Model Output Discussion 01/09/17

[tight isobar]

Not reload...

Overload..

When ec-starts smelling uppers its always a good thing...

And the daddy is taking the motherload..

Just the only annoy' is jet profile..

But thats a way off and dependant on variant!

Edited November 25, 2017 by tight isobar

[frosty ground]

2 minutes ago, karlos1983 said:

Reload then.....sigh 

Very much so but this has been on the cards for a while all we are seeing variations on the same theme 

[northwestsnow]

9 minutes ago, Geordiesnow said:

It does look like the Northerly will fizzle out after a few days but I think this has kind of been projected in previous runs also somewhat, its what happens after that is a massive uncertainty. Its ashame any Atlantic high may not last too long but as I said earlier on today, I still would not rule out the high in the Atlantic holding out for longer than we might think.

An Atlantic high was never going to last more than 4or5 days...what we are seeing on EC tonight is best case scenario ...imho of course

[feb1991blizzard]

8 minutes ago, nick sussex said:

Very good point made Feb , that’s why I’d rather the models went for the Scandi high because that’s easier to get through from where we start than the retrogression .

We don’t want half measures.

Problem with the scandi high though Nick is that to me it looks a lot more complex to avoid derailment where as the retrogression could mean we end up with a Northerly and topple to a scandi anyway and also looks less fraught with danger and more likely to materialise, also uppers wise it looks decent but nothing spectacular whereas a 2nd Northerly would deliver this time.

EDIT : yuk, maybe I was wrong, wouldn't fancy that 240 retrogression.

Edited November 25, 2017 by feb1991blizzard

[Geordiesnow]

One thing the ECM shows is that even if the Atlantic high does start to collapse, we can still stay on the cold side of the jet, its an interesting if rather complicated middle part of the run. I be more than happy for pressure to build over the UK locking in any cold airmass over the UK. That said, the forecast after midweek is still right up in the air and the next run will no doubt show something else, hopefully sticking with the cold theme.

[northwestsnow]

8 minutes ago, feb1991blizzard said:

The problem now is that Icelandic troughing at 192 we were willing on to move south with the retrogression to Greenland of the high, but now an Easterly is on the table its going to stop the cold getting right the way to the West and sustaining, we either need one or the other.

Feb can i ask what your expecting? The EC  is frigid!!! Enjoy it and relax !!!! 

[frosty ground]

Any one surpised?

[NorthernRab]

1 minute ago, frosty ground said:

Any one surpised?

That we look to be getting a reload?

If so then, yes.

[knocker]

17 minutes ago, That ECM said:

And not un blocked yer pays yer money yer takes yer chance.... 

 Oh I dunno, I don't like the look of a 100kt jet at 500mb south of Iceland on the ecm.

[feb1991blizzard]

1 minute ago, northwestsnow said:

Feb can i ask what your expecting? The EC  is frigid!!! Enjoy it and relax !!!! 

Don't know if you mean wanting or expecting, I'm Expecting max temps of 3 or 4c with nightime frosts and then something to get in the way of delivering potent cold with a dumping of snow, I want a dumping of snow and a week of daytime max's at freezing or below like we used to get every year when I was growing up.

[karyo]

The problem with the ECM is that it looks close to a northeasterly at 120 hours but somehow it loses its way before kind of finding it again. However, what it shows in the last few frames is less important than what happens in the middle (120-144 hours). If the 144 hours chart has 50% chance of coming off, the 192 chart has probably no more than 20%. 

[karlos1983]

I think you can be as philosophical about this as you like, bottom line is that the 12z today have been a bit of a disappointment. Yes it’s still going to be cold, no there isn’t an Atlantic about to crush through with a raging Jet, but it’s still not been a great afternoon. Is it fixed? no! Thank heavens 

Edited November 25, 2017 by karlos1983

[cyclonic happiness]

1 minute ago, feb1991blizzard said:

Don't know if you mean wanting or expecting, I'm Expecting max temps of 3 or 4c with nightime frosts and then something to get in the way of delivering potent cold with a dumping of snow, I want a dumping of snow and a week of daytime max's at freezing or below like we used to get every year when I was growing up.

Well, fridges are around 5'c so, it would be ok to expect that? 

[summer blizzard]

 

4 minutes ago, frosty ground said:

Any one surpised?

If that low keeps sinking due to the higher heights over Moscow then the result could be truly beautiful. 

[Frosty.]

Cracking Ecm 12z, plenty of cold, hardly any mild..feels like Christmas has come early for this coldie!

Edited November 25, 2017 by Frosty.

[Chesil View]

Just now, summer blizzard said:

 

If that low keeps sinking due to the higher heights over Moscow then the result could be truly beautiful. 

Quite so SB I'd be quite happy to thay low sink south or southeast with a pressure build over the top.

[Methuselah]

Right then, it's off to do some babysitting duty...Please don't throw bricks at NW's server while I'm gone?

[tight isobar]

3 minutes ago, summer blizzard said:

 

If that low keeps sinking due to the higher heights over Moscow then the result could be truly beautiful. 

Spot on.

And a 50/50 chance....

 

[Day 10]

A real positive to note is even when the models now and lately have wobbled the end result still seems to be cold and blocked, a good sign. Only viewing what's being posted as on phone but at least the Atlantic isn't charging through as per usual. Real fascinating viewing at the min and I wouldn't be surprised to see the wobbles replaced with upgrades in the morning.

[northwestsnow]

27 minutes ago, feb1991blizzard said:

Don't know if you mean wanting or expecting, I'm Expecting max temps of 3 or 4c with nightime frosts and then something to get in the way of delivering potent cold with a dumping of snow, I want a dumping of snow and a week of daytime max's at freezing or below like we used to get every year when I was growing up.

I cant recall many Decembers like you describe? 

I do agree with what you like but without wanting to drift off topic i think you have to factor in the warming globe we are living in.. :-)

[tight isobar]

9 minutes ago, northwestsnow said:

I cant recall many Decembers like you describe? 

I do agree with what you like but without wanting to drift off topic i think you have to factor in the warming globe we are living in.. :-)

Lets take this to pm.

Edited November 25, 2017 by Polar Maritime

[Tracy Flick]

The JMA at 192h keeps block-like:

 

Similar idea to ECM.

Edited November 25, 2017 by Ryerson

[Derecho]

Hello, thought I'd interpret the charts at different time steps and add my own personal rating to the output , I'll do this for the 00z and 12z when I've got time.

So for the 12z output today, no big changes at T96 but at T120 we have a consensus emerging that the block won't stick to Greenland and will sink back south. Not a huge surprise as it has been hinted at but I would like it to take a bit longer to pump more warm air further north into the arctic.

ECM T120                                                 GFS T120


Normally the high would just sink and we would go to cold and dry before an eventual return to westerlies but the Azores low means that the jet will remain quiet.

ECM T168                                                GFS T168


By T168 we end up with a slack northerly and there is actually pretty good agreement here between the GFS and ECM. It will be pretty cold at the surface during the early part of December, hopefully the UKMO will improve more.

ECM T240                                                GFS T240


By T240 we see that the high pressure slips away or breaks into two. The GFS shows a part sinking to Spain and the other moving towards Greenland. The jet coming out of Canada is absent at this point which is good. But we see high pressure to our South which is bad because that would stop cold from advancing towards the UK or leave the potential for a west based NAO. ECM however is a good deal better.

Overall next week is still looking cold but not particularly exciting either, some exposed areas could see wintry weather on Thursday and there will be air frosts. Though to get something greater will be more difficult due to the lack of retrogression in the medium term which is frustrating...but its still early days. Nothing amazing but pretty seasonal.

Overall here are my overall ratings for the 12zs upto T240

UKMO - 5/10 - We get some cold but not to the extent of the others, block sinks quicker and colder air to the NW is more organised so retrogression from here looks more difficult.
GFS     - 7/10 - Pretty good, cold throughout next week and a clean northerly on Thursday. Good build of pressure around NE Canada but I don't like the build of pressure over Spain
ECM     - 7.5-8/10 - The best of the bunch, heights build over Scandi allowing cold to last longer, has potential in later frames for another northerly. 

For context here is my scaling

1/10 - Bah! Ghastly relentless zonality or Bartlett's e.g. January 1989
2/10 - Warmer then average and little hope of that changing e.g December 2016
3/10 - Mix between mild and cold zonality not much prospect of blocking e.g. December 2014
4/10 - Some colder days at times and hints of potential on the horizon
5/10 - Cold weather likely but longer term prospects of sustained cold lacking e.g January 2017
6/10 - Some decent cold in the outlook though nothing exciting e.g. February 2013
7/10 - Potential for lowland snow in favoured spots  though not up there with the classics e.g. Early December 2012
8/10 - Good cold spell that will last for quite a while e.g. January 2013
9/10 - Very impressive, will be talked about for quite a while e.g. March 2013, February 1996
10/10 - Absolute classic sequence of weather! Big snow events and long lasting cold!! E.g. December 2010, January 1963, January 1987

Edited November 25, 2017 by Quicksilver1989

[phil nw.]

Inevitably with Atlantic ridging, rather than a standing blocking high(eg. over Greenland),means jet energy will sometimes spill through and at least temporary undermine it.After all ridging anywhere are just  pulses of sub-tropical air which ebb and flow hence we see the different wave heights across the Atlantic.

Looking at this evening's charts we see the next phase of ridging to our west which in tandem with a Scandinavian trough brings us a cold northerly over the coming few days.We see at day 4 the ridging on this occasion peaks around day 4 before gradually flattening.

However looking at the gefs and the earlier ecm means week 2 favours another bout of ridging in the Atlantic

Details after the northerly will of course change- as usual run to run- until modelling works out the extent of the next amplifying wave in week 2,ie.how much energy goes over the top.Added to this is the ridging out east and what effect this will have for the UK.At the moment this is locking us on the colder side of the Scandinavian trough as it can't progress further east.

 

[Summer Sun]

UKMO extended has a few showers scattered around but on the whole, it is dry with high pressure from Newfoundland right across to the UK