Model Output Discussion - Spring Has Sprung

[andymusic]

 SLEETY agreed fight between the two air masses will go on for a while yet

[feb1991blizzard]

GFS 12z is a stonker.

[Weather vane]

 Jordan S hope you get some snow. Nice fall today across a fair bit of Ireland. Here in Dublin quite a bit !!

[feb1991blizzard]

GFS strat split backed up by eps which must have a majority cluster showing it.

[Gowon]

 Cheshire Freeze

Can’t say I’m surprised by this as March always looked nailed on for N blocking to take hold.

I swear you're cursed - the promising charts seem to disappear every time you post. 

[Cheshire Freeze]

 Gowon

Exactly why I’ve always erred on the side of pessimism. Every time I let myself get mildly excited about something and think positively, the rug is pulled!

I once had a mate turn around to me and say, straight faced, ‘I think you might actually be cursed’!

Edited March 1 by Cheshire Freeze

[WYorksWeather]

In a way it's almost surprising how flat the 12z ensembles are looking. The mean is just totally uninterested in any deviation. Standard early Spring conditions apply, I guess.

Nothing to see here...

 

[stodge]

 WYorksWeather That's not how it works though.

If you have 10 of something at +10 and 10 of something at -10, the mean would be zero but there is no actual instance of zero.

I look at those two diagrams and I see a lot of cold options balanced out by a lot of mild options.

That doesn't mean "nothing to see here" - what it actually means is there are a number of warmer and colder evolutions in the mix as you would expect in March which is typically a time when warmer and colder airmasses meet and co-exist close to the British Isles. At the moment, the number ans strength of the former and the latter are roughly in balance. 

That means uncertainty and a lot to be resolved both in the near term and especially so in FI.

[WYorksWeather]

 stodge Yeah I get that. There's plenty of interest in the models in that sense. All I'm saying is that it's not all that inspiring - and we're at a time of year where average conditions are a bit devoid of interest. In December average conditions still bring snow to quite a few people on high ground, and of course in summer average conditions can be quite pleasant. But at this time of year, most people are either (like me) looking for the first truly spring-like spells of weather, or still looking for one last push for cold and snow.

And if you take those ensembles and put a cut-off on them for what would look interesting, maybe +5C or higher at 850hPa for likelihood of anything spring-like, -5C or lower for a late winter spell (maybe even -10C as we go later into March), there are only a few outliers that get into those ranges.

[Don]

2 hours ago, Cheshire Freeze said:

Exactly why I’ve always erred on the side of pessimism. Every time I let myself get mildly excited about something and think positively, the rug is pulled!

Well, there's the answer then.  Stay bloody negative about cold/snow and it just might come to fruition!! 

Edited March 1 by Don

[Lukesluckybunch]

Ukmo day 7 wasn't expecting to be quite as good..let's hope it sticks with its output this time!

[Lukesluckybunch]

Control day 9!

[Lukesluckybunch]

Big run at day 8 coming up on the ecm.. will it slide and open the door to the freezer?..no the low moved north and ruined the setup!..

Edited March 2 by Lukesluckybunch
Adding

[Lukesluckybunch]

Day 10 ecm..I can't take much more of this!

[January Snowstorm]

I've a feeling this setup could upgrade yet! The ingredients are there, we just need things to align a bit better. It's not too late for disruptive snow, as was proved across Dublin yesterday

[Crackerjack]

To all the people saying no chance of southern uk snow now and upper air temperatures etc well here’s 2” of something this morning and still coming down (I’m at 150’ asl)

Edited March 2 by Crackerjack
Spelling slip up

[Lukesluckybunch]

32 minutes ago, Crackerjack said:

To all the people saying no chance of southern uk snow now and upper air temperatures etc well here’s 2” of something this morning and still coming down (I’m at 150’ asl)

Amazon scenes!whereabouts is frampton?

[Lukesluckybunch]

1 hour ago, January Snowstorm said:

I've a feeling this setup could upgrade yet! The ingredients are there, we just need things to align a bit better. It's not too late for disruptive snow, as was proved across Dublin yesterday

A few runs from this morning..look particularly interesting..in the days 7-10 timeframe!

[Jacob]

 Crackerjack I’m in the south and I just got rain

[C J]

Beautiful snowy scenes in Penrith this morning! ️

[Lukesluckybunch]

Already upgraded on the icon..a stronger hp over scandi.and the cold to the east is slightly closer!

[damianslaw]

UKMO and ECM both show the atlantic trough undercutting scandi heights, GFS eventually goes there, but heights then oriententate in a position that prevents cold uppers invading.

In these set ups its a watching brief, usually need to see such evolution within 72 hrs to have a guarantee of verifying.

However, spring starting on an interesting note if you don't like seeing the atlantic in full steam, we haven't seen such synoptics since late November. 

Spring traditionally brings highest likelihood of northerly and easterly airstreams. 

Edited March 2 by damianslaw

[Lukesluckybunch]

120 icon has -4/6 uppers..compared to 0z run..with 0.850's

[Mike Poole]

ECM clusters again flirting with the easterly in the T192-T240 timeframe:

Both clusters 1 and 2 take the low to the SW on a very southerly track, allowing flow from the east or southeast across the UK, or part of it.  Together these are 46 of the 51 members.  Still fluctuating suite to suite, to be honest, as yesterdays 12z had more mild solutions.  You’d feel that with the strat situation as it is, the trend would against the Atlantic option, though.

And as I said yesterday, if we do get the continental flow, it may require some patience before any significant cold air heads our way.   

[Cambrian]

A big battle ensuing on the 0z ECM op through to day 10 with possibly the best example of Atlantic trough disruption that we have seen through these colder months. 

The first cut-off is rescued at day 2 as it joins the Greenland trough, but the reformed trough is sent sharply into reverse, pushed west, through to day 4 or 5, as heights build through Scandinavia, on their migration west to Iceland. The second cut-off is paid in instalments between day 6 and 8, and this is firmly forced southeast around the southern flank of the heights.

  

The steady reappearance of some very cold air over Scandinavia, extending southwestwards is intriguing to say the least. 

The ensemble mean shows a similar trend, ending up with positive heights extending from Scandinavia deep into Canada. The very strong heights anomalies (in black) over Scandinavia during the next few days is a particularly notable signal. It’s looking like developing into proper Northern blocking across the entire Atlantic sector. 

 

Some interesting discussions about the value of ensemble mean charts. I agree that they’re not offering a likely solution in themselves, but then neither for that matter, does the op or any of the individual ensemble members past day 6 or 7. The clusters are useful, but there we are still working with a representation of the cluster and at a relative probability in terms of the whole ensemble that can at times be quite modest.

What the ensemble mean does give is an idea of the general direction of travel of the whole pack for that particular timeframe. When, like with the above, this is in broad agreement with the op, this provides support for the general evolution being modelled, in this case a quite striking trough disruption at the hands of impressive and sustained heights to the north, which is undeniably of value. 

Edited March 2 by Cambrian
Removal of the word “mean” before “representation” to take on board Mike’s comments below