Model output discussion - Closing in on Christmas

[SMU]

Last one from me -

The angle of attack for deep cold from the North isnt great as its to far west - but look at the evolution post 220-250 everything sharpens up & that cold is edging our way...

Awsome!

[reef]

It would be just our luck to wait ages for a proper Greenland high and get stuck with a west-based -NAO setup with a trough sat over us giving rain.

Edited December 19, 2020 by reef

[Dancerwithwings]

Well for now if it’s no Snowfall come Christmas Day, at least the GFS 12z is showing cold day time temps and these are MAX temps regarding this chart, better than a full on mild zonal

 

 

Edited December 19, 2020 by Dancerwithwings

[Howie]

1 minute ago, Froze were the Days said:

As per 2 1/2 weeks ago...be nice for once to actually get into a cold air mass rather than just have displaced low pressure over us.

Very very frustrating indeed. I think the problem is that there's a ridge in South Eastern Europe which forces the low to the west instead of south east. Hopefully that ridge is downplayed in later runs

[bluearmy]

Gem isn’t great as too Far East and not a great evolution  - it’s consistent.   Ecm has often looked like gem when it comes out - if that happens in two hours  then this place will be fun! 

[daz_4]

Well this looks like a repeat of what we had earlier this month. That would be another bust for my location. Hopefully you guys in UK will get something out of it. Just wondering if we ever get rid of that HP to the east.

[Mapantz]

2 minutes ago, reef said:

It would be just our luck to wait ages for a proper Greenland high and get stuck with a west-based -NAO setup with a trough sat over us giving rain.

The 06Z ensembles showed the OP run to be pretty much on it's own in terms of depth of MSLP. With the 12Z going a similar way, I think the GFS is certainly overplaying the MSLP depth.

[Froze were the Days]

I don't think this GFS run in FI will end well, GH becoming less of a influence and pressure falling to the west.

OR it could just end in one big muddle = not a clue!

Edited December 19, 2020 by Froze were the Days

[Ice Day]

2 minutes ago, bluearmy said:

Gem isn’t great as too Far East and not a great evolution  - it’s consistent.   Ecm has often looked like gem when it comes out - if that happens in two hours  then this place will be fun! 

I can certainly think of a few posters who would suddenly become 'visible' 

Anyway, the potential SSW is still showing, not deepest FI either:

[MATTWOLVES 3]

8 minutes ago, Steve Murr said:

Last one from me -

The angle of attack for deep cold from the North isnt great as its to far west - but look at the evolution post 220-250 everything sharpens up & that cold is edging our way...

Awsome!

I agree Steve, I feel the cold to our North and East will have quite a say on the Progression of any Atlantic conditions, and will be diving SE rather than the normal West to East...its after Xmas I feel things will spice up...mind you going on tier 4,it may not be allowed in...last one from you??  Youve been saying that since you announced early retirement the other week...face it Steve...you love it..

[Scott Ingham]

As stated earlier even if the low doesnt move south east there will be a fine line of marginality between someone getting battered with several days of snow or getting cold rain. The freezing level will be low due to heights and snow cover will start to help build a cold pool. Its a fascinating period of model watching coming up!

[Ice Day]

Whilst we're not benefitting in our little corner this time, the GFS is throwing out yet another incredible run.  The NH profile is stunning.

[Mike Poole]

It seems to me that the GFS might have the better handle on the upstream amplification issue early on that gives (or doesn’t give) rise to the Greenland heights.  The consistency run to run supports that view.  However, that doesn’t mean it isn’t overblowing the (ex-vortex) low when it arrives in the vicinity of the UK, the GFS does overblow lows, we know that.  But for me that is down the line, let’s get the amplification issue sorted first, and then worry about where the snow might come from.

[blizzard81]

Much better mean chart at 7 days out

[bluearmy]

2 minutes ago, Ice Day said:

Whilst we're not benefitting in our little corner this time, the GFS is throwing out yet another incredible run.  The NH profile is stunning.

Looks like we could end up under a nice warm sou’wester by the time it’s finished ! tongue in cheek but it’s possible with this evolution ....

[Scott Ingham]

1 minute ago, bluearmy said:

Looks like we could end up under a nice warm sou’wester by the time it’s finished ! tongue in cheek but it’s possible with this evolution ....

Ive not got the time have you looked at predicted freezing levels, dew points etc for this filling low. I feel some are being a little too negative due to upper air temperatures etc

[nick sussex]

Ironically the UKMO which wasn’t good this morning but which has improved this evening might provide a better evolution post day 6 .

The GFS is too amplified at the wrong time , the UKMO is flatter but as that shortwave in the eastern USA amplifies the drop down point for the low near Greenland should be further to the east .

[swfc]

Amazing from a semi greenland high and northerly to a south westerly???

[Howie]

1 minute ago, nick sussex said:

Ironically the UKMO which wasn’t good this morning but which has improved this evening might provide a better evolution post day 6 .

The GFS is too amplified at the wrong time , the UKMO is flatter but as that shortwave in the eastern USA amplifies the drop down point for the low near Greenland should be further to the east .

Interesting! So hopefully a halfway house would be decent?

[Mike Poole]

1 minute ago, nick sussex said:

Ironically the UKMO which wasn’t good this morning but which has improved this evening might provide a better evolution post day 6 .

The GFS is too amplified at the wrong time , the UKMO is flatter but as that shortwave in the eastern USA amplifies the drop down point for the low near Greenland should be further to the east .

GFS 12z looked to me to be at the upper end of the envelope of amplification of that second ridge.  So 12z potentially a slight outlier - but the model more generally has been consistent in promoting this amplification for about 8 runs now.  

[Matt H]

Great GFS 12z run again, but the GEM 12z isn’t playing ball unfortunately.

Edited December 19, 2020 by Frosty Winter

[Paul_1978]

3 minutes ago, swfc said:

Amazing from a semi greenland high and northerly to a south westerly???

In case anyone is wondering who hasn’t looked at the run, this “south westerly” is 300 hours away. 

[blizzard81]

11 minutes ago, blizzard81 said:

Much better mean chart at 7 days out

And just keeps on giving. 

[Scott Ingham]

1 minute ago, Mike Poole said:

GFS 12z looked to me to be at the upper end of the envelope of amplification of that second ridge.  So 12z potentially a slight outlier - but the model more generally has been consistent in promoting this amplification for about 8 runs now.  

Its the model you want on board in this scenario. The american model is unsurprisingly better at modelling American weather and the North Atlantic

[swfc]

Just now, Paul_1978 said:

In case anyone is wondering who hasn’t looked at the run, this “south westerly” is 300 hours away. 

Sorry was just making the point how it turned around in fi