Model Output Discussion 18th Nov.2013-12z onwards.

[Summer Sun]

ECM lining up a northerly at t216 (December 1st)

 

Edited November 22, 2013 by Summer Sun

[Mark Parsons]

Welcome FC and I to, like many others share your disappointment in some of the behaviour!!!

[Summer Sun]

After the northerly at t216, t240 ends with high pressure over the UK

 

 

Coldest in the east and south east

 

[EML Network]

So the ECM  gives us a northerly sourced from the heart of the north pole ....

 

...AND the 850 uppers are warmer than they are right now....What a joke...If the cards are stacking themselves to the point where a direct northerly feed of air from the coldest place on earth (at this time of year) STILL won't get the UK a decent cold spell, then this Winter is properly cursed and I'm going into hibernation.

 

Edited November 22, 2013 by EML Network

[swfc]

Seems we finish on ecm back at square one altho the nh charts are encouraging and the amplification is better.Not a bad trend or run and thats about it imo

[NorthernRab]

So the ECM  gives us a northerly sourced from the heart of the north pole ....

 

...AND the 850 uppers are warmer than they are right now....What a joke...

That's why you use your common sense and don't take upper air temps at that time scale as gospel.

[swfc]

That's why you use your common sense and don't take upper air temps at that time scale as gospel.

Sigh!! its just a comment on the output in front of you Enjoy the 18z guys im off to the pub before i implode

[nick sussex]

Before people draw too many conclusions from tonights output we should bear in mind that upstream chaos ensues in the modelling. No consensus on phasing, amplitude and timing. Until that gets resolved then any northerly toppler is up in the air.

 

NOAA are close to giving up and going home early for Thanksgiving! Here was their latest update done before the ECM operational run which just muddies the waters even more.

 

...MODEL SPREAD--AND STAKES--REMAIN HIGH WITH FUTURE OF
SOUTHWESTERN TROUGH...

WITH THE FLOW OVER CENTRAL NORTH AMERICA EXPECTED TO OPEN BY THE
MEDIUM RANGE, IMPORTANT SHIFTS IN SENSIBLE WEATHER WILL FOLLOW.
UNFORTUNATELY, THE LOCATION AND TYPE OF POTENTIAL HAZARDS ARE FAR
FROM CLEAR AT THIS POINT. THE KEY PLAYERS ARE THE POSITIVE-TILT
TROUGH CURRENTLY LODGED OVER NORTHERN MEXICO AND THE UNITED STATES
DESERT SOUTHWEST, AND THE STREAM OF CLIPPER SYSTEMS DIPPING INTO
THE CANADIAN-BORDER STATES. TIMING AND AMPLITUDE ARE BOTH
CRITICAL--AND SERIOUSLY IN QUESTION. IF THE SOUTHWESTERN WAVE
EMERGES OVER THE NORTHERN GULF OF MEXICO DURING A SLACKENING OF
THE NORTHERN STREAM ENERGY, IT WILL MAKE CONSIDERABLE INROADS INTO
THE EASTERN UNITED STATES. IF NOT, MUCH OF THE SOUTHERN STREAM
MOISTURE AND DYNAMICS WILL BE HERDED TO THE ATLANTIC COAST OR
POINTS OFFSHORE. RELIED ON THE 00Z/22 EUROPEAN CENTRE ENSEMBLE
MEAN AS A SYNOPTIC GUIDE FOR THE WHOLE NATION, LARGELY DUE TO ITS
INHERENT STABILITY VIA THE SHEAR NUMBER OF INDIVIDUAL ENSEMBLE
MEMBERS--AND ITS SKILLFUL TRACK RECORD. RAIN, THUNDERSTORMS, ICE,
SNOW, AND HIGH WINDS ARE ALL POSSIBLE THREATS FACING MUCH OF THE
CENTRAL AND EASTERN UNITED STATES ON THE BUSY TRAVEL DAYS BEFORE
THANKSGIVING NEXT WEEK. WILL HOPEFULLY HAVE A BETTER HANDLE ON THE
SPECIFICS ONCE THE SOUTHWESTERN TROUGH ACTUALLY BEGINS TO MOVE.
 

[That ECM]

Before people draw too many conclusions from tonights output we should bear in mind that upstream chaos ensues in the modelling. No consensus on phasing, amplitude and timing. Until that gets resolved then any northerly toppler is up in the air.

 

NOAA are close to giving up and going home early for Thanksgiving! Here was their latest update done before the ECM operational run which just muddies the waters even more.

 

...MODEL SPREAD--AND STAKES--REMAIN HIGH WITH FUTURE OF

SOUTHWESTERN TROUGH...

WITH THE FLOW OVER CENTRAL NORTH AMERICA EXPECTED TO OPEN BY THE

MEDIUM RANGE, IMPORTANT SHIFTS IN SENSIBLE WEATHER WILL FOLLOW.

UNFORTUNATELY, THE LOCATION AND TYPE OF POTENTIAL HAZARDS ARE FAR

FROM CLEAR AT THIS POINT. THE KEY PLAYERS ARE THE POSITIVE-TILT

TROUGH CURRENTLY LODGED OVER NORTHERN MEXICO AND THE UNITED STATES

DESERT SOUTHWEST, AND THE STREAM OF CLIPPER SYSTEMS DIPPING INTO

THE CANADIAN-BORDER STATES. TIMING AND AMPLITUDE ARE BOTH

CRITICAL--AND SERIOUSLY IN QUESTION. IF THE SOUTHWESTERN WAVE

EMERGES OVER THE NORTHERN GULF OF MEXICO DURING A SLACKENING OF

THE NORTHERN STREAM ENERGY, IT WILL MAKE CONSIDERABLE INROADS INTO

THE EASTERN UNITED STATES. IF NOT, MUCH OF THE SOUTHERN STREAM

MOISTURE AND DYNAMICS WILL BE HERDED TO THE ATLANTIC COAST OR

POINTS OFFSHORE. RELIED ON THE 00Z/22 EUROPEAN CENTRE ENSEMBLE

MEAN AS A SYNOPTIC GUIDE FOR THE WHOLE NATION, LARGELY DUE TO ITS

INHERENT STABILITY VIA THE SHEAR NUMBER OF INDIVIDUAL ENSEMBLE

MEMBERS--AND ITS SKILLFUL TRACK RECORD. RAIN, THUNDERSTORMS, ICE,

SNOW, AND HIGH WINDS ARE ALL POSSIBLE THREATS FACING MUCH OF THE

CENTRAL AND EASTERN UNITED STATES ON THE BUSY TRAVEL DAYS BEFORE

THANKSGIVING NEXT WEEK. WILL HOPEFULLY HAVE A BETTER HANDLE ON THE

SPECIFICS ONCE THE SOUTHWESTERN TROUGH ACTUALLY BEGINS TO MOVE.

Honestly Nick, what's the matter with these people? Just tell them to PM some of the posters on here and they will give them all the clarity they need!!!

[bluearmy]

gem and ecm provide great interest at the back end of their runs from a hemispheric perpective. if they are close to right, we would be very unlucky to miss out on a proper december cold spell.

[I remember Atlantic 252]

So the ECM  gives us a northerly sourced from the heart of the north pole ....

 

...AND the 850 uppers are warmer than they are right now....What a joke...If the cards are stacking themselves to the point where a direct northerly feed of air from the coldest place on earth (at this time of year) STILL won't get the UK a decent cold spell, then this Winter is properly cursed and I'm going into hibernation.

 

 

could be to do with it only being 2nd Dec? and is missing us slightly to the east, 2nd Feb to 2nd Apr surely would be miles colder uppers

[weatherguy]

RE the model verification, it's important not to forget that it's not as clear cut as pitting mild v cold and seeing which model gets it right...If for example the ECM is gunning for cold while the GFS backs a relatively mild set up, it's quite easy to jump to the conclusion that the GFS has got it right.  Well, not necessarily, as of course there are many variances in a mild pattern that still lead to mild, while often very minor changes in a cold pattern can lead it to being mild.

[legritter]

Still some good interest towards the end of tonights ECM Run but we are only seeing these charts at the far range ,ecm on its last frame but one seems to throw the high at us shouting    Take this modellers thats all your getting from me .but certainly looking at all modelled predictions in northern Hemisphere theres a lot going on so i think any modell would be struggling at this stage .But taking the last 3 frames of ECM  it wouldnt take much adjusting if of course its there for a good blast .So we can only wait for overnight runs for hopefully an upgrade .PS its brass monkey weather out now and its only nov 22nd ,? 

[MR EXTREMES]

honestly I don't buy into any of the model out puts tonight the best models are by a million miles the ukmo and jma ok they only go out to a certain timeframe but are by far the most realistic models on the planet.

 

and nick sussex thanks for sharing your post always top notch steve murr absolutely agree ian no way a Bartlett no way respective way of looking at it all the most likely outlook is most certainly a nw flow perhaps west flow in time.

 

I can see the snow signs in peoples eyes but until we see a more favourable block in the northern hemisphere Greenland Iceland scandi then its worth keeping things more balanced and I see nothing remotely above well well into fi keep watching wave activity is doing its thing and there certainly some intresting for us coldies nothing remotely blow torch yet.

 

and my thoughts are gfs rubbish ecm rubbish jma and ukmo the way forward.

Edited November 22, 2013 by emotional rollercoaster

[nick sussex]

Honestly Nick, what's the matter with these people? Just tell them to PM some of the posters on here and they will give them all the clarity they need!!!

It's a complete mess in the USA regarding the possible northerly for the UK as the amplitude of low pressure aswell as the depth is up in the air over there. The ECM does develop some interest past 168hrs but even if showed a direct cold hit for the UK tonight I'd put low confidence in that because it needs to jump through too many hoops to get there.

 

Generally northerly topplers are not the biggest problems for the models but here they're determined to drag the drama out, normally its a deep low moving ene towards western Greenland, some WAA developing a transitory ridge over Greenland downstream northerly for the UK, energy eventually spills east ridge topples and that's it.

 

The UKMO from a cold perspective looks okay, even though we have some residual energy to the north as the low moves ene its likely we'd see a shortwave heading se from Greenland, that looks a decent chance for a northerly but its likely to be brief, the ECM if you compare at 144hrs has a totally different take on low pressure over the ne USA. If you look at the GFS/UKMO/GEM they all agree on a similar set up re the low, the ECM is the odd one out and considering its recent dismal performance especially with its modelling of upstream amplification I'd be inclined to view its operational output as an outlier solution.

 

I should add its best to view this northerly as a sub plot in a winter soap opera, I wouldn't get too disappointed if this doesn't verify, more important for prospects going forward in the more longer term is what happens to the PV after this. The overall NH pattern as BA mentioned does show some potential in the ECM/GEM, in terms of detail this will it won't it northerly won't make or break that.

 

Just reading through some of the state forecasts for the eastern USA and they're still not siding with a particular outcome re low pressure track and amplitude so we're going to have to wait till tomorrow to see which model has got closer to this. We need to see more of an inland runner to get the best northerly, the further out to sea any low pressure tracks the flatter the pattern ahead of it and so less retrogression of the high. Longer terms NOAA still go for high pressure to the west of the UK, again here the degree of amplification upstream will determine the flow into the UK.

Edited November 22, 2013 by nick sussex

[Man With Beard]

Been watching from the shadows for 3 years now and am getting bored of all the petty squabbling. I did want my first post to say thank you to all the regular posters who post and pass on their knowledge to the rest of us. The posters who do contribute know who they are and make this place fantastic. Its just a shame that the forum is now turning into a tantrum chamber full of hacked off moaners...... I'll come back in a few days I think when the toys are put back in the Pram and adults can be adults. (sorry for being a nag, but I like this place. Keep a lid on it I'm not happy, in fact I'm quite sad. The weather Will do what it does. Whether we like it or not.) FATCHAD

Don't disagree but would encourage you contribute your model thoughts to the thread as well, the more on-topic comments, the less the bickering will stand out. For instance, what do you make of this northerly at T192? I feel that, as long as the HP stays out to our west and diesnt sink, we're well in the game for a cold shot or two as December approaches since there's always the chance of cold plunging down the eastern flank.

[Cold Winter]

Tonight's ECM has high pressure over us for the forseeable future, apart from a brief northerly next Saturday/Sunday.

 

Uppers though not particularly cold except in northern Scotland with -5c 850 temps:

 

[Fozfoster]

Been watching from the shadows for 3 years now and am getting bored of all the petty squabbling. I did want my first post to say thank you to all the regular posters who post and pass on their knowledge to the rest of us. The posters who do contribute know who they are and make this place fantastic. Its just a shame that the forum is now turning into a tantrum chamber full of hacked off moaners...... I'll come back in a few days I think when the toys are put back in the Pram and adults can be adults. (sorry for being a nag, but I like this place. Keep a lid on it I'm not happy, in fact I'm quite sad. The weather Will do what it does. Whether we like it or not.) FATCHAD

All part of the fun FATCHAD, and welcome to NW.

[Summer Sun]

Latest from Gibby on the 12z models

 

All models continue to show quiet and benign conditions with some sunshine by day and frost and fog patches night and morning with just the far SE and North seeing somewhat more cloud and light showers at times. Towards midweek more cloud spreads down from the NW as a trough sinks SE with a little rain for a time before fine weather reasserts itself soon afterwards.

 

GFS then shows a short colder period as winds turn towards the North before High pressure reasserts itself over the UK with dry weather and mist and frost problems. There are short changeable spells though as systems pass East to the North of the UK with the North seeing the main share of any rain. Temperatures would remain close to average once the colder interlude passes.

 

UKMO tonight shows High pressure in a belt from mid Atlantic to the Southern UK with fine and dry conditions once a cloudier damp period midweek clears South. There will be a return to patchy frost and fog once more especially in the South.

 

GEM tonight shows a short Northerly flow as cold air floods South over Europe. For the UK only a glancing blow from this occurs before High pressure to the SW flattens the pattern once more with fine and dry conditions though a stronger NW flow would bring rain and hill snow at times to the North and East.

 

NAVGEM shows a cloudy High down to the SW of Britain sending cloud laden skies SE across the UK with very average temperatures in light winds with the likelihood of little if anything in the way of frost or widespread fog.

 

ECM also shows a cloudy High down to the SW with NW winds feeding plenty of cloud and benign weather over most of the UK in temperatures close to average. Towards the end of the run the NW flow strengthens somewhat as the High slips further out into the Atlantic and a weak Northerly flow brings clearer and colder air back South across Britain with an intensification of frost and fog problems once more.

 

The GFS Ensembles show a short milder interlude as well as an equally short colder spell before a huge range develops between members leveling the mean to a point close to the 30yr level for the rest of the run. Some rain is also shown to develop, especially across Northern areas later in the period.

 

The Jet Stream shows the flow maintained well to the North of the UK before a turn South over the UK occurs around the time of the projected sell of northerlies later next week. Thereafter the flow becomes more aligned across the UK.In Summary tonight it is more of the same with High pressure to the West and SW of the UK keeping things often rather cloudy, mostly dry with temperatures never overly cold or overly mild either. Some cloud breaks will allow some patchy frost and fog patches to occur haphazardly night to night and place to place. There seems little evidence to support that a change to this overall pattern either wet and mild or cold and snowy is likely to happen anywhere within the next week or two.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Frosty.]

The GEM model is showing great continuity with it's amplified upstream pattern with the atlantic high forced back into the mid-atlantic ridging north and a huge trough setting in across northern scandinavia, if this 12z trend continues, we would eventually see a proper arctic outbreak evolving by the end of next week onwards with progressively colder T850 hPa flooding south, it will be interesting to see how the gem handles this pattern as the clock ticks down to T-0.

Edited November 22, 2013 by Frosty.

[Cloud 10]

gem and ecm provide great interest at the back end of their runs from a hemispheric perpective. if they are close to right, we would be very unlucky to miss out on a proper december cold spell.

 

The GEM is at the top of its game at the moment as well. 

 

 

 

 

I would expect to see more of a mid-atlantic high influence on tonight's

NOAA update.

[phil nw.]

As Nick S said above a confused upstream  forecast re.500hPa pattern is keeping us guessing about our chances for downstream amplification of our high to bring us a colder snap from the north in a week or so.

In the meantime it's a waiting game as we settle in to a quiet and anticyclonic spell with some patchy night frost and fog where skies are clear for any length of time.

Encouraging that modeling still shows some continuing vortex disturbances,especially over the Alaskan side which may lead to further wave breaking down the line.

[Chess01]

It's worth noting that if the cold shot doesn't Happen it's not all bad because maybe it will be a wasted opportunity as Europe is still cooling so we might get a watered down version . I would much prefer to get the cold in the week before and week after Christmas

[johnholmes]

the pdf I promised

 

What might the upper air pattern be as we move into December-22 nov 13.pdf

[gottolovethisweather]

Frosty said: 

 

I think the gfs has out performed the ecm recently, the ecm has been shockingly poor with it's recent fantasy cold pattern, gfs never bought it.

 

 Frosty, that's because it has had an upgrade downgrade recently and its been rebranded as the "I don't do cold", Gav's Forecasting System.   I do wonder whether I should get remotely interested in the GFS pub run tonight or do I just  Off to read JH's input to search for some signs of hope in the meanwhile.

Edited November 22, 2013 by gottolovethisweather