Model Output Discussion 18th Nov.2013-12z onwards.

[Panayiotis]

Well that low leaving the US at 162hrs has Nick S's name on it! Anyway its this low which will cause the WAA up into Greeland which may give us the northerly toppler later on in the run. The more vertical the isobars running into Greenland the better:

Edited November 22, 2013 by Panayiotis

[Cecil Hogmanay Melchett]

GFS 12Z looks pretty much a copy of 06z with a mid Atlantic high and a strong jet streak scuppering any chance of ridging to Greenland.

Potentially some decent snow for the highlands as the depression south of Iceland swings SE and down through the North sea but not quite cold enough for most of the UK at this stage.

[Mucka]

GFS 12Z looks pretty much a copy of 06z with a mid Atlantic high and a strong jet streak scuppering any chance of ridging to Greenland.

Potentially some decent snow for the highlands as the depression south of Iceland swings SE and down through the North sea but not quite cold enough for most of the UK at this stage.

 

Yes, I still think we may have to wait for a second bite at the cherry around day 10/11 though I'm not sure this run is going to cut it. That said I don't think we should take any run on face value and the ensembles should be more revealing for trends.

Edited November 22, 2013 by Mucka

[Tom Jarvis]

UKMO at 144 is much better at getting hights into Greenland with not so many shortwaves to restrict a GH

[Panayiotis]

High now starting to topple but it looks to be ridging into Scandi, if it did that the easterly would be cold with the piece of the PV near Russia...

Nope it gets flattened by the PV..

Edited November 22, 2013 by Panayiotis

[Cecil Hogmanay Melchett]

UKMO at 144 is much better at getting hights into Greenland with not so many shortwaves to restrict a GH

 

Looks poor to me TJ.

[Tom Jarvis]

Looks poor to me TJ.

compared to the gfs its much better

[Methuselah]

Err No. I thought that you meant that westerlies are more likely to verify on computer models than other wind directions - but hadn't shown the statistical evidence to back this up. So is that not what you meant?

In a way I agree, Chio...But, in another, I agree with Shed: I do suspect - though cannot prove (this side of Eternity anyhow) - that, statistically, rather more FI Arctic incursions and 'stellar runs' fail to materialize than do episodes of bog-standard British mush? Then, that's only cos I don't credit FI charts with being all that much more than numerical guesswork, anyway???

 

Note: the above is not meant as a negative criticism of numerical models per se; just a comment on the present abilities of computers... 

[Cecil Hogmanay Melchett]

compared to the gfs its much better

Again,the differences are miniscule and there is little chance of a Greeny high anytime soon unfortunately..

[Summer Sun]

12z still offering something from the north later next week

 

 

But its shorter lived than the 00z and 06z runs

 

 

A strong PV this afternoon along with a powerful Jet as a result the coldest air stays in eastern Europe, whilst high pressure never goes far away from the UK when low pressure tries to get in

Edited November 22, 2013 by Summer Sun

[swfc]

gfs explodes the pv in fi

[Chess01]

Got to love the gfs when will it ever get something consistent

[Mucka]

Pretty awful GFS 12z taken in isolation though I suspect it is showing a worse case scenario and there will be more cheer among its ensembles

Edited November 22, 2013 by Mucka

[Cecil Hogmanay Melchett]

A most forgettable GFS 12z with a very powerful jet and a strong PV.

UKMo going the same way...

[MPG]

Regrettably MPG it's a fact of life that post 144hrs SW'erlies are more likely to verify as depicted than straight N'erlies. Clearly I'm talking from a statistical standpoint here, so there is nothing to say next weekends plunge will not deliver as shown by GFS, indeed it could even upgrade. However at the kind of range currently involved and particularly in view of the wider hemispheric pattern, a shift east over the coming days is more likely than not...that's if any potential N'erly doesn't get completely dropped of course.

 

 

Over the last few years, Shed, westerlies have been continually been programmed to return following easterlies, south easterlies, northerlies etc and have been delayed and not verified at all. Please show me the statistic that shows the number of westerlies forecast, compared to the verification of said westerlies for the UK in FI, to back up your standpoint.

 

 

Err No. I thought that you meant that westerlies are more likely to verify on computer models than other wind directions - but hadn't shown the statistical evidence to back this up. So is that not what you meant?

Thanks Chio for clearing that up. Always good to get a proper understanding...

Edited November 22, 2013 by A Boy Named Sue
No need for that last sentence.

[bluearmy]

the so p/v is either exploded or strong in fi gfs ........................................

[Methuselah]

Time for another wee warning: if you have a point to make, just make without resorting to churlish personal slights...You only slight yourself! 

[Frosty.]

There is far too much despondency with the Gfs 12z op run, there is nothing mild on this run, temps are generally below average, just about scratching average for a day or two and there are many rather cold days with overnight frosts and the 12z tries 3 times through the run to bring a cold blast from the nw / n....it's got potential.

[chionomaniac]

In a way I agree, Chio...But, in another, I agree with Shed: I do suspect - though cannot prove (this side of Eternity anyhow) - that, statistically, rather more FI Arctic incursions and 'stellar runs' fail to materialize than do episodes of bog-standard British mush? Then, that's only cos I don't credit FI charts with being all that much more than numerical guesswork, anyway???

 

Note: the above is not meant as a negative criticism of numerical models per se; just a comment on the present abilities of computers... 

I suspect that it is just far more noticeable on a forum like this because the majority of members are far more interested in this type of pattern than the westerly pattern.

 

I think that unless there is statistical evidence as CH suggests, then we won't really know.

[weatherguy]

I recall a poster, chio or lorenzo I believe (if someone else remembers so I can give proper credit), talking about the relationship between the stratosphere and troposphere being like a dance, where they take in turns to influence the PV.  Well, it seems that with the stratosphere continuing to cool rapidly and the PV becoming gradually more organised, the impact of MLB "buckling the system" seems to be becoming reduced and the state of the stratosphere is playing a greater role.  

 

In my opinion, I can't see any sustained cold for at least the next 2 weeks.  At the same time, it certainly doesn't look zonal, with positive HP anomalies centred near to the UK.  As a result, natural wobbles in the PV will leave us in with a chance of receiving topplers, so wintry weather is possible.

 

By no means a "winter's over" post, but my view with regards to pining for anything substantial/sustained  

[Mucka]

GFS short ensembles (Northern England to highlight possible northerly incursion toward end)

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=254&y=37

[Ian Brown]

Over the last few years, Shed, westerlies have been continually been programmed to return following easterlies, south easterlies, northerlies etc and have been delayed and not verified at all. Please show me the statistic that shows the number of westerlies forecast, compared to the verification of said westerlies for the UK in FI, to back up your standpoint.

Come on Chiono, the weather forums are littered with epic failures - especially of the easterly type. Next time we see an easterly, say agreed by 2 of the 3 big models, I will lay you appropriate odds on it actually verifying. Then when Uncle Barty is on the horizon at day 6, you can reciprocate ! 

Edited November 22, 2013 by Ian Brown

[EML Network]

Yuk, what an awful 12z. from the GFS. 

 

Rinse and repeat * 2 , High pressure meanders around and straddles the UK throughout the run, offering nothing of any real interest to anyone other than those who wear a wig.

[SMU]

Evening All-

 

Not much time to add to the discussion-

 

2 points-  It now seems that the GFS & MOGREPS & Decider models were wrong to topple the high & revert back to the westerlies- even though the ECM showed it for a couple of runs-

 

Also Shades of Nov 80 / Start Dec 81 from the models today ( moreso the ECM ) as we see atlantic pressure trying to ever so slowly nudge into southern Greenland....

expect the GFS to be useless as ever

 

S

Edited November 22, 2013 by Steve Murr

[Mucka]

So much for GFS ensembles giving any encouragement. Unimpressive.

8, 10, 12 and 18 for a little light relief in FI.

Edited November 22, 2013 by Mucka