Winter Model Discussion 18Z 19/1/13 onwards.

[bluearmy]

The blocking for next week which looks to have decent agreement doesnt look very warm to me. Where winds remain light there may be enough residual snowcover to give some low night time temps. Mid atlantic block to folllow i think.

[nick sussex]

The blocking for next week which looks to have decent agreement doesnt look very warm to me. Where winds remain light there may be enough residual snowcover to give some low night time temps. Mid atlantic block to folllow i think.

Morning BA yes it doesn't look mild.

The models bring some colder air in before the low heads away to the north, especially for eastern and se areas it could still be on the cold side.

In terms of the breakdown any thoughts on that, there still seems to be disagreements with whether there will be some snow off that.

[Timmytour]

There's been a lot of technical talk about what the models show, and how it leads to a breakdown of our cold spell, but what might keep it in place?

Where here's a non technical "birds-eye" view of it....

if you look at the 850hpa temps here at T168 which it must be stressed is, at this stage, deeper in FI than one might normally consider...

What you may be able to work out from the pattern of yellows and oranges, is the shape of the Great Atlantic Swan.

Now, at the moment, she is flying in a north north east direction, looking west. What we need her to do is fly north west, up the west coast of Greenland, while looking towards the UK. This would usually provide the conditions to allow an easterly into the UK, and if that's tapping into some cold uppers, that would be a legendary outcome!

There's still time for that to be happen..... the continuation of our cold spell is not so far away ....as the swan flies! [/tongue back in cheek]

[Ryan Dutch Weatherman]

Matthew Hugo â€@MattHugo81

Latest EC32 day maintains a trend as we progress further into Feb for northern blocking to return and for a trend towards cold weather again

[weather_it_will]

Direct pathway from the north at T384 which is what we would have seen as I mentioned last night on the 18Z GFS

[Jason M]

Wow, I wasn't expecting that overnight from the GFS 18z and 00z.

We end up with a Euro high scenario at +192 on both runs ? cant wait to

see what the more senior members make of it as I'm at a loss to be honest

It's the logical reaction to the PV being sat in the mid Atlantic tbh. A similar situation to Dec in truth.

Hints of HLB deep in FI now. We saw this in Dec also and it never happened although there are obvious differences this time, so maybe we will get a lucky break this time.

Jason

[IDO]

Morning BA yes it doesn't look mild.

The models bring some colder air in before the low heads away to the north, especially for eastern and se areas it could still be on the cold side.

In terms of the breakdown any thoughts on that, there still seems to be disagreements with whether there will be some snow off that.

The op does not, but thats a clear outlier for cooler temps. The mean (London):

Suggests average to mild. The ECM has long fetch SW'lys bringing even higher temps. It depends where the ridging settles so the Op/control could be onto something (or not).

[nick sussex]

The op does not, but thats a clear outlier for cooler temps. The mean (London):

Suggests average to mild. The ECM has long fetch SW'lys bringing even higher temps. It depends where the ridging settles so the Op/control could be onto something (or not).

If the models do develop that ridge to the south for a few days then it could stay cold if the surface flow is off the continent, this more likely though for eastern and se areas.

The ECM postage stamps are generally more mobile at 168hrs and milder than the operational with a more sw flow:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2013012200!!/

Given the NH profile with the PV moving out of Canada then I think the best scenario is for high pressure to ridge far enough north for a few days at least it will be drier and still be on the cold side.

The ridge though is unlikely to last as the energy will eventually flatten this but thats the best I can see this morning until theres a change upstream.

Theres always a bit of after the lord mayors show when those lucky enough to have seen some snow suffer the indignation of that melting!

And hence the mood in here normally implodes especially when the models don't show a quick return to colder conditions, however I think we just need to see what happens in a few days when the models settle down.

I think we have to accept that barring some astonishing backtrack it will turn milder either at the weekend or soon after and then its damage limitation for a while so a ridge getting far enough north might be okay and then hopefully any mild mush won't last too long.

[SMU]

I think a lot of people are in denial to what the models have been showing- there has been been clear agreement from the big 3 for a good few days - where as last week it was the GFS V Euros & finally we saw a swing back.

There does remain the chance of a snow event on the transition- the GFS is has been playing with it- we may be lucky & see the trough dig a little more south- the Euros sadly less enthusiastic & take it through faster.

Whats clear is generally after day 5 the flow is a very strong run from the azores- aimed right at northern Europe- the UK *MAY* be lucky - where if the energy drops a tad further south than anticipated we end up with southerlies or a slight tug off the continent which would keep it 'slightly' colder for longer- but only delay the inevitable.

Yesterdays 12z ECM pointed to a mild trend right out to day 15-

http://www.knmi.nl/e...agse/index.html

So whilst the 32 dat DET ecm may be shifting towards some Northern blocking those dates seem to range between at the earliest the 4/5 th feb all the way out to the 20th Feb-

8 weeks down so far & not a sniff of a greenland high this winter- only 4/5 to go- The fat lady warming up her X factor audition...

We will need to see some changes quite quickly once the the mild flow develops as its a difficult path back from there-

Im not saying it cant change- however there arent many signals infront of us to indicate it will change- THe only glimour of light is at day 10 in some of the GFS ensembles for heights towards greenland-

Anyway nobody should assume something is going to happen for the UK, thats possibly the worst strategy ever as nothing is ever certain.

It will be a long week in here so im going to steer clear.

S

Edited January 22, 2013 by Steve Murr

[Frosty.]

A much milder spell on the way, the ecm and gfs from sunday onwards once the back is broken on our current cold spell on saturday, next week shows pressure rising to the se, lower to the nw, sw/ne jet profile = yuck.. probably a nw/se split eventually (wettest nw/driest se) but unsettled and milder for all at least the first half of next week, beyond next week, who knows?Deep FI on Gfs 00z looks to be trending colder but nowhere near as good as the current synoptics, northerlies=topplers wishbone northerlies are good for 1 thing, wishing for an easterly

Edited January 22, 2013 by Frosty039

[Frosty.]

I agree with steve, the pattern from sunday onwards looks awful for coldies, a sw/ne aligned jet but maybe the next downwelling wave will shock the models into a sudden factory reboot (reset).

[Gibby]

Good morning. Here is the report on the 00z output from GFS, UKMO, GEM and ECM for today Tuesdat January 22nd 2013.

All models show the rest of the working week looking cold and frosty though amounts of snow will subside over the coming days as Low pressure areas slowly slacken their grip iver the UK, though frost and ice will continue as pressure builds somewhat over the UK. Late in the week and weekend will see a deep Low move into the Northern Atlantic with Southerly winds freshening with rain moving in from the West preceded by snow as it encounters the cold air over the UK.

GFS then shows a couple of troughs crossing the UK over the weekend, the first will more likely bring a spell of snow, turning to rain before clearing briefly before the second more vigorous feature brings gale Southerly winds and heavy rain East across the UK on Sunday. Next week then shows a NW/SE split developing with wind and rain at times while the SE half of the UK are more likely to see drier and brighter conditions with temperatures reaching normal levels or even a little above late in the week. In Far FI winds gradually veer West then North as a mid Atlantic Anticyclone allows a cold Northerly flow to drive cold Arctic winds down over the UK briefly at the end of the run.

The GFS Ensembles show a continuing trend for more average temperatures or a little above for a while next week. Rain at times is prevalent with the wettest conditions is Northern locations. As usual there is plenty of spread at the end with the operational being an outlier in it's cold blip at the end of the run.

The Jet Stream shows a steep rising through the Atlantic of the flow replacing it's current South of Britain location to ride high over the UK in a weeks time.

UKMO for midnight on Monday shows Low pressure crossing Scotland early next week with periods of rain followed by showers in very windy and milder conditions than of late.

GEM shows a cold front sweeping East on Sunday with a spell of heavy rain in cold and strong Southerly winds. The weather then quietens down somewhat as well as become much milder with rain at times, more especially in the North and West with temperatures returning to normal values.

ECM too shows a spell of rain and strong winds through the weekend before milder and drier conditions develop quickly next week in the South and east while Northern and Western areas continue to see mild SW winds and rain at times.

In Summary this morning from the look of all the output the cold spell will end at the weekend. the transition will involve a spell of strong winds and rain with some models showing the risk of snow at the transition point. thereafter it looks like a strong pressure rise to the SE will bring a spell of much milder conditions with rain at times, chiefly in the NW with no immediate sign of a return to cold in the reliable mid term frames this morning.

[Catacol]

I'm getting accused in the regional threads of being miserable... ironic in winter time when in fact I am a snow lover of epic proportions... but this is because fundamentally I am not seeing anything in the models to cheer me up at all. I posted this a few days back and I suspect was seen as an "outlier" in my views, but they are only firming up as the days pass. 3 days running now the model runs have been woeful, not just the op runs that we all know are liable to swing and duck and dive, but also ensemble means. Taking a longer term view than I would normally do - here is info as I see it for 10 days time: February 1.

ECM Op poor (notice the reformed vortex as promised by our gurus, but its positioning north of Iceland and the total loss of LP to our south)

GFS OP if anything is worse with the Canadian vortex back in a dominant position, reunited with its cousin and again no sign of anything but high pressure to our south:

Cant do a UKMO at 240h, but turning to GEM (sometimes a trendsetter and capable enough) slightly less on a pronounced LP signal to the north, but again consistent pressure rise to our south:

OK - so we all think op runs are dodgy. Let's look at means. ECM mean for 240h:

Swathe of vortex to our north and most importantly low pressure signalled over iceland and high pressure to our south. Terrible. Then run your eye over the GEFS ensemble postage stamps over on Meteociel - I wont bother to post them (too many) but they are also very poor for cold.

14 day CPC guidance also poor - more disappointing than at the weekend even because it too has the first sign of high pressure anomalies building over Spain:

All in all another very poor run if a return to cold is what you want. My mood has not been brightened any by rain overnight with the likelihood of heavy rain and perhaps more flooding at the weekend. Grass pitches for sport down here are in a terrible state and rivers are still high. No snow to brighten the mood either. Like TEITS I continue to have a horrible feeling of deja vu - December all over again? All still running counter to the MJO phase 7/8 and GP's very detailed post over on the Tech thread, but I'm afraid I have had my confidence in teleconnective forecasting seriously dented by what happened in December, and the mass of evidence from the models at the moment is average/mild and possibly wet as we head through next week and into February. With the pacific side enjoying most of the benefits of strat warming impact the immediate future looks bleak to me.

Hoping - very much hoping - to be proved wrong. Before this winter is out I want to see some winter!

Edited January 22, 2013 by Catacol_Highlander

[TEITS]

Im not surprised to see the poor output continue.

Those are shocking means and I dare anyone to find anything positive to say about the model output this morning from a coldies perspective.

The main reason for my negativity is when you have spent many years following the models you get to learn how some patterns can change more favourably towards cold and how some are locked in for a while. The current model output in the medium range i.e +168 to +240 is one of those patterns where the model output will be consistent and you won't see much change between runs. At the moment we're going to have to rely on charts at +384 for any cold charts.

My advice take a break for 7 days and then return!

[Severe Siberian icy blast]

I think a lot of people are in denial to what the models have been showing- there has been been clear agreement from the big 3 for a good few days - where as last week it was the GFS V Euros & finally we saw a swing back.

There does remain the chance of a snow event on the transition- the GFS is has been playing with it- we may be lucky & see the trough dig a little more south- the Euros sadly less enthusiastic & take it through faster.

Whats clear is generally after day 5 the flow is a very strong run from the azores- aimed right at northern Europe- the UK *MAY* be lucky - where if the energy drops a tad further south than anticipated we end up with southerlies or a slight tug off the continent which would keep it 'slightly' colder for longer- but only delay the inevitable.

Yesterdays 12z ECM pointed to a mild trend right out to day 15-

http://www.knmi.nl/e...agse/index.html

So whilst the 32 dat DET ecm may be shifting towards some Northern blocking those dates seem to range between at the earliest the 4/5 th feb all the way out to the 20th Feb-

8 weeks down so far & not a sniff of a greenland high this winter- only 4/5 to go- The fat lady warming up her X factor audition...

We will need to see some changes quite quickly once the the mild flow develops as its a difficult path back from there-

Im not saying it cant change- however there arent many signals infront of us to indicate it will change- THe only glimour of light is at day 10 in some of the GFS ensembles for heights towards greenland-

Anyway nobody should assume something is going to happen for the UK, thats possibly the worst strategy ever as nothing is ever certain.

It will be a long week in here so im going to steer clear.

S

Steve normally I read you posts with earnest , but you do seem very negative recently , we are 5 days or so past the mid way point through winter , you no the stats , and they are that statistically feb is by far the snowiest month for the uk , so although your right in pointing that the sun gains strength in feb , to say the clocks ticking and the fat lady is singing is a bit over the top .

I agree that the greeny high has been absent this year , but signs look good , to demolish the Canadian vortex , and with that gone , that screams one thing.

There's no denial about where we are , we face a breakdown , one that GP said would happen between the 20th and 24th with a renewed outbreak from the 28th , even if he's 7days out with the forecast , it's quite a remarkable forecast , granted there has been one hurdle after the other so far , mainly with the vortex segments in the wrong place , keeping the NAO positive , but things are about to change , and this less cold spell is something we have to go through to get the vortex finally away from the Atlantic .

I would be very supprised to see the milder spell go on any longer than 1wk

Edited January 22, 2013 by Severe Siberian icy blast

[Frosty.]

.

My advice take a break for 7 days and then return!

Sound advice but the crumb of comfort is always that the next run will show something better

[SMU]

Steve normally I read you posts with earnest , but you do seem very negative recently , we are 5 days or so past the mid way point through winter , you no the stats , and they are that statistically feb is by far the snowiest month for the uk , so although your right in pointing that the sun gains strength in feb , to say the clocks ticking and the fat lady is singing is a bit over the top .

I agree that the greeny high has been absent this year , but signs look good , to demolish the Canadian vortex , and with that gone , that screams one thing.

There's no denial about where we are , we face a breakdown , one that GP said would happen between the 20th and 24th with a renewed outbreak from the 28th , even if he's 7days out with the forecast , it's quite a remarkable forecast , granted there has been one hurdle after the other so far , mainly with the vortex segments in the wrong place , keeping the NAO positive , but things are about to change , and this less cold spell is something we have to go through to get the vortex finally away from the Atlantic .

I would be very supprised to see the milder spell go on any longer than 1wk

Im not negative- just realistic. The 'overall' winter to date has been rubbish. I cant even remember the December cold, im sure it delivered for some though.

This cold spell on the face of it, especially in comparison to the rest of THIS winter has been excellent, but shouldnt be considered to unusual,( a tad colder & snowier than the mean) perhaps out of kilter with what the UK have become accustomed to.

The bit ive highlighted---- I think you & maybe some others need to take a step back & read what your saying. again irrespective of WHO posted it, its the preverbial dangling of cold carrot-- What you are saying is a forecast of cold to reload on a specific date ( or close to it) but because it may turn cold 7/8 days later that forecast is now correct...??- you can certainly build it a margin of error for a forecast, a bit like the initial response from the stratosphere, but 7 -10 days is a bit loose.

Everyone seems to think Ive got a beef with GP & CH for that matter I havent. However more particular with Stewart- its a forecast.( the Winter one) Theres elements that have done well & elements that have been wide of the mark- especially the lead peice which focussed on blocking around greenland.-

What people forget is everything thats presented on here after the winter forecast is based on models & (some historic analogues), models that are sometimes right- when people can then shout about success, but equally when they are wrong I hear no comments about the route cause of failure ( when really its the model ) - & saying well the cold arrived at another time cuts no ice.

Here is where we are today-

Everything points to mild in the 5-10 day time frame.- there is nothing to suggest in ANY teleconnective paramenter that the cold will reload straight away EXCEPT historic stratosphere data around another wave after the main response.- however as with any signal the further you get away from the initial spike the signal will get weaker & less responsive.

So *IF* it gets cold post day 10 then it will be as much about luck & changing weather patterns as it is alligning with any forecast date- ( unless there is a sharp change once again in the mean zonal wind response across 60n)

S

Edited January 22, 2013 by Steve Murr

[Yarmy]

Posted 02 January 2013 - 19:28

snowking, on 02 January 2013 - 19:00 , said:

Well we've seen much much better but certainly not the end of the world on the ECM op tonight:

High pressure from the arctic starting to ridge towards the Greenland locale with slowly rising heights, amplified mid-atlantic, with further amplification just west of the states, and atlantic energy reducing significantly as the PV starts to move just west of Greenland (as suggested by 10-100mb profile), with the remaining atlantic energy digging SSE towards the med.

SK

Hi SK TBh I expected a better analysis- your clutching at straws- none of which exist.

Lets for one moment exclude the stratosphere talk & take what we have infront of us the most accurate peice of info we have then the day 10 chart is very poor.

* No Blocking anywhere.

* nop polar highs

* a 496 height polar vortex over Western Greenland sending relentless energy East

* A zonal flow across the atlantic with no ridging anywhere-

* 576 heights stretched East over Europe.

* the UK encapsulated in 4c air at 850- some 6/7 degrees above normal.

Call me scrooge, but another day down in this winter.- still no snow prospects within 8 days puts us on the cusp of the first half of winter snowless for the bulk of the UK....

That is shocking- especially against the expectation built up during autumn.....If the SSW / warmings dont deliver across the projected timeline- then its game over.

we have been here so many times in the past 10 years & on most occasions if lowland UK are snowless pre Jan 15th then the patterns dictate that on AVERAGE winter is already over.....

Scrooge.

(Just saying, like)

[mulzy]

Have to agree with TEITS and Steve M - the medium term pattern is very poor as far as cold is concerned. Yep, we know things can change pretty quickly but as it stands right now, no return to cold till Feb 10th at the earliest.

[Catacol]

I agree that the greeny high has been absent this year , but signs look good , to demolish the Canadian vortex , and with that gone , that screams one thing.

I think this is a key statement. The point is that the Canadian vortex will not be "gone". It is under attack and is set to empty into the atlantic giving us our breakdown... but then ensemble forecasts now have it reforming somewhat, and linking with the siberian half that shows no sign yet of dropping westwards towards us as long term forecasters believed it would.

Steve is right - if we get reformation of vortex low pressure to the north and a consequent rise of pressure to the south then this is a pattern that will probably lock in for a fortnight and by then winter is on the ebb. That is not to say that a cold spell in mid Feb is out of the question... and your stats on Feb snow are correct... but it is a long way from the wintry spell that forecasters predicted.

So far long term forecasting for this season has not done so well as previous winters. December went awry and with the breakdown on its way we will have had 1 week of coldish (it actually hasnt been that cold) weather with some snow but nothing especially remarkable on a national scale.

Snow is getting all the headlines in the press at the moment, but as winters go I think thusfar it has been very ordinary.

Edited January 22, 2013 by Catacol_Highlander

[Frosty.]

no return to cold till Feb 10th at the earliest.

unless the next downwelling wave stuns the models into a sudden u turn, miracles can happen as was proved last week. It dragged this winter from it's tailspin of turning into a poor winter into a fair winter, another freeze in feb will make it a good winter.

Edited January 22, 2013 by Frosty039

[Catacol]

unless the next downwelling wave stuns the models into a sudden u turn, miracles can happen as was proved last week.

I like the sound of that - a stun gun for the models. Where do I buy one? I have plenty of ammo for them at the moment!!

[Frosty.]

I like the sound of that - a stun gun for the models. Where do I buy one? I have plenty of ammo for them at the moment!!

GP owns 1, ask him

[snowblizzard]

Have to agree with TEITS and Steve M - the medium term pattern is very poor as far as cold is concerned. Yep, we know things can change pretty quickly but as it stands right now, no return to cold till Feb 10th at the earliest.

In my opinion, that's absolute nonsence!

Feb 10th is 20 days away and just look what's happened in terms of chopping & changing during the past 20 days!

Edited January 22, 2013 by snowblizzard

[Summer Sun]

The ensembles are showing the warm up nicely this morning

Edited January 22, 2013 by Gavin.