Usual rules.


M.

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A poster in the last thread asks is there still pessimism [regarding a cold spell] this morning? The answer is yes, there is. See my post in the last thread and see how many of the pointers I mention are present:

http://www.theweatheroutlook.com/twocommunity/yaf_postsm552483_Model-Output-Discussion-17-11-13.aspx#post552483 

The answer is very few. ECM this morning is atrocious if it's cold weather you're after, showing the polar vortex gathering strength, the Arctic high over Canada being ejected SE'wards and an exceptionally mild plume over the UK by day 10:

http://www.wetterzentrale.de/pics/Recm2402.gif 

With strong winds and such mild air aloft (mild even for July, let alone December!) there would be temperatures in the mid to high teens over parts of Scotland due to a Foehn effect. It's very unlikely to come off like that, of course, but the underlying signal by ECM (and EPS) for a spell of Atlantic-driven weather after our upcoming settled interlude cannot be ignored.

GEFS is a mixed bag and there are indeed some cold shots in there. Shots being the operative word, there's not much sign of anything sustained cold-wise in there. In the medium term GEFS also shows the potential for a mildish blip - the mean maximum for London reaches 11C on the 27th, for example.

In short, the outlook is pretty much seasonal. A settled interlude, then some Atlantic mildness would seem to be the favoured solution this morning. As ever what happens beyond 10 days is in the realms of fantasy, but given both EPS and GEFS show milder runs outnumbering cold ones you'd have to be a brave man to bet on a cold spell.

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Nicely put. We do seem a long way from a proper cold spell.

I can understand why there has been some interest looking at the NH charts because the PV isn't as strong as it could be. ECM in particular does seem to wind it up a bit though. The forecasted strat temps will be looked at a lot more if things carry on this way!

Looks like we are going to need an early SSW event to tilt things our way. The last few winters have shown what an effect it can have, but looking on Netweather, it seems unlikely that we will get one in the near term.

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Good morning folks. Here's this morning's account of the models taken from the midnight outputs for today Friday November 22nd 2013.

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.

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Looks like 4 touch -10 which is one of Retron's signs.           

http://www.wetterzentrale.de/pics/MT8_London_ens.png

 

 

 I think the period of interest though is still 350+ hours away. GFS has been consistent in finally building a GH which allows what looks like to me a prolonged cold spell to begin with a impressive northerly.

http://www.wetterzentrale.de/pics/Rtavn3721.png

 

 

 

 

 

 

 

 

 

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No sign of any meaningful height rises over Greenland, so our best hope are some brief northerly shots. Its not expected to be a memorable winter and so far appears to be going to plan.

 

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Too early to tell IMO; the winter season as defined by the MetO doesn't start until a week on Sunday, 1st December.

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. This Morning's 00z UKMO & GFS runs paint a mix of Northerly by NW flow and 5 day high pressure set Pattern for the UK.

 

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Actually - i think the period of interest begins at the start of December.  The Ensemble definetly picks up on a change around then.  Given its still 8 days away and some charts are showing a nortly plunge of sorts, we need to see the developments around that... apart from that - its a wait and see game.

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You could post this every week for the next three months and I suspect it will still be valid on most occasions
(This is not a forecast by the way)

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http://www.wetterzentrale.de/pics/Recm2402.gif  With strong winds and such mild air aloft (mild even for July, let alone December!) there would be temperatures in the mid to high teens over parts of Scotland due to a Foehn effect. It's very unlikely to come off like that, of course, but the underlying signal by ECM (and EPS) for a spell of Atlantic-driven weather after our upcoming settled interlude cannot be ignored. GEFS is a mixed bag and there are indeed some cold shots in there. Shots being the operative word, there's not much sign of anything sustained cold-wise in there. In the medium term GEFS also shows the potential for a mildish blip - the mean maximum for London reaches 11C on the 27th, for example. In short, the outlook is pretty much seasonal. A settled interlude, then some Atlantic mildness would seem to be the favoured solution this morning. As ever what happens beyond 10 days is in the realms of fantasy, but given both EPS and GEFS show milder runs outnumbering cold ones you'd have to be a brave man to bet on a cold spell.