Model output discussion - is the beast awakening?

[Don]

2 minutes ago, saintkip said:

You say slight alternative, it’s gone from 20cm’s of snow to nothing, that’s a pretty big change

If anything that just goes to show we cannot take anything at that range seriously!

[MATTWOLVES 3]

1 minute ago, Continental Climate said:

I'm with crewe here we have had quite severe downgrades in the last 48hrs. There is no point in sugar coating this. The usual places will do quite well but those in the south and west will likely miss out here as the 850s have went from -12 to currently -8. I hope I'm wrong but don't think I will be. 

I'm pretty sure the output has improved over the last 24 hours,and ECM as actually improved this evening,and the mean as most definitely improved. So the latest output has improved and the met update has improved,yet some are still unhappy!! Just what does it take to make some happy...I give in...time out for me im gerrin stressed  

 

[Jason H]

1 minute ago, saintkip said:

You say slight alternative, it’s gone from 20cm’s of snow to nothing, that’s a pretty big change

It's a change out in fantasy land, yes. No change from the GFS in the overall set-up, which is cold.

[Matt H]

FWIW the GEFS 18z ensemble mean is an improvement out to t162 with the high pressure ridging further north over the UK. Hopefully this is the start of a trend that continues to improve tomorrow morning. 

12z:

18z:

Edited January 30, 2021 by Frosty Winter

[feb1991blizzard]

This next 10 day period to me smacks of both cold uppers, and heavy PPN, but never at the same time!!

[northwestsnow]

18z is excellent..

Cold shots snowy shots,icy shots....

Mild air rarely into the UK ..

[chionomaniac]

That’s an ok 18ZGFS gfs. It’s too early to see how severe or prolonged any cold will be and I am more concerned about getting the cold to our shores at this point than anything else. We know that with true cold outbreaks any mild breakdown gets pushed back when we are in the cold, but getting proper cold in first is the priority.  I think that the ECM will slowly nudge towards the GFS and vice versa to a lesser degree. I’d definitely rather be watching these Synoptics than a SW to NE jet racing across the UK, so will continue to watch with interest in the next few days.

[Tim Bland]

GFSp more in sync with GEFS bringing the cold air in on Friday...

[Mike Poole]

Sorry, but I’ve been quite bemused by this thread over the last day or so, all the talk of upgrades or downgrades is well beyond the reliable in a very uncertain situation.  There’s hyperbole by some, who to be fair have form for that. But a bit of realism wouldn’t hurt, would it.  It is a foggy road ahead and we can see the first few steps and they are now looking very promising, with the Atlantic and Arctic highs now virtually guaranteed to advect a cold pool to our east/northeast in a few days.  That’s phase 1.  And that looks solid now.

Phase 2.  Can we get a northern block in the right place to bring this in to the UK but sufficiently far north that there can be instability in the flow?  That is still totally up for grabs but well within the envelope of possibilities.  What more can you say, to firm this up it isn’t we need more runs, we need to be a couple of days closer to it to close down the uncertainty.  

Edited January 30, 2021 by Mike Poole

[Scandinavian High.]

4 minutes ago, Continental Climate said:

I'm with crewe here we have had quite severe downgrades in the last 48hrs. There is no point in sugar coating this. The usual places will do quite well but those in the south and west will likely miss out here as the 850s have went from -12 to currently -8. I hope I'm wrong but don't think I will be. 

Some folks are never happy this possibly coldest  spell of winter coming up if we don’t get -20 uppers so be it you don’t need them sort of uppers  for uk freeze.

[Icebox]

4 minutes ago, MATTWOLVES said:

I'm pretty sure the output has improved over the last 24 hours,and ECM as actually improved this evening,and the mean as most definitely improved. So the latest output has improved and the met update has improved,yet some are still unhappy!! Just what does it take to make some happy...I give in...time out for me im gerrin stressed  

 

With respect Matt... you have had your snow fix, many of us are yet to see a flake blowing in the wind!

[Day_9]

DONT PANIC CAPTAIN MANNERING SIR.

the trend is a nosedive and a decent one at that.  That is all so, feet up and occupy thine selves in readiness for a sustained bout of monkeys.

[Daniel*]

You don’t need to be Einstein to know that these synoptics can generate significant snowfall in SE.. -10C uppers brisk ENE wind in southeastern parts forget PPN charts they’re useless especially with convection. 

[Captain Shortwave]

8 minutes ago, saintkip said:

You say slight alternative, it’s gone from 20cm’s of snow to nothing, that’s a pretty big change

Considering all that snow comes from one frontal system pushing off the continent, an adjusted of 20 miles could mean the difference between no snow and a large covering. For reference see what happened last weekend.

The pub run is okay, it is more important to get some solid confidence on an easterly and the worry about whether there will be enough instability and cold to deliver away from organised disturbances or fronts.

[Allseasons-Si]

I have seen enough to know that it will turn colder towards the end of next week with high pressure to the N of the UK and trough going under in some form and degree,..this is where we stop micro casting from there,these hp cells are very notoriously difficult to pinpoint thereafter in where they are placed

i tend to stick with the anomalies to see if the trend is the same,...

here are the latest cpc anomalies 6-10/8-14 days out...

the upper winds do back westerly from NW'ly in the ext with prob a trough engaging from the Atlantic against the block to our N/NE so possibly some kind of snow event where these two air masses collide,...where though? 

[sunnijim]

These patterns historically seem to produce one of two scenarios playing out.

The Cold arrives quicker than advirtised ( we start to see Thursday as the start of 'cold proper' instead of the weekend) 

Or we are looking at a 'false start' at the weekend with mid February a more likely countrywide freeze.

Rarely does it seem to play out how we are 'seeing it evolve' 7 days away.

May seem like i'm 'stating the bleeding obvious'  here but I just don't see the following weekend being any sort of widespread snowscapes we are all looking for.

Would love the sooner option of course,but the 'feel' from me tonight having taken outlooks, tweets, model runs,and my own gut feeling is that we may need to wait a little past next weekend.

[Stu_London]

4 minutes ago, chionomaniac said:

That’s an ok 18ZGFS gfs. It’s too early to see how severe or prolonged any cold will be and I am more concerned about getting the cold to our shores at this point than anything else. We know that with true cold outbreaks any mild breakdown gets pushed back when we are in the cold, but getting proper cold in first is the priority.  I think that the ECM will slowly nudge towards the GFS and vice versa to a lesser degree. I’d definitely rather be watching these Synoptics than a SW to NE jet racing across the UK, so will continue to watch with interest in the next few days.

Fairly cold at the surface, but not quite as cold as a good few inches snow cover which would inevitable drag cold inverted air to the surface, which was on the menu 12Z

[kold weather]

1 minute ago, Mike Poole said:

 It is a foggy road ahead and we can see the first few steps and they are now looking very promising, with the Atlantic and Arctic highs now virtually guaranteed to advection a cold pool to our east/northeast in a few days.  That’s phase 1.  And that looks solid now.

Phase 2.  Can we get a northern block in the right place to bring this in to the UK but sufficiently far north that there can be instability in the flow?  That is still totally up for grabs but well within the envelope of possibilities.  What more can you say, to firm this up it isn’t we need more runs, we need to be a couple of days closer to it to close down the uncertainty.  

I think unless the ECM pulls a crazy win out here we have probably as a baseline this:

1: A LP pushing gradually S/SE between Thursday-Sun and cold air coming down.

2: Some sort advection of cold air from the NE/E between Saturday-Monday. This may well come with decent snow event chances, but impossible to know where at this point. Could be a short lived event though and drier IF the HP sets up too close.

3: HP moves into our neck of the woods as per the 18z GFS, or some version of that.

I'd say thats my baseline

HOWEVER we could well end up in somewhat better set-up, and the ensembles are not without some exceptional looking evolution it has to be said. Maybe not super deer cold, but more than enough for widespread snow event chances.

 

[Stu_London]

3 minutes ago, Daniel* said:

You don’t need to be Einstein to know that these synoptics can generate significant snowfall in SE.. -10C uppers brisk ENE wind in southeastern parts forget PPN charts they’re useless especially with convection. 

12z got the PPN far enough north

18z didnt

I thought it was perhaps a bit early for southerly corrections but hey ho - French nick our snow again

[Arrows1986]

4 minutes ago, Daniel* said:

You don’t need to be Einstein to know that these synoptics can generate significant snowfall in SE.. -10C uppers brisk ENE wind in southeastern parts forget PPN charts they’re useless especially with convection. 

That right there would  provide a snow train to the east and se

[Tim Bland]

GFSp brining widespread snow showers and streamers next weekend...

 

Edited January 30, 2021 by Tim Bland

[chionomaniac]

1 minute ago, Stu_London said:

Fairly cold at the surface, but not quite as cold as a good few inches snow cover which would inevitable drag cold inverted air to the surface, which was on the menu 12Z

Concentration for me would be on getting the major models agreeing on a cold outlook by day 5.  When that happens then perhaps we can look further down the line. Hope you are well stu

[Stu_London]

2 minutes ago, kold weather said:

I think unless the ECM pulls a crazy win out here we have probably as a baseline this:

1: A LP pushing gradually S/SE between Thursday-Sun and cold air coming down.

2: Some sort advection of cold air from the NE/E between Saturday-Monday. This may well come with decent snow event chances, but impossible to know where at this point. Could be a short lived event though and drier IF the HP sets up too close.

3: HP moves into our neck of the woods as per the 18z GFS, or some version of that.

I'd say thats my baseline

HOWEVER we could well end up in somewhat better set-up, and the ensembles are not without some exceptional looking evolution it has to be said. Maybe not super deer cold, but more than enough for widespread snow event chances.

 

good summary would add surface cold from whenever the cold arrives for the forseeable

[ICE COLD]

4 minutes ago, Captain Shortwave said:

Considering all that snow comes from one frontal system pushing off the continent, an adjusted of 20 miles could mean the difference between no snow and a large covering. For reference see what happened last weekend.

The pub run is okay, it is more important to get some solid confidence on an easterly and the worry about whether there will be enough instability and cold to deliver away from organised disturbances or fronts.

Yep the models couldn’t get the snow line right at T24 last week lol . A little shift north of this little mucker and it would be a white out . Anyway no point worrying about it let’s get the cold in first.

[Stu_London]

Just now, chionomaniac said:

Concentration for me would be on getting the major models agreeing on a cold outlook by day 5.  When that happens then perhaps we can look further down the line. Hope you are well stu

Hi Ed, I'm good - self-isolating at the moment - but I think I have managed to avoid - hope you are good too. 

Agree - I said FI was 72hrs in an earlier post and I might have been being generous. until these 3 battleground scerarios are resolved - it could change as they all impact whats coming down the line

Good overall pattern though