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White Meadows
03 December 2022 22:56:14
Met office mid and long range upgrades today with regards to intensity and longevity widespread cold. Of course as usual in a NE setup the potential is reserved for far flung coasts and high ground. 
18z looks rather wet for the southern half of the UK later on. 
MRayner
03 December 2022 23:26:26
Not too worried about snow, but with I am fully expecting some pretty serious cold nights coming up next week, and a good few ice days too! Just when heating is at its most expensive, typical !🙄
Location Whisky 🥃 country, Cragganmore ,Moray, 440 AMSL
some faraway beach
03 December 2022 23:36:14
My relatives in Sumy, Ukraine, are currently suffering ice days. At least with this set-up the temperature will get above freezing in daytime over there at the end of next week.

I'm cheering on a prolonged UK cold spell for that reason.
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.
Tom Oxon
04 December 2022 01:18:57
Pretty strong swing on GFS 12 vs 18z ens to cold.

Birmingham:

12z
https://www.wetterzentrale.de/en/show_diagrams.php?geoid=50902&model=gfs&var=2&run=12&lid=ENS&bw=1 
18z
https://www.wetterzentrale.de/en/show_diagrams.php?geoid=50902&model=gfs&var=2&run=18&lid=ENS&bw=1 

If anything, the 18z op was a pretty signficant outlier on the mild side.  I would expect one of the 00z and 06z ops to fall in line with the cold theme, especially on the back of a solid ECM op tonight.
S Warwickshire countryside, c.375ft asl.
nsrobins
04 December 2022 06:59:32
We appear to have CMA (EC, UKM and GFS) at 120hrs (Thurs). A polar NNW airflow under an open low with the headline being potentially very low minina and some wintry ppn around, especially near coasts and generally in the North.
There is typical divergence in options after that, with a huge range of scenarios. A widespread snow event over next weekend is at about 40% at the moment.
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
+1
Heavy Weather 2013
04 December 2022 07:04:49

We appear to have CMA (EC, UKM and GFS) at 120hrs (Thurs). A polar NNW airflow under an open low with the headline being potentially very low minina and some wintry ppn around, especially near coasts and generally in the North.
There is typical divergence in options after that, with a huge range of scenarios. A widespread snow event over next weekend is at about 40% at the moment.

Originally Posted by: nsrobins 



A fair assessment. Next weekend Is a bit of a mess and hard to pin detail on anything right now. GFS spawns a low near Greenland and which heads south and phases with a giant low in the Atalantic. ECM has two giant lows in Atlantic. But interestingly, lots of blocking still around. 

I am not confined of some of these bombing lows, last nights 18z GFS had a low dropping almost 20mbs on 4hrs - a world record surely. 
Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Ally Pally Snowman
04 December 2022 07:29:02
Looking at the ensembles both GFS and GEM have a good solid week of cold from the 6th -6/-7c ish 850s  for London.  So hopefully some snow chances. After that could go milder and more unsettled but huge volatility. 
Bishop's Stortford 85m ASL.
+1
Ally Pally Snowman
04 December 2022 07:34:06
Underwhelming ECM Op it has to be said everything to far north less cold. Hopefully one of the milder options. 
 
Bishop's Stortford 85m ASL.
doctormog
04 December 2022 07:39:21
On the subject of cold. I wonder if the UKMO modelling is overdoing it when it shows an overnight low on Friday night of -20°C in the Cairngorm NP and NW Highland areas? https://www.wetterzentrale.de/maps/UKMHDOPUK00_150_38.png  
Aberdeen
Current conditions (personal WS) 
Surrey John
04 December 2022 08:07:02
Is it just me, or is the cold possibly going to have a pause about days 8-10

What seems to be giving some model trouble is a large depression that might bowl from Atlantic into Portugal or France, and the more northerly potential tracks obviously affect UK.  

But cold might all reload in longer time period, however in second week does rather seem to be stopping cold from fully reaching us Southerners.

As for snow, think temperatures are a bit marginal 

Just trying to be realistic, but probably be attacked now by a cold tamper
Bradford on Avon, Wiltshire
35m ASL
+1
DEW
  • DEW
  • Advanced Member
04 December 2022 08:14:29
WX charts show the area below freezing (as shown by 0C isotherm) breaking up in week 1 and retreting to the NE of a line from S Norway to N Ukraine in week 2. For all that, Britain remains cold for the time of year, with any advance of milder weather just about getting to N France (confirmed by temp chart shown on BBC last night). Dry in France and Germany in week 1 with pptn on all sides of that; in week 2 heavier from Atlantic through France and Spain and across the Med to the Balkans, with a tongue from the N Sea to the Baltic. Britain on the edge of this activity.

GFS Op - current cloudy E-lies replaced by N-lies, which should at least allow some sunshine even if colder, by Thu 8th under control of LP 1000mb S Norway. This sticks around, though without any connection to really cold air either to N or E until Mon 12th when no less than 3 LPs are close to but not directly affecting Britain; 990mb SW Iceland, 965 mb Azores (maybe not technically a hurricane, though if you were in a cruise ship in the middle of it, you could be forgiven for thinking so), and 995mb Adriatic. The two Atlantic disturbances join forces 990mb SW Ireland Thu 15th reviving the NE-lies for Britain and this time linking back to the Arctic. This moves off SE-wards and pressure rises over Britain with a promising large area of HP 1040 mb Severn Estuary Tue 20th. With areas of LP all moving around, I feel this outlook is unstable and subject to change.

ECM is simpler and only has one LP developed on Mon 12th, SW of Ireland, 955 mb (?isobars too close to count!) which fills as it moves to UK Wed 14th where it interacts with the LP over Scandinavia (which never goes away in this model) producing a rather indeterminate mix of temps, cold for the N and milder for the S maybe. Another deep LP has formed in mid-Atlantic at this time, as it does on GFS, but the ECM charts don't go forward far enough to indicate whether this is fended of by the rise of pressure.

GEFS - virtually all the ens members agree on a cold or very cold spell to Tue 13th, lowest 7 or 8C below norm around Fri 9th, after which the mean temp rises to or a little below seasonal norm by Fri 16th and stays there. There is a difference between N and S, the N having ens members broadly agreeing but in the S the mean is an average of widely contrasting runs. Pptn starting around Fri 9th, snow row figures from 20s in the N to single figures in the S at this date, but declining thereafter but not to zero. Heaviest pptn in the SW around Fri 16th.

Sorry this has gone on a bit, but blame the uncertainties in the charts!
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
+2
marting
04 December 2022 08:31:27
ECM is at the top end this morning past day 8 ( a long way ahead). The ensembles retain the majority in the colder options https://weather.us/forecast/11281273-greasby/ensemble/euro 
Plenty of interesting options, with a lot of interest Thurs to Sunday with a range of options possible. Enjoyable watching. (Not so on the gas bill!)
Martin
Martin
Greasby, Wirral.
Hippydave
04 December 2022 09:01:11
Looking through the ECM ens and the Op temps, IMBY colder air hits Wednesday, with a run of low single figure maxes until and including Monday 12th, at which point it goes much milder. There's what to me looks a majority chillier cluster that lasts until 15th before the scatter gets so much it's hard to tell what's in the majority.

GEFS for London are very similar.

I seem to remember when the models were initially toying with a colder start to December mid-month looked to be the likely point where milder air would return, as per comments in the Dec CET thread. Would be amusing if after a week or so of model watching that was the solution we land on but plenty of water under the bridge before then and relying on any model to correctly model LPs at day 6-7 is not entirely sensible.

As an aside and not being so IMBY I thought the T240 ECM chart looked pretty stellar for areas further North - somewhere around Northern England to Scotland looks to remain in cold air so that LP, assuming it retains enough precip, would presumably dump a reasonable amount of snow for some.  If the follow up monster LP did something similar it could be pretty memorable...  All a bit far out to do more than raise an eyebrow at but whilst it's game over for the South if that verified, it looks rather good for some areas still.
Home: Tunbridge Wells
Work: Tonbridge
+1
Brian Gaze
04 December 2022 09:03:03

On the subject of cold. I wonder if the UKMO modelling is overdoing it when it shows an overnight low on Friday night of -20°C in the Cairngorm NP and NW Highland areas? https://www.wetterzentrale.de/maps/UKMHDOPUK00_150_38.png  

Originally Posted by: doctormog 



It actually shows -21C and -23C

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=126&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=156&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

A couple of days ago it was showing -23C in northern England.

 
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
+1
Downpour
04 December 2022 09:09:00

Is it just me, or is the cold possibly going to have a pause about days 8-10

What seems to be giving some model trouble is a large depression that might bowl from Atlantic into Portugal or France, and the more northerly potential tracks obviously affect UK.  

But cold might all reload in longer time period, however in second week does rather seem to be stopping cold from fully reaching us Southerners.

As for snow, think temperatures are a bit marginal 

Just trying to be realistic, but probably be attacked now by a cold ramper

Originally Posted by: Surrey John 



No. I agree. I think it's perfectly valid to look at broad regional trends (as all weather is local). However, there remains room for improvement- a chilly week upcoming.
 
Chingford
London E4
147ft
doctormog
04 December 2022 09:16:29

It actually shows -21C and -23C

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=126&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=156&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

A couple of days ago it was showing -23C in northern England.

 

Originally Posted by: Brian Gaze 



Thanks Brian, I can only assume that is a bit of a flaw in that particular model (or I'd be amazed to see the temperature dip to below -20°C!).

Here's the ICON 06z so far and it is conducive to some very low temperatures but not that low I would have thought.

https://www.wetterzentrale.de/maps/ICOOPEU06_114_1.png  
Aberdeen
Current conditions (personal WS) 
Ally Pally Snowman
04 December 2022 09:20:28

It actually shows -21C and -23C

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=126&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

https://www.theweatheroutlook.com/twodata/ukmetuk.aspx?run=00&charthour=156&chartname=2m_min_temp&chartregion=uk-region&charttag=2m%20min%20temp%20C 

A couple of days ago it was showing -23C in northern England.

 

Originally Posted by: Brian Gaze 



Presume its factoring in significant snow cover as max temps for most of the country is -3c
 
Bishop's Stortford 85m ASL.
UncleAlbert
04 December 2022 09:46:48
Of the ops, the GEM looks the pick of the bunch this morning, for any longevity of cold conditions.  Looks like that might be reflected by that significant cluster that keeps near or sub -5 850s going to the end of the GFS ens.

​​​​​​https://www.netweather.tv/charts-and-data/ensembles 
idj20
04 December 2022 09:51:49
I've just had a "skeg" through the models and it looks set to be predominately dry all week here at my South Kent location. The first cold front expected to pass southwards over Kent on Tuesday may help to shift this anticyclone gloom by mixing up the air slightly and finally give me some sun, it looks good in terms of seeing the low Winter sun for the rest of the week as further weakening cold fronts move in from the north, trade off is being colder with an increased chance of frost and surface ice. Even looks similar by the weekend, but the real "fun" is the following week when Atlantic fronts try to push back in and producing a possible spell of transitional snow (probably all of 5 minutes here at Folkestone) before turning back to rain.

Sorry if this post has a NIMBY element, this is just me thinking aloud while composing a post for my own weather group on FB. 
Folkestone Harbour. 
nsrobins
04 December 2022 09:58:36
Predicting the 8+ day range at any time is really hard, but in winter especially so with snow in the mix. Broad patterns fine, but the minuscules of uppers and dps and mixing out make a snow forecast in lowland Uk nigh on impossible (unless it's a classic easterly).
Get the cold in and the snow will take care of itself. All major models have the UK in a polar origin cold airmass with -6/-7 uppers. That'll do for a start.
I see ICON is again more progressive with getting the first low further south, but the 'pseudocane' is still there.
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
doctormog
04 December 2022 10:19:55
The outlook in the medium term looks messy and volatile and this pattern continues on the 06z GFS op run so far: https://www.wetterzentrale.de/maps/GFSOPEU06_138_1.png  
Aberdeen
Current conditions (personal WS) 
Downpour
04 December 2022 10:21:26

I've just had a "skeg" through the models and it looks set to be predominately dry all week here at my South Kent location. The first cold front expected to pass southwards over Kent on Tuesday may help to shift this anticyclone gloom by mixing up the air slightly and finally give me some sun, it looks good in terms of seeing the low Winter

sun for the rest of the week as further weakening cold fronts move in from the north, trade off is being colder with an increased chance of frost and surface ice. Even looks similar by the weekend, but the real "fun" is the following week when Atlantic fronts try to push back in and producing a possible spell of transitional snow (probably all of 5 minutes here at Folkestone) before turning back to rain.

Sorry if this post has a NIMBY element, this is just me thinking aloud while composing a post for my own weather group on FB. 

Originally Posted by: idj20 



Not at all. All weather is local. I dare say few normal people would expect you to be massively interested in the weather on Rockall. IMBY is a trite cliche seen only on internet weather chat rooms! 

I agree with your analysis- looks dry if not very dry for the south. Very cold compared to recent Decembers though. Seasonal.
 
Chingford
London E4
147ft
fairweather
04 December 2022 10:34:58

On the subject of cold. I wonder if the UKMO modelling is overdoing it when it shows an overnight low on Friday night of -20°C in the Cairngorm NP and NW Highland areas? https://www.wetterzentrale.de/maps/UKMHDOPUK00_150_38.png  

Originally Posted by: doctormog 


Why would it? I don't really understand this concept of a model "over doing it". These anthropogenic connotations surely can't happen. If the model appears in error it can only because the data put in it is wrong or it used a different algorithm to the one that didn't "over do it". Clearly with indiviual peturbations some will be at the more extreme end.
S.Essex, 42m ASL
+1
beanoir
04 December 2022 10:39:11

Is it just me, or is the cold possibly going to have a pause about days 8-10

What seems to be giving some model trouble is a large depression that might bowl from Atlantic into Portugal or France, and the more northerly potential tracks obviously affect UK.  

But cold might all reload in longer time period, however in second week does rather seem to be stopping cold from fully reaching us Southerners.

As for snow, think temperatures are a bit marginal 

Just trying to be realistic, but probably be attacked now by a cold tamper

Originally Posted by: Surrey John 



it's always good to be realistic! 

The SW low is going to be a recurring theme, but it could bring some interesting opportunities too. 
Langford, Bedfordshire
doctormog
04 December 2022 10:43:02

Why would it? I don't really understand this concept of a model "over doing it". These anthropogenic connotations surely can't happen. If the model appears in error it can only because the data put in it is wrong or it used a different algorithm to the one that didn't "over do it". Clearly with indiviual peturbations some will be at the more extreme end.

Originally Posted by: fairweather 



The concept is that the algorithm is not dealing with the input parameters in an appropriate way. The extremely localised nature of the very low minima suggest a direct and possibly flawed correlation between snow depth and 2m temperature to me. I would expect this may be an issue that will be tweaked in future. I'm surprised you don't think a model could be overdoing temperature extremes based on flaws in an algorithm.

In this case we are not dealing with any random perturbation, rather the operational run. If, since the last update/version, the model has not encountered such synoptics as shown it is perfectly valid to assume the model may be "overdoing it".
Aberdeen
Current conditions (personal WS) 
+1

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