Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Jason M]

That comment can only be validated in 8-10 days time though!!!

Also to add, I think the GFS ensembles are not reasonably confident of anything at day 8-10

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Yep, but it shows on the models and having answered your question I'd be interested to know why you disagree with the points made above? It may all change by tomorrow but the reality is that things don't look good tonight although I'm interested if you can explain why I and others might be wrong based on current output?

Jason

[Cheshire Freeze]

Seasonal models are pretty useless and experimental. They mean little IMO.

That might be the case but when you've got a large proportion of them gunning for the same scenario you being to think it's more than coincidence. Then you add on top of that the trends from the NWP in the medium term and you have more of a bleak outlook than a rose tinted one.

Anyway, Steve Murr sums it up above if it helps you to hear my sentiments from a more 'looked up to' member. Fed up of having to defend my assessments when most of it is simple common sense meteorology.

Edited December 19, 2012 by CreweCold

[cold snap]

http://www.meteociel.fr/modeles/bome_cartes.php?&ech=228&mode=0&carte=0

Nice Bom model

Edited December 19, 2012 by cold snap

[UV-RAY]

Very poor outlook tonight from the models.

And no sign of anything sustantial in the way of cold and possible snow other than the odd transient affair for the north.

ive reduced my posts daily as I feel that as well as their being no signs of cold some are clinging on to the ensemble means from the NAEFS

that they clung onto last cycle.

a west based NAO is developing with blocking over canada, the axis of the high is WAY wrong for the uk.

To far North and to west with the CAA struggling to get south of iceland.

This pattern is MILD for the Uk because the teleconnection pattern is low pressure south of iceland and high pressure close to the SW of the uk.

We are nearly the point where the models can well and truly finish December off mild and miserable and with the CET leaping up towards above normal values.

I think we are pinning all hopes on a major warming event in the stratosphere delivering the blocking that it has the potential to do for the UK, if not I would revise my comments in the jan discussion of the in depth thread.

A ten degree mild xmas here and no sign of cold till jan unless the NAO can swing east, which is unlikley

s

A realistic post on where we are heading, makes for grim reading but if we don't see a SSW then January could well follow December as a month of nothingness.

[Downburst]

Seasonal models are pretty useless and experimental. They mean little IMO.

You have to be joking? Like the team turns up to work laughing out loud, "let's run another useless run for the laugh, sure we may as well as I've run out of seaweed.."

[Ian Brown]

That comment can only be validated in 8-10 days time though!!!

Also to add, I think the GFS ensembles are not reasonably confident of anything at day 8-10

http://www.wetterzen..._London_ens.png

We will see Chris, but what both the GFS and ECM are showing has a broad margin for error that actually won't make much difference either way in terms of the actual pattern for the UK. Basically as CC and Steve M say by days 8-10, everything is wrongly aligned for the UK, with the Euro High in place and nothing to flatten it in the way that you might have if you had depressions moving East or South East.

[Zakos]

It has to be said the heights to our south look like ruining the cold spell.But, the possible northerly is a long time away.

This chart is poor for cold prospects, but it it is 240 hours, a lot can change within that timeframe.

these charts show the 12z from today, 2 days ago and 4 days ago, for 1.00pm on Christmas day.

Look how much the hemispheric pattern improves

The Arctic high was forecast 240 hours ago, but look how, over the time period, the Arctic high moved closer and closer and closer to Greenland each day.The most important trend however is the weakening of heights to our south we must hope this trend continues.

With that in mind, I wonder how this 240 hour chart would look, were a similar change to occur?

All speculation at this point of course. But we are definitely going to see a significant rise in pressure over Greenland, and while HP to our south may prevent the Uk from receiving cold, there is still plenty of time for change.

It would be a cruel twist if a west based -NAO were to develop. Siberian high too far east, and then a Greenland High forms, only for it to be centred too far west!

Edited December 19, 2012 by Zakos

[LomondSnowstorm]

Fine then, I didn't want to have to do this but you've driven me to it. If you really want, you can spent the festive season at mine:

[ronan]

Very poor outlook tonight from the models.

And no sign of anything sustantial in the way of cold and possible snow other than the odd transient affair for the north.

ive reduced my posts daily as I feel that as well as their being no signs of cold some are clinging on to the ensemble means from the NAEFS

that they clung onto last cycle.

a west based NAO is developing with blocking over canada, the axis of the high is WAY wrong for the uk.

To far North and to west with the CAA struggling to get south of iceland.

This pattern is MILD for the Uk because the teleconnection pattern is low pressure south of iceland and high pressure close to the SW of the uk.

We are nearly the point where the models can well and truly finish December off mild and miserable and with the CET leaping up towards above normal values.

I think we are pinning all hopes on a major warming event in the stratosphere delivering the blocking that it has the potential to do for the UK, if not I would revise my comments in the jan discussion of the in depth thread.

A ten degree mild xmas here and no sign of cold till jan unless the NAO can swing east, which is unlikley

s

Are your views based on the fact that the chances of an Easterly has diminished and snow and cold chances have transferred to the NW/N?

[chris55]

Yep, but it shows on the models and having answered your question I'd be interested to know why you disagree with the points made above? It may all change by tomorrow but the reality is that things don't look good tonight although I'm interested if you can explain why I and others might be wrong based on current output?

Jason

My point is that we don't need a monumental shift in the pattern to get something more interesting to our shores. If we were staring down the barrel of a 1988 type flow with a strong PV to the north and west, I'd be agreeing that things look bad,

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00119890115.gif

But we are not,

http://www.wetterzentrale.de/pics/Rtavn1441.png

We have a potential negative NAO in the making with some very cold 850s spilling out of the Arctic on our side of the globe and a smallish shift in the projected pattern would put us in the colder scenario. I know we have a signal for the Azores/Euro/Iberian high to come into play to the south, but look at how the models have dealt with that this week, not so well. It has become more of a transitory feature as we have come into the closer timeframes.

When looking at the models at such timeframes we have to analyse them as we see fit, and not take them at face value. When we look to be heading for a cold spell, Steve is always telling us to ignore certain runs!! Why don't we hear that at the moment??

So overall I see some potential in the models, and as this is the hunt for cold thread, that is what I am doing, looking for the cold potential in the charts.

[nick sussex]

Yes, ironic how after all the chopping and changing and inconsistency in the NWP, we can now have reasonable confidence in where we are likely to be by days 8-10. And it's not a good place if your looking for cold.

Yes Ian you can always rely on consistency from the models when you're hoping they won't be!

The best hope is that the pattern is edged east and eventually the UK finds itself on the colder side of any troughing. Hopefully that happens sooner rather than later.

[Gibby]

Good evening. Here is the evening report on the 12z output from GFS, UKMO and ECM for today Wednesday December 19th 2012.

All models are agreed now on the pattern between now and Christmas Eve. A succession of Low pressure and associated troughs will continue to feed NE over the coming 5 days. There will be some drier and brighter interludes, the most noteworthy of these over Friday. Rainfall amounts will be large for many with flooding no doubt making the headlines again between tomorrow and Christmas as the weather remains deeply unsettled. There may be a little snow on the high ground of the far NE and a lot of snow for the mountains of Scotland as the SE flow carries some cold air in from Europe for a while. Temperatures elsewhere will remain well up to the seasonal normal but it will feel cold in the wind and rain.

GFS shows Christmas 2012 as a wet and soggy one as Low pressure remains over the UK for much of the time with heavy rain continuing to occur with frequency in the normal temperatures and winds from the West. As we approach New Year and beyond the unsettled weather persists with the heaviest of the rain transferring to more Northern areas while the South become rather mild at times.

The GFS Ensembles show a lot of precipitation over the coming two weeks, especially in the South. The temperatures though averaging near to normal on tonight's graph shield the fact that there is a lot of colder options shown with the operational very much on the milder side of the pack. In the second half of the output there is a huge spread between +6C 850's and -10C 850's indicating that the pattern is still very fluid.

The Jet Stream shows a continuation of the sine wave pattern to the flow for the next 5-7 days before the flow flattens West to East close to Southern Britain thereafter.

UKMO for midday on Christmas Day shows a green Christmas for the UK with Low pressure stretching from Norway to the Hebrides with a relatively mild and unsettled SW flow with rain or showers through the day.

ECM shows a deep Low to the North of Scotland with a colder and showery day shown following the Christmas Eve rain. There could be some snow on Northern hills and mountains from the showers with the risk of more prolonged rainfall in the South. In the days that follow something of a North/South split in temperature develops as the North stays rather cold with some wintry showers while the South stays cloudier and milder with some further rainfall creeping slowly Northwards at the end of the run.

In Summary tonight there is very little to say other than it looks like the weather is trying it's hardest to give disruption over the UK over the holiday period. Unfortunately for many it's likely to be disruption from rain rather than snow as the weather is stuck in a rut with Low after Low impacting on the UK with prolonged rainfall in temperatures close to normal for most. There will be a few drier interludes but they will be brief and fleeting and there may be some rather colder air at times in the North but away from higher hills and mountains there will be very little if any sustantial snowfall for any low lying areas of Britain in the forecast period.

[Bristawl Si]

Underwhelming charts today for next 10 days but the Strat 'experts' seem to be focusing on 10th Jan or thereabouts so i'll patiently wait til then.

[Cheshire Freeze]

Are your views based on the fact that the chances of an Easterly has diminished and snow and cold chances have transferred to the NW/N?

No he's summing up the model output as he sees it and FWIW, in my opinion he's on the money in what he says in relation to what is CURRENTLY shown.

[UV-RAY]

Are your views based on the fact that the chances of an Easterly has diminished and snow and cold chances have transferred to the NW/N?

Speaking as someone from the NW then no Steve isn't, a west based NAO is no good to anyone looking for cold, unless it's cold rain that floats your boat or you live on a mountain.

[chris55]

That might be the case but when you've got a large proportion of them gunning for the same scenario you being to think it's more than coincidence. Then you add on top of that the trends from the NWP in the medium term and you have more of a bleak outlook than a rose tinted one.

Anyway, Steve Murr sums it up above if it helps you to hear my sentiments from a more 'looked up to' member. Fed up of having to defend my assessments when most of it is simple common sense meteorology.

You have not got to defend your assessments, everyone is entitled to a different opinion. That is what makes this a forum.

[ANYWEATHER]

Ok for long term cold ATM, nothing really showing, but for the Xmas period, looks fairly cold with a polar maritime air in situ across the Uk, looks like this is more or less the final jurarsdiction ,but the devil is really in the detail! Really not what some cold lovers want, but at least it does not look as though we will see the the springlike christmas temps we did last year. As they say, theres gonna be a "nip" in the air. Certainly some snow for the high ground of Wales, Northern England, and Scotland. This may well upgrade nearer the time........

[Jason M]

You have not got to defend your assessments, everyone is entitled to a different opinion. That is what makes this a forum.

Indeed, and its good that this debate has stayed civil :-)

Just to pick up your point in relation to my earlier post, I don't take charts at face value especially at 8-10 days out. There is every chance that in 10 days the actual weather would look different, but the solution as showed by ECM tonight is credible and has support both between models and various runs. We should probably agree to disagree at this point :-)

Jason

[SMU]

Are your views based on the fact that the chances of an Easterly has diminished and snow and cold chances have transferred to the NW/N?

its based on the fact that the pattern is no good for anyone.Things may change in our favour and if they do the people of the NW and scotland may be the ones to benefit.As it stands though i would put it in the very unlikely catagory out to day 8, which will bring us to the cusp of 2013.S

[ronan]

Speaking as someone from the NW then no Steve isn't, a west based NAO is no good to anyone looking for cold, unless it's cold rain that floats your boat or you live on a mountain.

Wasn't having a go at Steve as I value his input on here. It's just been very confusing on here this evening as some are saying the charts are really good and some are saying that they are crap! Lol.

[Froze were the Days]

Unfortunately the milder breakdown over the xmas (and before) period was always on the cards once that Russian High shifted southwards and we have to start looking else where, unfortunately as mentioned by a few others a west based NAO is now setting up or appears to be towards FI and that again is not an encouraging sign.

Getting bad vibes about this winter, we've had sniff's of good synoptics ruined this month by small features and now I get the feeling the start of January isn't going to get any better - just a hunch.

Edited December 19, 2012 by Froze were the Days

[Captain Shortwave]

Given the way the charts have chopped and changed recently, I would want to give the models more time before writing off December. Look how much they have changed over the last few days. Whilst people seem to think that some are chasing cold. We have seen the azores high modelled to build only for that to back track. I wouldn't rule out mild or cold at the moment. As both seem to edge close to us only for them to slip away again.

I'm sure things will look a lot different tomorrow. Maybe better, but of course could be a lot worse.

The metoffice seem to be bullish about their average overall forecast temperature wise and that seems to be the way things are shaping up.

[Paul_1978]

its based on the fact that the pattern is no good for anyone.Things may change in our favour and if they do the people of the NW and scotland may be the ones to benefit.As it stands though i would put it in the very unlikely catagory out to day 8, which will bring us to the cusp of 2013.S

Who are you and what have you done with Steve Murr. Can we have the old 'Positive' Steve back please?!

[Spurry]

Given the way the charts have chopped and changed recently, I would want to give the models more time before writing off December. Look how much they have changed over the last few days. .

Have they changed that much? , apart from the odd run that predicted we may see some cold(er) weather over xmas,most of the models have been pretty consistent in my opinion ,pointing at a normal/average/wet run between now and the new year.

i would dearly love them to suddently change to a cold/snowy outlook ,but i suspect that we will be well into January before that materializes

[ANYWEATHER]

its based on the fact that the pattern is no good for anyone.Things may change in our favour and if they do the people of the NW and scotland may be the ones to benefit.As it stands though i would put it in the very unlikely catagory out to day 8, which will bring us to the cusp of 2013.S

Ok Steve, dont get too upset. things will get better, I think its quite a festive outlook, at least no dreaded Southwesterlies during Xmas...