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Retron
15 November 2024 17:13:07


I guess other than that it's worth noting Monday/Tuesdays feature is a touch snowier in terms of areas seeing falling snow at least, with a definite back edge effort on this run. The area most at risk of seeing 'proper snow' seems fairly consistent although probably needs another day or so before confidence is high enough to be a bit more definite about snow risk from it.

Originally Posted by: Hippydave 


The back edge effect is mentioned in the SE text forecast  from the Met Office, although I'm not sure the wording they've used is quite what you'd expect:

Colder but mainly fine Sunday. Cloudier and windier with some rain Monday, probably giving way to a brighter, colder Tuesday, perhaps with a parting shot of wintry flurries on hills.

If anything it looks like the uncertainty has increased a little here in the south, with the GEFS offering anything from a quick end (as per the op GFS) to a longer block with a Channel low bringing snow, only to be repelled away southwards again.

It is, of course, exactly what we're used to in terms of trying to pin down a cold spell. The only difference really is that we're getting to do it before winter's even started, which is unusual. The areas in the Met Office's warning, i.e. higher ground up north, look much more certain in terms of outlook - there will be snow around, just not necessarily down here.
Leysdown, north Kent
doctormog
15 November 2024 17:14:21

Well the GFS op is rather 'meh' in the medium and long term, although good for low heating bills I guess!

Looking at GEM and GFS at T201 they're very different, so more twists and turns likely. 

Originally Posted by: Hippydave 


Your heating bills maybe. 😛

https://www.wetterzentrale.de/maps/GFSOPUK12_114_48.png 

https://www.wetterzentrale.de/maps/GFSOPUK12_162_48.png 

https://www.wetterzentrale.de/maps/GFSOPUK12_186_48.png 


Chunky Pea
15 November 2024 17:18:23
The longer range EC this morning was holding on to the cooler spell for longer than previous runs. 
Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Jiries
15 November 2024 17:19:31

Heating bills got worst under the HP gloom than unsettled weather that i was using less due to more sun out.  Glad next week no HP so sod off and like those link charts meaning more sunny days as it not under the HP.  Any snow that come here will give lower temps at night.
Chunky Pea
15 November 2024 17:34:29

Heating bills got worst under the HP gloom than unsettled weather that i was using less due to more sun out.  Glad next week no HP so sod off and like those link charts meaning more sunny days as it not under the HP.  Any snow that come here will give lower temps at night.

Originally Posted by: Jiries 


I find that when the sun is out during the dark season that it is colder than when the sky is overcast. There is zero value in it. 
Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Retron
15 November 2024 17:39:53
Incidentally the 12z GEFS control run is keen to prolong the cold, even if the op isn't!
Leysdown, north Kent
Chunky Pea
15 November 2024 17:51:50

Incidentally the 12z GEFS control run is keen to prolong the cold, even if the op isn't!

Originally Posted by: Retron 


GEFS (mean) the same. 
Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Chunky Pea
15 November 2024 19:24:26
I notice that WetterZ have dropped the ECMWF 360hr again, and TWO ECMWF charts limited back to 240hrs again. (at least as far as I can tell). Too good to be true! 
Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Polar Low
15 November 2024 21:09:20

I find that when the sun is out during the dark season that it is colder than when the sky is overcast. There is zero value in it. 

Originally Posted by: Chunky Pea 



Strange one thou CP Jires does have a point if you touch a southerly facing brick wall on a bright winters day in Dec/Jan im always surprised how much conducive heat/energy is taking place.

On ecm it is running to 360 imo probably very limited use
https://www.wetterzentrale.de/en/topkarten.php?map=2&model=ecm&var=1&time=336&run=12&lid=OP&h=0&tr=6&mv=0 

Snow Hoper
15 November 2024 21:22:01

I notice that WetterZ have dropped the ECMWF 360hr again, and TWO ECMWF charts limited back to 240hrs again. (at least as far as I can tell). Too good to be true! 

Originally Posted by: Chunky Pea 


Working for me, just loads later.
Going to war over religion is like killing each other to see who has the better imaginary friend.


Home : Thorndon, Suffolk.
Ally Pally Snowman
16 November 2024 06:55:32
Poor set of 0z has to be said. The snow looks to be a Northern England affair now and any longevity has gone as well.
Bishop's Stortford 85m ASL.
Joe Bloggs
16 November 2024 06:57:19

Poor set of 0z has to be said. The snow looks to be a Northern England affair now and any longevity has gone as well.

Originally Posted by: Ally Pally Snowman 


Iberian High at day 5 is where it all starts to go the shape of the pear   .. 
https://www.wetterzentrale.de/maps/ECMOPEU00_120_1.png 

Manchester City Centre, 31m ASL

Joe Bloggs
16 November 2024 06:59:56
That said - arguably we should all be praying for an Iberian High right now - they could do with a break in the weather ♥️. Our anticylonic spell has been absolute hell for that part of the continent! 

Manchester City Centre, 31m ASL

Joe Bloggs
16 November 2024 07:03:45
Latter stages of ECM are still very blocked, wasn’t expecting that . 

Manchester City Centre, 31m ASL

Brian Gaze
16 November 2024 07:10:13

I notice that WetterZ have dropped the ECMWF 360hr again, and TWO ECMWF charts limited back to 240hrs again. (at least as far as I can tell). Too good to be true! 

Originally Posted by: Chunky Pea 



12Z run out to t+360 was available on TWO. Access here:

https://www.theweatheroutlook.com/twodata/ecmhr.aspx 




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
Retron
16 November 2024 07:13:39

Poor set of 0z has to be said. The snow looks to be a Northern England affair now and any longevity has gone as well.

Originally Posted by: Ally Pally Snowman 


Yup, there's a definite shift this morning towards it being a typical 3-day cold spell here in the south, with the block failing to establish in such a way as to prolong the cold. The week 2 subzeros on the good old temp4 chart have gone too, of course, as it reflects the GFS op run:

http://wxmaps.org/pix/temp4.png 

I'm still hopeful that there'll be the first ground frost of the season down here, and an outside chance of an air frost. Any more than that would be gravy!

Quite different up north, of course, and it'll be interesting to see how the snow warnings are refined over the weekend.
Leysdown, north Kent
doctormog
16 November 2024 07:24:00

Yup, there's a definite shift this morning towards it being a typical 3-day cold spell here in the south, with the block failing to establish in such a way as to prolong the cold. The week 2 subzeros on the good old temp4 chart have gone too, of course, as it reflects the GFS op run:

http://wxmaps.org/pix/temp4.png 

I'm still hopeful that there'll be the first ground frost of the season down here, and an outside chance of an air frost. Any more than that would be gravy!

Quite different up north, of course, and it'll be interesting to see how the snow warnings are refined over the weekend.

Originally Posted by: Retron 


Looking across the model output this morning it seems like the NW of Scotland (or further north from here), perhaps N Ireland (mainly higher ground?) and northern parts of England (especially the Pennines?) may be the favoured areas for snow as things stand.

It will be bright, breezy and chilly for many other parts.

Looking at next weekend and beyond there seems to ve a large range of possible outcomes on offer, from cold to mild.
DEW
  • DEW
  • Advanced Member
16 November 2024 08:20:40
WX temp charts - week 1, the bloc of freezing air typical of Russia at this season has withdrawn there but leaving cold air over most of NW Europe, notably freezing over N Britain and the Alps. In week 2 the cold air surges forward again from Russia but is limited as milder air works up from the SW, to France, S Britain and W Germany. PPtn in week 1 mainly for Britain, France and the Baltic, becoming heavier and moving south in week 2 - Britain, France and especially Portugal.

GFS Op 0z - N-lies down the N Sea at first under the direction of LP over Finland, but on Tue 19th Lp develops runs SW across Britain to 985mb Holland bringing much more direct N-lies and unsettled weather. Another LP runs across Cornwall into France Thu 21st, keeping the N-lies going though these never really reach the SW. By Sun 24th the main LP near Finland has filled and moved NW, and a series of  Atlantic LPs are the main influence - Sun 24th 975 mb off W Ireland,  crossing Scotland and dragging in N-lies behind; Fri 29th 965mb off NW Ireland moving to Iceland; Sun 1st 980mb Portugal reaching the Channel the next day.

ECM - Not unlike GFS but the atlantic LPs are treated slightly differently; that on Sun 24th becomes much deeper (960mb) and stormier as it passes Scotland; but dissipating quickly to makes room for another LP from the SW approaches to reach the N Sea 980mb Tue 26th

GEM - less emphasis on the LP Sun 24th but that on Tue 26th is quite deep and cold as it runs up the Channel

GEFS - In the S, cold spell lasting to Sun 24th then switching abruptly to mild before slowly dropping back, fair ens agreement, and rain in most runs at most times; brief chance (1/3) of snow as the cold air arrives on Tue. In the N, cold air arrives sooner and is followed by heavier rain from 24th - fairly dry until then but any pptn probably as snow. Less certainty about any mildness after 24th.  The location combining heavy pptn with low temps to generate a heavy snowfall is NE England and down the E Coast on the 19th.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
AJ*
  • AJ*
  • Advanced Member
16 November 2024 09:54:48

...
Personally, I like Arpege for snow forecasting.

Originally Posted by: Brian Gaze 


Me too. I've found it remarkably accurate on some occasions.
Angus; one of the Kent crew on TWO.
Tonbridge, 40m (131ft) asl
doctormog
16 November 2024 10:37:25
So much volatility in the output at the moment. Snow, rain gales, storm surged, sunshine, very cold, very mild - all int the output for the coming week and beyond.
For example this chart from the 06z GFS op run has temperatures in the ease/southeast of the UK in the mid to high teens and heavy snow in the northwest of the UK. 
https://www.wetterzentrale.de/maps/GFSOPEU06_228_1.png 

DPower
16 November 2024 12:03:54
I do not know if this has been mentioned before but this upcoming cold spell and threat of widespread snow early next week and again towards the end of the week remind me very much of December 1981. The whole set up looks very very similar and although I know no to set ups are the same, personally I think we will see a gradual shift south of the low in the models over the next three days with the Midlands, Wales and southern England being at risk of seeing snow.
The synoptic profile looks very similar, I do not know what people's memories are like but during the infamous December the cold set in on the 7th with a low tracking southeast from the north Atlantic running across southern England bringing up to 10cm of snow in areas on the northern side of the low. This was followed 4days later with another low which tracked along the channel bringing up to 25cm of snow to some southern areas ( here in southern Hertfordshire we had 15cm). The latest 06z gfs run is toying with the idea of flattening, stretching and disrupting the low which would increase the chances of snow for the south.
The main differences between now and Dec 81 is that this is 3 weeks earlier, and also the sea temperatures that will have an impact on the direction the low will take but, I am confident we will see a move in the models for a more southerly tracking low during Monday and Tuesday.
Rob K
16 November 2024 12:54:09

Me too. I've found it remarkably accurate on some occasions.

Originally Posted by: AJ* 


Talking of Arpege, the 6Z run really winds up the low pressure as it exits into the continent, producing gale force winds with a chance of back edge snow over parts of East Anglia and the SE.

6Z GEFS too my mind look like a slight swing back towards prolonging the cold, although still very uncertain.
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
Retron
16 November 2024 13:06:34

Talking of Arpege, the 6Z run really winds up the low pressure as it exits into the continent, producing gale force winds with a chance of back edge snow over parts of East Anglia and the SE.Rob K;1610197


Yes, both Arpege and ICON are modelling one heck of a blow - 85+ mph gusts over East Anglia as the low pulls away for the former, and 100 mph (!) over Thanet in Kent for the latter... ICON has a broad swathe of 72+ mph gusts across many parts of England and Wales.

Needless to say, I'm hoping they've overmodelled it. Otherwise it won't be the snow that most people end up talking about!
Leysdown, north Kent
Chunky Pea
16 November 2024 14:28:56
The lack of the typically vigorous zonal westerlies has been remarkable this Autumn so far, and nothing really in the offing regarding these either. 
Current Conditions
https://t.ly/MEYqg 


"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
Retron
16 November 2024 15:42:47
Good to see the 12z ICON has indeed moderated the winds in our part of the world - still in the 70s, briefly, over East Anglia, but the 100mph winds have moved further east, battering the Netherlands instead.
It all depends, of course, on when (and indeed whether) the low undergoes rapid cyclogenesis... funnily enough the GFS was the first to pick up the potential, a few days ago, but thankfully it too has moderated things (winds in the 40s here, rather than 70s as it showed a few days ago).
Leysdown, north Kent

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