Model Output Discussion

[johnholmes]

If we ignore the GFS latest run and have a look at what the northern hemisphere charts are starting to suggest then they are quite interesting in the run up to Christmas.

Its an exceptionally long shot but the wave length and pattern developing over the states allied to what all the hemispheric models are toying with does suggest that the cold MIGHT continue into Xmas-I say might. The 18z GFS chart for Christmas Day is of course way too far ahead to be believed on its own but the upper pattern and the tele' connections are pretty much singing from the same sheet it seems to me?

An interesting lrf to decide on for Friday that is for sure as it covers the period 21-31 December.

As to the shorter term then, as my blog explains, the lead in is pretty much as the models indicated over a week ago. The long wave pattern is such that it will be a far bigger turn round than last February if the wintry spell did not occur for next week, even more of a turn round than the January debacle several years ago.

Wait and be patient for the fine detail; absolutely no use expecting lows and wind flow to be verified this far out on the models-both crucial along with where the main high sits for the surface pattern. Watch the upper air pattern-the Omega block is going to occur. At a minimum from its creation we should expect 5 and more likely 7-10 days locked into an arctic airflow.

Edited December 9, 2009 by johnholmes

[German Sheperd]

OMG!!!!! have you seen the end of this run??!!!!! SNOWMAGEDDON!!!!!!!!!!!!!!

(actually I'm beginning to wonder whether to trust FI for once??) :winky:

I'm still holding my breath a bit longer yet, but these models are something special. Have never seen anything like this since joining NW.

I'm always wary that if something can go wrong it will, but maybe I'm turning into an old cynic....lol

However the building blocks well into the reliable time frame, so fingers crossed.

Cheers,

Kev

P.S. Paul are you working tomorrow??......coming down for my xmas tree. Can't believe you have used your passport photo for your avatar....lol

[Optimus Prime]

I do agree OP that a easterly off Europe will be colder then a NE but thats just about as cold as a NE airflow can get in December IMO,s however...

Then lets just agree it's very marginal and let everyone know that, that is the case because we're getting ramped out of hell high here.

Looking at the 2M surface temperature it's about as marginal as it gets for "Whiteout country crippling conditions". Yes there will be some snow but let's not think a Feb 2009 would happen from this set-up.

Anyway, yes it's a cold setup but it's not excessively so and posting charts from the 80s won't make it change this.

[TEITS]

I have to laugh at the Parallel run at +240. A LP system centred NW of Scotland performs a Beckham type swerve and curves its way past Ireland along the S of England before moving into Germany.

Whether any of this occurs is uncertain but this is model watching at its very best. I know some are cautious but lets just enjoy these models because there is nothing we can do to change them!

[Snow Queen one]

I still think it is too good to be true i hope it comes off but although we have never seen the likes of these charts on here before it is poss they are over egged and we will get cold but to a lesser extent. Still i will be happy i am in the SE so will get the showers off the sea if the wind is strong enough.

How many more runs do we have to see before we can say this is nailed to happen at T168 please i need some sleep lol

[kold weather]

No way not from a NE'rly. The came in from Northerlies.

Actually the flow on the GFS/ECM probably would be cold enough close to the low to spawn a secondary low which could be a polar low, esp given uppers are close to -40...but to be honest thats still a long way away.

xmas charts looks like cold rain, possibly freezing rain even

...

ps, tohugh I d agree, I'm not sure it'll be an exceptional spell unless we do get a E/ESE set-up.

Edited December 9, 2009 by kold weather

[NorthantsSnow]

Last frame of the parallel-

SNOWIEST Christmas EVER?!

http://91.121.94.83/modeles/gfsp/run/gfs-0-384.png?18

SW would be buried in the stuff.

[Polar Gael]

I realise it is the pub run, but we are getting closer and closer to something rather special coming within the reliable timeframe. Crucially, it is not there yet.

That said, exceptional charts today - the models would have us believe it is shaping up to be the most memorable December for coldies since 1995 and before that, 1981.

FI blizzards on Christmas Day? I'll take that.

Fingers crossed we can get the truly cold synoptics within T+96. I shall not believe it is going to happen until then, no matter how much I want to.

Edited December 9, 2009 by Polar Gael

[VillagePlank]

Nice parallel as usual

If that were to happen ...Decemeber 1981! OK, it's still a week away, but the odd ramp, or three, is permitted, isn't it?

[Optimus Prime]

ps, tohugh I d agree, I'm not sure it'll be an exceptional spell unless we do get a E/ESE set-up.

Do we all agree while being an exceptional setup for the time of year what the GFS is showing this isn't a 1981 and it won't bring us countrywide snowstorms ala Dec 62/78/81? And temperatures won't be that cold.

[Geordiesnow]

Then lets just agree it's very marginal and let everyone know that, that is the case because we're getting ramped out of hell high here.

Looking at the 2M surface temperature it's about as marginal as it gets for "Whiteout country crippling conditions". Yes there will be some snow but let's not think a Feb 2009 would happen from this set-up.

Anyway, yes it's a cold setup but it's not excessively so and posting charts from the 80s won't make it change this.

I suppose it is marginal this run especially the further South and east you go but i do feel it is just on the right side of marginal.

If this set up occured in Feb with cooler SST's, i think this sort of run would certainly be on the right side of marginal.

Anyways, tomorrow is another day but it is nice too see the 18Z continuing the trend. :winky:

[Nick L]

Last frame of the parallel-

SNOWIEST Christmas EVER?!

http://91.121.94.83/...fs-0-384.png?18

SW would be buried in the stuff.

Highly doubt it with these uppers:

http://212.100.247.145/viewimage.pbx?type=gfs;date=20091209;time=18;ext=384;file=tmp850;sess=e1be1fdf878165e6521378946eb4385d;

Doesn't matter anyway, far too far away to worry about and we have the small matter of next week's fun and games yet!

[TEITS]

Then lets just agree it's very marginal and let everyone know that, that is the case because we're getting ramped out of hell high here.

Are we referring to the E,ly on Sun/Mon? I certainly hope so because there is nothing marginal about the NE,lys that have been shown on todays model runs.

Your right E,lys are colder but its a case of swings and roundabouts because NE,lys would affect more regions that an E,ly. Furthermore the longer sea track would allow for greater convection.

Let me assure some members than when it comes to cold synoptic patterns you don't get much better than what we have seen today. This isn't a ramp but an accurate assesment.

[Snowaddict]

I am as excited as anyone however we just need to wait another short while to be guaranteed.

I would urge extreme caution as some people could become depressed if this one goes wrong!!

Ensemble agreement of -6 850's into SE @ T+96...

It's looking fantastic at the moment but caution still advised.

SA :winky:

[PersianPaladin]

Actually the flow on the GFS/ECM probably would be cold enough close to the low to spawn a secondary low which could be a polar low, esp given uppers are close to -40...but to be honest thats still a long way away.

xmas charts looks like cold rain, possibly freezing rain even

...

ps, tohugh I d agree, I'm not sure it'll be an exceptional spell unless we do get a E/ESE set-up.

Its a long way off, but the convection with those sorts of uppers over the northern north Sea could be very impressive indeed at this time of year.

[NorthantsSnow]

Highly doubt it with these uppers:

http://212.100.247.145/viewimage.pbx?type=gfs;date=20091209;time=18;ext=384;file=tmp850;sess=e1be1fdf878165e6521378946eb4385d;

Doesn't matter anyway, far too far away to worry about and we have the small matter of next week's fun and games yet!

Those are the uppers for the operational run. On the parallel run the colder uppers remain over the UK on Christmas Day:

http://91.121.94.83/modeles/gfsp/run/gfs-1-372.png?18

But yes, too far out of course. Just a bit of fun to end the run!

[John Snow]

I suppose it is marginal this run especially the further South and east you go but i do feel it is just on the right side of marginal.

If this set up occured in Feb with cooler SST's, i think this sort of run would certainly be on the right side of marginal.

Anyways, tomorrow is another day but it is nice too see the 18Z continuing the trend.

You are right in the sweet spot for all these charts

If I was to pick somewhere where the most snow will happen it would be right over you and rest of Newcastle, you are a lucky guy

[TEITS]

Do we all agree while being an exceptional setup for the time of year what the GFS is showing this isn't a 1981 and it won't bring us countrywide snowstorms ala Dec 62/78/81? And temperatures won't be that cold.

1981 wasn't actually that special with regards to cold upper temps. The main reason for the cold temps was deep snowfall, calm winds.

Nobody knows how cold it will be due to the uncertainity of the SW. Also like I said about 1981, snowcover can affect temps enormously especially under clear skies, calm winds.

[Nick F]

Many saying they have never seen charts projected like this before so close ... I'm sure I have seen charts projected like this a few or more times over the years at similar timeframes - just that the promise has either gone pear-shaped or ended-up much less cold and snowy than progged, so worth bearing in mind.

However, haven't seen the models be this consistent over consecutive runs this far out with a blocked and cold pattern ahead with no real threat to break it ... so we could be on the verge of something special that we haven't experienced for a while - i.e. a protracted cold and potentially snowy spell.

[Mark Bayley]

Highly doubt it with these uppers:

http://212.100.247.1...21378946eb4385d;

Doesn't matter anyway, far too far away to worry about and we have the small matter of next week's fun and games yet!

Thats the op run, this is uppers for the chart he posted

Overall another very good run from both the op and the parallel, prefer the parallel though. Hopefully the trend continues tomorrow!

Ensembles are also very good and a slight upgrade from the 12z ones

Edited December 9, 2009 by mark bayley

[ribster]

I would refute that it keeps getting delayed. I remember previously 17th being the key date but as the runs progressed it's now looking more like the 16th. The inital easterly shot from Sunday was actually upgraded on this morning's runs but was always a separate event with the coldest air waiting in the wings so to speak. Those in the SE will see it as a nice bonus I would imagine.

Indeed, there was a run on the 1st Dec that showed snow over large parts of the country for the 17th, not on my usual PC, but will post it up tomorrow if I can find it.

[Optimus Prime]

Are we referring to the E,ly on Sun/Mon? I certainly hope so because there is nothing marginal about the NE,lys that have been shown on todays model runs.

The whole setups marginal Eye. The NErly 144hrs+ is better suited for higher ground Scotland and NE England. With the low tracking so close to the SE the warm sector within the low would do nothing more then aid in stirring the mild air across the NE sea.

I'd say the easterly is likely to give a better ratio to rain snow then the NE'ly. But that's what I'm seeing.

[Guest North Sea Snow Convection]

Whilst we need a trigger to bring the coldest air in from the arctic across Scandi (Copenhagen) and all routes SW of there, it needs, yes, to be a feature that is significant enough to advect the arctic continental airflow right through the UK but not so over-developed that it becomes like a cyclonic frontal system that takes energy from the 'tropical' side of the system and then sets up a barrier zone to the cold air as it tries to move south and in turn forms a dynamic whereby it stops moving south and halts the progress of the cold air. If you see what my simple mind is trying to say!?

It is very early days, but there is just the hint in my mind that this sort of process as described is being sown and that this north sea low is going to become a more and more significant player (and spoiling nuisance for southern parts of the UK). The time period to get the colder air is not coming nearer, the advecton of cold period should be this weekend for a decisive countrywide event and that may be significant in terms of the extent of this very potent arctic outbreak.

But I think that we will find that the favoured areas will end up being NE parts of the UK (who could see some quite severe conditions)as the path of the low tracks less further south but further west from the north sea into central parts of the UK as the modelling progresses over the next day or so. It could be that SE parts in particular end up on the warm side of the low with a returning flow from the channel (ie a south westerly wind) as the low links up with the advancing southerly tracking troughs in the SW approaches.

[snowlover2009]

i dont know which gfs i likem parallell or gfs? parallell i think lol. Hard to think, just maybe around 10 months on from february, we could see much worse snow. crazy

some severe snow over the pennines too, blizzards

Edited December 9, 2009 by snowlover2009

[Nick L]

Thats the op run, this is uppers for the chart he posted

Overall another very good run from both the op and the parallel, prefer the parallel though. Hopefully the trend continues tomorrow!

Ensembles are also very good and a slight upgrade from the 12z ones

Yeah my bad