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Gandalf The White
03 December 2023 17:23:25

No comments on the 12Z GFS, rather says it all!

Originally Posted by: Rob K 



I was thinking how inconsistent it is beyond about a week.  Let’s see what ECM 12z makes of the state of the atmosphere.
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Brian Gaze
03 December 2023 17:37:13
GEFS 12Z looks consistent with recent updates. I still think flooding is a potential concern in parts of the UK during the coming weeks. 

UserPostedImage
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Saint Snow
03 December 2023 17:51:16
GFS really wants to get that PV organised

😡

 

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
The Beast from the East
03 December 2023 17:59:58
GEM offers some hope! 
"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President
Rob K
03 December 2023 18:43:22
ECM very different from GFS at 120hrs
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
Saint Snow
03 December 2023 19:04:49

ECM very different from GFS at 120hrs

Originally Posted by: Rob K 



And obviously at t+240.

ECM brings a plume - but with an overall promising set-up.

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan
Quantum
03 December 2023 19:48:14

No comments on the 12Z GFS, rather says it all!

Originally Posted by: Rob K 



P28 slides.

Its not over until all of the ensembles are on board.
 
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.
The Beast from the East
03 December 2023 19:51:40
ECM Day 10 means looks blocked.
"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President
Jiries
03 December 2023 21:41:35

GFS really wants to get that PV organised

😡

 

Originally Posted by: Saint Snow 



The americans don't want the mild weather so they use the that twat GFS to set up shop so they can get their winter back and not for NW Europe .
Bolty
03 December 2023 22:06:54

The americans don't want the mild weather so they use the that twat GFS to set up shop so they can get their winter back and not for NW Eurpoe.

Originally Posted by: Jiries 



Err... what? 😂

I pretty sure the GFS wasn't created with any particular preference. It's simply another model designed to try and predict the weather. The Eastern US gets more colder weather simply because it has a more favourable climate for colder weather in winter (and hotter in summer)... AKA a continental climate. We unfortunately (or fortunately, depending on your view) don't.
Scott
Blackrod, Lancashire (4 miles south of Chorley) at 156m asl.
My weather station 
Matty H
03 December 2023 22:11:26

The americans don't want the mild weather so they use the that twat GFS to set up shop so they can get their winter back and not for NW Eurpoe.

Originally Posted by: Jiries 



Amazing 🤣🤣🤣
CField
04 December 2023 06:34:05
Hopeful of a change to cooler conditions in the run up to Christmas. Always give the festive season an edge...nothing worse to have the alternative...see how things develop ..Still a bit of interest for the moment.
Favourite snowstorm
Famous channel low
Dec 31st 1978
Hastings East Sussex
Foot of level snow severe drifting
Next day max temp -4 degrees Celsius
Ally Pally Snowman
04 December 2023 07:37:38

The americans don't want the mild weather so they use the that twat GFS to set up shop so they can get their winter back and not for NW Europe .

Originally Posted by: Jiries 



Brilliant Classic Jiries.
😁
 
Bishop's Stortford 85m ASL.
DEW
  • DEW
  • Advanced Member
04 December 2023 07:43:20
WX temp summary has resumed its prediction of a retreat of cold air back towards the east. Week 1 has W Europe with temps not far from norm for the time of year, ranging from above in Spain to just below in Poland, and then in week 2 the area which is freezing pulls back well into Russia and the ultra-freezing virtually disappears to the far NE i.e. Siberia. Rain near the Atlantic week 1, heaviest around Britain, in week 2 moving to the NE with the wet area in the N Sea and from there extending to Baltic.

GFS Op - the HP block over Russia reaches its apogee Mon 11th, 1060mb, preventing LPs penetrating far into the Continent until then but then fades SE-wards with LPs moving ever further E-wards. For Britain this means current LP gets to Kent 1000mb Tue 5th, filling, then 970mb Clyde Fri 8th moving NE-wards, 980mb Orkney Mon 11th getting to the Baltic with N-lies behind, finally Britain is under W/NW-lies as the controlling LP 990mb becomes fixed in the Baltic Sun 17th. Prospects of cold weather for Christmas enhanced by secondary LPs in the latter's circulation with a blast from the NE on (FI) Wed 20th.

ECM - similar to GFS at first; the LP Mon 11th sticks over Britain as it fills becoming 1005mb N Sea Thu 14th.

GEFS - alternating milder (5th, 8th, 10th) and cooler, variation most visible in the S, while the far N simply becomes less cold around the 8th, all with good ens agreement, then mean close to norm but with increasing disagreement between individual runs to the point  of meaninglessness by Wed 20th. Wet to Mon 11th, somewhat drier after that.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
Brian Gaze
04 December 2023 08:18:29

Hopeful of a change to cooler conditions in the run up to Christmas. Always give the festive season an edge...nothing worse to have the alternative...see how things develop ..Still a bit of interest for the moment.

Originally Posted by: CField 



These days I just hope we don't have to open the patio doors on Xmas day. 
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
GezM
  • GezM
  • Advanced Member
04 December 2023 08:49:47
GFS Ops run still showing a mid-Atlantic high from mid-month which offers potential for something colder again. 
Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
Brian Gaze
04 December 2023 09:05:25
I wonder how long it will be before the focus shifts to SSW. 
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
David M Porter
04 December 2023 09:57:56

I wonder how long it will be before the focus shifts to SSW. 

Originally Posted by: Brian Gaze 



Someone mentioned something about a possible stratospheric warming over Canada later this month a week or so back in the last thread IIRC, Brian. I don't think much if anything has been said about it since, though.
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
Rob K
04 December 2023 11:23:23
Not much cause for excitement on this morning's runs. 

Bit until the Met Office remove the line "Perhaps a greater chance of a longer cold spell late in the period" from their long-ranger I am not giving up hope of a seasonal Xmas period.

(So, this afternoon then!)
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
04 December 2023 12:06:39

Not much cause for excitement on this morning's runs. 

Bit until the Met Office remove the line "Perhaps a greater chance of a longer cold spell late in the period" from their long-ranger I am not giving up hope of a seasonal Xmas period.

(So, this afternoon then!)

Originally Posted by: Rob K 



The extended ECM output to me suggests they will remove that line very soon.
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
David M Porter
04 December 2023 13:02:29
Christmas & late December are an eternity away in weather forecasting terms and at times in the last week or so, FI has commenced at a very early stage. It took the models quite a bit of time last week to properly resolve how this week would play out.

I can't remember exactly what stage the cold spell now ending was first seen by the models, but I don't think it was first spotted a very long time in advance of when it began.
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
Retron
04 December 2023 13:44:08

Someone mentioned something about a possible stratospheric warming over Canada later this month a week or so back in the last thread IIRC, Brian. I don't think much if anything has been said about it since, though.

Originally Posted by: David M Porter 


Unlike the tropospheric forecasts, the stratospheric ones have been much more consistent. Yes, they've been modelling a Canadian warming for quite some time, and it's happening as we speak:

https://charts.ecmwf.int/products/extended-anomaly-10t?base_time=202312030000&projection=opencharts_arctic&valid_time=202312110000 

The warming wanes somewhat, then rebuilds over the Pole towards the end of the year. In theory that's great news in terms of messing up the jet, assuming it works its way down, raising the odds of a more blocked outcome. However, it's only one piece of the puzzle, and we know it takes a lot of pieces to fall in place before we see anything interesting!

The vortex itself is forecast to be weaker than normal for pretty much the entire 42-day ECM run, with maybe a 1-in-5 chance of a major SSW by early January.

https://charts.ecmwf.int/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202312030000 

Bear in mind, though, that the forecast strength in the short term has increased over the past week, if you compare the chart from last Sunday you'll see the period from the 10th to the 17th Dec is now around 33m/s overall, whereas from the previous week's forecast it was to be about 27m/s. Longer term, though, the strength is forecast to be a fair bit lower than before, with far more members showing a reversal.

In other words - the textbook would say with warming over Canada migrating to the pole, a weakening vortex, a growing chance of a reversal, and the teleconnections such as MJO moving into a favourable phase in a couple of weeks... we should be in with a decent shout of a blocked spell, and that would quite probably be a cold one for us.

Hopefully in another 7 to 10 days we'll be seeing some eye-candy runs once again!

 
Leysdown, north Kent
CField
04 December 2023 14:29:39
[Good read ...quote=Retron;1553598]Unlike the tropospheric forecasts, the stratospheric ones have been much more consistent. Yes, they've been modelling a Canadian warming for quite some time, and it's happening as we speak:

https://charts.ecmwf.int/products/extended-anomaly-10t?base_time=202312030000&projection=opencharts_arctic&valid_time=202312110000 

The warming wanes somewhat, then rebuilds over the Pole towards the end of the year. In theory that's great news in terms of messing up the jet, assuming it works its way down, raising the odds of a more blocked outcome. However, it's only one piece of the puzzle, and we know it takes a lot of pieces to fall in place before we see anything interesting!

The vortex itself is forecast to be weaker than normal for pretty much the entire 42-day ECM run, with maybe a 1-in-5 chance of a major SSW by early January.

https://charts.ecmwf.int/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202312030000 

Bear in mind, though, that the forecast strength in the short term has increased over the past week, if you compare the chart from last Sunday you'll see the period from the 10th to the 17th Dec is now around 33m/s overall, whereas from the previous week's forecast it was to be about 27m/s. Longer term, though, the strength is forecast to be a fair bit lower than before, with far more members showing a reversal.

In other words - the textbook would say with warming over Canada migrating to the pole, a weakening vortex, a growing chance of a reversal, and the teleconnections such as MJO moving into a favourable phase in a couple of weeks... we should be in with a decent shout of a blocked spell, and that would quite probably be a cold one for us.

Hopefully in another 7 to 10 days we'll be seeing some eye-candy runs once again!

 


Favourite snowstorm
Famous channel low
Dec 31st 1978
Hastings East Sussex
Foot of level snow severe drifting
Next day max temp -4 degrees Celsius
overland
04 December 2023 14:43:14

Christmas & late December are an eternity away in weather forecasting terms and at times in the last week or so, FI has commenced at a very early stage. It took the models quite a bit of time last week to properly resolve how this week would play out.

I can't remember exactly what stage the cold spell now ending was first seen by the models, but I don't think it was first spotted a very long time in advance of when it began.

Originally Posted by: David M Porter 



I think the GFS did pick up on a colder spell out in FI. Obviously the detail varied overtime, but it was one of those occasions where it wasn't too far wrong with the general pattern. However, if I recall correctly, when the time period came into range of the other models they weren't so keen and that included the ECM. 
Mumbles, Swansea. 80m asl
Rob K
04 December 2023 17:01:55


I can't remember exactly what stage the cold spell now ending was first seen by the models, but I don't think it was first spotted a very long time in advance of when it began.

Originally Posted by: David M Porter 



I remember it was first shown up as a potent northerly arriving around Nov 27th, at about day 10. Then it was modelled as a toppler, before turning into the slack easterly that we ended up with.

Looking at today's 12Z output, both GFS and GEM are suggesting high pressure taking up residence over the UK, which would be quite welcome tbh.
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

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