Model output discussion - into Christmas

[Mike Poole]

ECM ensemble mean T96:

Can you see evidence of the big blow up low, south south west of Irrland?  If this doesn't resolve it in favour of UKMO, I don't know what will...

Edited December 22, 2019 by Mike Poole

[Mike Poole]

2 minutes ago, swfc said:

Sorry Mike I think you will see the result on "the week  a head "update on the beeb.updated not long ago.

Won't happen. 

[swfc]

4 minutes ago, Mike Poole said:

Won't happen. 

Sorry? It's showing what the models show that's all my point is.low crossing UK boxing day then moving away to the south east.high over UK then toppling

Edited December 22, 2019 by swfc

[LRD]

So, if I've read things correctly, in England and Wales we will get:

• average temps with rain clearing in the morning on Xmas Eve
• average temps and dry on Xmas Day
• average temps and wet on Boxing Day
• then a rapid (but brief) warm up from the 27th to the 30th/31st

And then the GFS and ECM, albeit with different timing, seem to want to bring in something colder at the turn of the year or soon after. But not deep, 'proper' cold that most on here want to see

Edited December 22, 2019 by LRD

[swfc]

3 minutes ago, LRD said:

So, if I've read things correctly, we will get:

• average temps and dry weather for most of Christmas Eve (rain clearing in the morning)
• average temps and dry on Xmas Day and
• average temps and wet onBoxing Day
• then a rapid (but brief) warm up from the 27th to the 30th/31st

And then the GFS and ECM, albeit with different timing, seem to want to bring in something colder at the turn of the year or soon after. But not deep, 'proper' cold that most on here want to see

Think that's a fair estimate imo

[bluearmy]

Extended eps showing some continuity with the scandi troughing  - perhaps backing further west and establishing more readily across nw Europe .....the gfs op fits in with this theme I guess .....though the strength of the upper ridge at the end would be out of kilter .... 

note this is not what the gefs or geps mean/anomoly are seeing as they generally maintain high anoms across nw Europe 

Edited December 22, 2019 by bluearmy

[LRD]

4 minutes ago, bluearmy said:

Extended eps showing some continuity with the scandi troughing  - perhaps backing further west and establishing more readily across nw Europe .....the gfs op fits in with this theme I guess .....though the strength of the upper ridge at the end would be out of kilter .... 

Thanks. Encouraging

When you say that the strength of the upper ridge is out of kilter with the eps on the GFS op, do you mean that it is stronger on the GFS 12z op or it's weaker and toppling too quickly?

[blizzard81]

Scandi high territory at day 5 on the latest icon. 

[bluearmy]

1 hour ago, LRD said:

Thanks. Encouraging

When you say that the strength of the upper ridge is out of kilter with the eps on the GFS op, do you mean that it is stronger on the GFS 12z op or it's weaker and toppling too quickly?

I mean that the mean and anomoly on the eps extended don’t support a 1025 mb upper ridge into nw Scotland...... the clusters may say different later but it prob wouldn’t be a big one .....

[SMU]

Evening

The ICON again corrects south with low & rather similar to the last evolution things trended south with that one as well

Whats becoming apparent this time around is the blocking ahead of it is slightly weaker & also the jet develops a shortwave in exactly the place where we want see ridging develop so it hampers the block ( circled here )

This is the second time in 2 weeks a shortwave has been in a location to block an emerging ridge

All very frustrating - 

Due to the track expected to push south ( rem GFS always last on board ) I expect the ENS to be colder than they are but not 'that cold' as the high cannot realistically gain enough latitude unless that shortwave develops much further west...

[January Snowstorm]

And of course with every correction South we have the chance increasing of stormy conditions further West, particularly in Southern Ireland!!

[Fozfoster]

15 minutes ago, Steve Murr said:

Evening

The ICON again corrects south with low & rather similar to the last evolution things trended south with that one as well

Whats becoming apparent this time around is the blocking ahead of it is slightly weaker & also the jet develops a shortwave in exactly the place where we want see ridging develop so it hampers the block ( circled here )

This is the second time in 2 weeks a shortwave has been in a location to block an emerging ridge

All very frustrating - 

Due to the track expected to push south ( rem GFS always last on board ) I expect the ENS to be colder than they are but not 'that cold' as the high cannot realistically gain enough latitude unless that shortwave develops much further west...

I know this may sound like a silly question but these shortwaves ! are they down to our changing climate or have they always been the spoiler for us in the UK? Thanks Foz

[damianslaw]

I said this evening would be last post for quite a few days - good to take a break from model watching I feel over the christmas period.

Alas, what are the models showing for next week - nothing particularly interesting overall, all very benign stuff, nothing to trouble anyone, travelling etc, so the weather won't feature in the headlines at all - other than there will be no white christmas.

Christmas Day just about looks a dry one, temps average, perhaps a touch of frost first thing and later on, so fairly seasonal. Boxing Day unfortunately sees a very annoying low pressure springing up out of nowhere to spoil the party, but tricky to call where and when the rain will arrive, and feeling quite cold I would imagine, so not the best day for a walk.

Thereafter, the 27-31 Dec period looking mild, very mild for some, with winds from a SW-SE quarter, damp and dank for many as well -very uninspiring.

Longer term signs of something colder from the NW as we see a scandi trough developing and mid atlantic ridge development - so something positive to focus on, for those wanting something colder and also brighter - 2019 looks like ending on a very dull note.

Hoping the models show something different when viewing them again just before New Year.

Happy Christmas!

[SMU]

1 minute ago, Fozfoster said:

I know this may sound like a silly question but these shortwaves ! are they down to our changing climate or have they always been the spoiler for us in the UK? Thanks Foz

They will have no doubt always been a part of the weather but perhaps seeing as we are seeing a reduced frequency of Northerlies & Easterlies you may argue that due to climate change the frequency of these has increased. 
Sadly they always seem to block rather than enhance our cold prospects. They will probably be a symptom of the changing speed of the jet - 

[damianslaw]

8 minutes ago, Steve Murr said:

They will have no doubt always been a part of the weather but perhaps seeing as we are seeing a reduced frequency of Northerlies & Easterlies you may argue that due to climate change the frequency of these has increased. 
Sadly they always seem to block rather than enhance our cold prospects. They will probably be a symptom of the changing speed of the jet - 

Yes they are just as common a feature in the summer as winter it seems, spoiling the prospect of extended warmth and dryness. This upcoming feature for Boxing Day does seem an unusual one though - very poor timing!

[swfc]

Very little change today in regard to the mo.pattern looks set up to the  new year on the models.slighty benign altho mostly dry and mild.i think the unsettled weather will return with the PV powering up from the north west.all with usual caveats and imo.uto

[MP-R]

A common theme away from the winter nirvana 18Zs is high pressure to back southwest into the Atlantic and the PV ramping up at least for the first week of January - that spells strong northwesterlies, undoubtedly with a few shortwaves in the flow, energised by the tropical waters of the north Atlantic. Could all change to something more mundane (wouldn't be surprised) but I'd take bright showery northwesterlies with a cold wind over the dross we've had for so much of this month! 

[bobbydog]

I wouldn't put too much faith in the model output beyond a week at most. When the world leading Met Office are using terms like "considerable uncertainty" in their own forecasts, it could go in any direction... even snow...

(We live in hope...)

[swfc]

6 minutes ago, bobbydog said:

I wouldn't put too much faith in the model output beyond a week at most. When the world leading Met Office are using terms like "considerable uncertainty" in their own forecasts, it could go in any direction... even snow...

(We live in hope...)

Really!!! I looked on all there links and havnt seen anything.maybe a change to come in there outlook

[Jason M]

This shortwave issue is the original 'chicken and egg'

My take is that these small features only 'seem to thwart' snowmaggeden. The reality is that the atmosphere simply isn't conducive and that's why the shortwave exists. 

Equally the famous 'trigger low' forms because the atmosphere is conducive and the low forms as the mechanism by which the atmosphere brings about its desired state.

Whatever people believe though, its clear that both the egg and the chicken are more likely to end up barbequed than frozen over the next few weeks  

 

Edited December 22, 2019 by Jason M

[bobbydog]

3 minutes ago, swfc said:

Really!!! I looked on all there links and havnt seen anything.maybe a change to come in there outlook

It's been a common theme recently. It's in the first line in the 27th Dec to 5th Jan forecast. They obviously don't see much consistency in the models either.

[swfc]

1 minute ago, bobbydog said:

It's been a common theme recently. It's in the first line in the 27th Dec to 5th Jan forecast. They obviously don't see much consistency in the models either.

The theme is mild tho tbh not really mentioning snow etc on that update.that said they were not great last year but havnt been far off with this year generally mild and unsettled outlook

[BLAST FROM THE PAST]

2 hours ago, LRD said:

So, if I've read things correctly, in England and Wales we will get:

• average temps with rain clearing in the morning on Xmas Eve
• average temps and dry on Xmas Day
• average temps and wet on Boxing Day
• then a rapid (but brief) warm up from the 27th to the 30th/31st

And then the GFS and ECM, albeit with different timing, seem to want to bring in something colder at the turn of the year or soon after. But not deep, 'proper' cold that most on here want to see

Spot on!  No HLB, transient flow....to dominate 

 

BFTP

[bobbydog]

14 minutes ago, swfc said:

The theme is mild tho tbh not really mentioning snow etc on that update.that said they were not great last year but havnt been far off with this year generally mild and unsettled outlook

Ah, no, they only mentioned "considerable uncertainty". It was me who mentioned snow. The GFS has shown the possibility so it's not off the table...

[blizzard81]

So glad this is the pub run mean at day 6. It means in reality the weather will be nowhere near as flat as a pancake come the actual day.