Model Output Discussion 19th January 2014-18z onwards.

[bluearmy]

Well the ECM ens have a NW/SE tilt on the jet, but with the pattern too far east so it's a generally west/north westerly flow. I'm guessing the op is in the minority in getting the Arctic ridge to push towards Greenland and instead transfer in to the north east of the UK, reinforcing the Scandi high and forces near enough all the Atlantic energy south east. Well we finally might get a decent Euro trough.Simply put it's not great at face value for the UK, but it would not take much to become epic.De Bilt looks rather chilly :)Atlantic ridge... where art thou???

I'll post some charts to illustrate my point later but the ecm ens mean has us well 'in the game' post day 6 with the mean trough less than a hundred miles off the east coast. thats the mean just a couple hundred miles away from where we need it and the spreads are all west of this. Infact, there are west spreads on the two troughs that precede it thus that westward corrections are still feasible on these. i expect an improvement on the london ens later - the 00z ones werent too shabby on v cold clusters.

[Blue max 90]

 

 

I am also a newbie who has been happily reading through these threads and thought I would pluck up the courage to post. Monday seems as though it could deliver some wintry weather to the UK, supported by the GFS, ECM and JMA to an extent. (please don't shoot me down if I am way off the mark!) I enjoy reading through comments and opinions on here and have managed to develop my knowledge significantly! I love the look of those ECM ensembles - lets be optimistic and see what tomorrows models bring

[supernova]

I don't think it's the Met's Further Outlook he's referring to, more Ian F's (paraphrasing) "there will hardly be any snow, but there is a concern over rain, and then we're back to westerlies".

But on the other hand he did say that the Met really respect the JMA (we already knew that from him saying the same last winter).

So with the JMA being quite bullish, then it's all a bit confused.com.

At least we have the whole of Feb and 10 days of Feb. I make that 5 weeks.......but don't forget what happened last March!

Or, erm, 10 days? Childish I know but it was there for the asking (sorry mate)! I know I'm one of the guilty parties tonight who have promoted the JMA from zero to hero but (not on my own mind you and when Fergieweather gave it colleague kudos it made my week) but it is neck and neck with GFS on verification stats (heights) according to the earlier link from Nick Sussex unless I'm reading it wrongly and as a result we'd be foolish to ignore its evolution which, most would agree, produces some of the charts of the winter in later time frames.

Actually it's slapped the GFS rudely over recent days but overall, across the whole time period, they're neck and neck. Good to know!

Edited January 20, 2014 by supernova

[fergieweather]

 

I'd watch the period between Thursday and Saturday for some frontal snowfall potential. It's a very messy pictures but inland Northern England/Scotland could see something quite wintry depending on how the block to our NE holds.

Snowfall looks very limited/muted on Thursday based on high-res modelling (Euro4) and WBFL's from likes of UKMO-GM. Some snow in north, predominantly over 500m (mostly north of the border). No big issue expected from all this (UKMo suggest treating the PPN signal as bands of showers, some merging into longer spells of rain).

[Panayiotis]

Well the ECM ensembles are out, and they are quite pleasing! Nice trough over Europe (due to blocking over Russia) and therefore we get them to cool down for the 1st time this winter! But whats nice is that the Britain is the on the boundary of the trough so we get energy digging SE,and with this occurring snowfall is likely wherever that boundary sets up across the UK!

Edited January 20, 2014 by Panayiotis

[Dancerwithwings]

Nice to have two new posters, Welcome to both of you... It can be like the lions den at first... But not to worry! there all just kittens really.

Just put your Locations in your profile

[Recretos]

I spy, with my little eye,...

  

[Man With Beard]

steve I seriously dont think this is over yet!!I have been analysing the charts over the past couple of hours and all it needs is a 100 mile or 200 hundred mile shift at t96 to make a good snow event!!see what the 00z runs bring and if it still shows the same then maybe a give up but not yet!!

How on earth can it be over? Just this morning both GFS and UKMO were showing fairly reasonable charts at T96, T144, and the GFS and JMA at T192. And just because the 12Z charts show something different doesn't mean we now completely discount the 00Z charts. There should be consistency first, we've learnt that by now, haven't we?

 

Until it's gone, the Scandi High may continue to make a mockery out of mid-term forecasts. It usually does. I do completely agree that snow this Thurs/Fri/Sun away from high ground is probably a 25% chance or less. But that is a chance. I agree it is utterly frustrating to see good synoptics marginally miss us. But that doesn't mean the next chart will turn out like that. 

 

I'm not saying there is no reason to be downbeat if you are a coldie - the odds are certainly not in the cold camp's favour this week, the last weeks of deep winter appear rushing towards us, and there is, it must be admitted, an apparent agreement at T168 that an Atlantic low will hurl towards us yet again. It's natural some are fearing the worst, considering we haven't got even close to a good cold chart inside T96 yet this winter. But it is definitely, definitely not over. Because just as it is normal for the UK to have zonal weather early in the winter, it would be abnormal for the Atlantic not to start slowing down from this point, especially as we go into February, and that means more chance of blocking and easterlies. If "normality" has anything to do with it, then the synoptics cold lovers are after will more than likely increase and increase from this point onwards. Not definitely, some winters it just doesn't work out, but 'more than likely'. 

 

And back to the beginning - I will not write off a Scandi High unless it is shown to be on the way out inside T72 - and even if the very likely Atlantic spell does materialise early next week, if it doesn't completely kill off the Scandi, I expect to see it bite back shortly after...

 

Just my opinion, hopefully based on a lot of experience of watching these charts rather too obsessively.

[chionomaniac]

& the updated ensembles for ECM.

 

Operational is the MILDEST run.

 

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

 

In short. The best set of short ensembles of the year with the -20c scale being used of the first time.S 

The ensemble trend also is for reduced energy crossing the Atlantic between T+168 and T+240. Not quite clear cut yet though.

[SMU]

In the interest of balance- for the mild fans I feel it only fair to pluck some eye candy from the ensembles.

 

Possibly the most +AO chart I have ever see. PV almost totally circular.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-9-1-372.png?12

 

S

PS yes chiono

Edited January 20, 2014 by Steve Murr

[Gibby]

Good evening. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday January 20th 2014.

 

All models show a similar sequence of events between now and the end of the weekend. Throughout this period several troughs will cross the UK from the NW bringing bands of rain which become slow moving in the East of the UK as they hit an European cold block. Behind the rain bands there will be a mix of clear or sunny intervals and showers which could be wintry on the hills. Some frost and/or fog can be expected between the rain bands as winds alternate between SW and NW while staying quite light.

 

GFS then shows a cold and windy first few days of next week with wintry showers on NW winds. By midweek a brief ridge of High pressure descends down over the UK with frost and fog patches overnight. The rest of the run then sees changeable conditions with occasional rain bearing troughs moving East over Britain with drier and brighter spells in between. Temperatures later in the run would probably return to near average in the North and rather above at times in the South.

 

The GFS Ensembles show a mean below the long term average tonight for much of the run and while not excessively low there is sufficiently low levels shown adequate enough to promote some higher ground snowfall at times with plenty of rain spread about over the run for all parts of the UK.

 

UKMO has another deep Low pressure area South of Iceland next Monday with a strengthening SW wind across the UK with rain sweeping East through the day.

 

GEM is very similar at Day 6 with a deep Low near Iceland firing strong Westerly winds and spells of rain followed by showers across the UK in temperatures close to average or a little below with little change in this overall setup even at Day 10.

 

NAVGEM has an intense depression moving slowly East then South across England early next week with gale or severe gale force winds with prolonged rain and showers, turning to snow on hills especially over the North. Temperatures will be slightly below average accentuated by the strength of the wind.

 

ECM has Low pressure areas slipping SE across the UK and North Sea from Iceland next week with areas of rain and strong winds and wintry showers in between. By Day 10 conditions across areas far away from the UK to the North and NE look like bringing a spell of wintry weather soon after the expiry of the run as synoptics look as though strong Northern blocking could be about to form.

 

The ECM 9 and 10 Day Mean Charts continue to show the pattern of High pressure strong to the SW and NE and Low to the NW and SE with the UK and North sea lying under a broad trough with largely unsettled and changeable conditions with rain at times and snow on hills most likely in 7-10 days with the UK still lying on the wrong side of the trough to promote UK wide cold.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

http://www.wetterzentrale.de/pics/Reem2401.gif

 

The Jet Stream Forecast shows the trajectory of flow over the Atlantic and to the South of the UK looking like persisting over the next 10-14 days made more complex by a strengthening of the Jet stream speed next week.

 

In Summary the weather is looking very confrontational tonight. On one hand we have a cold block over the Continent remaining in situ. On the other hand we have an active Atlantic fuelled even more next week by a strengthening Jet Stream. The result is a UK battleground where troughs slow and stall in their delivery of rain and showers. Later deep and parent depressions too are shown to slide SE up against the block and by the look of it the ECM operational offers something quite mouth watering beyond the end of it's run tonight. Model watching at the moment is very fascinating as we watch these two power horses of West vs East UK battle it out for supremacy over the coming weeks.

[syed2878]

@steve murr. Steve a question. I c u pointed out the falias but how many of the 240h charts from ecmf showing cold outputs since november verifyed? Not only that it didn't verify wouldn't u say the gfs done rather well for our part of the world? It's all good looking at 240h charts showing cold but lot of the models have the pv is too strong this time.

[fergieweather]

 

Strongly disagree, Since their very poor long range forecasts of the past they decided to play safe and sit on the fence. A big freeze has to be set in stone before they make announcements. Most of the more experienced members on nw could do a 6-15 day forecast based on data available. The met office have to be cagey because they are open to ridicule whereas nw members are not under the same scrutiny when they announce a raging easterly that doesn't materialise!

... and there's a very good reason why they'll not get drawn too hastily in making pronouncements based on speculative or non-consensual modelling: because they are the de facto underpinning of UK-PWS weather warnings etc., and moreover are more than aware of the public 'fatigue' with seeing supposed 'snowmageddon/arctic blast/Siberian whiteout' hyperbole peddled to a largely non-specialist population by certain newspapers. This distinction between scaring the horses through the voodoo of Maddenology, versus measured, timely use of *Meteorology* and expressions of confidence (something you won't ever see expressed in newspaper articles: they are always 'certain' of the scary outcome), is key here. Equally, the 6-15/6-30d web forecasts are not created or written with enthusiasts etc in mind: they are there for Jo Public to comprehend and for that reason, you won't see talk of 'northern blocking' or 'Spanish Plumes' or whatever mechanisms. It's a poisoned chalice (as I've often said) writing these outlooks: rest assured most bench forecasters would far rather stick to preparing the 1-5d period narrative, rather than try to offer a reasoned explanation a fortnight or more ahead, strewn with model caveats and divergences way beyond the comprehension of most people reading it and thus rarely expressed in any detail. As for the period ahead, the UKMO assessment - as it stands - looks just fine: a broadly westerly-dominated story punctuated by threat of colder phases. The JMA solution is, be assured, one of many possible outcomes keenly watched at Ops Centre in so far as the 'colder phases' might be manifested. It might be instructive if the JMA solution is cited at all when their internal 6-15d assessment, based on 12z output, is circulated to us later tonight. Edited January 20, 2014 by fergieweather

[Longshanks]

Couldn't agree more with weather eaters comments. With some of the more abstruse "chancer" forecasts, this winter, that might now have proven to be (maybe?) almost based upon selling sensation to the media, that the antithesis - the views of IF (etc), are now clung to as the advocates of better and objective science - forecasting fact - being protectors of established Reason and orthodoxy - from the position of having more information than is available to most of us public - and clamping down on aspirant amateurs, as they might yet, and probably prove to be? Quite a powerful position for the professionals now to be in and fascinating to watch, in my opinion - it's been great and compelling to read posts over the last 15 weeks!

[Captain Shortwave]

John Hammond just said mild air probably winning with rain pushing east during next weekend, so the odds favour a non event followed by more atlantic dross unfortunately.

just highlighting a key word Frosty.. keep the faith 

To be honest it would be foolish to ignore a very positive set of ECM ens tonight.

[Gibby]

I think that had it been not for the expected strengthening of the Jet flow next week giving extra oomph to the Atlantic push from the weekend the path to cold would have been very much easier given the synoptics to the NE.

[Frosty.]

In other words, more of the same as the last few months, sorry guys but even my enthusiasm will only stretch so far. I hope that you all take notice of the expert, fergieweather.

[SMU]

@steve murr. Steve a question. I c u pointed out the falias but how many of the 240h charts from ecmf showing cold outputs since november verifyed? Not only that it didn't verify wouldn't u say the gfs done rather well for our part of the world? It's all good looking at 240h charts showing cold but lot of the models have the pv is too strong this time.

 

ECM- NONE.

 

All the cold charts @ day 10 this year haven't made it to t-0. 

 

Why-  no high level blocking, or any blocking whatsoever actually. - however there haven't been that many runs of decent cold.

 

The ECM in December overdone the blocking over western Greenland-

http://www.meteociel.fr/modeles/ecmwf.php?jour=29&mois=11&annee=2013&heure=0&archive=1&mode=1&ech=72&map=1

 

With runs like this-  a simple miscalculation of pressure.  That run^^ of a few days - perhaps 7/8 runs was ECM's worst streak this winter-

 

Also this run more recently

http://www.meteociel.fr/modeles/ecmwf.php?jour=8&mois=1&annee=2014&heure=12&archive=1&mode=1&ech=72&map=1

ECMs worse run of the winter.

 

 

So yes it gets it wrong, it doesn't help this year that the atmosphere has been primed towards that +AO index. So the GFS bias has actually inadvertently helped it this year ( but note its still behind the ECM)

in Any year with a neutral AO, or periods of -AO hence coming up the ECM will trump the GFS - although this has slightly been obscured this year with some crappy volatile operational runs.

 

Cheers

S

 

take ALL the cold runs from this WINTER & zero have had any solid 500 heights over the pole.

Now look at the confidence at day 6 over the pole.-  looks stunning

Edited January 20, 2014 by Steve Murr

[karlos1983]

Well my goodness, I got home from work and was greeted by my wife saying, I've got you aloud of flat pack stuff to build while I'm at work tonigh, and I'll be honest, that was more enjoyable than some of the posts I've read through in the last few pages.

Do we never learn, or take note of some of the more knowledgable posters in here. One thing I have learnt while model watching the past few years as a learner myself, is that never trust one run from any model, await the ensembles, and even wait for the next run to see if it is trending, be it cold or otherwise, if you do that and try and take a balanced view from some of the experienced members of this forum, you will find the experience a lot less stressful.

Some great posts in here tonight from the likes of Steve, Nick, Tamara, chionomaiac to name a few, but also some very testing ones, I wish I waited to look at the models until after I had caught up now, I would have pleasantly been surprised after the doom and gloom I've read lol

Edited January 20, 2014 by karlos1983

[R.P. McMurphy]

Right then... After feeling like I have spent a day at Kindergarten, I thought with the volatile situation we should focus more on the reliable timeframe, ~72 hours.

 

Most charts will be based on 09:00AM & I will try and keep this simple, mainly for the newbies struggling to keep up with this ever expanding thread.

 

It might make a nice chance from all the mad FI charts being shown which change during each run, so a nice change to normality at the reliable timeframe.

 

SPLITTING INTO TWO POSTS DUE TO TOO MANY IMAGES

 

Based mainly on the GFS.

 

Temperatures.

 

It looks like a chilly frosty morning for most except for the far soutwest, where temperatures will be quite mild to say the least.

 

 

 

 

It's a warmer start on Wednesday morning than Tuesday, with most places above freezing, except for high ground.

 

 

 

Most places hovering around 1-3C on Thursday, so feeling chilly.

 

 

 

 

Upper Air Temperatures

 

The upper air temperatures (850's) are also a little bit on the chilly side. Hovering between -2C and +3C for Tuesday.

 

 

Wednesday see's more of the same for the 850's.

 

 

Thursday is quite a bigger change than of late, with cold WNW winds flooding in.

 

 

Note, the 528 DAM line covering a lot of the UK - could be some snowfall around.

 

The Jetstream

 

The Jetstream remains in a quite slack flow as it heads towards the UK taking a more Southerly track on Tuesday.

 

On Wednesday, the JetStream appears to get powered into some life.

 

 

While Thursday sees all change with a powerful Jet flirting with the UK.

 

 

Stratosphere

 

We can see from the below image, some warming is beginning to take place, increasing pressure on the Polar Vortex.

 

 

Little change in regards to the temperature over a 3 day period.

 

 

 

This chart is showing the 30-hPa Zonal Mean for 2013-14.

 

 

Here is the ECMWF Strat chart.

 

 

We can also see the recent change at 10-hPa level over a small period of time.

 

 

 

Precipitation Charts

 

Tuesday starts off quite dry for most, which is always welcome in the UK, before rain begins to press in from the West.

 

A closer look at Tuesday for the UK shows some unwelcomed rain to many parts of the UK.

 

 

Wednesday starts off fairly dry for most besides some Eastern areas.

 

 

Parts of Northern England remain wet for the night.

 

 

 

Thursday morning begins with another front of Precipitation approching from the West.

 

 

Moving on we see the front move across the UK.

 

 

A closer look.

 

[R.P. McMurphy]

Precipitation Type (Will it or Wont it Snow)

 

Tuesday sees a front moving across, but unless you live in the Scottish Highlands, you won't see snow.

 

 

Moving forward, most places becoming wet.

 

 

Wednesday morning sees some dry spells, but no snow around.

 

 

Moving on Wednesday night is much of the same.

 

 

Thursday morning starts off Wet, but some high ground in Northern England (Mountain areas) might see some of the white stuff.

 

 

Moving forward 3 hours, the threat remains for snow on High ground, but wouldn't count on it for lower levels at this stage.

 

 

The snow risk charts remain around 50%.

 

 

The H500 & SLP

 

Looking towards Thursday, we see a split Polar Vortex, with incursions coming from the NW in quite a cool feeling flow.

 

 

Ensembles (Surface AVG Temps) (850's)

 

I am basing this on Nottingham to try and give a Balanced view N/S divide, although may vary.

 

Not looking beyond Thursday we can see the GFS Ensembles hovering from 0C - 5C, so quite average.

 

 

Although as noted, this will vary on City, for example, Aberdeen shows the cold filtering in quite a lot on Thursday.

 

 

Lets take a look at the 850's for comparison. I expect Aberdeen will be a lot lower due to the feed on Thursday coming through.

 

 

And Nottingham for comparison.

 

 

We can see a good agreement North and Mid/South for a drop in 850's, one to watch for potential snow events.

 

Other Charts

 

It's almost worth having a look at some other charts on offer. Unfortunately I have had to delete a load as this Forum wont allow more images to be added, but worth checking out latest SAT Images, NOAA Charts etc.

 

 

Cross Model Agreement?

 

GFS

ECMWF

 

 

Met Office

 

 

FAX Charts

 

It's also worth having a look at the FAX charts for forecasts T72 - They are one of the most reliable.

 

Thursday showing the interest, expecially with the 528 across much of the country (Sometimes needed for low level snow)

 

 

Conclusion

 

So, after taking all of that in, Tuesday/Wednesday remain wet throughout the day, feeling chilly and nothing really of note. Thursday see's quite a change from recent weeks (or months!) as cold air filters in from the WNW. Thursday is one to watch if it's snow you are after, and may perhaps, crop up a couple of surprises.

 

I have tried to keep this as simple as possible, especially for the newbies who will struggle in this thread with all the constant bickering, point scoring, and completely irrelevant one liner posts without backing anything up (Yes thats my rant, so have it). So hopefully you will understand a little more, and might have even learnt a thing or two.

 

Got to dash, there is a Fishing match live on Radio 4.

 

Glenn

[SMU]

Look at the 18z @ 72 V 12z 78 & the package of cold air into the NW should be better with a sharper gradient- 

 

which will represent the possibility of more widespread snow-

 

heres 54 already more amplified

http://modeles.meteociel.fr/modeles/gfs/runs/2014012018/gfsnh-0-54.png?18

S

 

Nice Post Glenn

Edited January 20, 2014 by Steve Murr

[fergieweather]

 

In other words, more of the same as the last few months, sorry guys but even my enthusiasm will only stretch so far. I hope that you all take notice of the expert, fergieweather.

Ah but hang about: many very much more expert folk posting on here, I can assure you. Anyway - the similar trend in JMA and the 12z EC ENS has certainly caught the eye of colleagues. It's one to watch for where we head in the output over the next day or two, for sure.

[Paul White.]

I think that had it been not for the expected strengthening of the Jet flow next week giving extra oomph to the Atlantic push from the weekend the path to cold would have been very much easier given the synoptics to the NE.

Hi Martin don't you feel though that whatever models show they always seem to be over egged be it the jet stream forecast or a high to the east or a low to the west. In my ten years watching this forum I have seen 1050 highs and 950 lows modelled, but when it comes to the day the highs are about 1030 and lows at about 990 ish. We only get to see the GFS jet stream forecast and I believe that is fraught with the same model bias as it's H 500s that Steve Murr refers to often. I think this weekend is tough one to call. From what I have read tonight the Met are going for an Atlantic victory in thus occasion but I remember last March and if we can keep even a small wedge of heights to our north east it May deliver snowfall and if it's anything like last spring, well that was the mist epic snowfall in my memory ( even better than December 2010

[Frosty.]

Ah but hang about: many very much more expert folk posting on here, I can assure you. Anyway - the similar trend in JMA and the 12z EC ENS has certainly caught the eye of colleagues. It's one to watch for where we head in the output over the next day or two, for sure.

You are the expert ian, I think there is a lot of hopecasting going on in here tonight. I take notice of the met office above all and it just sounds like more of the same dross to me.