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

[That ECM]

Aren't they about to experience serious cold wave in US?

GFS 00z certainly makes the weather more interesting as we go into December. No frigid cold blast but it does mix it up a bit which I think is looking quite feasible.

Something I'm keeping eye on is the HP to back a touch west, maintains an intermittent feed of real cold air feeding into Scandinavia. Also this would also allow periods of pM air to affect UK rather than tM air to dominate. Chances are that the HP will settle in this sort of area

BFTP

ECM at t 192 illustrates your point well. Not a forgone conclusion that the high will drift se. Even meto have low confidence in this at this time.

[shaky]

Well well things looking a lot more interesting this morning than just 24 hours ago.are we about to see the beginning of the next cold saga?

[mountain shadow]

SMELL THE AIR .... THE COLD IS GONG TO BE HERE BY THE 3-12-2013 . NAFF THEM CHARTS , WE WILL GET A SNOW FEST THIS YEAR AND INTO JANUARY ... I KNOW IT AS I WAS A SEA WORTHY MAN AND I SMELT THE SEA MANY OF TIMES ... THE WEATHER IS IN THE WATER NOT IN THE ATMOSSPHERE ... OLD MAN TALKING HERE I SMELL COLD .

Eh! Are you a crazy snow fan from Luton by any chance?Lots of positivity in the output this morning.

[Ian Brown]

I think what the GFS shows is the best we can get out of the situation; a brief northerly toppler before the jet rides over the top again. ECM is less keen to have any core of heights shift from the anchor to the West.

[Severe Siberian icy blast]

There does appear to be a bit more interest in he models this morning . A warming forecast again , getting stronger . One to watch to see if it gains momentum .

Also with in deep fi the Atlantic ridge looks like coming back , maybe signs of a western -NAO ?

Edited November 22, 2013 by Severe Siberian icy blast

[Frosty.]

Some lovely wintry charts from the Gfs 00z op run from the end of next week onwards, I really think a cold spell is brewing through early December.

[Polar Maritime]

Morning Karl, Yes something is certainly starting to brew for the start of December, Matthugo over on the stratty thread has said the latest ECM32 continues showing high pressure over Greenland although week at this point, and with a slight warming of the stratt forecast to... Also the GFS has been toying with this idea of the vortex trying to split over the last few days.

[johnholmes]

The data suggests that 10 days or thereabouts will see the pattern change occurring; NOT cold northerly either, but I will do an update tomorrow morning.

Just my view of course which may well turn out to be a load of xxxxxxx!

 

sorry not enough time this morning, will do it this evening

[Summer Sun]

Some interesting charts at t192 for our cold weather friends

 

 

Only short lived but there is still a chance of a cold day popping up in the next 7 to 10 days

 

FI from GFS more unsettled as well

 

The ECM ensemble at t192 supports a cooler flow developing

 

 

The GFS ensemble goes further still shifting the high well out into the Atlantic

 

 

Before it moves back over within a few days

 

Edited November 22, 2013 by Summer Sun

[Frosty.]

The Ecm 00z op run is also showing cold potential around the turn of the month and into early December, I sense we could be entering a cycle of wintry reloads from the nw / n in the not too distant future, high pressure may migrate to the southwest of the uk and lows could then swing down from the northwest with progressively colder air flooding in behind them. So the gfs and ecm are offering hope to coldies so far today. 

[Cold Winter]

Signs of a brief northerly incursion towards the end of next week from both GFS and ECM. GFS has -5 uppers reaching the southwest briefly before the coldest air pulls away to the southeast.

 

 

Before that a mainly cloudy, dull week with high pressure slipping away to the west/southwest:

 

[shedhead]

Something of a reversal in outlooks this morning from the big two in a week or so, with GFS going for a temporary spell of increased amplification, whilst ECM swings back towards a flatter pattern than it's been showing of late.  As ever it's easy to get suckered into assuming the colder GFS solution is as right today as it was wrong yesterday, but as Ian B suggested even IF it's toppler does transpire a return to something flatter looks quite likely thereafter...at least based on the 00 run.

[Summer Sun]

Latest from Gibby on the 00z models

 

All models show High pressure just to the NW of the British Isles continuing to extend it's influence across the UK today and maintaining that hold and position through the weekend. As a result winds will be light and mostly still have a Northerly component to them which in the SE may drift the odd shower through at times. Elsewhere the emphasis will be on bright and dry days with good sunny spells but with frost and fog night and morning, slow to lift in places. Then as we move into next week the High changes it's orientation and position to be more to the SW of Britain allowing something of a NW drift down over the UK with cloudier skies and less in the way of frost and fog as well as dropping a weakening trough SE towards midweek with the risk of a little rain here and there.

 

GFS then pulls High pressure further out into mid Atlantic later next week opening the door for an attack from the North  with a spell of windy and rainy conditions followed by colder weather again with wintry showers in places next weekend and frost at night. This lasts for several days before a ridge topples SE over the UK cutting off the cold flow but maintaining frosts for a while before towards the end of the run the pendulum swings back to much more unsettled weather with spells of wind and rain for all with snow on hills as Low pressure takes a stranglehold over the UK.

 

UKMO today closes it's midnight output with High pressure over Ireland with another centre in mid Atlantic. The weather at that point would be dry and bright for many with frost and fog patches by night between cloudier patches floating about. It does look like a Northerly might develop by next weekend as the mid Atlantic high ridges North and absorbs the UK version.

 

GEM this morning shows this trend well but on it's first attempt only offers a glancing blow from breezier and chilly NW winds before things turn less cold again. On the second attempt towards the end of the run the High is pulled further West into mid Atlantic and a much more unsettled and chilly picture for the British Isles emerges with strong NW winds and rain and showers, wintry on high ground.

 

NAVGEM also shows a similar trend but as with GEM it maintains High pressure closer in towards the British Isles so any attempt of an interjection of colder North or NW winds is diluted down to some degree.

 

ECM is less excited about any movement West and shows the Western end of the High pressure being absorbed by the centre close to the UK maintaining the status-quo of basically quiet and settled weather with some mist and fog patches in the South-west while other areas see more cloud and wind with temperatures closer to average or above. Any colder weather from this run is held much more to the extreme North and NE of the UK fleetingly.

 

The GFS Ensembles are increasing their trend to show another dip in temperatures later next week as an attack from the North is attempted. The pattern thereafter becomes very mixed hence the wide range of temperatures shown between members. There does look to be scope for more unsettled conditions to affect at least the North later and the South too by a few.

 

The Jet Stream shows the flow well to the north of the UK currently. It strengthens markedly in this position next week with the colder phase hinted at by some of it's members showing the flow dipping sharply South down over the UK then in response to high pressure transferring to mid Atlantic.

 

In Summary there are some grains of comfort for cold lovers to mull over today as a new High in mid Atlantic looks like it could absorb our UK based feature late next week which would lead to some sort of attack from the North about a week from now. The extent and severity of such an attack is purely based on how far West the High can be pulled as the danger as highlighted by ECM and GEM is that it could just be partial or temporary or both as the High pressure area is in danger of then resetting to it's UK position soon after. The one constant is that High pressure remains dominant for the foreseeable future and although rather cloudy at times some frost and fog patches will give things a seasonal cheer over the next 3-4 days before the risk of a cloudy High develops.

 

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

[bluearmy]

weak high pressure is shown over greenland through dec. that is unlikely to provide anything of note in that area. that could change.

naefs 00z continues to provide interest re a slowly sinking trough from the n/ne as we head through the first week of dec. jet on a nw/se axis with the mid atlantic high dumbelling around in situ. the ecm ens mean for T360 yesterday looked similar.

Edited November 22, 2013 by bluearmy

[Frosty.]

The GEM 00z has built on the solid foundations it layed on the 12z last night, a powerful looking nw / se jet axis with progressively colder air flooding southeastwards across the uk, hope this trend continues to firm up.

[Summer Sun]

The one consistent thing shorter term is Wednesday looks mild for a lot of the UK with temperatures widely around 10 or 11c for England, wales, Ireland and Northern Ireland maybe as high as 13c in the south west, Scotland see's temperatures ranging from 7 to 11c

 

[snowmadchrisuk]

Something is brewing , the 6z is also showing a GL High after the brief Northerly next weekend ... I like this chart ....

 

[East_England_Stormchaser91]

How I love the bipolar FI ! From what was a Big Bad Barty showing last night, looks as if that idea has gone down the drain, and instead we are seeing the formation of a Greeny high flooding some lethal cold down! 

A real snowfest if this is to become a trend through December!

Edited November 22, 2013 by East_England_Stormchaser91

[Frosty.]

The Ecm 00z ensemble mean is now showing more of a nw / se jet alignment than recently, the high looks like it's being muscled out of the picture to the southwest of the uk by ever deepening depressions swinging southeastwards towards the uk. There is growing evidence this morning that either a spell of cold zonality is on the way by the end of next week and there is also potential for a more sustained arctic blast evolving, certainly there are signs of change in around a weeks time.

[Summer Sun]

Next Friday and Saturday (29th and 30th) may be worth keeping an eye on GFS and ECM both hinting at a cold snap

 

 

December opens with high pressure back over the UK

 

 

We than have hints of another cold snap this one has more to it cold wise and potentially snowy from some

 

 

Before pressure starts to build

 

 

It remains chilly though

 

Edited November 22, 2013 by Summer Sun

[Yarmy]

The one consistent thing shorter term is Wednesday looks mild for a lot of the UK with temperatures widely around 10 or 11c for England, wales, Ireland and Northern Ireland maybe as high as 13c in the south west, Scotland see's temperatures ranging from 7 to 11c

 

 

Gavin, I'll swap you a mild Wednesday next week for a cold, snowy Dec 25th.

 

Anyway, reliable range output says dry which I'm not going to complain about. Some hints of something more wintry further out, but it could all flatten out on the next set of runs of course. Patience required, I think. 

[swilliam]

Something of a reversal in outlooks this morning from the big two in a week or so, with GFS going for a temporary spell of increased amplification, whilst ECM swings back towards a flatter pattern than it's been showing of late.  As ever it's easy to get suckered into assuming the colder GFS solution is as right today as it was wrong yesterday, but as Ian B suggested even IF it's toppler does transpire a return to something flatter looks quite likely thereafter...at least based on the 00 run.

Not sure where you guys are getting this flatter pattern from. Obviously if you have a Northerly toppler it will be followed by a few days of a flatter profile with energy going over the top - otherwise it would not be a toppler. This is shown on the jet profiles for 192 and 300.

 

 

Thereafter there is tendency for the jet to become more amplified at a lower latitude and aligned nw/se. This is shown in the the jet profile of the OP GFS and it is clearly going to lead to a major cold outbreak as shown by the pressure profile.

 

 

This is also well supported by the ensembles with the ensemble mean at this time shows virtually no jet.This is because many solutions are going for the low latitude/high amplification/nwse alignment scenarios. There are very few that are flat or zonal

 

Just for example this is no 1 but there are many more like this (I am sure Frosty will post these up).

 

 

So for my money we will have a few days of dreary anticyclonic weather possibly followed by a Northerly toppler. Thereafter we will see the high move further west as the PV transfers more and more to the Russian side. This will allow ever more potent cold outbreaks alternating with wet and windy milder interludes as each depression tracks ese and pulls the colder air down. Whether we will ever get to a solution shown such as GEFS 1 (and others) remains to be seen but I do not see this flat profile that you and IB keep telling us will remain with very little potential for cold.

 

 

So I think it is a bit misleading to say everything will be flatter after the toppler (should it occur) - even from the 12z op.

[Severe Siberian icy blast]

How I love the bipolar FI ! From what was a Big Bad Barty showing last night, looks as if that idea has gone down the drain, and instead we are seeing the formation of a Greeny high flooding some lethal cold down! A real snowfest if this is to become a trend through December!

well not sure it will be a snowfest. But the bartlet zonal tosh some where loving to promote last night was a load of rubbish. I for one dont even look twice at one or two guys on hear who only ever want to wind people up. If you look at the bigger picture ie north hemisphere pattern its easy to see the outlook wasnt flat. A recurring pacific ridge . A weak jet stream . And a high pressure dominated atlantic is anything but zonal. Yes we have a strong pv . But its stretched and disrupted maybe even split , so cold outbreaks from the northwest seems to be a fair assessment , which can bring snow showers to many western and central areas when the airs cold enough.

[draztik]

Support for heights rising to our northwest from the models this morning, albeit deep in FI

 

GEFS Day 16 0z

 

 

ECM EPS Ens 0z / Heights and Temp Anomaly [day 15]

Edited November 22, 2013 by draztik

[Ian Brown]

well not sure it will be a snowfest. But the bartlet zonal tosh some where loving to promote last night was a load of rubbish. I for one dont even look twice at one or two guys on hear who only ever want to wind people up. If you look at the bigger picture ie north hemisphere pattern its easy to see the outlook wasnt flat. A recurring pacific ridge . A weak jet stream . And a high pressure dominated atlantic is anything but zonal. Yes we have a strong pv . But its stretched and disrupted maybe even split , so cold outbreaks from the northwest seems to be a fair assessment , which can bring snow showers to many western and central areas when the airs cold enough.

 

I wouldn't rule out the Bartlett scenario at all Shaun - continual depressions coming off the Seaboard can easily lead to a tramsferring of the core of heights from the Azores to mainland Europe.