Model Output Discussion - Colder spell ending, what's to follow?

[Drifter]

8 minutes ago, Tim Bland said:

I might still be playing the Grinch here but I’m struggling to see the excitement? UKMO and Icon both have zero cold anywhere in site ? Even if there was a true undercut there is no cold to draw west? 

I honestly thought you’d been around this place long enough to see the bigger picture on a chart like that....the massive Arctic high nosing in for example?

[SMU]

11 minutes ago, Tim Bland said:

I might still be playing the Grinch here but I’m struggling to see the excitement? UKMO and Icon both have zero cold anywhere in site ? Even if there was a true undercut there is no cold to draw west? 

 

Its the shape & viewpoint of the blocking over the pole > To bebin with a shout of deep cold from the East we have to actually have cold there which is stage 1 > Then the ridge to Greenland + atlantic nlock scenario is a well trodden route to cold day 10-12. 

Also the nearer term it keeps the atlantic at bay so a win win really.

[Mucka]

14 minutes ago, Tim Bland said:

I might still be playing the Grinch here but I’m struggling to see the excitement? UKMO and Icon both have zero cold anywhere in site ? Even if there was a true undercut there is no cold to draw west? 

That is because any blocking is not yet orientated to draw in cold polar air. It will only take around 48/72 hours to do so once the block is in place.

That will more likely come from the NE if it happens than off the continent IMO which will be a quicker process

The earliest any block can align from where we are now, barring rapid developments,  is likely 10 days or so. That means it is out of range of that ICON chart let alone the cold upper air flow.

Look out for developments around the 6 to 8 day timeframe for now which will indicate if we are likely to get the well orientated N blocking or not in the future.

Edited December 8, 2020 by Mucka

[Climate Man]

3 hours ago, Ali1977 said:

Not that balmy , look at those -10c Max’s over Belgium 

In spite of those wonderful pictures from Wally Weather as we liked to call him. Did not really notice anything abnormal,  though I was at Uni.....only a powering of snow and did not freeze in digs with no heating. 

[Tim Bland]

Thanks fir the replies guys. As someone said..I’ve been around long enough ...to know that  it will be at least 10-12 days before anything remotely cold, so that’s where my lack of enthusiasm currently lies. With charts like this being current best case scenario and cold completely absent even across to Russia then we are in for a long wait!...

[mountain shadow]

Meto 144 pretty uninspiring apart from the potential ridge out over the Eastern Seaboard of the States.

[chionomaniac]

Slight change in PV dynamics over Hudson Bay this run. I’m wondering how significant it will be

[swfc]

1 minute ago, chionomaniac said:

Slight change in PV dynamics over Hudson Bay this run. I’m wondering how significant it will be

Yes not quite as amplified is it. 

[Mucka]

UKMO, some Atlantic ridging. Could do with having the Scandi ridge stronger.

[frosty ground]

1 minute ago, swfc said:

Yes not quite as amplified is it. 

Can you expand that a bit more?

[jules216]

3 minutes ago, chionomaniac said:

Slight change in PV dynamics over Hudson Bay this run. I’m wondering how significant it will be

it didnt seems to matter much in 1984

[mountain shadow]

gfs 144 not as good as Meto 144 with the ridging in the Western Atlantic, lows will power through

[chionomaniac]

3 minutes ago, swfc said:

Yes not quite as amplified is it. 

No, the PV is stretching down into NE USA which could open the door towards height rises in Greenland.

[mountain shadow]

t+168 GFS not good with low pressure moving East off the American seaboard...

[swfc]

4 minutes ago, frosty ground said:

Can you expand that a bit more?

PV pulled south on the 12z around the esb USA. Ridging not as good 

[IDO]

The phazing of the low exiting Canada on this run is faster so we do not get the WAA to Greenland as per the 06z:

12z> 06z>

That has of late flattened the pattern. Hopefully other variables compensate for that downgrade?

[swfc]

3 minutes ago, mountain shadow said:

t+168 GFS not good with low pressure moving East off the American seaboard...

The low was there on the 6z and moved west. Problem is the 12z has the PV further south and phases with the said low

Edited December 8, 2020 by swfc

[mountain shadow]

Energy disrupting SE better at t+192 but can we get enough?

[frosty ground]

3 minutes ago, IDO said:

The phazing of the low exiting Canada on this run is faster so we do not get the WAA to Greenland as per the 06z:

12z> 06z>

That has of late flattened the pattern. Hopefully other variables compensate for that downgrade?

Was the high generated by WAA on the 06z?

[Weathizard]

Phasing Atlantic lows, Bain of our lives! UKMO is much better at day 6 than the GFS, much cleaner. See where the ECM goes later.

[IDO]

1 minute ago, frosty ground said:

Was the high generated by WAA on the 06z?

Yes:

The key for cold has been upstream amplification, Atlantic and/or Pacific Ridge, forget about cold from the east, it rarely happens from a standing Russian high and there is no cold there anyway. 

[phil nw.]

The trend on the 12s continue to push away the eastern block so the Atlantic just about struggles across the UK in the next few days.

No dramatic difference to the overall NH pattern to my eyes though with still a weak Atlantic profile and plenty of wedges of heights into the PV,enough to keep the mean jet path to the south.

Nothing dramatic just a very slow moving pattern as we wait for something to change the status quo.

 

Edited December 8, 2020 by phil nw.

[Mucka]

 

GFS 006z on the left, UKMO 12z on the right.

Given GFS 12z is a bit of a let down there is still room for some optimism as well.

Other than the orientation of the Atlantic low and corresponding weaker Scandi ridge you would probably say UKMO is the better chart and we know where the GFS 06z went.

Yes the UKMO is not the perfect chart for future N blocking but it is pretty good, much better than the usual Atlantic driven fodder we see this time of year.

It may not develop but we are definitely in the game for now.

Edited December 8, 2020 by Mucka

[Day 10]

Good to see the PV still in tatters, just need some of that cold air bottled up north to head this way.....Christmas time?

[Mucka]

Even GEM is sniffing an Atlantic ridge so it must be nailed on!