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Model Output Discussion 17th Dec.2013-12z onwards.


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The Ecm 00z ensemble mean shows no relaxation in the very unsettled and occasionally stormy pattern with low pressure in total control throughout with spells of heavy rain and gales interspersed with clearer, colder and showery intervals, by T+240 hours, the alignment of the jet looks better from a cold perspective with more of a northwest / southeast slant which bodes well for an increase in cold shots from the west / north west or even the north beyond day 10 with a higher risk of snow, frost and ice, more of a wintry flavour as we head deeper into January seems likely to me, hopefully the met office update today will carry on it's recent theme for a gradual decrease in temps with a higher risk of wintry ppn and ice.

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post-4783-0-47636200-1388311058_thumb.gi

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The wait continues,

Some excitement beginning to build in the strat thread which hopefully will be a precursor to some interesting synoptics via NWP.

This really has been like pulling teeth trying to rid Greenland of that horrid PV.

I know we have had a stormy December one wonders what the conditions have been like in Iceland!

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I love BA's incredible optimism about us heading into a cold phase! The models keep on and on underlinng the Atlantic driven picture of unsettled wndy dross with little sign of any proper cold weather. Oh yes the Scottish mountins may get some snow but for 99.99% of the population that is irrelevant.

 

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ENS very zonal and unsettled with one solitary cold outlier

 

Posted Image

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It looks at the moment that we will get 2 of the 3 required ridges needed to KO the polar vortex on the Greenland side. Trouble is it's the Russian/Pacific ones. We really need to get some downstream response from the Pacific ridge to get some amplification in the Atlantic or we end up in a scenario worse than zonal. One where low pressure continues to drain ESE from the northwest, slowing and disrupting over the UK as energy splits in response to the Russian  high. This would give copious amounts of rain for the UK. Not good.

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I mean from a Northern hemisphere point of view, this isn't a desperate situation, just our luck is currently pretty bad.

Fingers cross the Strat events might push us over the line. It wouldn't take much. But as long as we tread water like this, many many people will continue to suffer from the high rainfall totals a pattern like this provides.

Edited by Captain shortwave
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I love BA's incredible optimism about us heading into a cold phase! The models keep on and on underlinng the Atlantic driven picture of unsettled wndy dross with little sign of any proper cold weather. Oh yes the Scottish mountins may get some snow but for 99.99% of the population that is irrelevant.

 

Posted Image

Posted Image

ENS very zonal and unsettled with one solitary cold outlier

 

Posted Image

I think ba's optimism is justified as the strat is starting to show changes, this of course wont be shown in the model output yet.

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Early days but if the strat warming to the north of the UK is correct then we would be in

prime position for northern blocking and bitterly cold Arctic outbreaks from the east,

northeast. This could turn our winter on its head so to speak.

Also the NWP output would become even more inconsistent for a while offering a wide

range of solutions.

Back to the here and now and 15 days or so I think we are likely to see some colder

intrusions with hill snow and perhaps one or two surprises for lower elevations these

will be interspersed with milder wet windy and milder weather. The last two weeks of

January and on into February should become much more interesting.

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I love BA's incredible optimism about us heading into a cold phase! The models keep on and on underlinng the Atlantic driven picture of unsettled wndy dross with little sign of any proper cold weather. Oh yes the Scottish mountins may get some snow but for 99.99% of the population that is irrelevant.

 

 

 

ENS very zonal and unsettled with one solitary cold outlier

 

 

 

you misrepresent me a tad purga  - 'coldER phase' , absolutely but how much colder and for how long is the question.  tbh, my cup doth not runneth over this morning re sustainability nor depth of cold ,but i hadnt commented as i mentioned earlier that conflicting signals may mute the overall mean/anomoly output for a good few runs.

 

and PM, thanks for the comments but i havent taken possible strat events into account when perusing the models as yet. too early for that. the models all go high enough into the strat now to provide good consequential trop guidance within the 15 day timeframe.

Edited by bluearmy
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Goodness!

 

Model watching has been painful for coldies with SW bombardment (although the windspeed gave us it's moments up here) this festive time - especially in the snowless Northwestern reaches - Helvellyn had blizzards in storm force three figure windspeeds on Thursday and most of the snow has melted or just been blown into sizeable drifts above 1900ft the summit is totally clear of any snow due to blowing but large drifts are evident around the shelter - all in all exciting stuff but I digress....! - a nice brew and butty was had in Fellbites Glenridding Posted Image

 

FI FI FI FI alert Posted Image

 

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13th

 

 

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Will the real Cumbrian Winter please stand up?

 

Ian

Edited by Iceaxecrampon
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Hi BA, surely the stratt will be having some effect on the models at this point out in FI ? As the predicted warming signals are picked up on due to the flip flopping over the last few runs..? Sorry for the confusion.

 

FI the Polar Vortex looks very distorted..

 

Posted Image

Edited by Polar Maritime
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For someone like myself who has only basic grasp of model watching could someone help me out with a question.

I have been looking at archives on metociel and in particular winter 1946/47 and what struck me was the size of PV end of December through January am I reading the charts right?

 

Which brings me to my main question how can posters on here say winter is over nothing through January when we all know how that winter panned out.

 

Thanks in advance for any replies and everyone keep up the good work, special thanks to Nick Sussex and Steve Murr for your explanations and diagrams which help the less informed learn more.

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There is finally cooler air getting into Europe. The flow is even starting to be dragged West. Maybe we are not that far away at all for a decent pool to our East to "tap into".

 

Posted ImagePosted Image

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PM, events high up in the strat generally have little effect on the trop within normal semi reliable modelling timeframes. The overall picture (ie. strong, cold, organised strat vortex = strong, organised trop p/v) is generally the case. However, even now, we see a split trop vortex with a raging, cold strat vortex high up. The overall point is that now the ECM ens go to the top of the strat, all the nwp we look at should be factoring in events in the strat and their possible affect on trop patterns over the coming fortnight. The events now showing in gfs fi ops wrt to warming, stretching and indeed, splitting the strat vortex would have implications for the mid latitudes come the end of jan, should it verify. That's too far away for me to worry about.

IF, we do have a sudden warming shown on the strat charts, then my eye will wander to the trop output to see if we get a quick response within the following week which is often shown by a big ridge the other side of the pole appearing and driving the AO quickly neg whilst a ridge this side of the NH moves up to meet it. Thing is, we already have a pronged neg AO and Aleutian ridging so it may be hard to spot that anyway!

Overall, the jet meandering back to a less favourable position for cold through week 2, but I'm holding fire on judgement re my previous posts.

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Re strat warming, yes its good news, however

1. It’s still in its infancy and really remains a forecast for now

2. Even if it happens it may not benefit us and

3. It will take time before we feel any effects

 

Consequently I don’t see much change happening from that quarter in the next couple of weeks at least and more likely the last week of Jan – start of Feb, Of course if we get a change of pattern before then any strat warming effect could really beef things up.

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There seems to be a lot of hunting for cold, claims of patterns changes etc. the reality is more of the same.

Eventually , of course , there will be a pattern change but some people might have been calling for a pattern change for weeks by then. What huge change does occur does that mean kudos for people constantly talking of change/ cold.

The posters I follow closely are fergieweather and Martin Gibbs; impartial with no bias. Any profile that has any mention of cold in profile title/ name should be treated with caution lol

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Hi BA, surely the stratt will be having some effect on the models at this point out in FI ? As the predicted warming signals are picked up on due to the flip flopping over the last few runs..? Sorry for the confusion.

 

FI the Polar Vortex looks very distorted..

 

Posted Image

 

Yes great chart there with plenty of blocking in the high artic and Greenland.

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ECM control run is a block party this morning.

Posted Imageeps_z500a_c_exatl_39.pngPosted Imageeps_z500a_c_exatl_41.png

Thanks for putting those charts up, I was wondering what the control was upto having looked at the ECM De Bilt ensembles. Theres still a cluster of solutions that take lower heights further se towards Iberia and the western Med:

 

post-1206-0-80933700-1388317326_thumb.gi

 

In terms of the low which exits the ne USA the USA State forecasts still unsure as to what happens to that, whether its more of an inland runner or flatter and shallower.

 

Given a choice I think we'd need to see that deepen even more and run further ne, this made me laugh from NOAA another term to add to the thread:

 

THE LONGWAVE RIDGE/TROUGH PATTERN ACROSS THE CONUS WILL LARGELY

STAY IN TACT DURING THE MEDIUM RANGE. INITIAL HIGH LATITUDE VORTEX

WILL SWING THROUGH SOUTHEASTERN CANADA EARLY IN THE PERIOD BEFORE

LIFTING OUT... ONLY TO BE REPLACED BY ANOTHER COLD UPPER LOW

MOVING INTO HUDSON BAY NEXT WEEKEND. THERE REMAINS CONSIDERABLE

SPREAD AS TO THE SPECIFICS OF THE EVOLUTION OF THE SW PORTION OF

THE TROUGH LIFTING THROUGH THE SOUTHEAST WED-FRI/D3-5.

CYCLOGENESIS/BOMBOGENESIS IS STILL BEING INDICATED BY MANY

ENSEMBLE MEMBERS AND DETERMINISTIC RUNS BUT HOW QUICKLY AND HOW

CLOSE TO THE COAST THIS MAY OCCUR IS YET TO BE PINNED DOWN.

 

Looking at their comments re the PV, I think in terms of that the ECM is closer to the mark than the GFS, that low could still cause some volatility in terms of what happens to troughing over the UK, so the 144 to 168hrs still holds out some hope in terms of perhaps a surprise development.

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ECM control run is a block party this morning.

Posted Imageeps_z500a_c_exatl_39.pngPosted Imageeps_z500a_c_exatl_41.png

 

Yes saw that on the Dutch (wind direction): post-14819-0-43252500-1388316677_thumb.p

 

Not a lot of support, 2-3 keep an easterly of sorts.

 

The London extended ECM mean:

 

post-14819-0-75084800-1388316839_thumb.g  A cooling off of temps, more than you would expect from the tread of time.

 

The op at D10 showing most of the energy going through the UK rather than SE, though to our west the makings of an Atlantic ridge in the lull between the next vortex low:

 

post-14819-0-52217900-1388317500_thumb.g  But the GEFS ignore this option.

 

The AO mean continues to stay negative and the standard deviation remains negative so a good sign going forward:

 

post-14819-0-03063200-1388316995_thumb.p

 

The D10 GEFS for the 06z are rather uninspiring and seemingly continue with the general delay of surface cold to the UK: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=240

 

T324: http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=324

 

Looking like week 3 onwards for the search for cold now.

Edited by i'm dreaming of...
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Some poor output this morning from GFS, UKMO and GEM which all ramp up the energy pushing NE and weaken the Scandinavian ridge which in turn lessens the effective troughing into Europe and we have a less amplified pattern day 6/7+

ECM is better with the less energy moving NE with a stronger Scandinavian ridge resulting in the Atlantic being stalled, more energy being forced S/SE into Europe which in turn prevents the Azores high ridging back in and keeps the pattern amplified behind.

 

Obviously the pattern is resultant on many factors but these details are worth concentrating on as the ECM route will likely offer some decent cold zonal in the second week of Jan with better prospects (or at least a shorter route) to any sustained blocking later in the month.

 

Comparing day 10 charts ECM and GFS 00z we can see that on ECM the Siberian high ridges all the way into Scandinavia where as GFS has deep low pressure sat in the same vicinity. Essentially GFS has the pattern much further East and less amplified than ECM at this point due to the knock on affects of the flatter pattern earlier but one big difference , sticking out like a sore thumb, is the very strong ridge that GFS has thrown up (My geography fails me here but Steve M has referred to it as the Kumchatka ridge so I will do the same for continuity) while ECM undercuts the developing ridge and has modelled a cut off high. If ECM had modelled the ridge as GFS 00z its 10 day chart would look very interesting but it still a decent chart as is with the chance of the Atlantic low disrupting SE behind the ridge and the chance of weak high pressure to the North and the Siberian high having time to establish its presence against a disrupted Atlantic flow. 

 

Posted ImagePosted Image

 

 

So only positives for me this morning are ECM and bits and pieces of GFS. GFS ensembles aren't worth the cost of the electricity used to produce them at the moment so no comment there except to say they may be worth watching to see how many go the ECM route in the mid term.

 

If we are going to get some strong blocking and deep cold it is going to be a long process for sure but on the flip side some wintry output could be just around the corner if last nights GEM and this mornings ECM are onto something with a real prospect of snow falling to low levels, especially in the North and especially through the second week of Jan. (I would be happy with that at the moment as there hasn't even been a hint of a flake falling here thus far) 

If the flatter pattern is correct then any wintriness will be confined even further North and mainly to high ground with the end to the long slog in search of deep cold and blocking continuing to be just over the next mountain.

Edited by Mucka
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