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Ally Pally Snowman
13 January 2016 14:22:14


 


I don't have knowledge of ECM dataset variables but are those 2m temperatures?


Originally Posted by: Brian Gaze 


 


I don't know but I would presume so it doesn't actually say. it seems to be about 3 or 4c too low for anywhere in London. strange


Bishop's Stortford 85m ASL.
kmoorman
13 January 2016 14:22:38


ECM 00z ensemble for London:


Once again it shows how GFS is completely out of step with ECM on the evolution past Day 8.


Interesting that there is a strengthening of the cold cluster at the end of the period and a reasonable signal for cold to last into next weekend (i.e. days 11-12)


http://www.weathercast.co.uk/services/ensemble-forecast.html


 



Originally Posted by: Gandalf The White 


The difference between the 2 Op runs, particularly in term of surface temp is mental.   It does highlight that the GFS Op run is about as mild as you could possibly get within the combined ensembles.  


Home: Durrington, Worthing, West Sussex. (16 ASL)
Work: Canary Wharf, London
Follow me on Twitter @kmoorman1968
Gandalf The White
13 January 2016 14:41:40


 


Gandalf any explanation why the ecm has much colder temps than what the Beeb/Meto have for this period?


 


Originally Posted by: Ally Pally Snowman 


Well for one thing I doubt that the models allow for the heat island effect.  I may be wrong but that would be my guess as the most plausible reason.


It's only about 5.5C here at the moment, which isn't too far off.  GFS is showing a high of around 6.5C v ECM a shade under 5C.


I do know that the temperatures that you see on the BBC TV forecasts are city centre ones; indeed the forecasters often now put up a graphic for overnight minima 'in the countryside' because the city centre values are overstated.


 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Ally Pally Snowman
13 January 2016 14:47:07


 


Well for one thing I doubt that the models allow for the heat island effect.  I may be wrong but that would be my guess as the most plausible reason.


It's only about 5.5C here at the moment, which isn't too far off.  GFS is showing a high of around 6.5C v ECM a shade under 5C.


I do know that the temperatures that you see on the BBC TV forecasts are city centre ones; indeed the forecasters often now put up a graphic for overnight minima 'in the countryside' because the city centre values are overstated.


 


Originally Posted by: Gandalf The White 


 


OK thanks Heat island effect as Essan said as well, sounds the most plausible reason. That graph is a better guide to to temp in the countryside around London than London itself. 


Bishop's Stortford 85m ASL.
Downpour
13 January 2016 15:08:28
The temps within the bounds of London vary widely in winter. If you go to Pole Hill, 300ft asl in Chingford about a half mile from the boundary with Epping Forest, frosts can hang around all morning when they are wiped out by 9am in town. We are routinely 3-4 degrees colder than our friends in Brixton, because of the UHI effect.
Chingford
London E4
147ft
Gandalf The White
13 January 2016 15:18:38


 


 


OK thanks Heat island effect as Essan said as well, sounds the most plausible reason. That graph is a better guide to to temp in the countryside around London than London itself. 


Originally Posted by: Ally Pally Snowman 


I think if you're trying to provide information to the greatest number of people then 'urban heat island' values are probably what the majority experience.   If you were trying to be representative spatially then you'd do it differently. 


Whenever I see the BBC graphics in the current set-up I always assume 1-2 degrees lower by day and more at night.


 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Whiteout
13 January 2016 15:19:53

This must be the area of snow the Met are keeping an eye on:


http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2016/01/13/basis06/ukuk/prty/16011506_1306.gif


Home/Work - Dartmoor
240m/785 ft asl
picturesareme
13 January 2016 15:22:23


Gone very quiet in here, has something drastic happened / showing that I'm missing? 


Originally Posted by: Islander 


Perhaps people have finally come to realise & accept that this coming cold (ish) spell will be a largely uneventful one, but with plenty of dry usable sunny weather around. Maybe they are just having a little chill out from obsessive model watching 😄


 

kmoorman
13 January 2016 15:25:34


 


Perhaps people have finally come to realise & accept that this coming cold (ish) spell will be a largely uneventful one, but with plenty of dry usable sunny weather around. Maybe they are just having a little chill out from obsessive model watching 😄


 


Originally Posted by: picturesareme 


 


They're all outside making snow-persons and tobogganing 


Home: Durrington, Worthing, West Sussex. (16 ASL)
Work: Canary Wharf, London
Follow me on Twitter @kmoorman1968
Whiteout
13 January 2016 15:39:50

This highlights the snow possibility for the E and Northern Home counties tomorrow morning, also the heavy snow possible for S Scotland and NE England.


http://www.theweatheroutlook.com/charts/gfs/12_18_preciptype.png?cb=93


Home/Work - Dartmoor
240m/785 ft asl
Whiteout
13 January 2016 15:41:27

.....and the Thu pm snow for C and S areas:


http://www.theweatheroutlook.com/charts/gfs/12_27_preciptype.png?cb=271


Home/Work - Dartmoor
240m/785 ft asl
Whiteout
13 January 2016 15:43:36

....finally the SW snow that Ian has alluded to:


http://www.theweatheroutlook.com/charts/gfs/12_39_preciptype.png?cb=179


Home/Work - Dartmoor
240m/785 ft asl
Islander
13 January 2016 15:48:30


....finally the SW snow that Ian has alluded to:


http://www.theweatheroutlook.com/charts/gfs/12_39_preciptype.png?cb=179


Originally Posted by: Whiteout 


And a big heavy blob of rain over the channel islands... pahh!! 


Guernsey
Whiteout
13 January 2016 15:55:58

Looks to be an improvement on 06z:


http://modeles.meteociel.fr/modeles/gfs/runs/2016011312/gfs-0-84.png?12


Home/Work - Dartmoor
240m/785 ft asl
Rob K
13 January 2016 15:59:49
Just a note re the temp in central London and model accuracy.... St James's Park was 6.2C at 1pm, 6.8C at 2pm, 6.7C at 3pm. I doubt it got above 7C.


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
Whiteout
13 January 2016 16:04:05

Much better:


http://modeles.meteociel.fr/modeles/gfs/runs/2016011312/gfs-0-114.png?12


Home/Work - Dartmoor
240m/785 ft asl
Rob K
13 January 2016 16:06:35


-8C well into the UK on that one!


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
Whiteout
13 January 2016 16:07:15

UKMO currently holding firm:


http://www.meteociel.fr/ukmo/runs/2016011312/UW96-21.GIF?13-17


Home/Work - Dartmoor
240m/785 ft asl
Essan
13 January 2016 16:08:48


....finally the SW snow that Ian has alluded to:


http://www.theweatheroutlook.com/charts/gfs/12_39_preciptype.png?cb=179


Originally Posted by: Whiteout 


 


And if you put all those charts together, the total expected snowfall for the Vale of Evesham is almost as much as we had in July last year .... 


Andy
Evesham, Worcs, Albion - 35m asl
Weather & Earth Science News 

Anyone who is capable of getting themselves made President should on no account be allowed to do the job - DNA
soperman
13 January 2016 16:11:01

The precip feature running southwards on Sunday on the GFS 6z has disappeared so I'm back to my clear and frosty day but just the chance that it could be a snow covered walk in the Chilts. 


Looks like we have a good upgrade for both snow and the longevity - if that's the case I will bin all future 6z forever!! 


 


 

warrenb
13 January 2016 16:15:12
OK a day late,but told you easterlies didn't I.
Rob K
13 January 2016 16:15:59

OK a day late,but told you easterlies didn't I.

Originally Posted by: warrenb 


Not much of an easterly... pretty well a cold high sat right over us but I will take that!


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
13 January 2016 16:17:30

UKMO looking chilly at 120


 



 


Around 526 dam for London so not super cold but wouldn't turn that chart down!


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
13 January 2016 16:22:16


 


And UKMO 144 looks like maybe setting up some snow?


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
Maunder Minimum
13 January 2016 16:23:22


UKMO currently holding firm:


http://www.meteociel.fr/ukmo/runs/2016011312/UW96-21.GIF?13-17


Originally Posted by: Whiteout 


How can it be so different from the GFS at only t+96?


New world order coming.

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