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Gandalf The White
05 December 2017 11:20:37

Lack of cold air? Seriously? Snow only on higher ground in the north? Seriously?

Thicknesses once again near 510dam on this run.

The mainland UK also has sub -10 t850s across parts of it from +69 to +111 on the 06z GFS op run. The air is notably cold for early December, for a while at least. Some bizarre interpretation on here. Yes granted it will not be cold and snowy across the country indefinitely.

Originally Posted by: doctormog 


I was looking at the run out to T+240 and Scotland has only about 48 hours out of the next 240 with 500-1,000 thickness values above 528 dam.  Obviously the picture shows less cold the further south you go but it's seldom much above zero.


The 2m temperatures even in the south are rarely better than 4C-5C throughout.

Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Rob K
05 December 2017 11:48:18

Lack of cold air? Seriously? Snow only on higher ground in the north? Seriously?

Thicknesses once again near 510dam on this run.

The mainland UK also has sub -10 t850s across parts of it from +69 to +111 on the 06z GFS op run. The air is notably cold for early December, for a while at least. Some bizarre interpretation on here. Yes granted it will not be cold and snowy across the country indefinitely.

Originally Posted by: doctormog 


Sorry for any confusion, I am talking about after the initial northerly, once low pressure systems start showing up. I think it's taken for granted that the initial blast will be cold. 


 


we end up with a UK high and lower heights over the Med/SE Europe which is not a bad pattern really, at least more promising than the Euroslug of yore. With my optimistic hat on I'd say it's setting up for a Scandi high :)

Rob K wrote:


 


And that's exactly what the control run ends up with:


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
turbotubbs
05 December 2017 11:49:13


 


I was looking at the run out to T+240 and Scotland has only about 48 hours out of the next 240 with 500-1,000 thickness values above 528 dam.  Obviously the picture shows less cold the further south you go but it's seldom much above zero.


The 2m temperatures even in the south are rarely better than 4C-5C throughout.


Originally Posted by: Gandalf The White 

I wonder if this is one of the problems with this thread - some are happily focussing on Friday - Monday, others seem obsessed with the longer term, and fret that it isn't showing the UK bathed in -10 850's for the duration.


I am confident that many will see snow falling this week, accumulations in places. The evolution after Friday is up for grabs and will as always become clearer as we approach the weekend. I also think much more attention should be paid to ensemble data rather than the curse of (a) the main run and (b) the lovely GFS with its 4 runs a day...

Gandalf The White
05 December 2017 11:55:59


I wonder if this is one of the problems with this thread - some are happily focussing on Friday - Monday, others seem obsessed with the longer term, and fret that it isn't showing the UK bathed in -10 850's for the duration.


I am confident that many will see snow falling this week, accumulations in places. The evolution after Friday is up for grabs and will as always become clearer as we approach the weekend. I also think much more attention should be paid to ensemble data rather than the curse of (a) the main run and (b) the lovely GFS with its 4 runs a day...


Originally Posted by: turbotubbs 


Of course all of what you say is true.  But I was responding to Michael's specific point.


I posted earlier about the slider scenario - as well as overnight.   Certainly the evolution on Sunday and beyond is becoming clearer in broad terms but the specifics will remain elusive for some time.


As for the imminent cold spell, yes it looks like an exceptional cold airmass.  But away from favoured coastal areas a NW flow is essentially just useful for bringing cold air into place.  It has been said many times in recent days that the north of Scotland and exposed favoured western areas should do well for snowfall.

Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Rob K
05 December 2017 11:56:51

In the longer term, 13 out of the 20 ensemble members (plus the control) have some form of Scandinavian high set-up.


Here's the pressure ensemble for Trondheim in Norway - you can see that a pressure rise in that area looks pretty favourable:


 



 

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
Brian Gaze
05 December 2017 11:57:07

6z GEFS update offers plenty of interest I would have thought.


Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
warrenb
05 December 2017 12:04:52


6z GEFS update offers plenty of interest I would have thought.



Originally Posted by: Brian Gaze 


Can't grumble at that.. For London, that is marginal all the way, but probably the wrong side of marginal, but maxes of 5c at the surface for the foreseeable.

Tonbridge 45m 
Gooner
05 December 2017 12:15:54

Lack of cold air? Seriously? Snow only on higher ground in the north? Seriously?

Thicknesses once again near 510dam on this run.

The mainland UK also has sub -10 t850s across parts of it from +69 to +111 on the 06z GFS op run. The air is notably cold for early December, for a while at least. Some bizarre interpretation on here. Yes granted it will not be cold and snowy across the country indefinitely.

Originally Posted by: doctormog 


 


Agreed

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Rob K
05 December 2017 12:19:25

I'd love to see the synoptics for that outlier/trendsetter on the ECM ensemble at the end. Max of -9C in London on the 18th? 



 

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
Joe Bloggs
05 December 2017 12:41:44


 


Of course all of what you say is true.  But I was responding to Michael's specific point.


I posted earlier about the slider scenario - as well as overnight.   Certainly the evolution on Sunday and beyond is becoming clearer in broad terms but the specifics will remain elusive for some time.


As for the imminent cold spell, yes it looks like an exceptional cold airmass.  But away from favoured coastal areas a NW flow is essentially just useful for bringing cold air into place.  It has been said many times in recent days that the north of Scotland and exposed favoured western areas should do well for snowfall.


Originally Posted by: Gandalf The White 


To be fair, if you get a decent westerly tilt on the NW'ly (which this morning does look likely to be the case), heavy snow can push well inland.


I've often thought that convective showers can provide more fruitful snow than frontal setups on many occasions. 


At present (and it could well change), these showers will not be restricted to the coast.


Manchester City Centre, 31m ASL
picturesareme
05 December 2017 12:44:11
Met going for a very mild Thursday down here with a frostless night to follow, then cool but nothing exceptional high of 5C Friday (prob end up higher) followed by warmer Saturday, and a wet Sunday which has temps pushing double figures by then.

WHERE IS THIS ARCTIC COLD SPELL THEN?
Rob K
05 December 2017 12:46:27

The track of the low on Thursday/Friday is still far from nailed. The Arpege 06Z has the centre of the low nearly 300 miles further west than the 00Z, making the gradient even tighter.


00Z:



 


06Z:


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
Rob K
05 December 2017 12:48:01

Met going for a very mild Thursday down here with a frostless night to follow, then cool but nothing exceptional high of 5C Friday (prob end up higher) followed by warmer Saturday, and a wet Sunday which has temps pushing double figures by then.

WHERE IS THIS ARCTIC COLD SPELL THEN?

Originally Posted by: picturesareme 


 


In Scotland, and northern England, that's where. Northerlies never bring very cold weather to the south coast, as you should have learned by now!

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
picturesareme
05 December 2017 12:57:12


 


 


In Scotland, and northern England, that's where. Northerlies never bring very cold weather to the south coast, as you should have learned by now!


Originally Posted by: Rob K 


They do bring frost sometimes but even that is absent in the forecast at the moment.

turbotubbs
05 December 2017 13:06:55


 


They do bring frost sometimes but even that is absent in the forecast at the moment.


Originally Posted by: picturesareme 

Windchill will make it feel colder and to be fair you do live by a massive thermal reservoir...

Gooner
05 December 2017 13:08:38


 



 




 



 


So this isn't cold ?? Well switch the lights off then as we leave the building . I'm amazed by some of the comments , maybe some are just expecting 2010 every year

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


ballamar
05 December 2017 13:09:30

Met going for a very mild Thursday down here with a frostless night to follow, then cool but nothing exceptional high of 5C Friday (prob end up higher) followed by warmer Saturday, and a wet Sunday which has temps pushing double figures by then.

WHERE IS THIS ARCTIC COLD SPELL THEN?

Originally Posted by: picturesareme 


what is your average high for December?

fairweather
05 December 2017 13:13:34

Lack of cold air? Seriously? Snow only on higher ground in the north? Seriously?

Thicknesses once again near 510dam on this run.

The mainland UK also has sub -10 t850s across parts of it from +69 to +111 on the 06z GFS op run. The air is notably cold for early December, for a while at least. Some bizarre interpretation on here. Yes granted it will not be cold and snowy across the country indefinitely.

Originally Posted by: doctormog 


----------------------------------------------------------------------------------------------------------------------------------------------------------------


Yes. I think it's likely to snow in many places at the weekend and longer term prospects aren't exactly depressing by recent December standards. SSTs are naturally still relatively high as well so all in all it's a pretty good effort for the first week of December :-)

S.Essex, 42m ASL
picturesareme
05 December 2017 13:27:18


 


what is your average high for December?


Originally Posted by: ballamar 


8.7C for Solent and 10C for Southsea - met office.

picturesareme
05 December 2017 13:30:52



 



 




 



 


So this isn't cold ?? Well switch the lights off then as we leave the building . I'm amazed by some of the comments , maybe some are just expecting 2010 every year


Originally Posted by: Gooner 


Cherry picking charts from one run of one modle (of which some are nearly 2 weeks away) doesn't really show much.

Jeff
  • Jeff
  • Advanced Member
05 December 2017 13:38:09
Just as an aside as we wait for the 12s....

Take a look at the upper air temps from the Wetter archive for these two notable snow events for southern England in early December 1981. According to discussions here, this would be far too marginal for lying snow with southerly tracking secondary lows but we know that wasn’t the case. Perhaps the shorter duration of daytime hours (as well as a lack of strong winds) makes lying snow with these 850s much more likely in December than say February? Snow cover and short daylight period led to record low temps at the end of the second week of Dec, day and night, under fairly benign 850s

http://www.wetterzentrale.de/maps/archive/1981/noaa/NOAA_1_1981120806_2.png 

http://www.wetterzentrale.de/maps/archive/1981/noaa/NOAA_1_1981121112_2.png 

And the 12” of snow in Birmingham on 8th December 1990, with gale force winds fell with 850s of around -5

http://www.wetterzentrale.de/maps/archive/1990/noaa/NOAA_1_1990120806_2.png 



Jeff



On the East/West Sussex Border
70m ASL
Maunder Minimum
05 December 2017 13:46:20

1981 was a classic for the West Midlands - would love a repeat.


On the topic of the predicted cold spell, I have to say I am a glass half full man - much prefer to see seasonal weather than otherwise and will take any frost an snow which may come this way. Much better than the last few winters - we are like parched cold weather lovers looking for a winter oasis of seasonal temperatures.

New world order coming.
Gooner
05 December 2017 13:47:59


 


Cherry picking charts from one run of one modle (of which some are nearly 2 weeks away) doesn't really show much.


Originally Posted by: picturesareme 


It covers an 11 day period with only a few days between each......my point is that the cold is here , its crazy to say there isn't any cold on offer and its showing you in particular the artic air.................that's the blue bits

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Rob K
05 December 2017 13:58:23

For fans of long-range trends... here is the ensemble mean 500mb height anomaly chart for 360 hours on the GFS 06Z


 



 


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
Brian Gaze
05 December 2017 14:00:40


For fans of long-range trends... here is the ensemble mean 500mb height anomaly chart for 360 hours on the GFS 06Z


 



 



Originally Posted by: Rob K 


Worth emphasising the word anomaly. Anomaly. Anomaly. There was that debacle a few years ago when anomaly charts were misunderstood. We don't want to go there again. 

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

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