Model Output Discussion - Snow for some, but what else is in store?

[Garthvader]

Seems there hasnt as yet been a peak with the ssw in play!

[carinthian]

1 hour ago, carinthian said:

Defo up grade from UKMO regarding depth of cold. Much lower 850mb temps values shown by Friday even down to the south coast. Signs of cold air advection  out of Northern Scandinavia by end of run. Should be interesting to see the fax charts when updated. The lower temps more widespread over the North of the UK mid -week.  Could be some interesting weather to develop . GFS keeps less cold uppers out to 144t. See where ECM run goes . 

c

Latest UKMO fax at 72t , keeps things interesting. The frontal divide across Northern England a little further south on this out -put. Potential for a lot of snow on the high ground of the Northern  England , say Morecambe Bay to Scarborough and possibly at lower levels  by Thursday. Much of Scotland to remain on the colder side with the main activity further south .  Mild start for the south but should turn colder later on Thursday. Just a thought as to whether adjustments further south will occur over the coming days ? Should have an update tomorrow morning when the team are back in business. Those blown up Lows on ECM would call for Noah Ark constructions for the rain sodden south, hopefully not !

C

[Methuselah]

This thread's starting to do my 'ead in!

I know that Snowmageddon, at least in the immediate future, has locked itself firmly in the wardrobe -- but, really: oh yes it is, oh no it isn't (which would of course be a whole lot easier, were I able to discern the latest 'upgrade' from its doppelganger, the latest downgrade)

Aaaaaaaaaaaaaaaaaaaaaaaaaargh!

But, on the other side of the coin, what would this thread be like, were it only 'deemed' suitable for dry, reasoned scientific debate? Zzzzzzzzzzzzzzzz?

[chris55]

A few tweaks to the shape of the trough at 144 on EC and we would drag in a much much colder feed. Its not like we need to change an entire broadscale pattern, just elongate the trough a little....

 

Im still glass half full, as ever, but need to see a few more op runs going forward to see where the cold/mild boundary finally settles going into next weekend.

[Singularity]

Attempting some intuition, I can make some use of the ECM day 10 chart, as I think it's not a bad effort at what sort of thing may happen across the UK - it's just that we could well see some adjustment south.

The thinking here is that without a really strong jet stream, long stretches of uninterrupted flow across the North Atlantic are at a reduced probability. There's more likely to be small-scale disturbances making the flow more 'wavy'. 

That would then reduce the efficiency of 'pumping up heights' to our south i.e. the build of a ridge would be less.

Yes, this is speculative but I feel it's worth putting forward, based on how the models tend to behave in the 6-10 day range in general - but especially when there's a south-shifted jet stream. It may come to nothing but at this time, especially considering that GFS(P) 12z, I feel that there's a decent chance of staying on the cold side of the boundary as far south as the Midlands. Still some chance south of there too but it's looking a big ask!

If we can secure more of a ridge to our west UKMO-style, that will be helpful the trough will be slowed, giving more time for small-scale disturbances to develop. Not feeling so positive about that one though - we've recently seen GFS try that only to back off again.

[Cleeve Hill]

4 minutes ago, MATTWOLVES said:

Can't really agree with that mate...I respect your opinion of course,but firstly the initial SSW may not have impacted us,but we possibly have the outcome of a secondary warming...which COULD influence us more next time..The vortex is an a sorry state,and the NH still looks primed to blocking for me..I certainly can't see a raging Swtly getting going anytime soon..The models are all over the place beyond day 5 or 6,and its only gonna be foolish in making predictions at day 10 and beyond based on the GFS and many runs.Plenty of scope for improvement.

70% of the time SSW's provide colder weather for the UK. 

This one is an on-going event no signs of a return to the usual westerly regime. If you look at Scandinavia & Europe there's been a lot of cold and BIG snowfalls across the Alps. 

It that exclusively down to the SSW, probably not and its only now the effects of the SSW are being seen at the surface. 

[BLAST FROM THE PAST]

14 minutes ago, WINTRY WALES said:

Not lookimg good is it Chino

I think it’s looking better than yesterday.  Next proper review for me is on Tuesday.  T120 could be an interesting marker today

 

BFTP

[mb018538]

It’s just a pain in the backside that both a +NAO and -NAO pattern end up being wet for the UK. 

10 day accumulated ppn charts show 2-6 inches of rain (W/NW worst hit), so people should stop worrying about the snow and worry about more flooding!

[Anthony Burden]

Charts showing as Met office 30 day but still all depends on the tracking of lows across the Atlantic.

Still possible for Greenland high to strengthen and send lows further south and change things substantially.

That of course is in fantasy island.Second SSW though weaker can have an influence

 

[Timmytour]

19 minutes ago, E17boy said:

I think from the output the writing is on the wall. Unfortunately the jigsaw has not been our friend that high in the north is in the wrong place for us to achieve the cold we are hunting. Looks like as I suspected earlier the last 2 weeks of January of bringing some hope to us is at a distance. Instead we are now staring into the barrel of the Atlantic and some kind of weather from the SW.

I think a lot of hope was pinned on the SSW and I put my hands up to being guilty there as well to some extent. The SSW can only be a benefit to us if all the blocks fall into place. Unfortunately I think being realistic we have to say we have missed the ticket this time.

We still will have 4 weeks of February and some part of March left in our favour to have a chance to catch something worthwhile, but looks as if that clock will begin to tick now and time will not wait for us where we want it to. The ECM may be wrong and tomorrow we may see another flip but for now no bumming around the horizon seems to have darkened for us coldies. 

 

It has to be remembered that an SSW can be a hindrance.

While we would normally expect one to invigorate our hopes of cold snowy weather in a pattern that was otherwise shaped to deliver relentless south-westerlies, it can, in a pattern already  geared up to deliver us great winter weather, disrupt that pattern and have the opposite effect.

I can't help feeling to date that this winter has been a little more of the latter, rather than the former

[Mike Poole]

2 minutes ago, Timmytour said:

It has to be remembered that an SSW can be a hindrance.

While we would normally expect one to invigorate our hopes of cold snowy weather in a pattern that was otherwise shaped to deliver relentless south-westerlies, it can, in a pattern already  geared up to deliver us great winter weather, disrupt that pattern and have the opposite effect.

I can't help feeling to date that this winter has been a little more of the latter, rather than the former

That’s true, but I also think it can be a mistake to think of a SSW as a random event, it isn’t, it is part of a long term weather evolution over what can be two months long, and they are all different.  The thing they have in common is the sudden warming in the strat and the wind reversal at 10 hPa and 60N.  So that underlying high lat blocking in early winter (which didn’t do us any good, by the way) that caused the SSW was part and parcel of the weather evolution as much as what is happening now as we see the effects. And they are still uncertain...

[MattStoke]

14 minutes ago, Cleeve Hill said:

70% of the time SSW's provide colder weather for the UK. 

This one is an on-going event no signs of a return to the usual westerly regime. If you look at Scandinavia & Europe there's been a lot of cold and BIG snowfalls across the Alps. 

It that exclusively down to the SSW, probably not and its only now the effects of the SSW are being seen at the surface. 

That’s when the polar vortex is split. It’s a much lower percentage for a displacement.

[Mike Poole]

ECM mean T240, mother of god, what is this?  

Disregard my previous post, it has gone to hell in a handcart!

For tonight at least.

[Griff]

11 minutes ago, Anthony Burden said:

Charts showing as Met office 30 day but still all depends on the tracking of lows across the Atlantic.

Still possible for Greenland high to strengthen and send lows further south and change things substantially.

That of course is in fantasy island.Second SSW though weaker can have an influence

 

Not for one second am I saying ignore the Atlantic, but keep an eye on the Pacific and Arctic beyond the reliable. Changes there would indicate potential impacts from strat to trop. 

[IDO]

Just now, MattStoke said:

That’s when the polar vortex is split. It’s a much lower percentage for a displacement.

...and of course if you bin the clusters of an SSWE based on certain parameters then that changes that percentage. As the Met suggested, this type of SSWE is more likely to bring in a SW flow than the 30% figure suggests.

The gfs, gem and ecm d10 means:

For all intent and purpose a very similar synoptic UK-wise?

 

[Vikos]

One must seperate the outcomes of a SSWE. Displacement or even Split. If Split, where is the axis? If displacement, where are the boundaries, how are the flows affected?

This actual SSW is a displacement, and ME/WE is at the westerly boundaries, so to say battleground of air masses. That's a bit of bad luck ATM, but with some minor warmings, may it will split...

 

  

 

See left down corner? Temp_max is raising

 

Edited January 16, 2021 by Vikos

[feb1991blizzard]

Has anyone seen this run from the CFS for March, run the whole month through, this would absolutely cripple this country with snow and cold, even allowing for surface heating being stronger in March, you could be looking at the coldest March of all time, it is quite spectacular, it would be one of the best months in my life overall, never mind Marches.

https://www.meteociel.fr/modeles/cfse_cartes.php?ech=1074&code=0&carte=1&mode=0&run=0

 

Edited January 16, 2021 by feb1991blizzard

[northwestsnow]

5 minutes ago, Mike Poole said:

ECM mean T240, mother of god, what is this?  

Disregard my previous post, it has gone to hell in a handcart!

For tonight at least.

I was banking on ukmo mate.

EC and its mean do not reflect Exeters recent updates.

We do need a flip urgently.

[Vikos]

4 minutes ago, feb1991blizzard said:

Has anyone seen this run from the CFS for March, run the whole month through, this would absolutely cripple this country with snow and cold, even allowing for surface heating being stronger in March, you could be looking at the coldest March of all time, it is quite spectacular, it would be one of the best months in my life overall, never mind Marches.

WWW.METEOCIEL.FR

---

Meteociel propose le modèle deterministe GEM

 

It updated the charts, but the gif is still good

Edited January 16, 2021 by Vikos

[Roger J Smith]

GFS mean wasn't as strong as the ECM at 120h but five or six of the thirty perturbations show something similar. The main difference seems to be that the GFS has one additional wave in the chain of them, and that robs the ECM feature of some potential energy, and reserves it for a slightly later time when on average it doesn't deepen as rapidly. But as I say, some of the variants are just as strong, one or two look further south as well, reaching peak intensity closer to the Midlands than northeast England. 

At the risk of being Capt Obvious, the further north or west you are, the more likely you're going to see snow from this, at least up to a point, maybe some places would be too far northwest, let's say a zone from Aberdeen to Glasgow to Belfast to Yorkshire arcing around the ECM low at this point has a fairly high risk of disruptive snowfalls, the arc further out than that has somewhat less risk. 

[Mike Poole]

3 minutes ago, northwestsnow said:

I was banking on ukmo mate.

EC and its mean do not reflect Exeters recent updates.

We do need a flip urgently.

Agreed NWS, UKMO must have this right at T144 or we are all condemned to a weather purgatory of nothingness for the rest of winter.

[Had Worse]

3 minutes ago, northwestsnow said:

I was banking on ukmo mate.

EC and its mean do not reflect Exeters recent updates.

We do need a flip urgently.

More so if the winds end up from a SW source.  Major flooding would be on the cards given very wet forecast currently and beyond.

[David Haines]

11 minutes ago, Mike Poole said:

That’s true, but I also think it can be a mistake to think of a SSW as a random event, it isn’t, it is part of a long term weather evolution over what can be two months long, and they are all different.  The thing they have in common is the sudden warming in the strat and the wind reversal at 10 hPa and 60N.  So that underlying high lat blocking in early winter (which didn’t do us any good, by the way) that caused the SSW was part and parcel of the weather evolution as much as what is happening now as we see the effects. And they are still uncertain...

Not related to the ssw but i thought the same when it looked like it should all be falling into place on the models in december but no really cold air was near us us to tap into, but if there was cold air to tap into the weather patterns would of often probably not allowed what was showing with stronger temperature gradients... 

[swfc]

6 minutes ago, northwestsnow said:

I was banking on ukmo mate.

EC and its mean do not reflect Exeters recent updates.

We do need a flip urgently.

The UK would probably join the ec in later frames along with gfs. Not a given but a probable outcome. 144 hrs most output isn't dissimilar imo. Hope I'm wrong tho 

[Methuselah]

Another rather uninspiring set of GEFS temp ens:

    

But, unfortunately, the do tend to back up the recent northward shifts in things...?