Model output discussion - Winter has arrived and the hunt for cold is on

[frosty ground]

1 minute ago, Weathizard said:

Its a 24/36 hour transient period for favoured areas, IMO that’s pretty normal winter for the UK. Nothing sustained or cold enough for a cold spell at low levels across most of the UK at this point, subject to change of course.

Yeah we get that setup every year.

[mb018538]

The only good thing about that horrible Canadian vortex is that it's aligned NW-SE rather than the usual W-E, so the air stays pretty cold.

It's still frustrating though, this chart could lead to something special but for that 'orrible lump to our NW:





Cold enough for snow at elevation, but I suspect nothing at lower levels.

[Weathizard]

2 minutes ago, frosty ground said:

Yeah we get that setup every year.

You realise this is a cold rain chart? Aside from high ground in the north. Oh and the GFS always overplays the cold coming from the NW it’s almost always modified more.

To me given the way the Azores high is displaced out west I’m going to be very disappointed if we can’t at least get a half decent ridge up into Greenland at some point, as usual the energy around the eastern seaboard just will not play ball.

[Skullzrulerz]

In general GFS is only slightly better then last night but it's miles away from what showing the last few days... 

It's either pushed back further or has been wiped out

It's hard to believe overnight we're gone from a harsh cold spell to a topper but it was somewhat expected with seasonal forecasts mostly stating a cold spell around mid month

Unless things start changing soon I can't see anything noteworthy yet

Edited December 4, 2019 by Skullzrulerz

[frosty ground]

1 minute ago, Weathizard said:

You realise this is a cold rain chart? Aside from high ground in the north. Oh and the GFS always overplays the cold coming from the NW it’s almost always modified more.

To me given the way the Azores high is displaced out west I’m going to be very disappointed if we can’t at least get a half decent ridge up into Greenland at some point, as usual the energy around the eastern seaboard just will not play ball.

Specifics at this range is pointless

A few facts about this run.

More amplifications around day 7 compared to 0z
Mild sector getting squeezed out compared to 0z
Cold uppers with embedded cold surface conditions compared to 0z

Snow possible almost anywhere

This run sits well within the envelope of outcomes. 


 

[mountain shadow]

Just now, frosty ground said:

Specifics at this range is pointless

A few facts about this run.

More amplifications around day 7 compared to 0z
Mild sector getting squeezed out compared to 0z
Cold uppers with embedded cold surface conditions compared to 0z

Snow possible almost anywhere

This run sits well within the envelope of outcomes. 


 

That is a pretty dubious comment I think. I see nothing offering widespread snow in the next ten days and I'm in a location which is likely to do better than most from a transient North or North Westerly flow.

[frosty ground]

Just your typical winter chart with a southerly tracking jet cold uppers, embedded surface cold especially the further north you go and lots of moisture.

 

[frosty ground]

2 minutes ago, mountain shadow said:

That is a pretty dubious comment I think. I see nothing offering widespread snow in the next ten days and I'm in a location which is likely to do better than most from a transient North or North Westerly flow.

i never said widespread snow , I said there is possibility of snow almost anywhere. not going to go into specifics when its gonna change on the Macro level never mind the Micro level run to run.

One random chart for the time period I was discussing

Snow shown falling around north coast and the south coast

Edited December 4, 2019 by frosty ground

[northwestsnow]

6Z shows cold shots inc a colder 2 day northerly and goes onto produce plenty of snow for the North later..

granted it is FI and the uppers are only about -4 it still produces..

 

[Tim Bland]

I can see the express headline now..”Polar Vortex to batter Britain with a snowcane 

[swfc]

5 minutes ago, Weathizard said:

You realise this is a cold rain chart? Aside from high ground in the north. Oh and the GFS always overplays the cold coming from the NW it’s almost always modified more.

To me given the way the Azores high is displaced out west I’m going to be very disappointed if we can’t at least get a half decent ridge up into Greenland at some point, as usual the energy around the eastern seaboard just will not play ball.

Yes it's ok with altitude in the north etc.the run is close but without the heights or"wedge" to drag the ah up looks wet,cool-cold.im not a fan of Atlantic moderated 850s but you get what your given I guess.

[Man With Beard]

EC clusters: At D8, other ensembles are generally more amplified than the OP run:

Particularly clusters 1 and 2, which contain 63% of the runs - by D9, these clusters drop the trough further into Europe, leaving the UK on the cold side:

So plenty of water to go under the bridge before we firm up on week 2.

It's a fairly short cold snap next week (if it happens), but signs are there by D15 that the trough will try, again, to dive into Europe:

(If you use the link 

Spákort gert á VÍ

BRUNNUR.VEDUR.IS

and scroll through the timescales quickly, you can see this move by the Atlantic trough towards Europe more clearly) 

[booferking]

So as it stands no snow 120hr/144hr in the semi reliable time frame except for North Scotland.

[northwestsnow]

One has to say, hills across N Britain could be very very snowy in the run up to Christmas.

A lot of Polar maritime air involved in the latest GFS/EC...

[snowstorm27x]

24 minutes ago, Mr Frost said:

I will take snowfall this early in Winter anytime...whether that be for 1 hour, 24 hours or beyond! 
 

Even big @Steve Murr has a chance of a Kentimeter or two on this run down in New Ash Green. 

The risk of wintry weather from next Tuesday is a consistent theme currently and this applies to many parts of the UK and Ireland. 

Not a bad start to Meteorological Winter (if it does indeed become reality) and also makes for interesting/exciting model/charts/outlooks viewing. 

It’s the most wonderful time of the year...

Yh mate us Midlanders were Snow starved last year I would take a one day cold spell if it gave us a flake lol. Oh the Joy's of being a Snow freak lol.

[LRD]

6 minutes ago, Man With Beard said:

EC clusters: At D8, other ensembles are generally more amplified than the OP run:

Particularly clusters 1 and 2, which contain 63% of the runs - by D9, these clusters drop the trough further into Europe, leaving the UK on the cold side:

So plenty of water to go under the bridge before we firm up on week 2.

It's a fairly short cold snap next week (if it happens), but signs are there by D15 that the trough will try, again, to dive into Europe:

(If you use the link 

Spákort gert á VÍ

BRUNNUR.VEDUR.IS

and scroll through the timescales quickly, you can see this move by the Atlantic trough towards Europe more clearly) 

I don't trust pressure anomaly charts much but even up to the 19th Dec there are pretty clear signs that the jet wants to stay south of the UK

[Mr Frost]

That is one of the most insane GFS fantasy Island runs I have ever seen. (And there have been many )

At one stage there is 27 to 30 hours continuous snowfall for parts of Scotland - just need to count this down now into the reliable! 

Marginal snow events galore on this (for many of us) but they have delivered big snowfalls over the years - would take a Winter of that! 

As ever let’s see what becomes reality when the time comes. 

Edited December 4, 2019 by Mr Frost

[tight isobar]

I've counted 8/9 probable snow events for the UK as a whole in the 6z start-finish..

Most of a transitional nature..but I'm highlighting for note...that brutal cold isn't necessarily the be ALL for that notion..

 

Not to say as we are in somewhat of a stalemate juncture atm via modelling...that deep/notable cold isn't an option..dynamics/diagnostics...can and will change.

And certainly there is a case for that...even as where we currently are/stand...

 

Over to the supports...and next suites....keep em coming

 

Edited December 4, 2019 by tight isobar

[Iceaxecrampon]

23 minutes ago, Tim Bland said:

I can see the express headline now..”Polar Vortex to batter Britain with a snowcane 

....memories of 2010  

Same day too.

[Methuselah]

Sometimes I think that attempts at forecasting 'IMBY-snow' at day 16, have a similar success-rate as what using quantum mechanics to decide how to bend a free-kick around the wall and into the top left-hand corner might have...The information you require simply does not exist...Not at the scale you'd need, anyways...?

[StretfordEnd1996]

35 minutes ago, Skullzrulerz said:

In general GFS is only slightly better then last night but it's miles away from what showing the last few days... 

It's either pushed back further or has been wiped out

It's hard to believe overnight we're gone from a harsh cold spell to a topper

Unless things start changing soon I can't see anything noteworthy yet

In all fairness I don't think in realistic terms there was ever going to be a 'harsh cold spell' really - only the GFS showed this through various runs over the last 2 days most of which were outliers (or at least on the extreme cold end of the ensembles). I think anyone that was given the impression a 'harsh cold spell' lasting 5 days or more next week was always barking down the wrong tree

A good Northerly lasting a few days was always the most credible option for me and to an extent that is what's being shown in the models this morning - though it's just a standard affair really (nothing spectacular, nothing too shabby)

Still a lot to play for without question - often when the models 'backtrack' on a cold spell it results in virtually nothing being shown for us at all but that's definitely not the case this morning.

Still looking at a period that's 7-10 days away and I think that period could well still bring wintry weather to a good portion of the country. Upgrades could still happen before then.

I'd bank this setup at anytime for the first half of December.

ECM also still seeing it

Now this Northerly is modelled to happen around Thurs/Fri next week - this has always been the case, so it's still over 7 days away - some people have mentioned that they seem to think its constantly 'hanging' at D10 but in reality it isn't 

I think we'll know for fact in 48 hours as to whether it's going to happen or not (though not how potent it may be)

My basic feelings though this morning is as I mentioned - a lot of downgrades overnight but still a huge amount to play for (mostly after D7)

Edited December 4, 2019 by StretfordEnd1996

[feb1991blizzard]

The 6z mean is another downgrade on the 850hpa temps on the face of it but- i have only been up to around 5 and plucked a few more randomly out but looks like 2 distinct clusters to me - some bring the -8c quite far South, some completely implode and barely have the -4c to -6c in Scotland.

Edited December 4, 2019 by feb1991blizzard

[shaky]

6 minutes ago, feb1991blizzard said:

The 6z mean is another downgrade on the 850hpa temps on the face of it but- i have only been up to around 5 and plucked a few more randomly out but looks like 2 distinct clusters to me - some bring the -8c quite far South, some completely implode and barely have the -4c to -6c in Scotland.

Big 12zs this evening!!can we go back to what the models were showing 24 hours ago or continue in this depressing vein!!we want that shortwave in the atlantic at 120 hours to be really slack or so deep it sends more waa ahead of it!! Unfortunately whats gona happen is its gona get stuck in 2 minds and we probably end up really flat again!

[weirpig]

Ensembles     For Brumish area     Still showing a few that shows  wintry weather this far south.  It also as most have alluded to  shows the brief cold snap before a slight recovery    however still not to be sniffed at 

[StretfordEnd1996]

GEFS ensembles a tad on the disappointing side for me - though looking at it a different way perhaps it just adds to the uncertainty regarding next week now (especially days 7-10)

There's nothing overly wintry of note until D8 (aside from perhaps a snow-rain event around Tuesday?) and then after D8 is when the fun starts - we have a chunk of members including the op really going quite cold within the uppers, but then there are some that aren't as interested. Around D8-10 this is about a 50/50 split almost. 

Thereafter I seem to get the feeling that there's a steady recovery which suggests any cold spell may be a tad short lived - and beyond D10 there's actually a notable number that really want to go pretty mild

But still, D7-10 is where its all to play for - its completely plausible that we could see snow widely across the country but its also plausible that we could see very little