Model Output Discussion - New Year and Beyond

[KTtom]

Another possitive this week with crisp clearer skies, we should notice a difference, especially at night of an increase in daylight after the last few weeks of gloom. 

[January Snowstorm]

A high moving over us would finish off January I would think

Here's hoping it's transient 

[damianslaw]

1 minute ago, KTtom said:

Another possitive this week with crisp clearer skies, we should notice a difference, especially at night of an increase in daylight after the last few weeks of gloom. 

Yes, by mid Jan we do start to pull out of the long dark period evening wise at least, that starts preety much as soon as the clocks go back.. clearer skies at this time of year do make a marked difference, darkness not happening until nearer 5pm as opposed to before half 4 does make a difference, but its not until the end of the month we really start to see late afternoon light draw out. Still we are turning the corner and the light at the end of the tunnel is flickering brighter.

[Catacol]

EPS this morning painting a knife edge scenario

We have low pressure where we want it over Italy and we have a momentum pattern that is retracting, allowing (in theory) the pattern at high latitude to back west where eddies form. But any blocking that sets up near Scandy is perilously close to being too far south. Part of the cause, as BA has already correctly stated, might be the fact that - as movement towards a potential SSW gathers pace - the lower TPV is being forced towards Russia and acting against tropospheric forcing that I am sure favours heights in that area. Note however that some modelling is also splitting that low TPV as it is pushed towards Moscow

 

Short term pain for long term gain? Or short term pain on top of long term failure? U.K. cold weather fans could be excused for claiming that “if it can go wrong it will go wrong” - we will just have to wait and see. Those who have been on here a long time are hardened now to cold fails. But….the dice are still rolling on this one and I’m still seeing (as I always do) the chance of a double six. Scandy High = cold continental feed followed by SSW that drops a daughter vortex into Asia backing west. That will do fine and dandy thanks very much!

 

Edited January 15, 2023 by Catacol

[Lukesluckybunch]

lets face it looking at the models nothing looks prolonged or sustained at the moment..its going to be very hard for somthing like that to develop as the PV is currently looking too strong! best chance of somthing very cold would likely be from a easterly or somthing.we are not likely to see anything as cold this winter as we experienced at the start of december..that was quite exceptional!

[blizzard81]

16 minutes ago, damianslaw said:

Main thing to take away from the models for the foreseeable, is a change from a month of predominantly very unsettled atlantic driven weather to something much more settled and quieter as we see high pressure exerting greater influence once we lose the polar maritime flow by next weekend. Models are suggesting heights will be more southerly positioned at least to start with, and a return to mild conditions on the cards, though in clear spells frost will make a return. Further north more unsettled with a mild SW flow, rain or drizzle here.

In the short term - all eyes on whether any frontal/trough features pop up and bring surprise wintry falls. It is going to be a cold 4-5 day period ahead, not on the level of the Dec cold spell, but certainly below average with temps struggling to get out of the low single digits and sharp frosts for most. It will feel like mid winter.

We all know that in general thus far, this winter has not delivered for the vast majority. I think that will carry on unfortunately but hope I am wrong. On a much more positive note though, I will be relieved to see the back of the constant garbage of wind and rain. Absolutely horrendous. The worst return back to work weather-wise in 30 years of working. I will welcome a UK high with open arms. 

[MJB]

17 minutes ago, January Snowstorm said:

A high moving over us would finish off January I would think

Here's hoping it's transient 

Not sure I agree with that , get a high over us and it can trap the cold bring fog and frost - transient will move us back to the lovely wet and windy weather .

[northwestsnow]

3 minutes ago, blizzard81 said:

We all know that in general thus far, this winter has not delivered for the vast majority. I think that will carry on unfortunately but hope I am wrong. On a much more positive note though, I will be relieved to see the back of the constant garbage of wind and rain. Absolutely horrendous. The worst return back to work weather-wise in 30 years of working. I will welcome a UK high with open arms. 

It would be wrong to say there is no potential going into Feb but let's call a spade a spade, the TPV is exactly where we don't want it so with that in mind a period of HP near the UK eventually sinking from where I'm sat is the form horse.

And yes ,mid Dev to mid Jan has been horrific certainly locally its hardly stopped raining.

[blizzard81]

Just now, northwestsnow said:

It would be wrong to say there is no potential going into Feb but let's call a spade a spade, the TPV is exactly where we don't want it so with that in mind a period of HP near the UK eventually sinking from where I'm sat is the form horse.

And yes ,mid Dev to mid Jan has been horrific certainly locally its hardly stopped raining.

Indeed. One bit of hope is there is still a signal for the tpv to move away westwards from Greenland from day 8. 

[Catacol]

10 minutes ago, Lukesluckybunch said:

lets face it looking at the models nothing looks prolonged or sustained at the moment..its going to be very hard for somthing like that to develop as the PV is currently looking too strong! best chance of somthing very cold would likely be from a easterly or somthing.we are not likely to see anything as cold this winter as we experienced at the start of december..that was quite exceptional!

Undoubtedly vortex will be significantly weakened by 240h.

Much still needs to land favourably to advert cold towards us, but the negative impact of a steroid injected SPV with consequent impacts on the TPV is now time limited. Baby steps.

[mushymanrob]

33 minutes ago, Catacol said:

1980s SSWs =

Feb 79, Feb 80, Feb 81, Dec 81, Dec 85 (split), Jan 87. 6 SSWs in 8 years that had frequent cold spells. In the last 8 years we have had Feb 18 (cold that followed), Jan 19 and Jan 21 (chilly, very close to cold but didn’t quite land.) Three. Correlation is not the same as cause but the idea that the “cold” and seasonal 80s happened in the absence of strat action is not correct.

Pre 1979 data is much less available but there was certainly a Canadian Warming in Dec 62 and 8 warming events in total across the 1960s.

 

Not so sure thats strictly true though...

Febs of 79 and 80 occurred on the 22nd and 29th respecively, and werent really followed by anything other than a colder regime with the odd, short lived cold/snowy spell
Theres uncertainty on whether there was one in Feb 81, only the JRA55 has one, other suites dont and there was nothing very cold following...
Dec 81 probably caused the extreme cold of early jan 82..
Jan 87 (23rd) happened after the freeze earlier that month, and may have lead to further cold snaps, but nothing out of the ordinary?

Those from the 60's are equally as dubious, 2 of the 8 were in March and didnt lead to anything noteworthy

From the research ive done on SSWs, 1/3 have no impact on our weather, 1/3 may have been responsible for minor/localised/short lived cold spells, 1/3 were followed by a more wisdespread, longer lasting freeze of which 2013's / 2018s Beast From The East was probably the most extreme examples.

Id agree with the thought that "too much" emphisis is being put on them...

[Chesil View]

18 minutes ago, MJB said:

Not sure I agree with that , get a high over us and it can trap the cold bring fog and frost - transient will move us back to the lovely wet and windy weather .

I'm with you mjb  I would happily take a uk high for the last week of Jan before starting another snow chase.

I have recorded rain everyday so far in 2023 and will welcome some settled dry weather with open arms.

Plenty of time for wintry potential to appear as both Feb and March can deliver big on that front.  Especially if the pv is split or displaced via a ssw.

 

Edited January 15, 2023 by Chesil View

[Gowon]

8 minutes ago, Chesil View said:

I'm with you mjb  I would happily take a uk high for the last week of JN before starting another snow chase.

I have recorded rain everyday so far in 2023 and will welcome done settled dry weather with open arms.

Plenty of time for wintry potential appear as both Feb and March can deliver big on that front.  Especially if the pv is split or displaced via a ssw.

 

Feb - yes definitely.  March it has to be early and not last for too long. 

[Cymro]

Have we not got a PV thread? 

[alexisj9]

4 hours ago, syed2878 said:

 Interesting you mention the SSW, but if I’ve read Blue on Waze post regarding a split SSW that could do more harm than good not only that, but if you read the Met office 1630 day update it doesn’t look too encouraging for February by no means I am saying winter is over hell no way march 2013 was excellent for cold and snow.

Mostly looking like a displacement away from Greenland now, not a SSW. Just will it happen, and with it take the Greenland vortex with it.

[alexisj9]

1 hour ago, Gowon said:

 

Not very exciting but handy for drying out and getting out in the garden

Will have time to clear it for spring, if it's a warm high, I'm not gardening in the freezing cold. As the center looks near the se, no wind, I do expect fog and cold, but might be wrong. Haven't looked at day time temps yet 

[Gowon]

2 minutes ago, alexisj9 said:

Will have time to clear it for spring, if it's a warm high, I'm not gardening in the freezing cold. As the center looks near the se, no wind, I do expect fog and cold, but might be wrong. Haven't looked at day time temps yet 

That's what I had in mind

[Mike Poole]

6z HARMONIE looks to be very in tune with the Met Office snow warning for the far southeast, early hours of Monday:

Edited January 15, 2023 by Mike Poole

[Chesil View]

Latest Ukv for Tuesday morning will get us Dorset watchers raising an eyebrow or two

[Methuselah]

I don't know whether we'll be treated to an SSW in the coming days/weeks -- the models are still equivocal -- but such events have grown in prominence, these past 20-years or so. But, not, I think because they've become commoner, but because we seldom experience those potent northerlies and north-westerlies of yesteryear... IMO, without an SSW, the current rainy, sleety crud seems to be about the best we can hope for?

Edited January 15, 2023 by Ed Stone

[Mike Poole]

I think our longer term prospects for cold are in a bit of a state of flux at the moment.  I think that a scandi high as a longer term ‘destination’, which had been trending, is now receding as a possibility, more a transition towards possible heights further to the NW.  

Looking at the ECM mean, T192 and T360 - there is a trend towards retrogression of systems around the NH:

The consequences of this are varied, but

• The chances of a scandi high too far east, into Russia, are receding.
• The PV segment over Greenland, which some have been complaining about, looks to back west, giving us a bit more wriggle room there.
• The (approx) Ural high, Aleutian low signal (marked T192 chart), which has been present for some time now, will probably wane.
• This may mean that ‘fuel’ for causing the strat vortex pain may start to run out after 10 days or so, what we’ve had by then may be enough to cause a SSW, or maybe fall short.  Either way, the result is most likely to be a strat vortex displaced to the Asian side.  

I mentioned this retrogression signal yesterday in relation to the clusters, and again this morning, cluster 1 in the T264+ timeframe, shows high pressure on the move from scandi towards Greenland.

Bang on cue, the ECM control flirts with a Greenland high, T300:

I get the feeling we need some high lat block foothold before this shift happens, or it may be increasingly difficult to gain one as the help from the MJO (plus lag) disappears.  If there is a split SSW, that will be a different story, a displacement of the strat vortex will help, but we don’t want to be starting from scratch to build for cold in that scenario.  Interesting model watching continues, but I’m getting impatient to land something decent!

[Wetterfrosch]

3 hours ago, Penrith Snow said:

This winter is very different and with the El Nina signal of positive AO and NAO late winter I really don’t expect a notable cold spell in February 

Thinking back to the beginning of the season, didn't seasonal forecasts already see February as likely to be milder and wetter than Dec/Jan, see NW's own winter forecast. Without ruling out the odd short cold spell, it might well work out that way in general?!

[northwestsnow]

5 minutes ago, Mike Poole said:

I think our longer term prospects for cold are in a bit of a state of flux at the moment.  I think that a scandi high as a longer term ‘destination’, which had been trending, is now receding as a possibility, more a transition towards possible heights further to the NW.  

Looking at the ECM mean, T192 and T360 - there is a trend towards retrogression of systems around the NH:

The consequences of this are varied, but

• The chances of a scandi high too far east, into Russia, are receding.
• The PV segment over Greenland, which some have been complaining about, looks to back west, giving us a bit more wriggle room there.
• The (approx) Ural high, Aleutian low signal (marked T192 chart), which has been present for some time now, will probably wane.
• This may mean that ‘fuel’ for causing the strat vortex pain may start to run out after 10 days or so, what we’ve had by then may be enough to cause a SSW, or maybe fall short.  Either way, the result is most likely to be a strat vortex displaced to the Asian side.  

I mentioned this retrogression signal yesterday in relation to the clusters, and again this morning, cluster 1 in the T264+ timeframe, shows high pressure on the move from scandi towards Greenland.

Bang on cue, the ECM control flirts with a Greenland high, T300:

I get the feeling we need some high lat block foothold before this shift happens, or it may be increasingly difficult to gain one as the help from the MJO (plus lag) disappears.  If there is a split SSW, that will be a different story, a displacement of the strat vortex will help, but we don’t want to be starting from scratch to build for cold in that scenario.  Interesting model watching continues, but I’m getting impatient to land something decent!

Great Post Mike you are without doubt one of the " go to " posters on this site.

Thanks for your input it is very much appreciated.

[Chesil View]

3 hours ago, Penrith Snow said:

I think there is too much emphasis put on SSWs, winters were often cold and snowy between 1962 and 1987 but very few had SSW’s.

This emphasis on SSW is all down to the link identified with the BFTE in 2018 but the Trop that winter was already set up for HLB hence the cold spells well before the SSW occurred 

This winter is very different and with the El Nina signal of positive AO and NAO late winter I really don’t expect a notable cold spell in February 

Andy

You make an Interesting point Andy but I can't help but notice that the period you quote of 1962 -87  is prior to the latest undoubted bout of warming.   Hence the feeling amongst some is that for substantial deep cold  (as opposed to just bog standard chilliness) to be advected towards the UK. That an Ssw seems to be required as opposed to just helpful tropospheric set ups. 

You also quote the beast from the east as happening in a troposhere predisposed to cold but in truth that winter was running out of steam rapidly until yhe late Jan ssw kicked of the beast.

My feeling is that bog standard chilly spells such as early Dec 22 and the up coming week are still troposphericallly on the cards but for deep deep old fashion winter cold.  Ssw's are likely to become increasingly required.

Edited January 15, 2023 by Chesil View

[sebastiaan1973]

3 hours ago, Penrith Snow said:

I think there is too much emphasis put on SSWs, winters were often cold and snowy between 1962 and 1987 but very few had SSW’s.

This emphasis on SSW is all down to the link identified with the BFTE in 2018 but the Trop that winter was already set up for HLB hence the cold spells well before the SSW occurred 

This winter is very different and with the El Nina signal of positive AO and NAO late winter I really don’t expect a notable cold spell in February 

Andy

Well. The emphasis on SSW is, due to the changed atmosphere, where cold winter weather seems almost impossible with help of a SSW.