Model output discussion - late November

[Frosty.]

Looking at the GEFS 6z mean there's certainly strong support for the azores high ridging / building in longer term followed by a flattening out of the  pattern..excuse me I've been drinking but I still know what the GEFS is showing!

Edited November 23, 2019 by JON SNOW

[Jordan S]

1 minute ago, Don said:

Are we looking at a typical evolution which has plagued many of our winters since 2012/13!?

Hope you don't mind me replying.

Its simply too early to know but atleast for a time a more typical pattern shown for longer term but there's a lot of uncertainty on this and how long it may last. 

Edited November 23, 2019 by jordan smith

[Don]

8 minutes ago, jordan smith said:

Hope you don't mind me replying.

Its simply too early to know but atleast for a time a more typical pattern shown for longer term but there's a lot of uncertainty on this and how long it may last. 

Not at all! 

As long as the more 'typical' pattern does not lock in for the long term, we have plenty of time for interest during the winter ahead.  That's my main concern but like you say, plenty of uncertainty at this stage and still all to play for,

Edited November 23, 2019 by Don

[Gael_Force]

11 minutes ago, Don said:

Are we looking at a typical evolution which has plagued many of our winters since 2012/13!?

All in all a bit of a grim Saturday so far for coldies!

Why would something which is the NH climate norm be grim? As surely as (24 hour polar) night follows day, the vortex is going to strengthen approaching the winter solstice. it's now up to other sets of variables in the atmosphere to impact on the vortex and there's plenty of those in the mix for this season.

[Don]

5 minutes ago, Gael_Force said:

Why would something which is the NH climate norm be grim? As surely as (24 hour polar) night follows day, the vortex is going to strengthen approaching the winter solstice. it's now up to other sets of variables in the atmosphere to impact on the vortex and there's plenty of those in the mix for this season.

I was referring to the risk of a zonal pattern (+NAO/AO) setting up shop and eating away into winter (like it has in many years).  With the long range models consistently bullish about this scenario, it remains a concern.  However, it's still early days of course.

Edited November 23, 2019 by Don

[Kirkcaldy Weather]

Again just a few thoughts from me.

Even if we do enter a more zonal-esque period (which we would usually expect to see at some point during UK winters anyway so again no need for panic) zonal doesn't always = mild there is such a thing as cool zonality, example 19th January 2018 I got snow from this at 20M ASL     and given that the usual feedback / lag period from strat warmings is around 2 weeks + every chance that blocking of some variety will appear, I am thinking of it like this - having a dart to throw at the bullseye, will it 

A - Hit the bullseye = UK cold + snow 

B - hit the 25 (outer bull) = near miss cold and snow (although possibly still chances of tapping into cold later)

C - hit another segment on the board - UK ends up in no mans land - ie setup non conducive for cold / snow 

I would say it is still very much to play for.

Before 1962/63

Before 1947

again not saying anything similar to those is likely just highlighting what may have not looked like a good setup eventually evolved into one.

[Jordan S]

44 minutes ago, Kirkcaldy Weather said:

Again just a few thoughts from me.

Even if we do enter a more zonal-esque period (which we would usually expect to see at some point during UK winters anyway so again no need for panic) zonal doesn't always = mild there is such a thing as cool zonality, example 19th January 2018 I got snow from this at 20M ASL     

Cold zonality has been known to bring a fair amount of snow to northern and Western areas in particular in the past from long fetch northwesterely winds that have originated from the southern Greenland region with the jet stream to the south of the uk, also cold zonality can be very ideal in deepening low pressure systems rapidly as they cross the Atlantic with the below chart a good example of it and i'm assuming that snowfall was to the north of what was a named storm Which is the low pressure shown on this chart.. 

Anyway back to now..

In the longer term after perhaps a milder interlude and drier start to December from latest output with the Azores high close to the UK.. a reappearance of Northern blocking with a southerly tracking jet stream once again Woudn't be too suprising given the persistent nature of it during this autumn. Ofcourse that's not guaranteed. 

But if that happens it would likely sadly be more a story of more flooding grabbing the headlines rather than snow potential. 

Edited November 23, 2019 by jordan smith

[swfc]

1 hour ago, Don said:

Are we looking at a typical evolution which has plagued many of our winters since 2012/13!?

All in all a bit of a grim Saturday so far for coldies!

It's not great don but it's november.just as a side note solar activity-flatlined,enso-neutral,qbo moving towards an easterly phase.outlook and weather,no idea like everyone else.if they do get the lottery numbers and Wel split the money

[snowray]

3 hours ago, Met4Cast said:

The colder option is in the minority cluster on the EPS with the largest cluster supporting the return of an Atlantic, westerly regime. 

 

Funny how much that has changed in just 24hrs.

Anyway, all eyes on the 12z runs....ICON about to start rolling out, FI is around the T120 mark if you ask me.

[SMU]

Icon looking nice at 120 across the piste

I looked into the pacific jet location over the SW states at 48 V 54 06z & it was slower & more amplified >>>> Vis a vee this should snowball the atlantic ridge further west....

 

[WxHerts]

Beautiful start to the 12z runs from ICON, with ridge heading much further north whilst setup looks much less conducive for toppling. Now showing cold and frosty conditions by the end of November as opposed to chilly and drizzly on the 0z

[SMU]

Crazy Crazy Icon.... LOL...

[StretfordEnd1996]

Cold uppers beginning to claw themselves in by D7 on latest ICON

Looks chilly to me .. Brrr .. 

A nice little 'Hello' as Winter rolls in

[carinthian]

6 hours ago, carinthian said:

Morning all, yes that sliding low for next weekend was being flagged by our team over here yesterday. Possibly could be even further south. If that is the case , a cold wedge of air would be then established over much of the British Isles with an increasing threat of snow for Southern Britain next weekend. Will get an up date from the team later this morning to see if this possible development is on-going. Longer term at day 10 many models go to cut off the cold supply by toppling the Mid- Atlantic ridge although it is noted GFS this morning holds it a bit longer as @Steve Murr has indicted in his post.

C

Sorry a bit late with an up-date from the team as suggested in the above post sent earlier. Managed to have a discussion with specifics regarding the British Isles. They still in the thinking that a low will move close to Southern England next weekend before heading towards the Alps. Still a bit far out for their snow model predictions but indications that rain could turn to snow especially on the mountains of S. Wales and some other parts of Central Southern England later as the milder is under cut from much colder air mass established further north. Still a lot more runs needed but still showing also the low could easily move further south. Longer term, a switch to milder westerlies could be limited to the NW of Britain as their own model in now showing a resurgence of the Russian high again in its later span. What that leads to , not sure but could be back to square one ! Hope this helps.

C

[snowray]

ICON looking excellent to me at T180.

[WxHerts]

Wow! ICON very, very different to earlier with cold and snow likely by d10 if the run were to continue. UKMO out in around 25mins, let's hope for more of the same

 

[Mike Poole]

Yes, great start for the 12z on ICON T180:

Need to see if this increased amplification into Greenland replicated on the other runs! I'm reasonably hopeful, 12z often the givers, rather then the taker-awayers...

Edited November 23, 2019 by Mike Poole

[Allseasons-Si]

BIONIC ICONIC ICON!!!

huge heights into Greenland and a nice trough coming down from Iceland,get in there.

 

[January Snowstorm]

As I said a few days back the Icon is quite often a trend setter for the ECM.

Here's hoping we get a decent set of 12's now rolling!!

[WxHerts]

 Very big differences between UKMO and ICON at 144h, UKMO lacking WAA.  

[swfc]

Pretty average ukmo imo.nothing to scream about.pretty close to the 6zgfs

Edited November 23, 2019 by swfc

[Frosty.]

I never realized the icon was so iconic!!, but I guess that depends on whether or not it shows cold weather!!

[swfc]

1 minute ago, JON SNOW said:

I never realized the icon was so iconic!!, but I guess that depends on whether or not it shows cold weather!!

It's not really

[SMU]

UKMO fine just will be slower to ridge than ICON but a comparable location-m for the ridge to build North-

GFS pacific jet from the 06z V 12z much further west with the jet streak again leading to the assumption of westward ridging...

12z first

 

Edited November 23, 2019 by Steve Murr

[WxHerts]

 While UKMO appears to differ significantly to ICON,  GFS at 120h looks very similar indeed...!