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ballamar
11 December 2023 06:56:16
Take a break for a week now, business as usual!!
Brian Gaze
11 December 2023 07:09:10

Take a break for a week now, business as usual!!

Originally Posted by: ballamar 



If you're only interested in cold weather I can provisionally sign you off until the end of February. 😛
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Retron
11 December 2023 07:17:18

If you're only interested in cold weather I can provisionally sign you off until the end of February. 😛

Originally Posted by: Brian Gaze 


The morning GEFS would suggest you might be blown away by then...

Some of the members show some vicious lows near the UK just before Christmas. This is one example - widespread 70mph gusts, driven on by a deep low on a raging jet. I detest high winds and hope this signal disappears as quickly as it's appeared!

UserPostedImage
Leysdown, north Kent
Ally Pally Snowman
11 December 2023 07:22:13
Yep grim output.  GFS offers a 2 day northerly but the others don't even bother with that.  Flat as pancakes.  V v v dull. 

Maybe A SSW will save us. Some glimmers at day 16 perhaps.  That's the best straw I can clutch this morning. 

https://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=10&carte=1 
 

Brian's mild December looks like a dead cert atm.
 
Bishop's Stortford 85m ASL.
Brian Gaze
11 December 2023 07:28:33

The morning GEFS would suggest you might be blown away by then...

Some of the members show some vicious lows near the UK just before Christmas. This is one example - widespread 70mph gusts, driven on by a deep low on a raging jet. I detest high winds and hope this signal disappears as quickly as it's appeared!

UserPostedImage

Originally Posted by: Retron 



I wouldn't be at all surprised by further very wet and windy periods. Also, the first year on record with all months finishing above the 61-90 average looks more and more likely. 
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Retron
11 December 2023 07:39:23

I wouldn't be at all surprised by further very wet and windy periods. Also, the first year on record with all months finishing above the 61-90 average looks more and more likely. 

Originally Posted by: Brian Gaze 


Yes, much depends on how far north next weekend's high manages to ridge. If the centre's over the Channel, or further south, it should be very mild indeed - which will boost the CET massively. My thinking is that the high being south means more wind, meaning more mixing and less chance of an inversion. Indeed, with some of the 850s being modelled (one of the GFS runs yesterday had +12s over the Scottish borders), the chance of an exceptional maximum in a foehn-type effect rises markedly.

On the other hand, if that high drifts a bit further north again (as it did when the models first picked it up), some notably cold days under an inversion could result in the south.

There is still a chance of a glancing northerly in the run up to Christmas, but using "sod's law" would suggest it'll either miss us to the east, or end up as NW'lies instead as the ridge doesn't amplify as much as thought. We've seen that countless times before, but to be fair we're overdue a "toppler" - we've not had one of those in ages.

Regarding that 61-90 average, I'd say it's more than a 50% chance of happening...

Atlantic (and global) SSTs are at a record high:
https://climatereanalyzer.org/clim/sst_daily/ 

...and the NH air temperatures are the highest in the satellite era:
https://climatereanalyzer.org/clim/t2_daily/?dm_id=nh 

 
Leysdown, north Kent
DEW
  • DEW
  • Advanced Member
11 December 2023 07:54:23
WX summary - temps in week 1 quite mild across NW Europe with a steep temp gradient to very cold in E Russia. In week 2 the gradient flattens out, only just above freezing for Russia (unusual to say the least) but with a tongue of colder air picked out by the mountainous areas of Europe (Carpathians, Alps, even Pyrenees) and their neighbourhoods. Pptn in two areas in week 1, N Atlantic incl N Scotland and a band from France to Spain. Both these areas move a little S-wards in week 2.

GFS Op - LP 995mb tracking across England tomorrow, replaced by HP 1040mb Hampshire Fri 15th, staying around with SW-lies for Scotland until Wed 20th when the HP departs to C Atlantic 1050mb giving Britain N-ly gales for two days. The HP then slowly re-establishes though rather more located to the SW, and the period through to Wed 27th has strong wind flow from points between SW and NW (but still mild) according to exact positions of HP near SW Britain and LP near/over Norway.

ECM - compared to GFS, the initial LP is a day later to move away, and the HP a day later to establish. When the HP arrives it's broader, less localised to Britain and strong enough to deflect any N-lies to the other side of the N Sea. But in the end it agrees with GFS on a strong zonal W-ly. 

GEFS - a little cooler with some rain around Thu 14th then very mild and dry around Mon 18th. Most ens members agree on a steep drop in temp Wed 20th, some like the control run taking this down to 10C below norm while many others treat the cooling as a blip and regain mildness almost immediately i.e. no agreement after this date. More rain in more runs shown from Thu 21st than was the case yesterday, most of the rain in the S & W.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
nsrobins
11 December 2023 08:42:28
Whilst the mean, longer term, stays about the same the spread of solutions increases so to me that says increased uncertainty. When attempting a forecast you then turn to climatology that suggests the milder, flatter option is the most likely.
In truth it’s 14 days to Christmas and way too soon to be calling it. Claiming your forecast is based on a gut feeling is valid, and I respect more of the gut feelings expressed on here than some of the so-called forecasting agencies, but at >10days the low confidence has to be emphasised, especially when the SD of members is so high. 
 
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
chelseagirl
11 December 2023 08:53:15

lol I'm.actually a Kent County Council gritter driver....might pick up a few runs before Xmas....worse case was this time last year Tunbridge Wells  got 6 inches ...Town centre was full of Xmas shoppers who didn't take heed of the Met Office warning...the shout was too late and the result was gridlock chaos and roads like skating rinks...cars were literally sliding down the hill....

Originally Posted by: CField 



Bit like when hubby was a driver for Northants. 

“The roads haven’t been gritted again”

Id love to know where my hubby has been for the last three nights then. 😂
The Fenlands of Cambridgeshire
Brian Gaze
11 December 2023 08:55:51

Whilst the mean, longer term, stays about the same the spread of solutions increases so to me that says increased uncertainty. When attempting a forecast you then turn to climatology that suggests the milder, flatter option is the most likely.

 

Originally Posted by: nsrobins 



I think the question is whether that trumps tenuous teleconnection links. My own view is that it probably does. Whilst it is for others to spend their time as they wish, it strikes me that some people (I'm not talking about on this forum) are using a sledgehammer to crack a nut. 
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Rob K
11 December 2023 08:56:01
A couple of days ago it looked as if there might be some interesting model watching to come. But apparently not. 

Orange to the south of me, purple to the north; here I am, stuck in the jet stream with you….
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
Russwirral
11 December 2023 09:13:10

A couple of days ago it looked as if there might be some interesting model watching to come. But apparently not. 

Orange to the south of me, purple to the north; here I am, stuck in the jet stream with you….

Originally Posted by: Rob K 



yeh its all gone a bit pear shaped hasnt it.  Anywhere with elevation in Scotland looks ok though, their Ski season will do well over Xmas.
White Meadows
11 December 2023 09:29:29

Except for the slight mid Atlantic loop at 384hrs 0z run that's got to be the longest flat long fetch south westerly I've ever seen....from New York to Vladivostock.....

Originally Posted by: CField 



Indeed. Very flat and south westerly with very mild temps possible as discussed yesterday.

 
David M Porter
11 December 2023 09:42:22

Yep grim output.  GFS offers a 2 day northerly but the others don't even bother with that.  Flat as pancakes.  V v v dull. 

Maybe A SSW will save us. Some glimmers at day 16 perhaps.  That's the best straw I can clutch this morning. 

https://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=10&carte=1 
 

Brian's mild December looks like a dead cert atm.
 

Originally Posted by: Ally Pally Snowman 



Wrt the sentence in bold, I wonder if that if the same SSW/ stratospheric warming that was mentioned in here a week/ a couple of weeks ago. IIRC, early last week Darren (Retron) commented on a stratospheric warming that some models had been showing occuring over Canada during this month, and I think someone else made mention of this not long beforehand. It might not mean anything for our weather even if it does happen, right enough.
 
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
Brian Gaze
11 December 2023 09:46:25
The problem with falling back to SSWs is that (to borrow a phrase from economics) they have successfully predicted nine of the last five cold snaps. 😅
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
Retron
11 December 2023 10:16:35

Wrt the sentence in bold, I wonder if that if the same SSW/ stratospheric warming that was mentioned in here a week/ a couple of weeks ago. IIRC, early last week Darren (Retron) commented on a stratospheric warming that some models had been showing occuring over Canada during this month, and I think someone else made mention of this not long beforehand. It might not mean anything for our weather even if it does happen, right enough.
 

Originally Posted by: David M Porter 


Yes, the warming over Canada was interesting to see - and it happened, just not to the extent that was forecast:

https://charts.ecmwf.int/products/extended-anomaly-10t?base_time=202312100000&projection=opencharts_north_pole&valid_time=202312180000 

It's just one of many pieces of the puzzle - some of the winters in the 80s featured them, but as ever it's "chicken and egg" (much like the oft-vaunted MJO forecasts on NW - they're just another way of looking at the model output, and as reliable (or not!) as any given run.

FWIW, the stratosphere stuff does continue to look interesting - as can be seen, the ECM has continued to show a weaker vortex than normal, and for the first time the mean goes below the 10th percentile within a month, which is about as strong a signal as you'll ever see at that range.

https://charts.ecmwf.int/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202312100000 

While it's interesting, it doesn't of course mean a wintry nirvana for us.
Leysdown, north Kent
Gandalf The White
11 December 2023 11:36:27

The problem with falling back to SSWs is that (to borrow a phrase from economics) they have successfully predicted nine of the last five cold snaps. 😅

Originally Posted by: Brian Gaze 



There is of course the old joke about the civil service, which adapted for the weather, says, “If I just reject any forecast of an Arctic cold spell I will only very rarely be wrong”……

😉
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Retron
11 December 2023 11:48:54
Some of the 6z GEFS set are absolutely bonkers. There are still plenty of gales on offer, some snow from a northerly (generally mutually exclusive with the former), and one run which combines the two:

80mph winds and heavy snow over Scotland, anyone? The whole mess then sinks southwards over the next couple of frames.
https://images.meteociel.fr/im/16/23996/gens_27_1_252qxz7.png 

UserPostedImage
Leysdown, north Kent
ballamar
11 December 2023 16:37:55
Keeping an eye out gfs op run is a little better for a cold shot in 9/10 days time
doctormog
11 December 2023 16:48:43
The majority of recent GFS op runs have shown that scenario to one extent or another. At present the other models seem less interested.

Having said that the GEM 12z op is a bit closer to the GFS scenario than has been the case in previous runs.
CField
11 December 2023 18:22:48
Outside outside chance maybe that  the colder air will be harder to shift with a possible slider scenario around the 25th,  as with Cumbria last week will this winter turn out to be one of suprise snowfalls?
Favourite snowstorm
Famous channel low
Dec 31st 1978
Hastings East Sussex
Foot of level snow severe drifting
Next day max temp -4 degrees Celsius
tallyho_83
11 December 2023 18:24:20
Has anyone seen the latest met office seasonal ensemble mean forecast? 
Lot's of HLB - check the pressure charts.
interesting eh,
Maybe they're picking up on an SSW mid winter and a blocked 2nd half.

https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean 
Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
---------------------------------------
Sean Moon
Magical Moon
www.magical-moon.com


Brian Gaze
11 December 2023 19:09:22
Should keep the interest in Christmas going a tad longer.

UserPostedImage
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
Gandalf The White
11 December 2023 19:11:35

Should keep the interest in Christmas going a tad longer.

UserPostedImage

Originally Posted by: Brian Gaze 



As does Day 10 of the ECM op run….
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


ballamar
11 December 2023 19:27:21
Worth keeping an eye on how quickly the strength of the high builds. Perhaps over next couple of days things could change for the better in terms of xmas

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