Model Output Discussion 01/09/17

[Met4Cast]

The fat lady is back from weight watchers and she's just turned her karaoke machine on.

I think we can kiss goodbye to any hope of a prolonged coldspell from this now. The trend is clearly for the Atlantic to burst through despite blocking over Greenland. It's gone from "Wow this is an amazing setup we just need to get the cold in" to "If that short wave doesn't do this thing then it's over"

Well, tonights ECM pretty much confirms it for me. Game over for this one. Lets hope December offers something of interest within T124 

[booferking]

Lots of flipping in the models another day or so to go until we get full agreement on this low by the way CFS says yes.

Edited November 14, 2017 by booferking

[knocker]

The gfs has post the weekend very unsettled and although the evolution is somewhat different so does the ecm

At 12 Monday the weekend disturbance is slipping south east whilst the HP ridges briefly to the west. But there is a major upper trough in mid Atlantic that stretches all the way down to Morocco, On the surface a very positively tilted trough with a very active surface front swinging south west of the Azores. The main llow tracks north east and by 12 Tuesday the active front has brought strong south west winds and heavy rain to N. Ireland and Scotland. This passes quickly through and by 12 Wednesday the low is just north of Scotland and the whole of the UK is in gale force north westerly winds, severe gales possible in Scotland with more heavy rain. Further complicated by another disturbance that has swung up from the same source (different trough) and is running across southern England accompanied by heavy rain, And another low is on the way next. Obviously this merely be noted at the moment but it's not without interest

Edited November 14, 2017 by knocker

[chris55]

Milder southerly airmass looks odds on in the mid term, as opposed to the potentially colder medium range outlook we were seeing a few days back. 

12zens highlight the firming up of the milder outlook, still some scatter and some colder runs not out of the question, but the overall shift is to move the colder air from the incoming high latitude block to far north and west to effect the U.K. 

 

 

[blizzard81]

Just now, booferking said:

Lots of flipping in the models another day or so to go until we get full agreement on this low by the way CFS says yes.

I would consider that another nail in the coffin lol

[Frosty.]

5 minutes ago, Daniel Smith said:

The fat lady is back 

Oh yes she's singing after viewing the Ecm 12z...and she hasn't even seen the latest Gfs  run yet!! There will be no stopping her

[nick sussex]

As much as I'd like to find a few positive crumbs in tonights outputs I think the prognosis for a decent spell of colder weather isn't looking good.

The big problem is the block is too far west and not orientated favourably with low pressure deepening to the sw as it engages energy from the ne.

Of the 3 the GFS is by far the worst in terms of salvageable by T120hrs the games up as the shortwave is much further north than the ECM/UKMO.

The UKMO is the pick of the big 3 with a stronger block and less energy to the ne with the shortwave cutting ese towards the Low Countries.

The ECM at least cuts the shortwave east further south than the GFS but then we see it hit the buffers after that.

We're still waiting to see what the UKMO at T168hrs shows but the only feasible way to see an improvement in the outputs is to see some energy from this shortwave circled to disrupt quickly towards Iberia this means your engagement point as the energy heads sw from the ne is further se.

 

 

[Tracy Flick]

The JMA at 192h gives breezy, unsettled, cool, returning polar maritime.  Seems to be the theme now.

 

[Mucka]

In reality there is no cold spell looming for the UK in the models this evening in the 10 day time-frame. only UKMO offers a straw.

Nothing to be downbeat about though as we are only just at mid Nov and hopefully there could still be a turn around or the prospect of cold being modelled for the last week in November.

[karlos1983]

20 minutes ago, Geordiesnow said:

Think your being optimistic there in all honesty, from what I can see, the models are in solid agreement on a west based Nao and perhaps a slider low heading through the UK but nothing is suggesting the UK will see NE'lies next week, that looks very much the outside bet and instead the weather will be milder as the case is with west based NAO's.

Its one of those in that if the first part of the jigsaw is wrong then you can scrap all the output which showed the cold NE'lies heading our way because that will just not happen under a west based NAO, infact its probably meteologically impossible. In fairness, all the models(apart from the UKMO but then that model showed something else at times) hinted at times we may see a west based NAO and some others shown an Atlantic ridge so the threat was always theren and unfortunately for cold lovers, its the former that is set to become the reality.

As ever with model watching things can alter again and details will still no doubt change but the trend is there I'm afraid.

You may well be correct, or I’m wrong, but I don’t really get hung up on that. What can not be ignored is the GFS and the UKMO made positive moves (if cold is your thing) towards a colder outbreak. ECM went the other way. 

Time will tell. I won’t lose sleep over it. 

[Geordiesnow]

7 minutes ago, Daniel Smith said:

The fat lady is back from weight watchers and she's just turned her karaoke machine on.

I think we can kiss goodbye to any hope of a prolonged coldspell from this now. The trend is clearly for the Atlantic to burst through despite blocking over Greenland. It's gone from "Wow this is an amazing setup we just need to get the cold in" to "If that short wave doesn't do this thing then it's over"

Well, tonights ECM pretty much confirms it for me. Game over for this one. Lets hope December offers something of interest within T124 

You see, the mentality is always seems to be that once the weather models shows mild then we can write off weeks ahead but despite the odds heavily favouring a west based NAO, nobody knows what could happen as the weather is always changing and this morning's ECM to an extent shows what could happen despite a west based NAO.

To give an example of how looking at the details of long range forecasting is kind of pointless, the ECM yesterday on both 00Z and 12Z runs showed an monster 950MB rounded low on the Pacific side of the Arctic at 216-240 hour range, today runs has nothing like that whatsoever.

Its interesting both the UKMO and ECM is going for a 1050MB Arctic high, may mean nothing for us but it'll be interesting how much this alters by this time tomorrow night and what affects that has on the output this time tomorrow.

[Northwest NI]

8 minutes ago, Frosty. said:

Oh yes she's singing after viewing the Ecm 12z...and she hasn't even seen the latest Gfs  run yet!! There will be no stopping her

It'll never verify. I'll wait til T24hrs before I'll believe it!

(reverse psychology)

[Met4Cast]

1 minute ago, Geordiesnow said:

You see, the mentality is always seems to be that once the weather models shows mild then we can write off weeks ahead but despite the odds heavily favouring a west based NAO, nobody knows what could happen as the weather is always changing and this morning's ECM to an extent shows what could happen despite a west based NAO.

Experience. Experience tells us this to be the case.

For the UK to not just get cold, but for snow as well so many things have to fall into place. The setup has to basically be perfect, especially this early in the season. So when the models go from showing the cold hitting the UK to showing mild Southerly winds and short waves all over the place, the chances of something actually happening to get a pattern we actually want is slim.

The "epic" charts haven't got any closer, they just get watered down until we end up not with cold, but milder/wetter/windier weather. 

That's exactly whats happened since 2012 and seems to be whats happening with this upcoming "cold spell". 

[Summer Sun]

UKMO at t168 has a southwesterly flow for the UK wetter the further west you are

[Daniel*]

32 minutes ago, Frosty. said:

I'm seeing lots of potential for a change to mild next week from the Gfs  / Ecm  12z, no point trying to sugar coat it. On the plus side, it's still autumn!!.

Since you’ve been on this forum for years, I thought you’d know better seems not. You can not extrapolate anything with OP that change run to run, only when it is consistent you can have some confidence of such. Nonetheless, quite rightly things are not trending the right way that’s not to mean, they can trend the other way. 

The UKMO this evening is good, however I’m not inclined to agree with it going by its recent performance. However, it has never been eager to develop something wintry we shall see as ever. My concern is that with the stratospheric vortex being stronger than average, with no indication of that in NWP yet, relatively soon it will filter down to the troposphere and oh boy we’d have problems. If we fail to develop blocking where it’s needed within this month - I fear December will be a complete write off for lowland snow, I’d see it being a zonal miserable month and there goes 33% of the winter. Where we are positioned we must grab at any opportunity we can get, like the upcoming one, failure to do so may have a truly negative impact on overall winter - particularly with La Niña does not favour backend cold whatsoever. While it is early days it may be make or break for winter 17/18. 

[Geordiesnow]

4 minutes ago, Daniel Smith said:

Experience. Experience tells us this to be the case.

For the UK to not just get cold, but for snow as well so many things have to fall into place. The setup has to basically be perfect, especially this early in the season. So when the models go from showing the cold hitting the UK to showing mild Southerly winds and short waves all over the place, the chances of something actually happening to get a pattern we actually want is slim.

The "epic" charts haven't got any closer, they just get watered down until we end up not with cold, but milder/wetter/windier weather. 

That's exactly whats happened since 2012 and seems to be whats happening with this upcoming "cold spell". 

But its a myth that if the models show mild set ups in the next 2 weeks then that what will happen because no matter what weather set ups we have, changes always happen in the atmosphere in the short term which affects the long term picture, this is more exaggerated with cold set ups as they are more complicated and we focus on them a lot more.

I have not personally seen any epic charts from this period of model watching but I have seen charts which suggested blocking and this look like this is what will happen in terms of a west based NAO and we seem to be in more agreement we may get a slider low crossing the UK but how this happens and what happens after that is not clear cut by any means although the odds of milder weather does seem to be more in favour especially with what this afternoon runs have shown.

[Man With Beard]

There's only one bet I'm going to place tonight, and that's to bet that we won't see conformity on all the op runs in the next 48 hours!!! We have a -AO and -NAO coming up, anyone who thinks the models have it nailed beyond D5 is very, very optimistic about their ability!!!

[markw2680]

Just because they show mild southwesterlys does not mean it’s gospel!! Couple of days ago was cold now mild, I’m pretty sure by Thursday there will be a completely different outcome showing for next week, haven’t got a clue what it will show but I’m pretty sure it will be different to now

[Walsall Wood Snow]

1 minute ago, markw2680 said:

Just because they show mild southwesterlys does not mean it’s gospel!! Couple of days ago was cold now mild, I’m pretty sure by Thursday there will be a completely different outcome showing for next week, haven’t got a clue what it will show but I’m pretty sure it will be different to now

Oh yeah, we all know tomorrow or the day after there's every chance more building blocks start popping up on some model and cheering everybody up again. Always happens whether it comes to anything or not.

[Methuselah]

2 minutes ago, Walsall Wood Snow said:

Oh yeah, we all know tomorrow or the day after there's every chance more building blocks start popping up on some model and cheering everybody up again. Always happens whether it comes to anything or not.

Aye, it's going to rain Lego bricks!

[Dennis]

there is time.....

[knocker]

The anomalies are pretty much saying the same as last night. so I'm not going to through all the spiel

The essential features in the Atlantic arena are the ridge into southern Greenland and Northern Canada, the trough south of this (which actually is a vortex lobe and shows up in a loop of the lower Strat at 150mb) and the trough to the south west in mid Atlantic and the other trough over Scandinavia. The high pressure has been relegated to a bit part

Not forgetting that some of the upstream energy is nipping around the ridge over N. Greenland en route to the Scandinavian trough but the main burst exits the eastern Seaboard as a strong westerly south of the trough, pays a quick visit the trough into the south west of the UK and swings W or NW over the UK. This would suggest some unsettled weather for the period with the temps edging above average.

The 150mb loop

http://weather.uwyo.edu/cgi-bin/model?MODEL=GFS003&TIME=2017111412&REGION=NHEM&FCST=all&LEVEL=150&F1=none&F2=none&C1=hght&C2=none&VEC=none

Edited November 14, 2017 by knocker

[blizzard81]

6 minutes ago, Dennis said:

there is time.....

When the models we've hardly heard of get wheeled out we know we are in trouble lol.

[carinthian]

Well there we have it folks. Latest ECM at 168t seems to be backed by UKMO now on their extended chart for the same time with isobar flow bringing air mass flow sourced way down in the tropics at 20N!  A complete turnaround from the charts shown this time last week. All my precious snow to melt according to the latest charts. However, based on present form, another complete flip in 7 days time more than likely.

C 

 

[Cheshire Freeze]

3 minutes ago, carinthian said:

Well there we have it folks. Latest ECM at 168t seems to be backed by UKMO now on their extended chart for the same time with isobar flow bringing air mass flow sourced way down in the tropics at 20N!  A complete turnaround from the charts shown this time last week. All my precious snow to melt according to the latest charts. However, based on present form, another complete flip in 7 days time more than likely.

C 

 

What is of most concern (to me) is the omnipresent limpet heights either to our SW, S or SE. It's almost as if they're consistently being displaced N towards our shores. We saw last winter just how stubborn these heights are.