Model Output Discussion - The Start Of Winter

[blizzard81]

The 120hr fax chart has updated but the 96hr hasn't - a tad frustrating!

 

Just updated now.

Edited December 8, 2014 by blizzard81

[Mark Neal.]

The 120hr fax chart has updated but the 96hr hasn't - a tad frustrating!

Just updated  

[blizzard81]

Just updated  PPVM89.gif

Thanks just spotted it. For some strange reason the 120 chart updated first.

When I look at the 96hr chart and 120hr chart, a standard toppler is not what springs to mind.

The Azores high is quite a lot further out into the atlantic than it would normally be

under a toppler scenario.

Edited December 8, 2014 by blizzard81

[phil nw.]

A  recent post has been moved here

https://forum.netweather.tv/topic/81281-model-banter-moans-and-ramps-autumnwinter-2014/

 

where it is more suited.

 

Only proper discussion in here please all-moans and ramps into the thread linked above.

 

Thank you.

[Frosty.]

EC32 retains marked low anomalies to N right through run. So no significant change in emphasis worth detailing, nor is any expected for a while.

Thank god we have a nw / se jet with polar maritime and borderline arctic incursions for the foreseeable future..after last month's dull mild stalemate, this is a good start.

[Frosty.]

yeah but after so long with not a lot to shout about us coldies deserve something.

Hang in there mate, at least the models are showing some cold weather, especially for our northern friends..it's a good solid platform to build on IMO. A sw / ne jet profile would have been too much to stomach at this point after the turgid November but the models have improved at least. :-)

[BlueHedgehog074]

Come on guys, let's please keep this thread friendly and stop all the arguing. Really does feel like a 'bomb' has gone off in here at times tonight. Like the other mods/hosts have said, there are other threads for that kind of thing. Thanks.

[Argyle1980]

GFS is showing us a good cold blast for Christmas day.

Let's hope ita on to something with maybe the start of some northern blocking.

Have a good day.

[Captain Shortwave]

Day 5 charts

ECM

UKMO

GFS

Parallel

GEM

All similar in clearing the colder air by Sunday, making it a brief event. The following week looks like a case of trying to make the best of a westerly pattern and hope for as potent a polar maritime blast as possible. There is still no real sign of removal of low heights to our north, well at least at a timeframe that we can have a relatively good amount of faith in.

Edited December 9, 2014 by Captain shortwave

[Iceaxecrampon]

Merry Christmas

 

 

Way way in FI  - it will be interesting to say the least.

 

Ian

[Nick F]

Seems to be an enthusiasm from American forecasts + forums for a return of the western North American (PNA+) ridge later this month as the raging Pacific jet eases to allow the NE Pacific trough to retrogress. Although this may not have any quick impact on the pattern for Europe, I can see we will be stuck with the vortex close to our north for another good 10-15 days, the +ve anomaly showing over arctic Canada on the GEFS and ECM ens mean/anomaly charts may progress far enough NE into Greenland to allow heights to become more +ve here with time. And/or we may also see Greenland height rises ahead of any trough that deepens over Ern N America - as Ian's been hinting at with the extended EPS.

 

Back to the more realistic future, some pretty wild weather to come for the rest of the week, Azores high is extending quite far north over the Atlantic, so this is really tightening the isobars on the southern flank of tomorrow's 'Weather Bomb' (as the daily Mirror likes to call it) - and it's not only the winds and snow showers that look hazardous - but also the storm surge with 60ft+ waves possible for the west coast. The Scottish hills, mountains and coasts not the place to be over the next few days!

 

Couple of waves in the strong westerly flow following in the wake of tomorrow's storm, the one on Friday looks quite active - and could bring some significant snow to parts of EIRE, N. Ireland, northern England and N Wales as it bumps into the colder air feeding down from the north - one to keep an eye on!

Edited December 9, 2014 by Nick F

[Recretos]

As far as ECM32 is concerned, it has a model top at 5mb, so that could perhaps have an effect regarding the upcoming strat dynamics and coupling down the line.

And it is run at 00z on Mondays and Thursdays, so before any 12z of the day.

[IDO]

ECM are finally realising the overriding signal and are toning day their D10 teases:

 

   GEM at D10: 

 

The D16 GEFS mean has not improved over the last 5 days and the odd semi-blocked member remains less than a handful, so reasonable to assume this remains background noise. The mean 850s and 500hPa's are what we expect from  an ongoing pattern:

 

 

 

It shows you can have a beaten up PV and still get no blocking, with zonal weather for a good period. The GFS P still has warming at 10hPa right out in FI:

 

 

 

This should be a good test for the Strat experts as their confidence has been very high since November, and will certainly be another plus for that area of NH weather prediction. In the interim we have the incoming storm:

 

 T48:  T96: 

Edited December 9, 2014 by Paul

[fergieweather]

As far as ECM32 is concerned, it has a model top at 5mb, so that could perhaps have an effect regarding the upcoming strat dynamics and coupling down the line.

And it is run at 00z on Mondays and Thursdays, so before any 12z of the day.

A key watching brief hereafter is whether EC begins to bolster any notion of weakening ongoing MSLP pattern & decreasing zonality/westerlies late Dec, as presently has some support in GloSea.

[Penrith Snow]

No let up in the cold zonality for the next 10 days and GFS has dropped the Christmas Bartlett in FI at least for the moment.

All in all some very interesting weather for northerners, it's just a shame it's not mid January as the colder Atlantic sea temps then would have led to much more low level snow. The Synoptics are similar to January 1984 which was very snowy from the Midlands northwards on an unusually cold zonal flow. However sea temperatures are currently about 3c higher so this is reflected in the air temperature.

I would forget northern blocking for a while and just be glad we are not stuck with a Euro slug but plenty of interesting and at times wintry and sometimes sunny weather instead.

Northern blocking may come in January, remember all the cold winters of the mid 1980's had mild zonal Decembers, the cold winters of recent years were unusual in having the cold 'front loaded' , a mild December followed by a cold January/February is much more typical of the UK climate if you look back over the decades.

Already I have seen more snow and frosts than during the whole of last winter.

Andy

[Frosty.]

The Gfs 00z op run shows a severe winter storm about to batter scotland with major impact to the far northwest and northern coastlines bringing huge waves during the next few days, not only that, highland snow piling up and blowing around into drifts as the air turns colder, especially once the complex trough pushes further to the east and opens the ice gates to an even colder N'ly blast. we keep the generally nw / se jet next week and beyond with a risk of snow, especially in the north but still with less cold, wet and windy episodes. The immediate run up to christmas looks wintry on a nationwide scale with snow, frost and ice galore as arctic influence increases...in the short term it's a story of severe gale to storm force westerly winds up north with squally wintry showers, even the south should get some wintry showers later this week.

[MR EXTREMES]

The distant realm EPS clusters offer a (highly inconclusive) raft of outcomes but it's cluster 2 that offers the hint of emerging mid-Atlantic to Greenland block. Anyway... EC32 awaited with interest.

It does seem to be heading towards this possibility although as a amateur and after my some what excitable post yesterday I'm more reluctant to post my ideas.

As some of the more experienced posters like yourself and others most suggested a mid month change !.

Of coarse still very uncertain but almost all models suggesting a similar idea.

Whether it happens around Greenland or not is debatable.

But in my amateur opinion I think there is a clear indication that the focus point is Greenland.

I would like to apologise to people for my posts yesterday I'm not a very educated person but spent my life fascinating over weather types the jargon used is something I'm still learning.

Slightly of topic I know but I do see a quick shift to some form of blocking ,

Whether we benefit from this is open to debate but Greenland block always seems to lead to something more wintry with better chances across more of the uk.

So I'm confident the models are sniffing at Greenland area or mid Atlantic heights.

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY TUESDAY DECEMBER 9TH 2014.

NEXT UPDATE WEDNESDAY DECEMBER 10TH 08:00

THE CURRENT GENERAL SITUATION An intense depression close to Iceland tonight will move slowly East driving an active cold front SE across the UK today and tonight with storm force Westerly gales across Northern areas tomorrow.

MODELS-2 WEEK HEADLINE Rather cold and windy for most with wintry showers or longer spells of rain or sleet with snow on hills especially in the North later this week. Perhaps milder especially in the South next week. Some night frosts where skies clear.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble forecast shows the strong flow continuing to the South of the UK under a deep trough over the next few days gradually moving North and weakening somewhat next week with a mix of solutions shown but still with a bias for the flow to travel West to East in the vicinity of the UK between lower pressure to the North of the UK and High to the South.

GFS OPERATIONAL The GFS operational this morning shows a continuation in the very changeable and often windy pattern of weather with a continuation of Low pressure areas driving East close to Northern Scotland with spells of rain followed by showers and sunny intervals with the showers wintry on hills at times. Little change to this pattern is shown right through to the end of the run taking us up to the run up to Christmas 2014.

THE GFS PARALLEL RUN The GFS Parallel run is much the same as the operational with only day to day differences shown between the changeable and Westerly theme which continues through to the end of the run. All areas would see spells of rain and average temperatures and spells of chillier conditions with wintry showers in the North and patchy frosts on occasions between weather systems.

THE GFS CONTROL The GFS control run also shows a similar pattern to the operational above but shows a more defined pull of milder tropical maritime air across the UK in conjunction with higher pressure over France through week 2 with less rainfall likely too especially over the South.

THE GEFS ENSEMBLES The GEFS Ensembles are indicative that Low pressure to the North of the UK and High to the South and SW will be the dominant pattern over the whole period. There will be a period through the start of the second week when High pressure comes close to Southern Britain for a time lessening the effects of wind and rain to a spell of milder weather before the return of polar maritime air at times brings back more volatile conditions with rain or showers at times as we approach Christmas.

UKMO UKMO today shows milder air returning from the West later in the weekend as the North flow early in the weekend backs Westerly. There will be spells of rain followed by showers at the start of next week with any wintry showers more confined to Scottish high ground by then.

THE FAX CHARTS The Fax Charts show a cold front sweeping SE tonight followed by a cold and very strong Westerly flow with showers tomorrow and Thursday. A secondary depression then is shown to deepen and move quickly NE across England Thursday night with rain and strong winds clearing to lighter NW winds and wintry showers at the weekend with milder westerly air over the Atlantic poised to approach the UK at the start of next week.

GEM GEM this morning maintains the basic pattern of Low pressure to the North and High to the SW over it's run this morning. This means a continuation of spells of wind and rain and average temperatures will be mixed with periods of sunshine and showers, wintry at times over the North. Patchy frost is likely in the quieter periods between weather systems.

NAVGEM NAVGEM this morning shows windy weather continuing for the whole of the run with further Low pressure areas crossing a point to the North of Scotland at various occasions over the week, each bringing a spell of rain and followed by clearer and colder weather with sunshine and showers, wintry on the hills.

ECM ECM this morning shows a very mobile pattern with strong Low pressure areas crossing East to the North of Scotland with strong winds and rain affecting all areas at times alternating with clearer and colder conditions with sunshine and showers in blustery WNW winds. Late in the run a flatter westerly flow develops which if transpired would bring milder and cloudy weather to many with rain more restricted towards the North and West in tropical maritime air for a time..

ECM ENSEMBLES This morning's Ensemble data remains largely unchanged with the overriding factor likely to be one of Low pressure situated to the North of the UK and High pressure to the SW. There will be spells ofstrong winds, rain and showers likely across all areas interspersed with colder and more showery spells with snowfall on Northern hills at times. Overall temperatures will be in the range of near or slightly below normal at times over the North and near to or slightly above average at times in the South but windchill will be a notable factor at times.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS Not any major shift in trend this morning with no cross model or high percentage chance of anything majorly cold affecting the UK in the run up to Christmas shown by any output this morning.

MY THOUGHTS  The volatile pattern of strong Westerly winds and occasional periods of rain and wintry showers look likely to be maintained across the UK in the next week or two. Despite some indications from good sources to the contrary of what the current model output available to the general public shows there remains little indication of anything other than changeable weather with some strong winds at times accompanying the heady mix of rain and wintry showers. It remains unlikely than the South will see anything other than the odd flake in the showery periods whereas the high ground of the North could see copious amounts of snow at times. Looking longer term there seems little sign of anything exciting affecting the UK in the run up to Chrsistmas with broadly Westerly winds maintained. It maybe in fact thet a flatter pattern for a time brings a milder and less wet period in part of week 2 before the undulating pattern between mild and cold periods return late in the period but there still seems a lot of work to be dome in the atmosphere if we are going to see a major shift towards universally UK wide cold and wintry weather this side of the New year. Of course we must always be mindful that we are not privvy to data that some of our powers at Exeter see so what I've described above is only indicative of what we can see and doesn't cater for hinted differences to the pattern that the Met boys see so we will have to see whether any differences manifest or transpire across the mainstream model outputs in the coming days.

[nick sussex]

The ECM ensemble mean suggests the operational run might be too Azores high friendly, thats kept further sw with troughing over the UK rather than to the north. Theres a spread running nw/se to the south of the UK indicative of low heights pushing further se into Europe.

 

I think theres still the opportunity for some PM incursions but I think we need to see whether that suggested PNA plus pattern does indeed verify to have a better chance of something colder.

[Recretos]

A key watching brief hereafter is whether EC begins to bolster any notion of weakening ongoing MSLP pattern & decreasing zonality/westerlies late Dec, as presently has some support in GloSea.

I hear you. I was targeting more on the "down the line" part, into the last quarter of the model.

Edited December 9, 2014 by Recretos

[fergieweather]

I hear you. I was targeting more on the "down the line" part, into the last quarter of the model.

Indeed - agreed!

[Dibdabbers]

Indeed - agreed!

Hi what does this mean in basic terms?

[IDO]

It does seem to be heading towards this possibility although as a amateur and after my some what excitable post yesterday I'm more reluctant to post my ideas.

As some of the more experienced posters like yourself and others most suggested a mid month change !.

Of coarse still very uncertain but almost all models suggesting a similar idea.

Whether it happens around Greenland or not is debatable.

But in my amateur opinion I think there is a clear indication that the focus point is Greenland.

I would like to apologise to people for my posts yesterday I'm not a very educated person but spent my life fascinating over weather types the jargon used is something I'm still learning.

Slightly of topic I know but I do see a quick shift to some form of blocking ,

Whether we benefit from this is open to debate but Greenland block always seems to lead to something more wintry with better chances across more of the uk.

So I'm confident the models are sniffing at Greenland area or mid Atlantic heights.

Hi. I do agree that Greenland is on the mark for height rises rather than from the east. The fact the models keep trying to build there suggests this is the weakest spot in the current pattern, but with the jet on supercharge and the PV fighting back it may be later rather than sooner.

FWIW the continued CFS monthly for Feb and March still show strong Northern blocking. January still suggests the PV is recovering early month before becoming less organised later.

Keep up with the enthusiasm as it is needed when we enter a holding pattern like the current setup.

[Chris W]

Comparing this in my memory (and limited analysis) to last year, the setup is very active north of the UK but with the vortex much further east and with very little persistent cold air for the Atlantic to draw strength from over eastern Canada.  The heights over North America in the GFS and ECM are quite something.  The upcoming storm is concerning, as last year's were and with 950mb being something that would but for last year have seemed very unusual so close to the UK, but it does not look to be a case of very strong low pressure systems lining up in succession from south of Newfoundland like last year.  I will have to do more model watching to see what heights build to the west of Greenland and get up to speed in general, but there seems to be the potential for that to occur and for the mid-Atlantic high to edge northwestwards.  Definitely colder in general than last December, and going off the GFS 00z op that is an impressive fetch on this week's northerly:

 

[fergieweather]

Hi what does this mean in basic terms?

That at far reaches of model runs, it may be a while before they show clear signs of synthesising change via drivers such as stratospheric warming. The tail-end of 00z EC EPS clusters, for example of inter-run oscillations, return to status-quo with no hint of possible NW heights as signalled in yesterday's 12z. Thus, it now aligns with latest EC32.