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

[Dancerwithwings]

Then again, should the models do their usual, we might enjoy optimal conditions for seeing whatever's left of Comet ISON?

Sod ...Comet ISON...This is rarer

[The PIT]

Well into FI GFS and ECM both offer a northerly although getting there is slightly different. Now we need a few more runs to see if it comes off.

[UV-RAY]

Fantastic charts for cold and snow for IMBY and other NW parts of the UK, the usual caveats apply though in these cases at this range, with the danger of all this being shunted further East nearer the time. Just for once lets hope not and instead lets see further upgrades for longevity next. Please weather gods be kind to us all, more so for those of us in the NW.

Edited November 29, 2013 by Sceptical Inquirer

[Mucka]

Fantastic charts for cold and snow for IMBY and other NW parts of the UK, the usual caveats apple though in these cases at this range, with the danger of all this being shunted further East nearer the time. Just for once lets hope not and instead lets see further upgrades for longevity next, please weather gods be kind to us all more those of us in the NW.

 

 

Amen

[SMU]

Im off out-

 

I would just offer 1 word of caution

 

This Shortwave is the one to watch with keen eyes-

 

ALL the models even possibly the UKMO recurve this SE NOT north up through Greenland

 

 

If theres to be any downgrades from the ECM they will come from this -

 

However if ECM Is correct- remember its against every model then every model will UPGRADE!

 

S

 

 

[Ladyofthestorm]

4 days ago the GFS picked up this Nly pattern, and for the most part stuck to its guns, it isn't the first time its picked up a trend in the far reaches of the forecast, dropped the idea for 4-6 runs and then go it right. Ok Nly aint great for Southern snow lovers but if the 12Z is even within a sniff of what it has projected, the NE  of Scotland, the Northern Isles and Highlands are stuffed with widespread blizzards even to lower levels.

 

And right now there is nothing to doubt what it is telling me given the GEM, ECM and ensembles are heading exactly the same way too.

 

The key is this low and when it begins too deepen, Its timing is crucial to a wintry outbreak. However there is no doubt in my mind that given the pressure over Greenland, eventually this set sup will cause an outbreak of significantly  colder air from the north. How long it lasts for is another matter.. I suspect it will be a relatively short sharp blast of around 4 days.

[Frosty.]

Well i'm awarding this Ecm 12z op run a 10 for pure excitement and potential, I posted these charts for the business end of the run, the cold air already flooding across scotland during next thursday and then all hell breaks loose, this is what I call a screaming northerly, the atlantic high is far enough west and linking up with the greenie high, this really is BEAUTY....I still think the longevity will extend rather than reduce, some parts of the uk exposed to the full force of this would be buried in deep snowdrifts and as for the wind chill factor. and 510 dam into the southeast.  it's a carlsberg special...all aboard the polar express..drinks are on me .........choooooooooooo...choooooooooo

[Gibby]

Good evening everyone. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday November 29h 2013.

 

All models remain in unison between now and the middle of next week with High pressure in control over or to the West of the UK with fine and dry weather. Some brighter conditions are likely tomorrow but anticyclonic gloom will gain momentum again across all areas through Sunday then likely last until midweek when Westerly winds freshen markedly across the North of the UK. Temperatures though not spectacular will likely remain average for the time of year with little in the way of frost and fog.

 

GFS then shows a deepening Low move East close to Northern Scotland bringing stronger winds and rain followed by a dramatic drop in temperature as a cold front sweeps SE bringing rain to all and then following it with sleet and snow showers extending SE across many areas through Friday and into Saturday. Winds then steadily decreases and less cold conditions for a day next weekend with sharp overnight frost. Thereafter the operational model sees a rapid change to more active Atlantic based weather with spells of rain and severe gales at times but with some quieter and brighter spells in between. Temperatures will be close to average but it would sure feel cold in the windy and rainier periods with some snowfall at times on Scottish hills.

 

UKMO tonight shows next Thursday as a much windier day with increasing Westerly winds veering NW or North later in the North. Rain crosses SE through the day with an abrupt drop in temperature behind it with snow showers affecting Northern and Western hills and coasts by the end of the day spreading SE.

 

GEM shows a more glancing blow from the Northerly at the end of next week and start to the weekend with some wintry showers in the NE. The rest of the weekend becomes dry and cold as High pressure transfers across before deep Low pressure near Iceland and Greenland has a broad SW flow across the entire North Atlantic with disturbances running NE in the flow bringing rain at times in relatively mild conditions, the most rain likely towards the North and West.

 

NAVGEM ends next week with no Northerly at all and instead keeping things very basic and ordinary for early December as High pressure slowly recedes away SE and allows a moderate and milder SW flow to bring the threat of rain at times, more especially towards Northern and Western areas.

 

ECM tonight shows a colder snap later next week and the start of the weekend as a deepening Low runs East into Northern Europe and sends a plunge of cold air down across the UK with rain followed by a period of frequent sleet and snow showers with some accumulations in places over the hills of the North. As with previous runs the cold is relatively short-lived as High pressure moves ESE down across the South cutting off the flow and bringing less cold air back down over the UK by the start of the new week. Sharp night frosts could persist somewhat longer though in the South.

 

The GFS Ensembles shows good support for a short cold snap late next week and equally good support for a warm up thereafter with temperatures likely to be exceeding the average in the week after next but with a more changeable weather pattern looking likely with rain at times.

 

The Jet Stream shows the flow well to the North of the UK for the next three to four days before it moves SE down over the UK while the cold snap occurs next weekend. Thereafter the flow blows in a NE direction quite strongly over the Atlantic and across the British Isles pulling milder air NE over the UK should it evolve as shown.

 

In Summary tonight the weather remains benign for the next four to five days with anticyclonic gloom and temperatures uninspiring but not cold. Soon after midweek much colder air is shown to blow down across all areas for a time. There would be snow showers coming thick and fast to Northern and Western coastal hills with drifting of the snow in the bitter wind through Friday and Saturday. The depth of cold is short-lived by all models but there are variations in the details of the weather to follow with much more mobility looking likely later with mild SW winds, rain and gales all featured in the later outputs supported too by many members of the GFS Ensembles. While all models as already stated support just a short cold snap late next week the depth of cold is quite marked this early in the season and the evolution taking us out of the cold may be more gradual than is currently shown in my opinion.

[Joe Levy]

Well i'm awarding this Ecm 12z op run a 10 for pure excitement and potential, I posted these charts for the business end of the run, the cold air already flooding across scotland during next thursday and then all hell breaks loose, this is what I call a screaming northerly, the atlantic high is far enough west and linking up with the greenie high, this really is BEAUTY....I still think the longevity will extend rather than reduce, some parts of the uk exposed to the full force of this would be buried in deep snowdrifts and as for the wind chill factor. and 510 dam into the southeast.  it's a carlsberg special...all aboard the polar express..drinks are on me .........choooooooooooo...choooooooooo

I couldn't help but chuckle to myself reading this. I was thinking the same thing when I saw the charts, but only you could express it in such a fabulous way!

[Gaz1985]

JMA says no chance to any cold spell, instead it sends the cold a long way east

 

Edited November 29, 2013 by Gaz1985

[tight isobar]

Im off out-

 

I would just offer 1 word of caution

 

This Shortwave is the one to watch with keen eyes-

 

ALL the models even possibly the UKMO recurve this SE NOT north up through Greenland

 

ECH1-144WAVE2.jpg

 

If theres to be any downgrades from the ECM they will come from this -

 

However if ECM Is correct- remember its against every model then every model will UPGRADE!

 

S

..quite agree "SM.ecm may as much be leading atm as be behind and or on failure synopsis! And most certain (as per) shortwaving will be significant...I'm confident However ECM(although variables recently, may well become form horse, with catch up play cross!!!

[swfc]

JMA says no chance to any cold spell

 

really??? .Still a lot to be resolved model output wise regarding the eastern seaboard low exiting ete but imo jma is probably not on the money

Edited November 29, 2013 by swfc

[bradymk]

Just for a bit of fun, the CFS daily has got its own take on the cold. Extends the cold a lot longer with height rises to the N & NE. Only a bit of fun though http://www.meteociel.fr/modeles/cfse_cartes.php?ech=174&mode=0&carte=0&run=10   Great run from ECM, as Steve says above, its that shortwave that needs watching. Still to many disagreements upstream to be confident of any outlook however i'd rather have the ECM on our side than the GFS!!

[Summer Sun]

JMA says no chance to any cold spell, instead it sends the cold a long way east

 

 

Its not quite no chance as cold air does hit the north looks similar to GEM by keeping any cold short lived

 

[NorthernRab]

JMA says no chance to any cold spell, instead it sends the cold a long way east

 

 

That actually still shows a cold spell for the north. 

[ChartViewer]

Not really seeing the optimism for a longer protracted spell of cold to be honest as much as I would like it. ECM shows a 4 day cold snap but at 216, 240 you can see a Vortex re forming flatter surpressed and high pressure west/over UK after day 4 of the cold snap.

 

High pressure to west of us or over us and ties in with anomaly charts.

 

After the cold northerly we sort of await the next chapter:-)

 

Edited November 29, 2013 by ChartViewer

[Gaz1985]

Its not quite no chance as cold air does hit the north looks similar to GEM by keeping any cold short lived

 

 

Indeed a glancing blow, more like a 2 day cold snap for far north not really proper cold spell. ECM was showing -10 uppers creeping into Northern England. JMA seems much more tame.

[Stuie]

That`s not you speaking to yourself Summer is it? i.e Gaz?

 

Anyway, you can shove very cold air away but following behind is cold.

[TootyFruity]

It seems to me from a simple novice point of view that the charts just keep getting colder and better and pushing the high further back into FI (don't shout if I'm wrong)

Also can I just mention Old Met Man and his posts from last night were really informative what a star he is .

[stewfox]

Good evening everyone. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday November 29h 2013.

 

 While all models as already stated support just a short cold snap late next week the depth of cold is quite marked this early in the season and the evolution taking us out of the cold may be more gradual than is currently shown in my opinion.

 

Thanks for the detail as ever and your overall opinion which is welcome by us few trying to learn. A steady pair of hands in a choppy sea.

Edited November 29, 2013 by stewfox

[Spah1]

Fantastic charts for cold and snow for IMBY and other NW parts of the UK, the usual caveats apply though in these cases at this range, with the danger of all this being shunted further East nearer the time. Just for once lets hope not and instead lets see further upgrades for longevity next. Please weather gods be kind to us all, more so for those of us in the NW.

You think the uppers will be cold enough at -6/-8 or are we looking at marginal conditions away from the peaks etc?

[nick sussex]

Indeed a glancing blow, more like a 2 day cold snap for far north not really proper cold spell. ECM was showing -10 uppers creeping into Northern England. JMA seems much more tame.

The GEM was seen as an outlier solution and ditched by NOAA this evening, the JMA is the Brut of the aftershave world.It's really what the GFS/ECM/UKMO agree on that will decide things. There are no guarantees either way regarding the northerly, it might get watered down. Certainly makes for avid model watching, its the first real drama of the season!

[Jason M]

Just for a bit of fun, the CFS daily has got its own take on the cold. Extends the cold a lot longer with height rises to the N & NE. Only a bit of fun though http://www.meteociel.fr/modeles/cfse_cartes.php?ech=174&mode=0&carte=0&run=10   Great run from ECM, as Steve says above, its that shortwave that needs watching. Still to many disagreements upstream to be confident of any outlook however i'd rather have the ECM on our side than the GFS!!

Not just a bit of fun tbh. This evolution is perfectly possible and there have been a few similar charts popping up in the GEFS over the last 24 hours. Jason

[pip22]

I think the mild SW after the cold snap will be a few days affair as the low pressure making its way eastwards towards Scandinavia and then its cold north-westerlies. This is on GFS. I am pretty sure alot will change in few days though.

 

 

 

Edited November 29, 2013 by pip22

[Paul_1978]

That was a very good run of the ECM and more than I would expect at this time of year. As a child of the mid-late 90s and early 2000s, 3-4 days of cold would be mega long in my books if it were not for the last 4 or 5 years, so these charts are exactly what I am looking for this winter! Even in the last chart there is long term potential as high pressure ridges into Scandinavia

OK it's 240 hours away, but that high looks like it's only going one way to me if there was a 268 ECM, and that's south, unless anyone can advise me of the error of my ways :-D