Winter Model Discussion 12Z 22/1/13 onwards.

[shaky]

Anybody going to mention the undercutter on friday from the ecm!!maybe bring a lot of snow across england before it clears away!!

[Summer Sun]

A good run from GFS this morning if you've had enough of this cold after an unsettled start to next week high pressure slowly builds up from the south with conditions becoming more settled over time

The week starts with a deep depression

By Friday high pressure is coming closer

This process continues into the start of February

ECM also show pressure rising to the south at the end of next week

So in summary a rapid snow melt seems likely into next week with a risk of flooding for some before things look like becoming more settled as we enter February

[mulzy]

As suggested by members, very poor output again. The PV looks very organised and intense and by the looks of it it ain't moving too much (i.e. a big lobe of remaining in Eastern Canada /Western Greenland). Azores High also evident (like it has been most of this winter and most of last winter) thus leading to a largely positive NAO. Things may change and it may change quickly but for now (according to NWP), average to mild (perhaps very mild) is the order of the day in the medium term. And as I suggested yesterday, no cold before Feb 10th (maybe even later) - the pattern we are entering is a pattern that can remain entreched for weeks.

We can continue to pin our hopes on the SSW, MJO and the other teleconnections stuff, but currently the NWP models are not buying a quick return to cold.

Edited January 23, 2013 by mulzy

[bluearmy]

As the nearermodelling shows, without the second depression coming along behind, our block may have held out. Anyway, that's all irrelevant now. Can't see how we get back to deep cold until after the first week feb. Decent consistency on low heights over scandi around the 7th from naefs. Will the period leading up deliver a more settled spell or are we destined to sit under more atlantic troughing? Those saying that there are no signs of cold returning are not looking at the bigger picture.

[Summer Sun]

This mornings ECM ensembles

[TEITS]

We can continue to pin our hopes on the SSW, MJO and the other teleconnections stuff, but currently the NWP models are not buying a quick return to cold.

Pretty much the point I was making yesterday. It doesn't matter whether the SSW, MJO, AO, NAO, BO, M&S, B&Q, WHS, are looking promising it doesn't mean sweet FA if this isn't being shown in the model output.

Very little has changed in this mornings output as we need to search into deep FI for any hope of a cold spell which looks unlikely to return until the 4th Feb at the earliest.

Edited January 23, 2013 by THE EYE IN THE SKY

[markg]

up to 126 hrs on the 0600 gfs is the azores high trying to link up with the euro/scandi high and would that be good or bad for our next return to cold as at the moment everything is 300hrs plus for cold?

[Weathizard]

Those ECM ens are certainly the mildest I've seen for a long time. Outlook is bleak at best currently, I'm trying to find something positive to say about any of the models but looking through them they are awful for cold within 240-300hrs. The real killer for deep prolonged cold this winter has been that ruddy daughter vortex over eastern Canada/Greenland to my eyes, a few times we have had a ridge of high pressure pushing north but it just cannot go towards Greenland with that lobe there. Its a shame really I think we have just been very unlucky because of this piece of vortex setting up shop here.

Still time for things to change though of course, 6 or so weeks left for something but there are no real positives in the models at the moment and no real sign in a reliable of the Canada daughter vortex moving very far and if it does it seems to reform over the pole which would be a real killer with the azores high in situ.

[BLAST FROM THE PAST]

Whats the 06z upto? Atlantic getting held with a strengthening N/Euro Scandi HP devloping t132 on?

BFTP

Edited January 23, 2013 by BLAST FROM THE PAST

[Craigers]

Once again gfs throws in another change on the 06z chart.

00z

06z

[SnowBallz]

This mornings ECM ensembles

In the extended ENS, its fairly pronounced we can see signs of gradual cooling down, following the brief mild incursion; clustering groups more away from 10c and towards 5c. Somewhat de ja vu here, as I recall similar drop-off tight clustering (mean convergence) appearing in extended ENS in late Dec and into early Jan. Thereafter, the signal become more and more amplified and we all saw a sharp drop in ENS, to sub-zero indices.

For me, that's enough to give me confidence that NWP is toying with the idea of moving back towards another outbreak of cold. It would be an entirely different picture were the spaghetti scatter to be favourably mild or, at best, broadly neutral - but this isn't the case. Where do we go from here? Personally, I'll be looking to see whether this MR-LR pattern remains consistent and moreover whether it begins to amplify ala late-Dec.

If I recall correctly, the guidance was for a transient return to mild, before a return to colder conditions set-in thereafter. If we look objectively at the ENS - as a 15-day story - this guidance is quite well illustrated. Always good to take a step-back and look at the broader picture, because often the biggest change in patterns are not immediately obvious when analysing at the micro-level; they become lost in the obvious background noise which is evident in a stochastic algorithm.

What will be of increasing interest, is whether more perturbations within the EC32 trend favourably towards colder evolutions; I think Matt informed us yesterday that 26 out of 52 were of this inclination, so precisely a 50:50 split. If we take a guidance from the 15-day ENS of a move towards a colder evolution, then you'd logically expect to see perhaps growth in those EC32 perturbations, possibly 32/52 (62%) when the next cycle is run. Obviously, the probability would remain only two-thirds, but it's the growth of a trend which important here; again, micro v macro.

For me, the story is not what's immediately in the road in front of our car, but more over the hill and into the horizon. We need to widen our field of vision, if we want to spot the next cold spell of weather coming up. Interesting 5 days or so coming up...

[Tim Bland]

Hmm Not looking good is it. Lets hope something changes soon and we loose that blimin PV over Greenland. I fear if the models aren't looking better next week then we will have pages and pages about how it takes us to the end of Feb and the sun is getting stronger...Followed by a flood of winter is over posts.

Lets hope it doesnt come to that and just as the last snow is melting up pops the eyecandy end Epic comments from Steve M. Hopefully GP will give us some input in the comming days as well and throw us a straw or two!

[Robbie Garrett]

The models are still struggling with the vortex chunk and it's ultimate destination, I remember from my email the MetOffice forecaster that replied if ever there was a westerly bias built into the models, with lack of data from north/northeast and east quadrants of the country. I suspect as they said it may be something to do with climatology, hence why we are see Bartlett High in the later stages of the GFS and hence why the GFS defaults to what we would hate to see..

One thing to mention is that within the next 200 hours, it is looking very likely that low heights across the Atlantic with high pressure to our south. Like all year around, the models will change but just how quickly.

It looks likely high pressure should start to build in the Atlantic and go upwards towards Greenland, for something mid month but as early as the first week of February.;

Edited January 23, 2013 by Robbie Garrett

[bradymk]

Unfortunately a poor output for cold in the future at the moment however I think we are going to have to put up with it if we want another cold spell. Some beauty members at the end of the 00z GEFS suite. I know this is well in FI but thats about all we can look at at the moment for any cold. A Greenland High still a good possibility beginning at this timeframe so hopefully more members start to show this and they move closer to a more reliable timeframe. We shall see.

[nick sussex]

In the shorter term still alot of uncertainty with Friday in terms of snow.

Much depends on how much trough disruption occurs and the surface flow ahead of the fronts.

The medium term looks very unsettled and milder but before everyone starts writing winter off its best to wait to see where exactly these lobes of the PV end up, the remnants of the Canadian vortex will weaken and the models still haven't decided what happens afterwards.

Taking output at face value while a pattern change is taking place is liable to lead to the wrong conclusions.So best we wait for that change and see what the models then want to do after things settle down.

[lord stratus]

Unfortunately a poor output for cold in the future at the moment however I think we are going to have to put up with it if we want another cold spell. Some beauty members at the end of the 00z GEFS suite. I know this is well in FI but thats about all we can look at at the moment for any cold. A Greenland High still a good possibility beginning at this timeframe so hopefully more members start to show this and they move closer to a more reliable timeframe. We shall see.

Give it a couple of days of the upcoming mild weather and the forum will start getting excited about those FI charts. I believe we won't have to wait long for another cold spell, I feel height rises from the south will eventually return us to much colder conditions.

[Tamara]

The operational ECM for a week Saturday at the start of February is an amazing resemblance for exactly the same chart at the same time in the first weekend at the start of February 1985 . Extra scary I was only thinking about Jan/Feb 1985 yesterday. Worth looking in the archives at what had preceeded it...and more importantly what came after it just a week later... The background pattern now is not too different to then either..

Edited January 23, 2013 by Tamara Road

[bluearmy]

big change in the meto 30 dayer re the dropping of 'colder conditions by mid feb'. very odd considering no 32 dayer today. can ian maybe enlighten us as to the reasons. the only thing i can think of is advice from the strat people re downwelling not being likely to affect the uk in receiving a cold pattern which was the previous way of thinking.

the wed update appears to have been taken off the website. very odd.

[Blizzardof82]

big change in the meto 30 dayer re the dropping of 'colder conditions by mid feb'. very odd considering no 32 dayer today. can ian maybe enlighten us as to the reasons. the only thing i can think of is advice from the strat people re downwelling not being likely to affect the uk in receiving a cold pattern which was the previous way of thinking.

the wed update appears to have been taken off the website. very odd.

As I have said before the MetO are as fickle as the models and only can report on what they see in the output, closer range is when the human input comes in and that is not always correct. I think we will have a better understanding where winter is taking us after the weekend when hopefully the models will start picking up trends.

Edited January 23, 2013 by Blizzardof82

[bluearmy]

big change in the meto 30 dayer re the dropping of 'colder conditions by mid feb'. very odd considering no 32 dayer today. can ian maybe enlighten us as to the reasons. the only thing i can think of is advice from the strat people re downwelling not being likely to affect the uk in receiving a cold pattern which was the previous way of thinking.

the wed update appears to have been taken off the website. very odd.

they have now amended with a reference taht temps are expected to be 'not far from seasonal norm'. that contrasts with yesterday's colder condition dominating again. so my question is valid. mogreps-15 must be throwing out a scenario at two weeks which cant evolve into what they were previously looking at. any other explanation ?

[nick sussex]

they have now amended with a reference taht temps are expected to be 'not far from seasonal norm'. that contrasts with yesterday's colder condition dominating again. so my question is valid. mogreps-15 must be throwing out a scenario at two weeks which cant evolve into what they were previously looking at. any other explanation ?

In terms of the downwelling of the SSW I don't see how they can definitely know at this stage what impact that will have at this range.

IMO its just not worth reading too much into those updates especially when they haven't even seen the latest ECM update.

Its just a cover all bases forecast, I mean not far from the seasonal norm means exactly what. Why not just say temps close to average.

[BLAST FROM THE PAST]

The operational ECM for a week Saturday at the start of February is an amazing resemblance for exactly the same chart at the same time in the first weekend at the start of February 1985 . Extra scary I was only thinking about Jan/Feb 1985 yesterday. Worth looking in the archives at what had preceeded it...and more importantly what came after it just a week later... The background pattern now is not too different to then either..

From this

to this.......in 7 days

BFTP

Edited January 23, 2013 by BLAST FROM THE PAST

[snow drift]

In terms of the downwelling of the SSW I don't see how they can definitely know at this stage what impact that will have at this range.

IMO its just not worth reading too much into those updates especially when they haven't even seen the latest ECM update.

Its just a cover all bases forecast, I mean not far from the seasonal norm means exactly what. Why not just say temps close to average.

They must have had a stonrg signal for cold and that has reduced and therefore gone for the middle ground. I would agree with regards SSW and would be more how they see the upper air pattern at that time. If it changed back, most of ther population would not notice. Its only us that hang on every word.

Edited January 23, 2013 by snow drift

[Catacol]

Back after 1 day away from this to calm down a bit. Apologies for the moments of "ranting."

MetO may well be responding directly to strat warming in their forecasts. I said it a few days ago, and will say it again - the strat warming is displacing the canadian vortex to the atlantic where it will sit and then join with the siberian one. This produces low heights to the north and rising pressure to the south that will be very hard to shift. It isnt really about single op runs or ensemble means - though these continue to be poor - it is about a displaced vortex being in exactly the wrong position for cold and an interpretation of this being the dominant driver of conditions in our sector of the NH.

It is not all doom and gloom though, because for as long as we have the residual impact of the warming episode we have a very much weakened vortex and we know already that this had had big tropospheric impacts. This should allow high pressure to build more easily... BUT this will only occur to our north if the section of displaced/split vortex moves away. Others seem certain this will happen; some others talk of the vortex dying in situ over the atlantic. I am not convinced by either in the next 2 weeks.

So in conclusion I think we have a period of mobile weather for about a fortnight and then we need to see what happens to our poor ailing vortex. GP's call of a drop towards us on the flank of a Greenland High matches the MJO phase and growing tendency in angular momentum, so maybe this is a pattern that will begin to emerge. Notable that RJS is still keen on a very cold February with strong heights to our north. What these guys know and understand dwarfs my own knowledge so I bow to their feelings quite happily. However the Met update is indeed significant and perhaps points to the ex-Canadian Vortex being a major party pooper beyond the medium term.

We have been talking about the Canadian vortex all winter, right back to Chio's correct call of a CW episode in the threads in November. I think winter 2012/13 may go down as the year we all learned how significant conditions over Canada can be for our chances in winter (those of use who, like me, hadnt really appreciated that before!)

[Tamara]

From this

to this.......in 7 days

BFTP

I think taking into account what had happened in January 1985 with a lot of cold snowy weather (and following a big warming in the stratosphere at the very start of the year) then we see an example of the initial downwelling effects over our part of the NH, and then a break as the polar vortex re-adjusted, and then a secondary effect a little while after - such as that February spell provided. I think the point is that one can draw reasonable comparisons with the here and now. We are about to see a break here in the cold pattern as the vortex remnants over Canada are transported east, and whilst we obviously can't guarantee the same thing will happen again this time with a February cold spell - it does illustrate how these stratospheric/tropospheric patterns often evolve. And how long the lag period can be from the initial significant polar vortex disruption time.

Edited January 23, 2013 by Tamara Road