Model output discussion - cold spell approaching?

[Battleground Snow]

GFS op trying to cut the low off once more?

I think this will be a better run than the 06z

 

[frosty ground]

[bluearmy]

It occurs to me and I apologise if this point has already been made that once we get a split in the strat vortex (which is progged over the n Atlantic within the next couple days ) we should see the nwp unable to progress troughs to the east of the meridian.  Let’s see if this begins to play out ......

[That ECM]

Although said in jest wrt the T72 look at these at T120.

[nick sussex]

The low to the ne is more elongated and the phasing point here should be better than the earlier GFS run.

[Cold Winter Night]

UKMO interesting. Changes all around. Different angle to the High, that is getting undercut from the West.

[Frostbite1980]

4 minutes ago, bluearmy said:

It occurs to me and I apologise if this point has already been made that once we get a split in the strat vortex (which is progged over the n Atlantic within the next couple days ) we should see the nwp unable to progress troughs to the east of the meridian.  Let’s see if this begins to play out ......

What effect if that plays out does that have for the UK down the line? 

[That ECM]

Just now, nick sussex said:

The low to the ne is more elongated and the phasing point here should be better than the earlier GFS run.

Better from Ukmo.

[Severe Siberian icy blast]

Just now, That ECM said:

Although said in jest wrt the T72 look at these at T120.

Well the UKMO fazes the 2 lows East Iceland and the Gfs doesn't, the Gfs has the cold air flooding south the UKMO has it trapped to our north 

[Cold Winter Night]

1 minute ago, That ECM said:

Better from Ukmo.

Much better. This is something we can work with.
High sets up more to the East, closer to the Arctic High as well.

[Mike Poole]

5 minutes ago, bluearmy said:

It occurs to me and I apologise if this point has already been made that once we get a split in the strat vortex (which is progged over the n Atlantic within the next couple days ) we should see the nwp unable to progress troughs to the east of the meridian.  Let’s see if this begins to play out ......

Not another invisible block!  It’s hard enough making predictions when you can see them!

Edited January 13, 2021 by Mike Poole

[nick sussex]

Just now, That ECM said:

Better from Ukmo.

It makes a miracle recovery ! Its earlier output was like a few days ago when it wanted to bring in something from the east at day 4.

 

[Tim Bland]

Aperge (now coming into UK view) will raise an eyebrow for midlands! Even across to oxfordshire  bucks & Herts late afternoon 

[Battleground Snow]

GFS a bit better at 144 than earlier..

Colder air over the UK too.

 

[Singularity]

Well then - this takes what we thought we knew and gives it a twist!

Less concentration of positive vorticity - it gets strung out between the troughs to the west and east. This causes the western trough to become negatively tilted which means that establishing an omega block (or at least trying to) becomes favoured more toward Iceland instead of Greenland.

So, I *think* this is a path toward some manner of northerly for 20th-21st, albeit not an especially cold one to begin with.

[That ECM]

1 minute ago, nick sussex said:

It makes a miracle recovery ! Its earlier output was like a few days ago when it wanted to bring in something from the east at day 4.

 

I honestly believe there is so much going on it’s a nightmare to call past t120. Frustrating, intriguing and everything is possible.

[Stationary Front]

UKMO better as part of Asian vortex already SE of the Arctic high, any Strat induced force to move things east from here will be beneficial for cold

Edited January 13, 2021 by Stationary Front
Spelling

[Methuselah]

Up to T+123 and the 12Z is well on the way to discovering a cure for insomnia:

     

[nick sussex]

What to cheer on !

The UKMO disrupts the shortwave se between day 3 and 4 .

If there’s any further westwards corrections this could be an even better  snow event but then this makes the later hurdles to get the pattern sufficiently east more difficult .

Somehow here the UKMO manages to walk a fine line and recovers to a decent day 6 chart .

[chris55]

Much much better UKMO tonight with the fly in the ointment (that Atlantic low) disrupting between 120-144 allowing the pattern to force south with the UK just about on the correct side!! 

[Johnp]

Big differences in pressure patterns on this run to our east. I fancy an easterly in FI. 

[northwestsnow]

10 minutes ago, nick sussex said:

It makes a miracle recovery ! Its earlier output was like a few days ago when it wanted to bring in something from the east at day 4.

 

Ukmo is a big upgrade for me Nick.

We can work with 144...

Trouble is 144 seems way into FI !

[Johnp]

3 minutes ago, chris55 said:

Much much better UKMO tonight with the fly in the ointment (that Atlantic low) disrupting between 120-144 allowing the pattern to force south with the UK just about on the correct side!! 

Not cold at all unfortunately, however the cold air should move south over the following days 

[ItNeverSnowsInWindsor]

6 minutes ago, chris55 said:

Much much better UKMO tonight with the fly in the ointment (that Atlantic low) disrupting between 120-144 allowing the pattern to force south with the UK just about on the correct side!! 

When will the low to the west of Norway get lost ?

[Singularity]

 

GFS 12z is essentially the ECM 00z but with the omega block (of sorts) shifted a little east. That might move more in the way of cold air toward the UK but the low will need to shift east a bit too. Ideally southeast.