Model output discussion - Closing in on Christmas

[Frosty.]

Cold crimbo day according too the Gfs 12z op!...it’s hard too keep up with the speed of this thread even though I’ve been here for the last 15 years..go figure!

[Neilsouth]

I see the GFS is doing its usual blow up the lows again, wont be anything like that within the next couple of model upgrades

[Anthony Burden]

23 minutes ago, WxHerts said:

I think what's most important is what's going on to our west and really they look quite similar in that regard!

 

Yes the UKMO at 144hrs is totally different I mentioned this in earlier blog.The key to the overall weather

pattern is undoubtedly 144 hrs,also Met office 30 day going for high pressure all the way into January.

GFS going in opposite direction my money with Met office.

[swfc]

15 minutes ago, swfc said:

Day ten wouldn't be great on the 12z gfs. Possible flooding on the east coast ete

Why is that funny rainbows end???

[Allseasons-Si]

what happens next!...another pv visit

 

[Allseasons-Si]

The gem isn't three bad.

[northwestsnow]

Models going for another big big + EA mountain torque incoming which will hopefully benefit amplification in the Atlantic...

Hope my twitter source doesn't mind me sharing this ...

[northwestsnow]

6 minutes ago, Allseasons-si said:

what happens next!...another pv visit

 

Likely as a result of getting enough energy into Europe to prevent a Euro high get a foothold.

Repeated winds north of west will also hopefully lower ssts which is really important.

[Mapantz]

Looking at the 06Z ensemble this morning, for Oslo, the OP was a huge outlier for MSLP at 968mb. The 12Z OP is showing that LP at 956mb now, so it'll be interesting to see if the MSLP is an outlier on the 12Z too.

That would suggest the GFS is doing it's usual thing of going over the top with those systems.

[swfc]

6 minutes ago, northwestsnow said:

Models going for another big big + EA mountain torque incoming which will hopefully benefit amplification in the Atlantic...

Hope my twitter source doesn't mind me sharing this ...

Is this rossby wave induced? 

[sheikhy]

Gona stick my neck out and say a massive flip is about to happen to much more colder snowier charts in the next day or so!!the models especialy the gfs just trying to get round to it!!!

[Pembroke Dangler]

6 minutes ago, Mapantz said:

Looking at the 06Z ensemble this morning, for Oslo, the OP was a huge outlier for MSLP at 968mb. The 12Z OP is showing that LP at 956mb now, so it'll be interesting to see if the MSLP is an outlier on the 12Z too.

That would suggest the GFS is doing it's usual thing of going over the top with those systems.

Yes also if the pattern did head down the repeating northerly Toppler route you’d hope for a far less intense hurricane force storm tracking down the North Sea so that there’s less mixing out of the colder air coming from the north/ North west. So purely from a pattern perspective it’s good we just need the systems to be less intense say a MSLP of around 990- 1000. 

[southbank]

14 minutes ago, northwestsnow said:

Models going for another big big + EA mountain torque incoming which will hopefully benefit amplification in the Atlantic...

Hope my twitter source doesn't mind me sharing this ...

That something defo watching - events like that when the PV is decoupled can have surprising results to cold outcome 

[TSNWK]

15 minutes ago, Allseasons-si said:

The gem isn't three bad.

This interests me a lot.. start of the week there was a theme for the Christmas Atlantic heights to shuffle towards scandi instead of the more traditional topple which has been the trend.. is this the first sign that the scandi high signal had been picked up again.

I hope so. Visit from the PV look really tough and open to danger in the modelling and more importantly on the ground. 

Much more palatable are cold easterly wafts with the occasion trough..  

[That ECM]

7 minutes ago, sheikhy said:

Gona stick my neck out and say a massive flip is about to happen to much more colder snowier charts in the next day or so!!the models especialy the gfs just trying to get round to it!!!

Of course the models might just say”b******s to that”

[northwestsnow]

2 minutes ago, southbank said:

That something defo watching - events like that when the PV is decoupled can have surprising results to cold outcome 

Part of the reason I follow Matt is the amount of info he is happy to share.

Just hope he doesn't mind myself,and others passing it on.

UKMO 144 looks knife edge...

[Uncertainty]

This really has been a tricky pattern for the det runs to nail down. There is as much spread in the strength and amplitude of the incoming Atlantic ridge tonight as there was 3-4 days ago. Some GFS ensembles have prize winning blocks, representative example perturbation 9 

Which isn’t dissimilar to the Icon which has been separating and cutting off the low to the south west consistently for days now...

A good size cluster of the GEFS resemble the mean, which in itself is more amplified than the 6z

Recent ECM ops resemble this mean but beforehand they have powered the low to the SW through the UK bringing heavy rain and, presumably, local flooding 
 

This unpalatable scenario is also linked to a weaker upstream ridge and less amplification of the Eastern Seaboard. This could lead to a toppler and west north westerlies behind at best.

The good news is the UKMO says absolutely not to this scenario, tracks the first low to the south of the UK, doesn’t really develop it and cuts off the second low, here at 120

The low to the southwest gets trapped under the building ridge to the west, I think the 168 would lead to a cold UK high and a frosty, seasonal Xmas day many on this forum and beyond would happily settle for. With potential for this to move NE with time and keep things interesting.

As noted by @Allseasons-siThe GEM after some fodder has produced an interesting outcome at day 10, deja vu to the evolution at the start of this amplification journey we are on, back in V late November, a ridge building through the UK to form a wedgey Scandi high. Another positive solution, if not well supported as yet.

 

So lots to like for cold seekers out there so far this evening. Let’s hope the ECM sacks off this nasty second low and gives its best GFS perturbation 9 impression. We all know that if it does it’ll kick off in here and, before Christmas in this vile year, what a tonic that would be.

[northwestsnow]

23 minutes ago, sheikhy said:

Gona stick my neck out and say a massive flip is about to happen to much more colder snowier charts in the next day or so!!the models especialy the gfs just trying to get round to it!!!

I'm thinking the complete opposite!!

My hunch is HP will allow for a brief North westerly over Christmas and beyond.

I see Exeter have a cold high in place out to the NY !!

[Uncertainty]

18 minutes ago, sheikhy said:

Gona stick my neck out and say a massive flip is about to happen to much more colder snowier charts in the next day or so!!the models especialy the gfs just trying to get round to it!!!

It’s still there pal, this Late December  cold pattern has been progged for months by the seasonals, for weeks and weeks by the EC46 and for 4/5 days on the ENS/EPS. It’s hardly an aberration. It’s still not in the bag though so don’t pop champagne just yet! Don’t want a Jan 19 rerun!

[West is Best]

A particularly stormy 12z GFS. If that came off it would cause a large amount of chaos. There's a vicious storm on Christmas Eve but the real humdinger is reserved for Dec 27th/28th. Would be nigh-disastrous.

The GFS does this regularly: wildly over-ramping Atlantic and polar storms only to downgrade, sometimes at the last minute. 

However ... just in case you think this couldn't materialise at this time of year I can still vividly remember the infamous storm of New Year 1976 "The Capella Storm" which caused chaos across the UK and especially Europe. It killed c. 100 people, 24 of whom were in Britain:

Gale of January 1976 - Wikipedia

EN.WIKIPEDIA.ORG

 

So this chart is very similar to those synoptics and would be pretty dramatic:

Edited December 17, 2020 by West is Best

[Cheshire Freeze]

Continued suggestions the SPV will not be a happy chappy come the new year-

[mb018538]

5 minutes ago, CreweCold said:

Continued suggestions the SPV will not be a happy chappy come the new year-

Perhaps we should rename him stretch this year? Murmurings of a fatal blow in January grow....

[Allseasons-Si]

The control now sizing the gfs up with it also sending a part of the trop pv in our vicinity.

day ten gefs mean showing this Atlantic ridge nicely so it's looking like a cool/cold shot from the NW.

 

 

[Ventnor Viking]

Looking at the latest models, it looks as though there is too much energy just west of Greenland to allow any linking or ridging to form a decent block. 

The most probable outcome based on the latest runs are that the cold spell/s will continue to be watered down. Any cold spells will be short lived and if we dont get a SSW warming then things could become more zonal when the energy from Canada/Greenland push the HP east/south east.  

[Mike Poole]

Just now, mb018538 said:

Perhaps we should rename him stretch this year? Murmurings of a fatal blow in January grow....

Yes, could be on the cards, latest NAM plot from Stratobserve show it is on the rocks:

Zonal winds:

One member reverses.  Well worth watching in the coming days...but there is plenty going on down here at the surface too!