Model output discussion - 5th December 2016 - Into Winter we go

[Captain Shortwave]

A rather strange situation model wise to see the GFS going against the ECM by sending that low on Christmas day ESE whilst the ECM takes a more typical east or ENE track.

Its track seems set based on the amplification following behind that low and the rapid build of heights into the UK from the south on Boxing day. This settled pattern actually has a good chance of being quite sunny as winds fall light and mainly from the south after a brief polar maritime incursion. So we hopefully shouldn't get the import of moist tropical maritime air so frosts and patchy fog will hopefully prevail with sunny days.

The GFS also seems keen on developing an area of heights right over the pole (albeit rather weak). The mid-range continues to offer promise if we can move the Euro/Scandi high into a better position.

At the moment Boxing day/27th look cold with middle single figures at best with widespread frosts after a rather mild Christmas day (especially in the south where it could very well be the mildest day of the month). Beyond that it is all down to the position of that high.

Edited December 20, 2016 by Captain Shortwave

[Summer Sun]

GFS and ECM still at odd's with the low over Christmas and what track it will take hopefully by Thursday we should have better agreement

[West is Best]

GFS 6z also now for the first time showing a 3rd storm before New Year. I have to say, I think this is more likely. We may have a prolonged stormy spell ahead:

[West is Best]

Well some very interesting developments right at the end of the 6z with the GFS picking up what UKMO 12z yesterday hinted i.e. mid Atlantic blocking:

In the meantime though we have some serious storms ahead  

[Banbury]

Chilly days with the HP over us

 

[pip22]

1 minute ago, Banbury said:

Chilly days with the HP over us

 

That seems to me coming from the warm direction for the North.

[Seasonality]

34 minutes ago, Summer Sun said:

Doesn't look like its going to happen for the UK on this run

Forgive me for posting such a far FI chart Summer Sun but the 06z ends on another interesting note. Ridging towards Greenland and frigid air descending. Some 'happy endings' appearing at least make the output interesting. Needs to be taken with a fleet of gritter lorries of salt but it seems to me there are tentative, nascent signs of an interesting January.

 

[Banbury]

9 minutes ago, West is Best said:

Well some very interesting developments right at the end of the 6z with the GFS picking up what UKMO 12z yesterday hinted i.e. mid Atlantic blocking:

In the meantime though we have some serious storms ahead  

And if verified would bring some decent temps across the UK

[Banbury]

6 minutes ago, pip22 said:

That seems to me coming from the warm direction for the North.

Chilly enough at ground level

[Dennis]

SnowLow for Scotland poss

[Summer Sun]

UKMO extended shows high pressure back by the 27th

[Methuselah]

Interesting 06Z today: two potentially damaging storms in the short-term; in the middle-term, a few days' TM air with 850s of almost 10C, and, last but not least, the one that will never verify: the magic that frequents the T+384 time period!

So, it's as you were: all to play for and more runs needed!

[karyo]

31 minutes ago, Seasonality said:

Forgive me for posting such a far FI chart Summer Sun but the 06z ends on another interesting note. Ridging towards Greenland and frigid air descending. Some 'happy endings' appearing at least make the output interesting. Needs to be taken with a fleet of gritter lorries of salt but it seems to me there are tentative, nascent signs of an interesting January.

 

This may look kind of promising (apart from the fact it is in the far depts. of FI) but I can't see it lasting as the stratospheric profile for the same timeframe couldn't be more hostile for Northern blocking.

[knocker]

3 minutes ago, Ed Stone said:

Interesting 06Z today: two potentially damaging storms in the short-term; in the middle-term, a few days' TM air with 850s of almost 10C, and, last but not least, the one that will never verify: the magic that frequents the T+384 time period!

So, it's as you were: all to play for and more runs needed!

Yes indeed Pete. Quite interesting

[knocker]

3 minutes ago, karyo said:

This may look kind of promising (apart from the fact it is in the far depts. of FI) but I can't see it lasting as the stratospheric profile for the same timeframe couldn't be more hostile for Northern blocking.

But it does rather support the anomalies

[karyo]

3 minutes ago, knocker said:

But it does rather support the anomalies

Those look like supporting a mid latitude high rather than northern blocking.

Besides, the 6z has a stronger vortex.

[mb018538]

Yes, the nice bulge there ties in with the height rises now shown.....but anything longer lasting over the pole is nigh on impossible with that set up. It would soon get obliterated and squeezed back south.

[knocker]

1 minute ago, karyo said:

Those look like supporting a mid latitude high rather than northern blocking.

Besides, the 6z has a stronger vortex.

That's why i said supporting the anomalies.

[knocker]

8 minutes ago, karyo said:

Those look like supporting a mid latitude high rather than northern blocking.

Besides, the 6z has a stronger vortex.

I'm not sure what you are indicating by that but yes the 06z has an organised Canadian vortex and confirmation of the Azores influence vis the UK

 

Edited December 20, 2016 by knocker

[karyo]

1 minute ago, knocker said:

I'm not sure what you are indicating by that but yes the 06z has an organised Canadian vortex and confirmation of the Azores influence vis the UK

 

The 30hpa charts show a stronger, flatter vortex centered in the Arctic.

I always follow the chart provided by  netweather : http://www.netweather.tv/index.cgi?action=nwdc;sess=

[Interitus]

57 minutes ago, Banbury said:

Chilly enough at ground level

They really aren't cold temperatures for midday on 26th December.

[Seasonality]

10 minutes ago, karyo said:

The 30hpa charts show a stronger, flatter vortex centered in the Arctic.

I always follow the chart provided by  netweather : http://www.netweather.tv/index.cgi?action=nwdc;sess=

No criticism of either you or knocker, but one thing this winter has shown so far is a disconnect between longer term forecasting and the resulting weather. At this range you both have a valid point and show signals both supporting and discounting such an outcome. But going back to the disconnect is it not possible we will have an unforeseen situation arise that goes against what some signals show. In a probabilistic sense we were meant to have a blocked "front loaded" (for cold) winter due to various supporting factors. The lower probability outcome has ended up prevailing due to other factors. Moving forward we could just as easily have a situation where a lower probability cold outcome could arise, potentially against some factors as Karyo has already put so well. It could be a winter of surprises in the timing of mild and cold outcomes. 

PS I do like seeing discussions like the two of you are having, improves everyone's knowledge

[stewfox]

44 minutes ago, knocker said:

Yes indeed Pete. Quite interesting

I think the T384 chart is below

The period your referring to is before that.

 

[Methuselah]

2 minutes ago, stewfox said:

I think the T384 chart is below

The period your referring to is before that.

 

I think knocker was referring to the warm part of 'interesting', Stew. Not that either scenario will likely ever become reality...

[mulzy]

Decent deep FI chart from the 0z GFS Parallel:

Edited December 20, 2016 by mulzy