theweatheroutlook

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Brian Gaze
27 November 2023 21:14:06
ECM 12Z op looks like a big outlier by t+10 days.

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Brian Gaze
Berkhamsted
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Gandalf The White
27 November 2023 21:19:57

ECM 12Z op looks like a big outlier by t+10 days.

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Originally Posted by: Brian Gaze 



The op looks like it sits at the lower end of the range of the ensemble suite before dipping just outside the range at the end?  Not sure I’d label that as a ‘big outlier’?
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


doctormog
27 November 2023 21:31:20

The op looks like it sits at the lower end of the range of the ensemble suite before dipping just outside the range at the end?  Not sure I’d label that as a ‘big outlier’?

Originally Posted by: Gandalf The White 



Yes it is one of the colder/est options in the longer term but not really an outlier: https://www.meteociel.fr/cartes_obs/ecmwfens_display.php?lat=51.5085&lon=-0.12574&ville=Londres&mode=1  
Aberdeen
Current conditions (personal WS) 
Brian Gaze
27 November 2023 21:33:51

The op looks like it sits at the lower end of the range of the ensemble suite before dipping just outside the range at the end?  Not sure I’d label that as a ‘big outlier’?

Originally Posted by: Gandalf The White 



It's outside the standard deviation at the end so is clearly an outlier by that point. The full 50 member 15 day plot looks reasonably consistent with recent updates, but I would note the big spread and not discount a cold outcome at this stage.

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Brian Gaze
Berkhamsted
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White Meadows
27 November 2023 21:37:55

The op looks like it sits at the lower end of the range of the ensemble suite before dipping just outside the range at the end?  Not sure I’d label that as a ‘big outlier’?

Originally Posted by: Gandalf The White 


It is clearly an outlier. No debate there. 
 
Matty H
27 November 2023 21:46:23

Latest Met office contingency planners 3 month update is out this morning, and they are going for a slight chance of milder than colder overall. Also more chance of cold impacting later in winter, as one would expect with the El Niño profile.

link here: 

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/business/public-sector/civil-contingency/3moutlook_djf-v1.pdf 

Discuss…

Originally Posted by: White Meadows 



Yeah, they were expecting a summer with frequent heatwaves as well…
Yate, Nr Bristol
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+1
ballamar
27 November 2023 22:11:33
Think the models do struggle when it isn’t a zonal flow - could easily be quite a cold period. GFS op run shaping up like it could be a very cold one
squish
27 November 2023 22:14:07
The Greenland high is ridging more strongly SW on the 18z which should keep the succession of Atlantic lows sliding SE and the UK in the cold air mass. Plenty of interest for the east.

The Sunday low threatens the SW but otherwise they all look like missing...although the 18z ICON is a bit more promising for the south. 

EDIT: I probably spoke too soon!
 
D.E.W on Dartmoor. 300m asl
White Meadows
27 November 2023 22:37:14
Looks like Brian’s aforementioned ‘flattening’ is taking place on 18z
ballamar
27 November 2023 22:41:31
Looks like a decent slider incoming at 264 - all FI but nice to see
Joe Bloggs
27 November 2023 22:47:25
18z GFS into FI is entertaining if nothing else. 🤣

Blizzards and severe disruption if it were to verify. Very unlikely but goes to show what is possible with a persistent and stubborn block to the NE. 

Will be gone in the morning I’m sure. 😊😇

Manchester City Centre, 31m ASL
David M Porter
27 November 2023 22:52:17
What the GFS 18z op does demonstrate IMO is that even if the atlantic does come back into play after next week, it may not necessarily be a straight-forward return to mild as some seem to think is likely. As Joe says above, as long as that block to the NE persists, then there could be some surprises along the way.
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
+1
Quantum
27 November 2023 23:32:03
In the short term I absolutely love the ICON18Z, amazing snow potential for NE England.

GFS and ARPEGE are okay. I would expect to see snow on Thursday/Friday (maybe even Wednesday) but not any coverings. ICON would provide that.
 
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
fairweather
27 November 2023 23:37:20

Not at all, in the same way as you were not trying to be condescending.

Anyway the point is that we can get excited about the weather on a weather enthusiasts’ forum. It’s not immaturity or lack of objectivity no matter how much that is insinuated.  

The model output is fascinating and uncertain just now. The outlook beyond the next week or so is very much uncertain. The higher probability would be a return to something closer to average after the colder than average wintry type weather, bearing in mind it is both meteorological and astronomical autumn as I write this. 

One look at that standard deviation in the ensembles in both t850hPa and 500hPa terms shows that uncertainty, more so than is often the case. Call it FI if you wish. The bottom line is there are hints in “FI” but in a probability game there are other realistic albeit lesser probabilities. If you can’t see that just look at the ECM 12z output. 

On a final note, people get excited about the prospect of snow, it’s not wrong or something to be patronising about.

Originally Posted by: doctormog 


I don't disagree with any of that and who was being patronising?  which is why I was a bit surprised at your "dig" considering I had said that the the ensembles were showing a week long cold spell with a risk of snow which I am happy about being a known snow fan. The fact of the matter of whether I get very excited about the current prospects or not is surely up to me as it is with your or others level of excitement. 🙂 You're seeing all sorts of things here that aren't there - well certainly not in my post. 
S.Essex, 42m ASL
+2
Ally Pally Snowman
28 November 2023 07:06:16
Down to earth with a bump this morning.  Poor set of 0z. Looking like a cold snap now 5 or 6 days but limited snow potential.  
Bishop's Stortford 85m ASL.
squish
28 November 2023 07:24:05
I’ll take the JMA and GFS control this morning ! 
D.E.W on Dartmoor. 300m asl
Brian Gaze
28 November 2023 07:28:05
There is (IMO) a realistic chance of 2023 being the first year ever to record all months above the 61-90 CET. The extended range output has been consistently signalling a relatively mild December.  Imagine if things were reversed and all 12 months were below it. 😇
Brian Gaze
Berkhamsted
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doctormog
28 November 2023 07:43:06
As has been the case for a few days now, not much clarity beyond the 5th or 6th of December. Cold before then and a range of options after, as summarised on the 00z GEFS set:

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Aberdeen
Current conditions (personal WS) 
nsrobins
28 November 2023 07:53:17

I’ll take the JMA and GFS control this morning ! 

Originally Posted by: squish 


When desperate the JMA often delivers 🧐
The GFS suite (not OP which typically and understandably wobbles around long range) has as Brian says routinely signalled a gradual return of the ‘normal’ pattern from around 6th Dec and as EC and GEM get into that range they too are getting the message.
No guarantee of course but that’s how it looks. 
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
doctormog
28 November 2023 07:58:24
I’d say the ECM ensemble mean t850hPa deviation chart shows things as clearly as it gets at that range: https://www.wetterzentrale.de/maps/ECMAVGEU00_240_34.png  
Aberdeen
Current conditions (personal WS) 
Brian Gaze
28 November 2023 08:03:56
One thing to look for is the possibility of it turning very mild through December and January. I'm absolutely not saying it will happen, but years like 1989 and 1988 have featured highly in the analogues, as well as very cold winters like 2009. It's possible that blocking to the northeast will slowly sink southwards and block mobility across north western Europe. Therefore, we could end-up under a long fetch southwesterly for extended periods this winter. 
Brian Gaze
Berkhamsted
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DEW
  • DEW
  • Advanced Member
28 November 2023 08:05:45
As for what the charts actually show ...

WX temp charts keep freezing weather as far west as E France and N Britain in week 1 but then continue yesterdays' theme of a slow retreat of freezing weather back to the NE, as far as Czechia/Poland with a finger over the  Alps, the rest of NW Europe on the cold side but an extensive introduction of ultra-cold into N Russia. Pptn maps for week 1 show patches of rain across S Europe (Britain mainly dry) followed in week 2 by a return to the scenario which has been common this winter, pptn for Atlantic coastal countries and a separate area for Greece & Turkey.

GFS Op - starts with a controlling LP over the Baltic 1000mb and light N or E-ly flow for Britain. On Thu 30th LP develops near Brittany 1000mb linking to the Baltic LP with a cold NE-ly mostly affecting England. There follows a week with the LP back over Scandinavia  and Britain again under light N-lies. From Wed 6th there is more action with LP from the Atlantic over or close to Britain (Thu 7th 985mb SW approaches, Sat 9th 965mb NE Scotland, Mon 11th 970 mb N Ireland with increasingly strong Arctic feed. Then a switch to HP Wed 13th 1040mb in the Channel with strong SW-lies for Scotland. Quite different from yesterday's 00z and also from the 18z, the latter having an interesting sequence of 'slider' LPs, so the model is struggling!

ECM - begins to differ from GFS Op as early as Mon 4th when a small LP 1000mb slides across Brittany and a strong rise of HP behind; by Fri 8th this has become a block from Spain to Finland, Britain at first getting mild S-lies but by that Fri those S-lies have been fed by returning Polar Maritime air.

GEM - similar to ECM

GEFS - remaining cold or very cold with moderately good ens agreement to Thu 7th (a few runs have a milder outcome from the 5th) after which considerable variation. The mean stays near norm but e.g. the op swings from mild to cold and the control just the opposite. Chance of pptn  gradually increasing , most likely around Sat 9th in the S, a couple of days later in Scotland.

Snow row figures very high for the NE at first but minimal amounts of snow to go with that; otherwise no great chance of snow.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
+5
ballamar
28 November 2023 08:09:38
Shows how volatile it is at the moment - big step towards milder today. Reckon by the evening it will look different- not necessarily colder but the pattern. Hopefully the 6z will give some cold hope for Dec
BJBlake
28 November 2023 08:31:58

Shows how volatile it is at the moment - big step towards milder today. Reckon by the evening it will look different- not necessarily colder but the pattern. Hopefully the 6z will give some cold hope for Dec

Originally Posted by: ballamar 

Just about sums it up. Last night’s 18z outlier was pleasing eye-candy, but the trend looks like a stronger zonal jet is coming. The current amplification might well be recurring theme though. However, plenty of runs say otherwise, so we’ll enjoy this week and see how these runs develop before we are forced to accept advent as being a boringly mild mud and muck fest.
Brecklands, South Norfolk 28m ASL
Gusty
28 November 2023 08:39:09
A new signal picking up our good friend 'higher heights to the south' around 144 hours appears, for now, to be the catalyst for the return of a more Atlantic based weather pattern next week. All conjecture for now. (as was that Arctic High and -25-30 air appearing to the far NE last night).

Until then we have the best part of a week with 850's wobbling in that -6c to -7c range under a slack set up after the Thurs/Fri period that offers wintry potential down the eastern half and dare I say parts of the SE of the UK. Cheeky little features as seen on yesterdays GFS have the potential to offer surprise localised events in this set up feeding off our warm maritime waters in the arctic based light steering flow.

 
Steve - Folkestone, Kent
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