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Retron
29 December 2015 17:38:19
The 12z GEFS suite has some remarkable permutations in it - if anything, the odds on a cold (as opposed to colder) spell have shortened again this evening, I'd say it's now as high as 25% or so (and higher in Scotland!).

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=14&mode=0&carte=1 

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=15&mode=0&carte=1 

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=16&mode=0&carte=1 

and so on.
Leysdown, north Kent
Whether Idle
29 December 2015 17:40:51


I'm not a huge fan of the accuracy of the UKMO at T144, and of course their own forecast doesn't support what COULD be the outcome if that chart went to T168 - though they do see a T168 chart at Exeter.


 


I think the ECM will be more like the GFS though probably somewhere in between the GFS/UKMO as the GFS can be too aggressive with LP development.


 


 


Originally Posted by: Shropshire 


 It is helpful to have "old Shroppers" here to keep expectations low when this situation is knife edge stuff and will probably goes t*ts up in the great tradition of two winter model watching.

Dover, 5m asl. Half a mile from the south coast.
Solar Cycles
29 December 2015 17:41:42

The 12z GEFS suite has some remarkable permutations in it - if anything, the odds on a cold (as opposed to colder) spell have shortened again this evening, I'd say it's now as high as 25% or so (and higher in Scotland!).

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=14&mode=0&carte=1

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=15&mode=0&carte=1

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=16&mode=0&carte=1

and so on.

Originally Posted by: Retron 

By George there's some crackers amongst that lot.

Fothergill
29 December 2015 17:47:48

GEFS height anomalies day 10. Upper anomalies day 8



Brian Gaze
29 December 2015 17:52:24

GEFS12 look fractionally milder than the 6z set.


Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
squish
29 December 2015 17:53:46
12z NAVGEM is less progressive than the 00z/06z runs and has plenty of potential

http://modeles.meteociel.fr/modeles/navgem/runs/2015122912/navgemnh-0-180.png?29-18 
D.E.W on Dartmoor. 300m asl
Gooner
29 December 2015 17:58:04

As UKMO note (in briefing earlier today about this unfolding situation early Jan), the dichotomy of GFS versus other deterministic models is all the more eye-catching this occasion because - as Exeter puts it - "....it (GFS) is often the least progressive of the main models...".


(Emphasis on 'least')!! 


 


^^^^^^^ From Fergie on NW ^^^^^^^


 

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


squish
29 December 2015 18:00:52
00z UKMO +84 FAX
http://www.meteociel.fr/ukmo/fax/fax84s.gif?2 

last nights 12z UKMO +96 FAX
http://www.meteociel.fr/ukmo/fax/fax96s.gif?2 

The handling of this low to the SW seems to play a role in whether the cold pool to the east is drawn westwards quick enough to engage with the next trough at +120 to give us some fun and games. Tonights +72 FAX isn't out yet, but the difference on the two charts posted above is quite notable. The 00z run this morning has the low further SW than yesterday's 12z and it sends another shot of WAA northwards to bolster the scandinavian high. This in turn helps deflect the next low further SW.

I would keep very tuned in to how this low develops over the next 36/48 hours as there is potential for a much earlier shot at cold from the east than perhaps is generally showing up in the models (save one or two ensemble runs)

Reagrds,
D.E.W on Dartmoor. 300m asl
Retron
29 December 2015 18:07:08

00z UKMO +84 FAX
http://www.meteociel.fr/ukmo/fax/fax84s.gif?2

last nights 12z UKMO +96 FAX
http://www.meteociel.fr/ukmo/fax/fax96s.gif?2

Originally Posted by: squish 


And tonight's T+72 for comparison:


http://www.wetterzentrale.de/pics/brack2.gif


 

Leysdown, north Kent
Arbroath 1320
29 December 2015 18:22:03


GEFS12 look fractionally milder than the 6z set.



Originally Posted by: Brian Gaze 


The Aberdeen set look colder than the 6z Brian, with several very cold runs. The op and control are above the mean for much of the run which skirts -5 in the main:


http://www.theweatheroutlook.com/twodata/chart.aspx?chart=/charts/gefs/gefsens850Aberdeen0.png


 

GGTTH
Arbroath 1320
29 December 2015 18:25:07

The 12z GEFS suite has some remarkable permutations in it - if anything, the odds on a cold (as opposed to colder) spell have shortened again this evening, I'd say it's now as high as 25% or so (and higher in Scotland!).

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=14&mode=0&carte=1

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=15&mode=0&carte=1

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=16&mode=0&carte=1

and so on.

Originally Posted by: Retron 


Agreed. There's a good few other decent ones as well. No 19 is actually my favourite:


http://www.meteociel.fr/modeles/gefs_cartes.php?code=19&ech=204&mode=0&carte=0


 

GGTTH
Whether Idle
29 December 2015 18:34:42

Well into FI here I know, (ECM, 144)and there is considerable room for improvement here.


Dover, 5m asl. Half a mile from the south coast.
David M Porter
29 December 2015 18:46:07


Well into FI here I know, (ECM, 144)and there is considerable room for improvement here.



Originally Posted by: Whether Idle 


Patience grasshopper, patience.

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Whether Idle
29 December 2015 18:53:33

As things stand before viewing all ensembles etc Id say we've moved to a 30% chance of cold setting in around 4th January, BUT as we get closer to somewhere around t96 (0z New Year's Day at the latest) coldies will want to see the odds flip from 70% likelihood of "mild" as they are at the moment, to 70% likelihood of cold.  That will take some doing, but there's still 24-36  hours for a turnaround.


By tomorrow's 12z I think we need to be in a 50-50 situation, I d say superficially we are some way from that yet.


More runs needed.

Dover, 5m asl. Half a mile from the south coast.
David M Porter
29 December 2015 19:02:41

In my opinion, ECM 12z 216hr chart has almost a January 1984 look about it:


http://www.wetterzentrale.de/pics/Recm2161.gif


 

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Gooner
29 December 2015 19:04:41


As things stand before viewing all ensembles etc Id say we've moved to a 30% chance of cold setting in around 4th January, BUT as we get closer to somewhere around t96 (0z New Year's Day at the latest) coldies will want to see the odds flip from 70% likelihood of "mild" as they are at the moment, to 70% likelihood of cold.  That will take some doing, but there's still 24-36  hours for a turnaround.


By tomorrow's 12z I think we need to be in a 50-50 situation, I d say superficially we are some way from that yet.


More runs needed.


Originally Posted by: Whether Idle 


really????


I'd say average to colder than what we have .


I certainly wouldn't say there is a 70% likelihood of mild weather

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


Whether Idle
29 December 2015 19:10:44


 


really????


I'd say average to colder than what we have .


I certainly wouldn't say there is a 70% likelihood of mild weather


Originally Posted by: Gooner 


Marcus, I was attempting to distinguish between a scenario where we have surface temperatures , say 0 to 4c (cold) and then, say, 7 to 10c which I would class as "mild" , and a stark contrast to the uber-mild we have endured since November 1st.

Dover, 5m asl. Half a mile from the south coast.
White Meadows
29 December 2015 19:11:31


In my opinion, ECM 12z 216hr chart has almost a January 1984 look about it:


http://www.wetterzentrale.de/pics/Recm2161.gif


 


Originally Posted by: David M Porter 

looks very wet and too mild to me.

some faraway beach
29 December 2015 19:12:09


As things stand before viewing all ensembles etc Id say we've moved to a 30% chance of cold setting in around 4th January, BUT as we get closer to somewhere around t96 (0z New Year's Day at the latest) coldies will want to see the odds flip from 70% likelihood of "mild" as they are at the moment, to 70% likelihood of cold.  That will take some doing, but there's still 24-36  hours for a turnaround.


By tomorrow's 12z I think we need to be in a 50-50 situation, I d say superficially we are some way from that yet.


More runs needed.


Originally Posted by: Whether Idle 


London GEFS 850 mean bang on the January 30-year mean of 0C for the entire run.


I can't see that suggesting "mild" weather, never mind a 70% chance of it.


2 miles west of Taunton, 32 m asl, where "milder air moving in from the west" becomes SNOWMAGEDDON.
Well, two or three times a decade it does, anyway.
Whether Idle
29 December 2015 19:14:23


 


London GEFS 850 mean bang on the January 30-year mean of 0C for the entire run.


I can't see that suggesting "mild" weather, never mind a 70% chance of it.



Originally Posted by: some faraway beach 


See my post above, upon reflection I would perhaps change "milder" as per my original post,  to seasonal, if that keeps people happier.

Dover, 5m asl. Half a mile from the south coast.
Polar Low
29 December 2015 19:16:13

Disappointed with that from ecm tonight but still the whole pattern and the amount of upstream amplification stateside looks very complicated at the moment


confusion even at t96 for ecm


http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!96!pop!od!enfo!enplot!2015122900!!/


But still the ukmo t 144 must be the best chart for quite sometime for coldies all fantasy off course at that range


as always more runs required


 


 

some faraway beach
29 December 2015 19:19:17


 


See my post above, upon reflection I would perhaps change "milder" as per my original post,  to seasonal, if that keeps people happier.


Originally Posted by: Whether Idle 


Fair enough. Some serious technicolour precipitation spikes on that GEFS diagram too.

2 miles west of Taunton, 32 m asl, where "milder air moving in from the west" becomes SNOWMAGEDDON.
Well, two or three times a decade it does, anyway.
Quantum
29 December 2015 19:21:04


In my opinion, ECM 12z 216hr chart has almost a January 1984 look about it:


http://www.wetterzentrale.de/pics/Recm2161.gif


 


Originally Posted by: David M Porter 


Whenever anyone mentions January 1984, I think they have given up!


 


Still finely balanced and could go either way.


 

2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
squish
29 December 2015 19:30:54
No, 2 months to go ....
D.E.W on Dartmoor. 300m asl
David M Porter
29 December 2015 19:36:38


looks very wet and too mild to me.


Originally Posted by: White Meadows 


In your area quite possibly, but it doesn't look overly mild to me as far as Scotland is concerned. Certainly nothing like the model output of recent weeks; there are no yellows covering any part of the British Isles for one thing.

Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022

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