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JACKO4EVER
13 December 2013 16:56:17




The models have changed from showing HP lodged over Europe to showing a maritime flow with the jet sweeping south and possible polar maritime conditions post Christmas.

I'd take a bit of that - it's not likely to deliver snow to me in the SE but at least conditions should be wintry for a couple of days at least.

There is also some minor strat warming being modelled by GFS from about 204h over the North Atlantic, the UK and Scandinavia at 10hPa level. It will be interesting to see if it verifies or upgrades and if so can it be linked to any downstream effects.

I think model watching is quite interesting right now.

Originally Posted by: White Meadows 


The strat warming thing again? 


I might be completely wrong about this, but modest warming at the highest level in the stratosphere over the UK and other southern latitutes will have absolutely no effect on the PV whatsoever. If anything strat warming at lower latitues, like I have said before will have the opposite effect. Look at the chart from last year where the PV was displaced by SSW over N asia. It got significantly colder in the strat in the UK.


Originally Posted by: nouska 


This type of modest warming at the 10  hPa level was one of the precursor events for the January 1963 SSW. A screenshot of the page http://i.imgur.com/uFK0skO.png


The full paper.   http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281964%29003%3C0001%3ATMWSWA%3E2.0.CO%3B2


Originally Posted by: Quantum 


Beat me to it!


Very true, it is warming at the 10hpa level which 'cascades' across the rest of the strat and so the slowing of the vortex begins.


Fongers crossed!!


Originally Posted by: johnm1976 


Trouble is other key factors aren't playing ball at the moment. A step in the right direction if its cold your looking for, but just that single signal isn't the game changer. In the meantime, as Stophe pointed out earlier, some 40mm rain progged quite widely in the next 10 days or so.


Flooding may become a problem, not mentioning the wind.

White Meadows
13 December 2013 17:01:22

 


True Jacko, although I don't think you'll need to worry too much about flooding in Melton Mowbray!!

JACKO4EVER
13 December 2013 17:04:54


 


True Jacko, although I don't think you'll need to worry too much about flooding in Melton Mowbray!!


Originally Posted by: White Meadows 


Ha ha too true, but the River Eye has been known to flood the lower end of town before the flood defences were introduced some years ago.


Perhaps "cold zonality" may be the ticket if its wintry stuff your looking for? I am struggling to pick anything positive out of this situation atm

Gandalf The White
13 December 2013 17:08:31

Yes I know it is low res. and deep in FI. But even still it shows the potential still available for Christmas Day Originally Posted by: doctormog 

">http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfs-2-288.png?12?12


Yes, and that's several runs in a row to show those cold uppers making it across all the way from the eastern side of North America.  If that were to verify it would be quite rare - I recall years ago a similar pattern (because Bill Giles, I think, commented on the westerlies bringing exceptionally cold air).  That tells you how long ago it must have been.


Anyway, for Xmas Day:


500hPa/SLP: http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfsnh-0-288.png?12


850hPa: http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfsnh-1-288.png?12


500-1,000hPa thickness: http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfsnh-3-288.png?12


The latter is particularly impressive.


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Gandalf The White
13 December 2013 17:10:31


Flooding may become a problem, not mentioning the wind.


Originally Posted by: JACKO4EVER 


http://modeles2.meteociel.fr/modeles_gfs/runs/2013121312/192-777.GIF?13-12 


 Edit: Just discovered that you can get a British Isles view of the GFS 0.5* on Meteociel: http://modeles2.meteociel.fr/modeles_gfs/runs/2013121312/192-777UK.GIF?13-12


The western side of Scotland and the Lake District get 100-200mm



 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Zubzero
13 December 2013 17:11:41

Yes I know it is low res. and deep in FI. But even still it shows the potential still available for Christmas Day Originally Posted by: doctormog 

">http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfs-2-288.png?12?12


Yes doc, continued sign's of the pv nudging futher South around xmas time. Good chance for the North and Higher parts of England,seeing something wintry over the christmas period if the trend continues.


Imby I fear mild rain, will be replaced with cold rain 


 

Rob K
13 December 2013 17:20:38

Yes I know it is low res. and deep in FI. But even still it shows the potential still available for Christmas Day Originally Posted by: doctormog 

">http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfs-2-288.png?12?12


Looks accurate - Jason's area snow free! 


Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
LA2B MeridFlowEuro09
13 December 2013 17:30:03
The GFS and UKMO Outputs Strat Wise, MSLP 500hPa, T850's, Surface Temps and Weather, PV Vorticity, Short and Long Waves, Trofs, Strong Winds, Low P Vs High P Strat wise, and MSLP 500 hPa and Strat Temp Low and High based all these pointers etc where the Cold Pools are most spread and really impacting and where they really are just normal UK impacts, and the Average Temps UK with short and lengthy less cold Waves all are in the Progged 0-240 hr time Frame.

Saying that and what it means for the NE N and NW USA, Siberia West and NW and NE, and Newfoundland Greenland PV and West SW Arctic PV Low P Zonality etc and same for NE and NW Europe and N and West To NW Russia - the -2 to -4 at T850 hPa, and the 0 to 6 at T850's as well in the UK is in charge at times.

Yep Strong winds and heavy rain some deep low's and some cold frosty nights possible and a few ridges high also on offer for UK, and also Some Severe Gales.

The Heavy Snows and very low Record break temps in other areas are there and so is Stratospheric High and also very Low Temps, that over the UK is show not too cold nor too warm! - so there is my analysis for the 12z GFS and UKMO outputs!.

The Siberian and E NW and NE Arctic Sea is also prevailing.

And the SW Arctic PV as well as Norwegian plus Svalbard areas PV Low's and Very Cold air also there, and that with Deep low's and Cold Strat Temps inc Zonal Strength- this also for much of next 2 weeks plus same goes to our NW North and NE plus our East in NE E Europe as well cold and Wintry so any one want Xmas snow then go there rather than the paltry UK Weather Sitauation.

The Pesky Low as we all know to well.

Wanting long cold spells is not on offer if you check all this online..
Climate is warming up, Scotland and N Ireland and North England still often gets some Winter frost, ice and snow, November to March, but the SE and South UK including S Central England and Wales, together with the West and North through the year, they sometimes get more rain than London and S SE England, where some longer dry fine spells without much heavy rain is seen every year.

The North Atlantic Sea often gets some much Colder Wintry conditions from November to March Months, and Mild SW and South winds tend to be more frequent over the East and SE of North Atlantic Sea, as the Azores High tends to stay in charge. 

With this warmth and heat, the Central and South UK has become mostly free of snow and frost.
Charmhills
13 December 2013 17:30:11





The models have changed from showing HP lodged over Europe to showing a maritime flow with the jet sweeping south and possible polar maritime conditions post Christmas.

I'd take a bit of that - it's not likely to deliver snow to me in the SE but at least conditions should be wintry for a couple of days at least.

There is also some minor strat warming being modelled by GFS from about 204h over the North Atlantic, the UK and Scandinavia at 10hPa level. It will be interesting to see if it verifies or upgrades and if so can it be linked to any downstream effects.

I think model watching is quite interesting right now.

Originally Posted by: JACKO4EVER 


The strat warming thing again? 


I might be completely wrong about this, but modest warming at the highest level in the stratosphere over the UK and other southern latitutes will have absolutely no effect on the PV whatsoever. If anything strat warming at lower latitues, like I have said before will have the opposite effect. Look at the chart from last year where the PV was displaced by SSW over N asia. It got significantly colder in the strat in the UK.


Originally Posted by: White Meadows 


This type of modest warming at the 10  hPa level was one of the precursor events for the January 1963 SSW. A screenshot of the page http://i.imgur.com/uFK0skO.png


The full paper.   http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281964%29003%3C0001%3ATMWSWA%3E2.0.CO%3B2


Originally Posted by: nouska 


Beat me to it!


Very true, it is warming at the 10hpa level which 'cascades' across the rest of the strat and so the slowing of the vortex begins.


Fongers crossed!!


Originally Posted by: Quantum 


Flooding may become a problem, not mentioning the wind.


Originally Posted by: johnm1976 


Its been dry for 3 weeks flooding seems unlikely for now.


Loughborough, EM.

Knowledge is power, ignorance is weakness.

Duane.
Gooner
13 December 2013 17:48:56

http://www.wetterzentrale.de/pics/Rtavn24017.png


http://www.wetterzentrale.de/pics/Rtavn26417.png


http://www.wetterzentrale.de/pics/Rtavn28817.png


http://www.wetterzentrale.de/pics/Rtavn31217.png


If verified at least Xmas will feel seasonal


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


JACKO4EVER
13 December 2013 18:03:56


Yes I know it is low res. and deep in FI. But even still it shows the potential still available for Christmas Day Originally Posted by: Rob K 

">http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfs-2-288.png?12?12

Originally Posted by: doctormog 


Looks accurate - Jason's area snow free! 



Perfect snow deflector

JACKO4EVER
13 December 2013 18:05:11



Flooding may become a problem, not mentioning the wind.


Originally Posted by: Gandalf The White 


http://modeles2.meteociel.fr/modeles_gfs/runs/2013121312/192-777.GIF?13-12 


 Edit: Just discovered that you can get a British Isles view of the GFS 0.5* on Meteociel: http://modeles2.meteociel.fr/modeles_gfs/runs/2013121312/192-777UK.GIF?13-12


The western side of Scotland and the Lake District get 100-200mm



 


Originally Posted by: JACKO4EVER 


Thanks for sharing- never knew these charts existed! Thats some serious rainfall should it verify

sriram
13 December 2013 18:31:55

Hi all,


Here's today's video update;


JMA Friday (13/12/13)


http://www.gavsweathervids.com


A look at the month ahead and then beyond with the Korean model.


Have to say, things aren't looking terribly inspiring this winter.

Originally Posted by: Gavin P 




Gavin, that's a really extremely grim outlook for winter fans

When you issued you winter forecast recently you mentioned it was difficult to pin down - but if this anything to go by its a really uninspiring winter !


Sriram
Sedgley, West Midlands ( just south of Wolverhampton )
162m ASL
nsrobins
13 December 2013 18:46:43

I concede that the ENS are trending slightly more towards average to just the cool side of average zonal later on, but the outlook still looks grim for fans of half-decent cold conditions.


And I don't get what all the talk of SSW is coming from - I can't find any charts anywhere that suggest any sort of reasonable warming is about to occur at any level in the next few weeks.

Have a nice evening


Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
White Meadows
13 December 2013 19:19:38
Remarkable consistency from ECM. The north west is going to be wet & windy over Xmas, much calmer further south.
Then the infamous 'Bearing high' looks like nosing in: resulting in what hopefully Quantum can explain?...
GIBBY
13 December 2013 19:25:47

 


Good evening. Here is the latest report from me on the midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday December 13th 2013.


All models show a volatile period of weather to come with quickly changing weather from day to day all in association with rapidly deepening depressions moving quickly NE close to NW Scotland and a strong SW wind across the UK with gale and severe gale force winds in the NW at times. There will be some drier spells too, especially across the South as cold fronts clear East tonight and again tomorrow night leaving much of Saturday and Sunday daytime in the SE not too bad. Tuesday too looks an OK day in the South as transitory High pressure runs quickly East across Northern France through the day while the North stays breezy and showery with generally mild conditions for most areas for much of the time as well.


GFS shows very windy and unsettled weather across all areas for the remainder of the run with gale and severe gale force winds at times with spells of heavy rain followed by squally and possibly wintry showers before a return to mild and windy weather returns again in oscillating fashion through the Christmas period and beyond.


UKMO tonight shows a strong WSW flow later next week with rain and strong winds followed by more showery conditions when it will become a little colder with some snow on Northern hills in the showers.


GEM maintains a strong WSW flow too from the end of next week until the end of the run with periods of rain and relatively mild conditions alternating with colder and more showery weather with some potent showers at times falling as snow on higher ground.


NAVGEM is little different with very windy weather the biggest feature with heavy rain at times but with some chillier and more showery interludes in between.


ECM is less keen on deep Low pressure reaching the South maintaining High pressure over Europe where it remains very mild. Over the UK winds would be strong and SW'ly. There would be spells of rain and strong winds, particularly heavy in the NW but much less so in the South and East where some longer drier spells look possible. Overall milder conditions should outweigh colder interludes which will be more likely to occur in the North.


The GFS Ensembles show less range than usual especially for Northern locations where there is the most solid support for spells of wet and very windy weather with Low pressure rattling over or just to the North of the UK. Things are a little more varied in the South where some longer drier spells seem possible at times. Temperatures never look like being particularly low with most members opting for a green Christmas rather than a white one but this doesn't exclude the risk of some snowfall on Northern high ground at times.


The Jet Stream shows the flow powering across the Atlantic and the UK for the reliable future. In the latter part of the forecast in the less reliable time frames it shows the flow slipping South of the UK and possibly meaning at least a chance of rather colder conditions developing.


In Summary tonight the Jet Stream spawns some major storm systems out to the NW of the UK over the whole output period. How far South the influence of these storm systems come is unclear and it maybe away from the far NW that it will be just windy and wet rather than stormy and wet with some colder spells developing when snowfall could turn up abruptly. ECM shows Low pressure much further NW tonight with High pressure solidly holding firm over Europe steering the worst of the weather out to the NW. The rest of the output is much more determined to bring stormy conditions to all areas at times with some colder polar maritime air capable of delivering some snowfall at times, especially through the Christmas period. Which 1s right is yet to be determined in this very volatile unstable situation synoptically and time alone will tell.


Martin G
Kilmersdon Radstock Bath Somerset



Look up my New Facebook Weather Page  for all the latest up to the minute weather stories as they happen
Karl Guille
13 December 2013 19:48:54

Well, certainly no point looking east for the forseeable so might as well look west and it is interesting to see that GFS 12z still shows precipitation widely as snow on 25th December (Channel Islands excluded of course)!!


St. Sampson
Guernsey
Gooner
13 December 2013 19:52:31


I concede that the ENS are trending slightly more towards average to just the cool side of average zonal later on, but the outlook still looks grim for fans of half-decent cold conditions.


And I don't get what all the talk of SSW is coming from - I can't find any charts anywhere that suggest any sort of reasonable warming is about to occur at any level in the next few weeks.

Have a nice evening


Originally Posted by: nsrobins 


Agreed, there looks naff all on the horizon


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Gandalf The White
13 December 2013 20:14:29


I concede that the ENS are trending slightly more towards average to just the cool side of average zonal later on, but the outlook still looks grim for fans of half-decent cold conditions.


And I don't get what all the talk of SSW is coming from - I can't find any charts anywhere that suggest any sort of reasonable warming is about to occur at any level in the next few weeks.

Have a nice evening


Originally Posted by: nsrobins 


Based on the GFS output, which has been showing consistently for several days some warming in the Atlantic and east Asian sides of the Pole: http://modeles.meteociel.fr/modeles/gfs/runs/2013121312/gfsnh-10-180.png?12


Someone earlier suggested that SSW was defined as a warming of, IIRC, 20C.


Nouska linked to an interesting paper earlier in the thread (a page back, I think) that cited 1962/63 as a year when a similarly modest warming pattern was a signal for the subsequent break up of the PV. 



Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Hungry Tiger
13 December 2013 20:51:35

Sounds like it's a bit hard to call here.


Seems like a boring set of west to SW winds here for me.


Nothing special at all.


 


Gavin S. FRmetS.
TWO Moderator.
Contact the TWO team - [email protected]
South Cambridgeshire. 93 metres or 302.25 feet ASL.


Gavin P
13 December 2013 21:08:34


Hi all,


Here's today's video update;


JMA Friday (13/12/13)


http://www.gavsweathervids.com


A look at the month ahead and then beyond with the Korean model.


Have to say, things aren't looking terribly inspiring this winter.


Originally Posted by: sriram 




Gavin, that's a really extremely grim outlook for winter fans

When you issued you winter forecast recently you mentioned it was difficult to pin down - but if this anything to go by its a really uninspiring winter !

Originally Posted by: Gavin P 


Well it is a bit grim, but we know things can change very quickly.


Rural West Northants 120m asl
Short, medium and long range weather forecast videos @ https://www.youtube.com/user/GavsWeatherVids
nickl
13 December 2013 22:05:13


Someone earlier suggested that SSW was defined as a warming of, IIRC, 20C.


Originally Posted by: Gandalf The White 


seeing as its quiet, hopefully this wont get flipped over to the next page and everyone can read it.


AN SSW IS DEFINED AS ZONAL WINDS REVERSING AT 10HPA AT 60N.


nothing to do with themperature, although the quick rise in temperature will bring about the event. (and i would estimate that around 40/50c rise required around the pole).


there are warmings forecast in the upper strat but they dont appear to be large enough to break apart the p/v and they dont look like working down too far anyway.  anything that stops the current vortex from strengthening more than it already has done it to be welcomed though. last few days of gfs week 2 modelling was stretching the cold centre of the vortex but todays runs have rowed back on that somewhat.

Hippydave
13 December 2013 22:11:49



Hi all,


Here's today's video update;


JMA Friday (13/12/13)


http://www.gavsweathervids.com


A look at the month ahead and then beyond with the Korean model.


Have to say, things aren't looking terribly inspiring this winter.


Originally Posted by: Gavin P 




Gavin, that's a really extremely grim outlook for winter fans

When you issued you winter forecast recently you mentioned it was difficult to pin down - but if this anything to go by its a really uninspiring winter !

Originally Posted by: sriram 


Well it is a bit grim, but we know things can change very quickly.


Originally Posted by: Gavin P 


Uninspiring


It might not be a wall to wall snowfest but it is interesting imo


Wet, windy and a possibility of part of the PV wandering over us bringing snow to the North (on GFS FI) really shouldn't be uninspiring. It's interesting winter weather alright


Yup I'd prefer something cold and snowy over my back yard but in the absence of that mobile, sometimes chilly and interesting will do


 


 


 


Home: Tunbridge Wells
Work: Tonbridge
Chiltern Blizzard
13 December 2013 22:16:07

 



http://www.wetterzentrale.de/pics/Rtavn1321.png


Low pressure far further south than the 12z, and extremely intense!   Notable weather event if that verified!


Andrew


Rendlesham, Suffolk 20m asl
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