Model Output Discussion - Colder spell ending, what's to follow?

[West is Best]

24 minutes ago, SLEETY said:

Nice ecm at the end, not much adjustment needed to put the whole of Europe in the Freezer

That really is a case of straw clutching I fear. The GFS 0z ensembles have a couple of wildly cold members, although in the interest of balance it needs to be stated that they also have the opposite. However, the ECM doesn't show anything other than an Atlantic-driven scenario with temps heading above average for the time of year. Moreover, there's no cold pool in Europe.

 

This place is going to go bonkers if we get some properly cold FI runs as has happened from time to time even in recent years. So far there hasn't been an operational to make me sit up.

[121]

1 hour ago, Dimie10 said:

I am what you would call an avid lurker on this site. I have been interested in weather (especially cold) all my life. I used to be on the old BBC weather site like a few of you on here i presume.

I just wondered why so many of you say not to trust forecasts past 5 days, yet talk about runs so far ahead that rarely come to fruition. What do you genuinely believe? will we have any cold weather in the next 10 days or should just keep away until after then to see if our chances improve?!!

Morning - same as yourself (it’s literally in my name). The trick (and what everyone is doing with FL charts) is to spot trends amongst all the available runs

Yes, they maybe unlikely but;

a) fun to look at
b) the more that come onboard with a certain trend, (in theory) a higher rate of verifying.

[TSNWK]

13 minutes ago, IDO said:

The main models, not counting the ever-promising d6 UKMO that never gets anywhere, had been killing the Atlantic nascent ridging, and there was plenty of evidence that this would mean an incoming flatter pattern as the Arctic high drives the dynamics. Zero signs of the promised land of a Pacific ridge and the usual caveat with MJO signals, sometimes they are trumped by another variable (eg last year).

No comment on the d10 ecm chart for obvious reasons and the overall consensus from the gfs op backed up by the mean is the recurring pattern:

d8-16 gfs mean>> 

> A wedge near Greenland from failed Atlantic ridging, a meandering Arctic high not drawn anywhere due to the slack flow of the NH profile, and remaining the *potential* for cold to lower latitudes if and when we see more amplification in the system. A front-loaded winter they promised and for all intent and purpose the ingredients are there apart from the main one, and it will be a wasted December if we are stuck in this Groundhog day!

 

As always IDO a well reasoned, backed up with objective facts post.. 

One of my go to reads when scrolling through the phone over the years - just a god darn Shame you've been annoyingly accurate

Thank you..:)

[Guest]

Models looking Dec 2013 now opposed to Dec 2010, western areas could see a few problems from rainfall in the coming weeks unless there is a significant pattern reset. Will have to be careful and hope phasing doesn't come together in the next week or so for something more damaging. Both ECM and GFS starting to hint that some lows coming across the UK could be quite nasty.  

[SMU]

1 hour ago, IDO said:

The main models, not counting the ever-promising d6 UKMO that never gets anywhere, had been killing the Atlantic nascent ridging, and there was plenty of evidence that this would mean an incoming flatter pattern as the Arctic high drives the dynamics. Zero signs of the promised land of a Pacific ridge and the usual caveat with MJO signals, sometimes they are trumped by another variable (eg last year).

No comment on the d10 ecm chart for obvious reasons and the overall consensus from the gfs op backed up by the mean is the recurring pattern:

d8-16 gfs mean>> 

> A wedge near Greenland from failed Atlantic ridging, a meandering Arctic high not drawn anywhere due to the slack flow of the NH profile, and remaining the *potential* for cold to lower latitudes if and when we see more amplification in the system. A front-loaded winter they promised and for all intent and purpose the ingredients are there apart from the main one, and it will be a wasted December if we are stuck in this Groundhog day!

 

Not counting the UKMO & expending all the time on the GFS. >>> So essentially wasting your time then.

This is the same model / OP & GEFS thats totally followed the UKMOS lead for the past 4 days.

Shall we do another exercise on the GFS mean like did this week where it has no clue whats going on over the pole..

Edited December 10, 2020 by Paul
Removed extra lines

[LRD]

11 minutes ago, Steve Murr said:

Not counting the UKMO & expending all the time on the GFS. >>> So essentially wasting your time then.

This is the same model / OP & GEFS thats totally followed the UKMOS lead for the past 4 days.

Shall we do another exercise on the GFS mean like did this week where it has no clue whats going on over the pole..

What do you make of the overnight runs Steve? The change from 18z to 0z is suspiciously quick and I don't completely buy the trend away from cold in the ensembles (yet), especially when an Arctic High is lurking, as they are difficult to model - but whatever way we look at it this morning has been a bit deflating

Edited December 10, 2020 by LRD

[mb018538]

7 minutes ago, Steve Murr said:

Not counting the UKMO & expending all the time on the GFS. >>> So essentially wasting your time then.

This is the same model / OP & GEFS thats totally followed the UKMOS lead for the past 4 days.

Shall we do another exercise on the GFS mean like did this week where it has no clue whats going on over the pole..

Doesn't look great for the UK at the moment though Steve?

Low pressure is pinned in our locale with high pressure surrounding it on all sides! It literally can't go anywhere. Not zonal, but stuck in a rut. Something needs a shake up, hopefully the heights to the east decline, northern blocking stays and we get a re-shuffle.

[feb1991blizzard]

4 minutes ago, mb018538 said:

Doesn't look great for the UK at the moment though Steve?

Low pressure is pinned in our locale with high pressure surrounding it on all sides! It literally can't go anywhere. Not zonal, but stuck in a rut. Something needs a shake up, hopefully the heights to the east decline, northern blocking stays and we get a re-shuffle.

Ha, now i am very slightly climbing aboard it seems like everyone else's bailing, first step towards proper cold is seeing the GEFS showing a few members flatlining below -10c, can't see it getting all the way in but you never know - that is how all the great cold spells started, so you have to start somewhere, you need over 50% to do it once it gets to 168-192 range, remember, 2 or 3 successive downgrades in the numbers flatlining and it usually means game over, in other words the GEFS were doing the opposite of what they do in the shorter range - ie - over estimating the blocking and underestimating the Jet, so lets just see how the next suites go, my slight optimism is from the eps doing something similar yesterday 12z judging by the 360 mean chart.

[Jeremy Shockey]

GEFS 0z ensemble 2m temp

The Op is one of the mildest solutions. Plenty of much colder options.

Lets hope that UKMO has modelled the Arctic high more accurately than the GFS ( highly likely IMO ) . I cant believe that Northern blocking can just vanish overnight after what we have seen modelled for many weeks.   

[SMU]

24 minutes ago, LRD said:

What do you make of the overnight runs Steve? The change from 18z to 0z is suspiciously quick and I don't completely buy the trend away from cold in the ensembles (yet), especially when an Arctic High is lurking, as they are difficult to model - but whatever way we look at it this morning has been a bit deflating

Difficult to explain.. however...

The emotion & posting in this thread is dictated by many things - firstly the GFS despite by woeful at modelling polar heights is followed by many, but worse still is all the people that just want mild  weather or want cold weather to fail or the emotional wrecks follow it. 

So in the morning the usual culprits on here posting the GFS / mean / op etc when its proven time again its pretty much rubbish.

Since 2010 every single Proper cold spell from the East or NE ( 2012 / 2013 / 2018 ) has been modelled woefully by the GFS > Reasonable by the ECM & excellent by the UKMO ( with the occasional wobble ) > in a nutshell 

In developing polar heights scenarios at day 6-9 

- The GFS will be wrong most of the time, the GEFS will be even more wrong most of the time

- The UKMO will be right most of the time.

So until the UKMO drops the promising evolution then the GEFS can be generally discounted past day 7 if its being to progressive.

I use the GEFS for 1 comparison & thats for trending> ideally across 24 / 48 / 72 periods to remove the element of volatility.

The period of interest for NW Europe is set at Dec 18- 25 given the current profiles & the time it will take to * potentially influence these areas *

Thats our Window.

That means UKMO 2-3 days away & GFS 3-4 days away > GEFS 4-5 days away.

Edited December 10, 2020 by Steve Murr

[phil nw.]

It's no surprise that we are seeing the Atlantic lows moving in now on the modeling.This has been on the cards for some days.

Ens.guidance shows we could well be looking at this slow moving pattern for  at least 10 days so although disappointing from a cold pov not at all unexpected.

The  +ve ht anomalies over the pole,ie Arctic high is still being shown as are weak hts to the north .

Day 10

Frustrating that we see such a disrupted trop.pv but just lacking stronger northern blocking,The wedges appearing on the Atlantic side not sufficient to drive the Atlantic trough further south and east. 

 

 

 

[jules216]

5 minutes ago, Steve Murr said:

Difficult to explain.. however...

The emotion & posting in this thread is dictated by many things - firstly the GFS despite by woeful at modelling polar heights is followed by many, but worse still is all the people that just want mild  weather or want cold weather to fail or the emotional wrecks follow it. 

So in the morning the usual culprits on here posting the GFS / mean / op etc when its proven time again its pretty much rubbish.

Since 2010 every single Proper cold spell from the East or NE ( 2012 / 2013 / 2018 ) has been modelled woefully by the GFS > Reasonable by the ECM & excellent by the UKMO ( with the occasional wobble ) > in a nutshell 

In developing polar heights scenarios at day 6-9 

- The GFS will be wrong most of the time, the GEFS will be even more wrong most of the time

- The UKMO will be right most of the time.

So until the UKMO drops the promising evolution then the GEFS can be generally discounted past day 7 if its being to progressive.

I use the GEFS for 1 comparison & thats for trending> ideally across 24 / 48 / 72 periods to remove the element of volatility.

The period of interest for NW Europe is set at Dec 18- 25 given the current profiles & the time it will take to * potentially influence these areas *

Thats our Window.

That means UKMO 2-3 days away & GFS 3-4 days away > GEFS 4-5 days away.

But even the UKMO has changed their text wording from getting drier from east/northeast not west/north west as previously stated. I would reckon the route to cold would be for a wedge of high pressure to build above the cut of low that can become stagnant and slowly fill while the block establishes around Northeast rather then northwest

[IDO]

48 minutes ago, Steve Murr said:

Not counting the UKMO & expending all the time on the GFS. >>> So essentially wasting your time then.

This is the same model / OP & GEFS thats totally followed the UKMOS lead for the past 4 days.

Shall we do another exercise on the GFS mean like did this week where it has no clue whats going on over the pole..

...of course, the gfs is not the Holy Grail, and mean charts are disposable most times, and I have refrained from including them of late as entropy has ruled. I did have a go this morning as the gefs seem to be colliding on a way forward and the mean would likely represent that path more accurately than the op? [nb. usual caveats as this is gfs and la la land!]

We are in a good position, as the NH is primed and just needs to ignite which can happen very quickly, maybe that UKMO-0z-d6 chart verifies for once, but it is a lone ranger at the moment, and it is probably fair to call it out? [nb. my issue on this UKMO run is that it blows the low up = more WAA and neither ecm or gfs does that]:

Edited December 10, 2020 by IDO

[feb1991blizzard]

Agree with most of your post @Steve Murr but the GEFS always serve me well when it comes to predicting (or not) a PROPER cold spell from the East, not just one of those slushfest marginals, i use them very differently from most though.

EDIT : The EPS would probably serve me even better if they were available in meteociel format right out to 360 though, just to point out.

Edited December 10, 2020 by feb1991blizzard

[Weathizard]

It’s game over with that phasing across the Atlantic at day 6ish now I think, not ideal but longer term prospects still aren’t bad, I’d be very surprised with such an unusual hemispheric pattern if there isn’t opportunities between day 10-15 

[mushymanrob]

4 hours ago, West is Best said:

 

It has vanished on the GFS 0z.

It'll be interesting to see how the 0z ensembles shape up in FI. The 18z had some really cold ones, the first time there's been a properly cold cluster:

 

The problem is that imho anything past T168 is next to useless on the GFS these days. I've been monitoring it for months and it's all over the place with constant yoyo-ing.

I'm not sure if the word 'zonal' is inflammatory, although there's no reason why it should be especially given where we live, but let's just say that in the reliable timeframe we are in for a week of more Atlantic-influenced weather ... it certainly felt that way to me yesterday with the wind sweeping across the clifftops here in Poldark country. 

Which is why some of us use the anomaly charts, as they iron out the yo-yoing the ops are prone too. That way we get a clearer more accurate view on what really is most likely to lie ahead.

The anomalies from all sources are consistent in gradually building hights to our north, the chances IMHO of a cold spell this winter are far greater then usual... and im no coldie as you know.

[Methuselah]

Och well, we're up to 120 and there's no sign of any snow. Must be a lack of balloon data?!

    

[swfc]

1 minute ago, General Cluster said:

Och well, we're up to 120 and there's no sign of any snow. Must be a lack of balloon data?!

    

I'm up to 150 hrs and still no balloon data.

[weirpig]

Why anyone Takes charts after 144  serious is beyond me .  Trends  maybe  but OP runs?.

Compare 6z  0z   

      

[frosty ground]

Just now, weirpig said:

Why anyone Takes charts after 144  serious is beyond me .  Trends  maybe  but OP runs?.

Compare 6z  0z   

      

Can you find one post, just one post of someone taking a chart after 144 seriously? 

[mountain shadow]

6z gfs looking decent, for what it's worth. Lows moving East

[weirpig]

Just now, frosty ground said:

Can you find one post, just one post of someone taking a chart after 144 seriously? 

Really?.  You dont notice  the wrist slashing   after a bad OP?.   

[frosty ground]

Just now, weirpig said:

Really?.  You dont notice  the wrist slashing   after a bad OP?.   

Yes, but I don't take that nonsense seriously and more importantly it more than just one run its usually a trend.

Also the Ignore feature helps.

[Ali1977]

A bit more WAA around southern Greenland and we may tap into a decent Northerly, if the heights could link up we’d be on to a winner ️ 

[Cold Winter]

6z looking interesting to me around the T204 mark... northeasterly imminent? 
 

In all seriousness, think we’re going to see a lot of model flip flopping over the next few days while they try to get to grips with the Arctic high.

Edited December 10, 2020 by Cold Winter