General Model Output Discussion

[Cecil Hogmanay Melchett]

Swings and roundabouts that low wont be modelled 100% until saturday IMO.

I wouldnt be suprised to see it shunted south again in the next 24hrs.

[swfc]

Cant believe the panic over the position of a low pressure that hasnt even arrived.?????.Why. :whistling.Has everyone forgot this mornings output from ecm.Its xmas day with snow about and the outlook is very cold.Christ.

[Eugene]

Absolutely nothing to worry about people the initial setup might bring cold rain to the midlands southwards as the risk was always there but its still a cold trend with a greenland high and cold northerly winds, i remember panic before the cold spell we still have now and look what that delivered to places and gave an excellent cold spell to the midlands, its saying something when 7C/8C on just one day in the next week or two is the warmest we can get midlands northwards

Edited December 25, 2009 by Eugene

[The PIT]

Lack of air traffic does not exist, when you have your trans-Atlantic and also your other air traffic!

At 5-6 days out, your already looking for excuses when 1 run go's tit's up for your location.

No wonder this thread at peak becomes trash.

The current 12z is fantastic for everyone.

Take one run at a time,

Simple

Lewis

Not for everyone it also means a lot of extra stress.

For snow lovers I wouldn't call the ukmo a total write off. For the south yes but for northern areas it looks very good.

For me it still looks like we're going to have a winter for once. Time to brush up your driving skills and Eurostar to learn how to keep trains running.

[Mark Bayley]

Yes UKMO is a horror show. Dear me.

I was expecting to see some kind of bartlett with south westerlies like geordiesnow said! I still think this low is being progged to North and i would expect it to trend slowly south. The charts all show potential for the long term. The GFS, UKMO and the GME (which incidentally has the low far better positioned!)

We await the ECM

Edited December 25, 2009 by mark bayley

[Barb]

Maybe put the razor blades away for now, the GFS ensembles look better. In fact they seem better than the 06z in keepin the cold and snow south.

[Geordiesnow]

I think that its just one blip in the trend, the trend is is for it to move southwards so I believe so I still believe south mids and south/mid wales will be hit the worst. The reason that its not good for all is because only the north will be cold while it would be mild over most of the south so dont say its good for all because 4c uppers arent good are they.

But the uppers are -5 and below for the Midlands North and whilst people in Scotland sometimes don't want to be class as being in the UK, it's still relevant to talk about the cold air that has not downgraded there. Yes, this run for YOUR location is not as good, for someone elses(e.g Cumbria) it's an upgrade regarding the persistent snow potential.

Yeah, let's bring some Christmas cheer and hope to this thread. It isn't a downgrade. I used the term loosely.

I tend to focus on the shorter term rather than the wider evolution. Once a pattern emerges, over a number of runs, i'll begin to follow it. Let's hope the later evolution can become the trend and eventual provider for us all

ITs very easy to get sucked into one good/bad run and we all have done it... I know i have but if you look at the general trend on all the models, then a risk for a colder shot with snow is there. even the UKMO run is not that bad regarding potential imo, we all know what a 100-200 miles north/south difference can have on our weather.

I'll be more concerned if all the models start showing what the UKMO shows on a consistent basis. And also remember, just because a model run has been consistant showing a particular weather pattern does not mean that is more likely as we know things can quickly change with one model run.

[Barb]

The GFS control is a corker...

For south.

[swilliam]

Good post,

Just wish some of the more senior members and forecasters thought like that, it saves mood changing every run, like i said yesterday, one model won't confirm it almost a week out. The models chop and change all the time, i just take it as "what's gunna happen will happen", regardless of every single run.

This run looks fantastic for us up North.

Merry Xmas mate

Lewis

Sorry Lewis I don't understand this post. You agree that we should not focus on one run and unfairly chastise the senior posters and forecasters for doing so and then state

This run looks fantastic for us up North.

????????????????

[SMU]

Lewis / All-

I am calling the models as they come out- Also-

The 12z UKMO V the 12z GFS isnt a swing & a rounabout its a chalk & a Cheese-they are 2 different evoltions with the UKMO going for a big easterly around 168 ( if it existed )- its also inline with the GONAPS 06z-

The GFS + Ensemble suite is excellent- no doubt about that, infact as some have highlighted the trend in the ensembles are further south-

However you cant dismiss the UKMO-

I am weary of the GFS even though its almost a DREAM scenario-we got burnt last year & the year before by the GFS - especially with that huge cold easterly from the artic high- the UKMO said no with the shortwave over Norway & turned out right...

I am still with the GFS- not because its the GFS but because the evolution feels inline with the most recent track of the jet across the atlantic-

ECM will be interesting tonight- & then the 120 hr FAX- If the ECM is inline with the GFS it will be a mile away from the UKMO & the fax will see where the METO confidnce is-

hope this clears things up-- UKMO V GFS is a huge differential tonight- not a 50 mile gap amounst friends.....

S

Edited December 25, 2009 by Steve Murr

[Cecil Hogmanay Melchett]

Lewis / All-

I am calling the models as they come out- Also-

The 12z UKMO V the 12z GFS isnt a swing & a rounabout its a chalk & a Cheese-they are 2 different evoltions with the UKMO going for a big easterly around 168 ( if it existed )- its also inline with the GONAPS 06z-

The GFS + Ensemble suite is excellent- no doubt about that, infact as some have highlighted the trend in the ensembles are further south-

However you cant dismiss the UKMO-

I am weary of the GFS even though its almost a DREAM scenario-we got burnt last year & the year before by the GFS - especially with that huge cold easterly from the artic high- the UKMO said no with the shortwave over Norway & turned out right...

I am still with the GFS- not because its the GFS but because the evolution feels inline with the most recent track of the jet across the atlantic-

ECM will be interesting tonight- & then the 120 hr FAX- If the ECM is inline with the GFS it will be a mile away from the UKMO & the fax will see where the METO confidnce is-

hope this clears things up-- UKMO V GFS is a huge differential tonight- not a 50 mile gap amounst friends.....

S

He he nothing gets past you mr murr.I was wondering how long it would be before someone mentioned that ukmo144 chart,you can see the Greenland high ridging west and a siberian high moving towards scandy.

As you say,setting up for an Easterly ukmo.

Edited December 25, 2009 by happy days

[SMU]

He he nothing gets past you mr murr.I was wondering how long it would be before someone mentioned that ukmo144 chart,you can see the Greenland high ridging west and a siberian high moving towards scandy.

As you say,setting up for an Easterly ukmo.

indeed- thats why I always view the updates on the NH charts rather than the europe ones - gives you perspective then...

dinner time for me-- Fingers crossed for the ECM-

S

Edited December 25, 2009 by Steve Murr

[Costa Del Fal]

The 12z GFS is quite different. Most runs have showed it like where it was in the 06z which for now is where i still think it wont be far off. Its still way too early to call any specifics yet. Dont get disheartened or excited over 1 run!

[swilliam]

I think the main factor determining how far the low gets North and the angle of the extended trough is how much pressure is put on them by the HP ridging from the North. Looking at the UKMO chart we can see that there is none of this at all.

Compare this for example to the GEM at the same time

The difference is marked. This has the advantage of tightening the gradient and probably increasing the intensity of the precipitation. More importantly though it increases the rate and intensity of the undercutting of the cold air. This would mean that many places would see snow rather than rain. The UKMO chart to me seems to indicate mostly rain - even in the North and especially anywhere near the East Coast. As I have suggested previously this looks quite a marginal event really and it certainly relies on reinforcement of the cold air from the far North.

Another issue is that with the LP further North and poorly aligned we run the risk of not getting our extended cold spell as Kold has discussed. It is essential that the LP moves East after generating the large amounts of precipitation. To do that it needs to be engaged with jet stream that will be running through France

If the LP is to far north and/or West there is a danger that it will stall and fill out near SW Ireland. This is evidenced already by the UKMO chart for T144

You can see the LP has moved slowly North and does not show much sign of moving East.

The 2nd possible problem is that if the LP is too far North this pushes the block further North and as Kold has suggested we then run the risk of a LP from out West coming through the South of our block. There is evidence of this beginning to happen on the UKMO T144 as well. This could be a good thing in that we may get another battleground (assuming the cold air has flooded over us) or it could end the cold spell completely.

So I think it would be good if we had less discussion about snow in the North v South and concentrated more on making sure we get a real snow event and also get the extended cold spell that would, in the end, give us all some snow

Stewart

Sorry about the extra map - I can't get rid of it.

Edited December 25, 2009 by swilliam

[Eugene]

http://www.wetterzen...chester_ens.png

LOL no total agreement for even around the 30th it could be cold rain or snow for manchester we just don't know yet, some people have short memories too this time last week i remember some GFS runs showing an absolutely awful mild atlantic pattern for next week now its looking cold and beyond.

Edited December 25, 2009 by Eugene

[butler_son]

The GFS control is a corker...

For south.

I see the Dorset snow shield has been included into the models now!

Anyhow, Merry Christmas to all!

[rbw]

Can someone explain to a novice like me as to what the "GFS Control" is, please as opposed to the normal GFS

Thanks

Richard

[Eugene]

Air frosts return sunday night, wow just one night break from them, saturday night we`ll just have to put up with a ground frost with temps around 3C, bu*mer isn't it :lol:

http://www.wetterzentrale.de/pics/Rtavn6617.png

[nick sussex]

Before i settle down for an evening of Xmas television! a few thoughts regarding the output so far, the gfs is okay but i concur with Steve here, we need to see that elongated low pressure, the ukmo is exactly what i was concerned about yesterday evening, its too far north which may suit some members but ultimately puts into question how cold the pattern can get, if the low becomes slow moving the coldest air heads into the Atlantic. The gem and gme are very good so we wait on the ecm, if you want a chance at a longer cold spell we need to see the ecm take the low further south, the sooner this happens the less chance for things to go wrong.

At T-96hrs the ecm has the low better orientated, the 120hrs is unlikely to back the ukmo, the ukmo starts going wrong at T-96hrs so for the moment I would expect a better run upto 144hrs from the ecm, after this we keep our fingers crossed.

Edited December 25, 2009 by nick sussex

[West is Best]

Totally agree Nick (and Steve and Ian).

Fortunately the operational has very little ensemble support for that more northerly track. The mean has the low across the north French coast: ideal.

Let's see what the ECM shows, but I was thinking this afternoon that it's surely about the time for a model wobble isn't it?!

Edited December 25, 2009 by West is Best

[Snowstorm1]

At T+72 The low is 10mb deeper than on the 00z run and less favourably angled. But then the T+96 is looking better

[SMU]

At T+72 The low is 10mb deeper than on the 00z run and less favourably angled. But then the T+96 is looking better

The ECM 120 is a very very good chart in itself- superb snow prospects for a line from Yorks / lincs down to wales-

just north of the GFS suite-

Good strong GH as well-

Also the 120 sees the low elongated so a secondary system looks to move along the channel at 144-

S

Edited December 25, 2009 by Steve Murr

[swfc]

Well ecm seems to be sticking to its guns on the position of the yet to be low pressure :lol: .

[Barb]

Phew, ECM is still good. UKMO looking very isolated now.

[Snowaddict]

STUNNING ECMWF @ T+120..

Even @ T+96 the approach of low is PERFECT with strong easterly winds across the UK & Ireland..