Winter Model Output Discussion - 06Z 09/02/13 onwards

[Gibby]

Good evening. Here is the latest report from me on the 12z output from GFS, UKMO and ECM for today Saturday February 9th 2013.

All models show a deepening trough and developing depression moving steadily SE towards SW England. Other weaker troughs to the East of this one lie down the centre of the UK with occasional rain and possible sleet in the East. Overnight the trough moving into the West will develop heavier and more organized rainfall as it tracks slowly East and North over the UK. As it hits colder air currently stagnated over the East and Central UK the rain will turn to snow with some variable but appreciable accumulations possible later tomorrow and overnight in a belt NE of a line from the SE up to the NW including much of the Midlands. Later in the night the rain and snow with attendant depression will slip slowly away SE into Europe leaving a cold and cloudy period under a slack easterly flow and a weak ridge of High pressure towards midweek.

GFS then shows a new trough moving slowly East later Wednesday and Thursday bringing a spell of rain and hill snow across the UK, the snow once more only likely on the hills in the East. Then over next weekend the weather settles down as a ridge slowly develops over the UK. A lot of cloudy conditions would likely ensue with light winds and temperatures just a little below normal. Through the end of the weekend and start to the second week the weather is shown to turn colder again as pressure builds to the North and falls to the SW with increasingly cold Easterly winds developing with snow showers moving West across England and Wales. Later in the week and out to the end of FI the weather is shown to stay cold with some snow about at times with some dry and cold weather too with High pressure close to the North.

The GFS Ensembles show the operational as something of a cold outlier later in the run while there is a good deal of spread shown between the members. The unsettled pattern is still shown too with some rain or snow events, rather more so in the South indicative of Higher pressure to the North at times.

The Jet Stream continues to flow on an Easterly drift across Southern Europe. As far as the UK is concerned the Southward moving flow over Britain is weakening currently and breaks up to realign across the Atlantic down to the SW of Britain on its journey down to Spain to join the Southern European arm.

UKMO shows a front moving East over the UK on Wednesday with rain and hill snow for a time moving East through the day. Thereafter, a more Westerly flow sets up between Low pressure to the North and High pressure West of Portugal with less cold conditions than recently with rain at times.

ECM too shows another trough staggering East over the UK with rain and hill snow in fresh winds for a while. The West becomes less cold and brighter over Thursday with High pressure slowly building from the South to bring all of the UK into milder winds from a West or SW direction with some rain at times in the North and West from troughs passing close by in association with Low pressure way North over Iceland. To end the run a trough pulls winds into the NW with scattered showers in places, especially in the North and West.

In Summary tonight the rather cold and blocked pattern remains in place until the middle of next week at least. After tomorrows rain and snowfall clears a new trough moves East midweek with rain and further hill snow for a while.Its at that point when the models diverge with GFS showing cold and potentially wintry conditions developing in the second half of its run while the Euro's couldn't look more different with UKMO taking us quickly into milder and changeable weather after Wednesday while ECM takes a slightly slower route but shows the cold block retreating over Europe by the end of the run.

[lord stratus]

Looks to me from recent output that beyond mid week none of the models seem to have much of a clue, in terms of trends rather than consistency the GFS seems to be the pack leader (if only just) with several recent runs trying to build heights to our north and north west, the ECMs latter output keeps jumping about like a frog on a hot plate, so nothing clear cut yet and it’s really a case of wait and see if a clear pattern emerges. On a better note I got my test results back from the hospital and I'm clear of thyroid cancer so winter can whistle, because I'm happy regardless, cold and snow or mild and wet is of no importance and there will be winter output to mull over and ponder for a good few years yet hopefully.

Very pleased to hear your excellent news, it makes us realise that we should never get hung up on model outputs when they are not showing what we want to see, it's just not that important!

I am very pleased for you and your family.

[phil nw.]

We can see the models are now trying to solve the balance of energy off the weakening Atlantic v the now developing heights to the north and the differences show up around T120hrs.

If we look at the GFS mean run and note that there are signs of retrogression of that energy spilling SE from Greenland- compare these

http://modeles.meteo...-21-1-96.png?12

http://modeles.meteo...21-1-132.png?12

and by T168hrs

http://modeles.meteo...21-1-168.png?12

see the vortex has retreated and mean heights are now building towards Greenland- a trend showing in the forecast mean Ht. anomalies.

Take a look at the GEM -it`s Op shows again signs of vortex energy retreat as soon as T144hrs,as far as it goes on the the 12z run

http://modeles.meteo...gem-0-96.png?12

run it through to T144hrs on meteoceil to this at T144hrs

http://modeles.meteo...em-0-144.png?12

you can see the retreat of that energy as the high ridges north.

Yes UKMO and ECM not there at T120-144 with this but even the poor ECM has a look north in it`s later frames

http://www.meteociel...M1-240.GIF?09-0

but by this point too much energy has already leaked over the top which would delay things.

We dont know which models are closest on the evolution but there are signs of that retrogression of the vortex and the ensuing push west of those heights towards Greenland.

Edited February 9, 2013 by phil nw.

[Fisherman]

Since finding this forum, specifically this particular thread not a day goes by without me spending considerable time reading it. Great content, great people - keep it up!

I have to say I find it mildly amusing how until this morning a lot of people were critisising the GFS, saying how it should be ignored etc. But now it is showing potential for a possible sting in Winter's tail people's attitude towards it have changed massively!

Now, my level of understanding is beyond basic but one of the small pieces of information I recall is the theory that the GFS handles developments on the US eastern seaboard better then the euros - if true, perhaps this increases that glimmer of light that started shining at 06z and maybe just maybe we could well see decent heights over GL before Winter is done with us?

Apologies if I'm talking out my backside, as said I am a complete newbie to all this weather lark!

[Methuselah]

Since finding this forum, specifically this particular thread not a day goes by without me spending considerable time reading it. Great content, great people - keep it up!

I have to say I find it mildly amusing how until this morning a lot of people were critisising the GFS, saying how it should be ignored etc. But now it is showing potential for a possible sting in Winter's tail people's attitude towards it have changed massively!

Now, my level of understanding is beyond basic but one of the small pieces of information I recall is the theory that the GFS handles developments on the US eastern seaboard better then the euros - if true, perhaps this increases that glimmer of light that started shining at 06z and maybe just maybe we could well see decent heights over GL before Winter is done with us?

Apologies if I'm talking out my backside, as said I am a complete newbie to all this weather lark!

On the contrary. It's always good when folks try to blend in!

[bluearmy]

unfortunately fisherman, storm nemo doesnt help your case as gfs didnt spot it until very late this week. ecm had it nailed more than a week ago (probably in tandem with our undercut)

anyway, interesting developments on the ecm ens. not had a chance to look through the stamps yet but there must be a few with a decent undercut midweek. late in the run we dig a big west russian trough. now that looks significant to me as i expect pressure to be rising to our north in general and assuming we advect an easterly/continental flow, some cold pools wouldnt go amiss.

incidentally, not surprising that the op was a warm outlier post day 6 in holland.

[cooling climate]

unfortunately fisherman, storm nemo doesnt help your case as gfs didnt spot it until very late this week. ecm had it nailed more than a week ago (probably in tandem with our undercut)

anyway, interesting developments on the ecm ens. not had a chance to look through the stamps yet but there must be a few with a decent undercut midweek. late in the run we dig a big west russian trough. now that looks significant to me as i expect pressure to be rising to our north in general and assuming we advect an easterly/continental flow, some cold pools wouldnt go amiss.

incidentally, not surprising that the op was a warm outlier post day 6 in holland.

That sounds very interesting could bring us the coldest weather of the winter. Hopefully

this will develope further.

[Cloud 10]

Yes,the ecm 12z operational seems to have gone off on one this evening with its gung-ho

atlantic attack.

[bluearmy]

That sounds very interesting could bring us the coldest weather of the winter. Hopefully

this will develope further.

Looking through the postage stamps, i'd be surprised if the week pans out how most are currently expecting

[Dunstable Snow]

Yes,the ecm 12z operational seems to have gone off on one this evening with its gung-ho

atlantic attack.

Very interesting set of ECM ensembles tonight. Not surprised Gavin has'nt posted them !

[Timmytour]

Yes,the ecm 12z operational seems to have gone off on one this evening with its gung-ho

atlantic attack.

But don't forget to take into account that the ECM always tends to over do the Atlantic.....whoops sorry....wrong model!

[Methuselah]

Looking through the postage stamps, i'd be surprised if the week pans out how most are currently expecting

You mean the cold, damp, sleety stuff, followed by the end-of-week 'warm'-up has been cancelled?

[bluearmy]

You mean the cold, damp, sleety stuff, followed by the end-of-week 'warm'-up has been cancelled?

I'll let you know next weekend!

[ChartViewer]

Still showing heigher anomalies over greenland...caveats apply

Edited February 9, 2013 by ChartViewer

[TEITS]

Thats really interesting TEITS, you would take GFS over the high res models in the short term? What is the reason for that, surely the likes of the NAE and others will give a better prediction at this very short timescale?

Simply down to experience.

Obviously I have known the NAE to be proved correct over the GFS but I have also known the reverse to be true. On balance though I find the GFS precip predictions in the +48hr range to be excellent.

Have no doubts the 18Z NAE will be different.

[snow mad]

unfortunately fisherman, storm nemo doesnt help your case as gfs didnt spot it until very late this week. ecm had it nailed more than a week ago (probably in tandem with our undercut)

anyway, interesting developments on the ecm ens. not had a chance to look through the stamps yet but there must be a few with a decent undercut midweek. late in the run we dig a big west russian trough. now that looks significant to me as i expect pressure to be rising to our north in general and assuming we advect an easterly/continental flow, some cold pools wouldnt go amiss.

incidentally, not surprising that the op was a warm outlier post day 6 in holland.

I know that the gfs didn't pick up the under cutting signal but the fact that its not constantly showing a return to raging zonal pattern gives me the confidence to think that it won't pan out the way the ecm is predicting if you see what I mean?

[snowking]

6-10 day means not publishing properly over on Raleigh WX for some reason, but needless to say i'm fairly pleased with the following EPS mean progression:

Still that signal persists within the ensemble means for heights towards Greenland

SK

EDIT: These may interest a few too:

Strong ensemble signal remains - could we have seen the 6z GFS be the first operational to catch the trend?! Would be a turn up for the books given its usual slating.

Edited February 9, 2013 by snowking

[Tamara]

Still showing heigher anomalies over greenland...caveats apply

Yes, that seduction scenario we have seen and awaited through the winter But to clarify that, the overall anomalies have been in the right place - afterall, we have to differentiate between anomalies and actual height pressure. I think that this may well be the issue here

[phil nw.]

12z NAEF`s and ECM mean Ht. anomls. show the core of the higher anoml. around Greenland at day 10.

http://176.31.229.22...-0-0-240.png?12

http://www.meteociel...01-240.GIF?09-0

no early sign of a Scandi trough dropping down off the vortex but the angle of any Atlantic attack looks better for cold with a mean jet to the south.

With the ECM Op showing as a mild run beyond day 5 perhaps the American models may be leading the way on the retrogression next week-time will tell.

[TEITS]

Don't often post these but I shall accept this from the 18Z.

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130209/18/30/prectypeuktopo.png

[SMU]

hi teits.

The GFS will be to far NE/E.

It always is.

S

[Snowman.]

Don't often post these but I shall accept this from the 18Z.

http://cdn.nwstatic....ctypeuktopo.png

Shift that 5 Miles south I am in the game.

[suxer]

6-10 day means not publishing properly over on Raleigh WX for some reason, but needless to say i'm fairly pleased with the following EPS mean progression:

Still that signal persists within the ensemble means for heights towards Greenland

SK

should get a greenland high by next xmas maybe?

[TEITS]

hi teits.

The GFS will be to far NE/E.

It always is.

S

Not in my experience and especially considering we are looking at tomorrow.

[Mini tiger]

Don't often post these but I shall accept this from the 18Z.

http://cdn.nwstatic....ctypeuktopo.png

I just watched News 24 and according to the forecaster he mentioned a similar pattern but the graphics had it a fair bit

further south with the northern extent from Suffolk NW across to Birmingham, he did mentioned there could be isolated snow

flurries further north almost anywhere, but some places could get none. Going by his graphics the heaviest snow seemed to be from Kent

north west through London and up towards Oxford. But more like rain for Dorset, and somerset and Wiltshire.