Model Output Discussion - Into 2024

[Catacol]

17 minutes ago, Drifter said:

Looks deep cold to me? 

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about.

As I see it taking into account usual U.K. winter synoptics:

850s of 0 = Cool

850s of -4 = Cold (has to be, given at -4 snow is in the mix)

850s of -8 = Very Cold (rare, and snow over rain nearly ever time)

850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!)

850s of -16 = Exceptional Cold (how often in the last 50 years?)

 

On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix.

Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential.

[That ECM]

1 minute ago, terrier said:

Much better GFS06Z but I remain sceptical. Until we have the ECM on board I’d be very wary of what the GFS is showing at the moment. 

I’d be sceptical of what the ecm is showing until the gfs is on board.

[blizzard81]

I really don't see any reason for any dispondency with regards to the model output this morning. Looks chuffing fantastic to me. I'm very excited about the rest of January now. 

[Day 10]

1 minute ago, Mike Poole said:

As I understand it, it is the one area relevant to UK cold setups that the GFS has modelled better than the others in the past.  One possible way to read recent runs is that GFS had its wobble in that area a 24 hours in advance of that of the ECM’s wobble.  But there are many other ways to read things as well, so I’m not saying this is necessarily the case.  

Thanks for the response Mike

[Anthony Burden]

Just now, Hullsnow87 said:

What do you mean?

-10 hpa showing it’s hand over the UK that does not happen much in this country the met office has stated that severe weather looks a small bet,my version is that the more we see those -10hpa temperatures a loft the greater the chance.

[cheshire snow]

1 minute ago, terrier said:

Much better GFS06Z but I remain sceptical. Until we have the ECM on board I’d be very wary of what the GFS is showing at the moment. 

Don’t quite get the fascination with the ECM if it was the other way round folk would be saying I would be wary until the GFS is on board.

[Ricardo23]

Day 8 Looks Cold it changes daily but the theme of a colder January is building at least until the 20th at the moment.

 

Edited January 7 by Ricardo23

[Met4Cast]

1 minute ago, cheshire snow said:

Don’t quite get the fascination with the ECM if it was the other way round folk would be saying I would be wary until the GFS is on board.

The ECM is generally the best performing model & certainly the best performing ensemble suite. Having ANY model disagreeing causes concern because on occasion, the model disagreeing is right!

[Catacol]

2 minutes ago, That ECM said:

I’d be sceptical of what the ecm is showing until the gfs is on board.

Data is clear. ECM beats GFS hands down at 120h. But at 240h the gap is slight to very slight. At 192 and lower ECM holds the whip hand most of the time - though not all of the time! At 240h they are both valuable.

[Dignity]

Addressing the models variations, you get the idea there's a couple of factors which are presenting themselves which are triggering more spread in the ensembles.

ECM has had a bit of a wobble, GFS before it, looks linked to N.Pacific and Arctic heights affecting how the GH develops. 

Bit of an IMBY perspective here but I'm east coast of Scotland and I'm fairly confident that I'll get a dump of snow in the next couple of weeks.

The Thames streamer for tomorrow looks interesting for the majority of population down that way.

At least it's going to be dry bright and cold for a while, everyone can do with that for now, next week up for grabs in terms of how cold and snowy it will get.

[BLAST FROM THE PAST]

1 minute ago, Zero Visability said:

But definitely positive, showing this is far from game over.

Exactly that, 

 

BFTP

[Drifter]

9 minutes ago, Anthony Burden said:

GFS Nudging towards severe weather,met office update 

Are those two linked? I doubt the Met Office mentioned GFS. 

[Neilsouth]

10 minutes ago, BLAST FROM THE PAST said:

The theme remains generally.  There’s no upgrade or downgrade at day 8+, just variations.  Like I said last week, we won’t resolve the detail for midmonth until into next week

 

BFTP

 

Case and point look at the upgrades in the short term for the east and south east...

" DRY " " High pressure is too high " people said, and here we are with rain/sleet and possible snow tomorrow! - I do wonder if after all this we get a true scandi high down the line rather than a more dominate greenland high?

[Bricriu]

1 hour ago, offerman said:

Good post Frosty. But the fact of the lack of Greenland and Arctic Heights is allowing Iberian and Hadley cells to expand as everything is out of kilter 

if you had an expanding Greenland high and Arctic high, this could balance things out, and probably reduce the constant influence of the resource, and Iberian Heights.

so good post from you as to look at it from that direction of the lack of the Heights in the north.

 

I guess the way I could summit up is look at it like a pair of scales.

On the left side, let’s go it, Greenland Arctic Heights and on the right side let’s call it, Iberian , Hadley cell azores.

If we reduce the weight on the left side, then the right side will be the dominant factor.

 

so thanks for your post. Good information that Adds to the reasoning of the high-pressure systems dominance to our south, which I sometimes post about. 
 

I guess the next thing we could look at is, why are the Greenland and Arctic Heights so much less dominant than they were previously, and also as someone mentioned earlier, there is no consistency on a day-to-day basis. 

is this down to a disrupted or broken current polar vortex or is this something else? 

 

The MJO in a less favourable phase than it was back in 2018 and the absence of a major SSW might be the difference. When we are relying on a stretched or displaced  vortex there is always a risk that elements of the tpv move back to the wrong  place in terms of getting cold in.

[January Snowstorm]

5 minutes ago, Catacol said:

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about.

As I see it taking into account usual U.K. winter synoptics:

850s of 0 = Cool

850s of -4 = Cold (has to be, given at -4 snow is in the mix)

850s of -8 = Very Cold (rare, and snow over rain nearly ever time)

850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!)

850s of -16 = Exceptional Cold (how often in the last 50 years?)

 

On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix.

Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential.

You make some very good points Catacol and your knowledge of the Strat/background signals is superb. Yes you are right if you want deep deep cold move to Canada and that 06z gfs is very cold. But most have not seen one snowflake all Winter and the wait remains on that front for now. I guess that's the disappointing fact. We are located far enough North in the hemisphere to expect at least a few days of snow....obviously keeping in mind we are island nations etc. So yes fantastic charts but none show snow for now, even for the North

[Ice Day]

The 6z GEFS mean has improved vs the 0z at 144

 

Not dramatic, but it's arrested the slide at least.  

[snowblizzard]

7 minutes ago, Catacol said:

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about.

As I see it taking into account usual U.K. winter synoptics:

850s of 0 = Cool

850s of -4 = Cold (has to be, given at -4 snow is in the mix)

850s of -8 = Very Cold (rare, and snow over rain nearly ever time)

850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!)

850s of -16 = Exceptional Cold (how often in the last 50 years?)

 

On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix.

Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential.

Never?

Surely there's potential for deep cold across UK, if only short lived?

1981 1987 1991 2010 2013 2018

[MJB]

10 minutes ago, Catacol said:

Maybe we should put some numbers to the language so that when some shout “a deep freeze is now off the table” we know what we are talking about.

As I see it taking into account usual U.K. winter synoptics:

850s of 0 = Cool

850s of -4 = Cold (has to be, given at -4 snow is in the mix)

850s of -8 = Very Cold (rare, and snow over rain nearly ever time)

850s of -12 = Severe Cold (very rare in truth, if you want lots of these go to Canada!)

850s of -16 = Exceptional Cold (how often in the last 50 years?)

 

On this basis I will say again - we are looking at a spell of very cold weather off and on for the extended. At times it will be cool to cold, and at best we might hit the odd moment of severe cold if the dice roll kindly. And snow is in the mix.

Do some folk need to get realistic about U.K. winter? We will never hit continental levels of freeze potential.

Too true Cat  -5c ( 2m daytime temps not 850's were hit in '47 '63 ( sadly i didn't experience those ) '79 '81 '84 '87 '91 '10 close to it in March 2018, severe cold is rare 

[winterof79]

45 minutes ago, Catacol said:

Some things never change. It is as though model watchers wake up every morning determined to be gloomy.

ECM 240

GFS 240

GEM 240

I'd give my right army for charts like these in any winter. 

My only comment would be to address the delay issue. Those long in the tooth on watching models know that high pressure is often, if not always, modelled to move faster than actually occurs in practice. So seeing the trough arrive a day or two later fits the observation. No issue with this provided we maintain low pressure to the south and dont see a sub-tropical high resurge. Any signs of this?

Well - on the EPS not really at realistic range. Weds 17 and the midnight EPS still have pressure lowered over the continent

and yesterday's EPS the same out to 300h.

There are too many on here who get the magnifying glass out at 192h+ and see slight shifts as a disaster. There are always going to be shifts - it is absolutely impossible for one complex run produced out of Tb of data to be the same as another and these will sometimes "improve" or "downgrade". But one thing is for sure - getting hung up on 850 spaghetti charts at 192-240h range is 100% guaranteed to drive you nuts. As I said yesterday NWP is hopeless at getting 850s right even within high resolution range, and an 850 spaghetti does not really therefore give you much of an idea of synoptics.

Enjoy the ride. This has a long way to run yet - hopefully a very long way to run. Patience, stamina and a very healthy dose of perspective required.

Allelujah man

[BLAST FROM THE PAST]

6 minutes ago, MJB said:

Too true Cat  -5c ( 2m daytime temps not 850's were hit in '47 '63 ( sadly i didn't experience those ) '79 '81 '84 '87 '91 '10 close to it in March 2018, severe cold is rare 

You forgot 86….Feb 86 was a sub zero month.

For those micro analysing the runs upgrade/downgrade etc and how 06z is upgrade.  Very cold, dry and complete collapse in deep FI with no cold come back

 BFTP

 

 

Edited January 7 by BLAST FROM THE PAST

[Battleground Snow]

Small pocket of -14 uppers into the extreme south east on the latest 06z ukmo,

Good luck to you guys, I think some places may get a fair few CMS under  streamers.

 

[Chesil View]

Trying to look at the output at the moment can be a bit  nerve shredding for southernsnow lovers at the best of times. 

A couple of days back, we had cleaner retrogression and northerly plunge of some note covering the whole UK. 

Now as Scott Ingham day nears the models seem a bit more reticent to go full on cold for the whole UK although the latest 06z does bring that back.

I can only assume that the various variables are making this something of a knife edge scenario which can of course bring big rewards but can equally give snow starved southerners sod all. Maybe this is one of those instances where we literally won't really have the best idea until 24/48 hours before things align.

Edited January 7 by Chesil View

[MJB]

3 minutes ago, BLAST FROM THE PAST said:

You forgot 86….Feb 86 was a sub zero month.

For those micro analysing the runs upgrade/downgrade etc and how 06z is upgrade.  Very cold, dry and complete collapse in FI with no cold cone back

 BFTP

 

 

Sorry I was talking about where somewhere in the UK hit -5 as a daytime temp .....cheers 

[Bricriu]

6 minutes ago, January Snowstorm said:

You make some very good points Catacol and your knowledge of the Strat/background signals is superb. Yes you are right if you want deep deep cold move to Canada and that 06z gfs is very cold. But most have not seen one snowflake all Winter and the wait remains on that front for now. I guess that's the disappointing fact. We are located far enough North in the hemisphere to expect at least a few days of snow....obviously keeping in mind we are island nations etc. So yes fantastic charts but none show snow for now, even for the North

All this talk about climate change, some of us might be happy if it led to a shutdown or a real slowing down of the North Atlantic Drift in our lifetime, then we would be getting something like the winters they have in Canada. Although some would miss the drama of model output in that scenario. 

[January Snowstorm]

The arome is showing a dusting for my area on Monday night. Can work with that, It's usually conservative with amounts