.png

If these were to verify them I'd imagine some cool/cold surface conditions and hopefully some frost if skies remain clear enough. Further into FI things are looking settled with cooler uppers. Still no real changes over Greenland re the PV, unless I have read the model wrong.

Edited December 17, 2011 by Grimsby Snow Lover

[A Winter's Tale]

Run up to christmas

http://www.wetterzen...s/Rtavn1501.png

http://www.wetterzen...s/Rtavn1741.png

http://www.wetterzen...s/Rtavn1921.png

Some very high pressure developing in FI 1050mb

http://www.wetterzen...s/Rtavn2881.png

End of FI as you were high pressure firmly in charge

http://www.wetterzen...s/Rtavn3841.png

Watch this space! I really am keeping my eye on that potential polar maritime incursion before Xmas and that disasterous area of High Pressure. If the polar maritime spell is good enough, we might have some lying snow at midnight Christmas Day. But I'm not banking on that, I'm just hoping that the area of High Pressure will disapear just as it appeared. If that were to happen, then I would bet on a white xmas for the north - of course, that won't happen.

[SnowObsessor90]

If these were to verify them I'd imagine some cool/cold surface conditions and hopefully some frost if skies remain clear enough. Further into FI things are looking settled with cooler uppers. Still no real changes over Greenland re the PV, unless I have read the model wrong.

What do you make of Gavin D profile picture btw? Personally I die a little inside every time I look at it, it's that unbearable and what's worse is that it's nigh on impossible to ignore unlike the actual content of his posts.

Yes I know this post is off topic and probably will be deleted for doing so but something had to be said.

Edited December 17, 2011 by Anonymous21

[Snowy Easterly]

Run up to christmas

http://www.wetterzen...s/Rtavn1501.png

http://www.wetterzen...s/Rtavn1741.png

http://www.wetterzen...s/Rtavn1921.png

Some very high pressure developing in FI 1050mb

http://www.wetterzen...s/Rtavn2881.png

End of FI as you were high pressure firmly in charge

http://www.wetterzen...s/Rtavn3841.png

Just because its high pressure it don't mean it will me mild, we can get an inversion which could lead to cold days and frosty nights

[Summer Sun]

Just because its high pressure it don't mean it will me mild, we can get an inversion which could lead to cold days and frosty nights

Indeed cold and frosty at times after this mid week mild spell it looks like turning colder which is fine if you like cold and dry but not if you want snow.

[Frosty.]

Indeed cold and frosty at times after this mid week mild spell it looks like turning colder which is fine if you like cold and dry but not if you want snow.

Good to see the mild will only be a blip before it turns cold again and a fairly high risk of a lot of snow showers into the far north and to coastal areas with strong N or NWly winds...fingers crossed..

[Summer Sun]

UKMO may be on to something tonight

http://www.wetterzen...cs/Rukm1441.gif

And an Hemispheric view

http://www.meteociel...=144&carte=1021

[wolvesfan]

If these were to verify them I'd imagine some cool/cold surface conditions and hopefully some frost if skies remain clear enough. Further into FI things are looking settled with cooler uppers. Still no real changes over Greenland re the PV, unless I have read the model wrong.

Hi GSL,

There is a change regarding the tropospheric vortex,if you look at the northern hemisphere chart you will see it transfer from west of Greenland eastwards towards northern Russia,i'm not sure but this may be to do with the stratospheric warming thats being forecast around north America and Canada.