Model Output Discussion 29th December - Into mid-Winter.

[ArHu3]

1 minute ago, Gael_Force said:

Try using the geopotential heights chart before making such an erroneous claim.

where can we find these?

[Snowman.]

1 minute ago, ArHu3 said:

where can we find these?

http://www.instantweathermaps.com/GFS-php/strat.php

[Stuie]

16 minutes ago, karlos1983 said:

Very odd chart

Well that`s Brexit for you Karlos, even Greece are taking the P.......

If we are looking at FI then the 850`s look pretty epic a stones throw away.

[Mucka]

1 minute ago, karlos1983 said:

Browsing the ensembles at 192 And they are very reassuring if it's cold you like

They are poor compared to the 06 suite for any sustained cold Karlos with the ridge much flatter and Northerly short lived where it makes it in the majority of runs.

Still, if you are glass half full type then there are enough decent runs in there to keep you optimistic.

[Captain Shortwave]

Whilst we are seeing a swing to the UKMO evolution, it is nice to see a sharper and more amplified pattern emerge when you compared the UKMO today to yesterdays. If we could amplify things a little further we might see a quicker Scandi high evolution develop.

   

 

Arpege at around day 5

A good chance of an easterly from here, we might not get the retrograde but the high could lift northwards close to the UK and bring a deep cold easterly later on.

[legritter]

Although the  gfs run as just changed its mind again ,look at the cold its only a stones throw away and at 7 days away it could easily flip back tonight with a stonker . Ecm of course critical but with todays met update in our favour its still looking good ,we all know good things take time ,are we approaching A knife edge situation ,that could be good seen it many times before in winters past ,stay calm gang  catch you all up later ,from behind settee 

[Iceberg]

5 minutes ago, Mucka said:

You won't really see the move toward UKMO manifest that way. It will generally lead to a less potent more short lived Northerly with flatter upstream.

If you wait for the 192/240 mean pressure charts and compare to the 06z I think that will show you how far they have actually shifted.

Here's the ens mean compared 06z an 12z at t240. I can't see a huge difference , except the higher pressure. 

[snowking]

Well a lot of overreaction in here as ever

Firstly - anyone who had thought before this that any sort of scenario was nailed at such a range is rather short sighted. We vaguely know that we're looking at high pressure somewhere close to the N of the UK (or potentially even over it) - the exact placement/alignment will not be clear for some days yet.

Secondly, there's a reason for running ensemble suites - to try and minimise the chaos of an operational run. The NOAA and ECMWF are not just running these suites for our entertainment. Looking through the individual GEFS very little (if any) support for the operational solution there. Not to say that this automatically makes the operational wrong, but you work based off of the evidence in front of you.

Finally, even if we want to take the GFS operational at face value, I've seen a lot worse endings hemispherically than this:

Aleutian Low - Check. Scandi High - Check. Result - trouble for the vortex.

All academic at this range.

It's always difficult to rein in expectation, but for now the form horse is still dry and rather cold, and that is the way the Ensembles have been painting the picture for the last 48 hours or so. Of course with some of the Day 11-15 eye candy and lower than average heights running underneath any future high, there's always the hope of something more interesting manifesting.

SK

[Gael_Force]

1 minute ago, ArHu3 said:

where can we find these?

http://www.instantweathermaps.com/GFS-php/strat.php

or on netweather charts here though it is for 30hPa rather than 10hPa

http://www.netweather.tv/index.cgi?action=nwdc;sess=

[Banbury]

14 minutes ago, Ali1977 said:

GFS ENS looking good, the mean is way colder than the Op at day 8

Yep totally agree , its always best to wait until the ENS are coming out

Up to 174 the OP is on its own in the ENS set the P's below bring in a Northerly on days 6-7

20 , 18 , 17 , 16 , 13 , 12 , 11 , 8 , 7 , 5 , 4 , 3 , 2 , 1 ( just )

[Snowman.]

 

 

3 minutes ago, Iceberg said:

Here's the ens mean compared 06z an 12z at t240. I can't see a huge difference , except the higher pressure. 

The massive cold to east should show it. -8 off the coast on 6z and its inland on the 12z. 

Edited December 30, 2016 by SN0WM4N

[Banbury]

9 minutes ago, Summer Sun said:

 

 

How can Matt say on the one hand GFS 12z wont be any good for coldies out there and then say wait for full data set before drawing a conclusion ????

[karlos1983]

9 minutes ago, Mucka said:

They are poor compared to the 06 suite for any sustained cold Karlos with the ridge much flatter and Northerly short lived where it makes it in the majority of runs.

Still, if you are glass half full type then there are enough decent runs in there to keep you optimistic.

Yes I am a half glass full person. So is the control 

 

 

Edited December 30, 2016 by karlos1983

[IDO]

Just now, karlos1983 said:

Yes I am a half glass full person. So is the control 

 

That's the 06z, the 12z is relatively poor up till D12.

[The PIT]

1 minute ago, Banbury said:

How can Matt say on the one hand GFS 12z wont be any good for coldies out there and then say wait for full data set before drawing a conclusion ????

He'll be referring to the UKMO run.

[Iceberg]

That's just the -6 line being where the -8 line was for an ens mean 10 days out that's a tiny change !

[AWD]

Just now, Banbury said:

How can Matt say on the one hand GFS 12z wont be any good for coldies out there and then say wait for full data set before drawing a conclusion ????

Because the 12z GFS isn't of too much interest to coldies compared to recent GFS Op runs (although perhaps change coldies to snowies as generally speaking it still remains on the cool side of average with surface cold etc for the reliable).

He then goes onto suggest to wait for all operational and ensemble data to be released before making any conclusions regarding tonights 12z forecast for next weekend & beyond.

Rather sensible I think but I'm probably speaking for relatively few members on here?

[karlos1983]

3 minutes ago, IDO said:

That's the 06z, the 12z is relatively poor up till D12.

Posted wrong chart. But point still stands.control looks good to me?

[mhielte]

5 minutes ago, Banbury said:

How can Matt say on the one hand GFS 12z wont be any good for coldies out there and then say wait for full data set before drawing a conclusion ????

Well he can, and he did. However the GFS op is way out on its own after the 6th. Matt is a knowledgeable chap but he jumped the gun a little on this one!

[chris55]

I think with a lot of runs churning out charts "against climatology" i.e these cold synoptics are not very common in more recent winters. Then i do wonder if inter-run inter-model changes has something to do with how all the data and leanings of the models in recent years may actually make them worse at picking out a proper cold spell.

UKMO seems determined to push everything back into a more "normal" pattern with that azores low doing its best to end up "where it should be".

Its probably rubbish, but i will sit back and reflect come the middle of Jan and see what has actually happens. 

I am fascinated to see where ECM ends up tonight.

[JOPRO]

Well it wouldn't be a uk cold spell without some drama, let's hope for us coldies this is it and we get back on track for cold soon. Thanks for the replys ref the ukmo. Is the model corrected anyway to take into account the uk location and the lower chance on the more extreme outputs coming off? Also this is the first really test of the updated ECM with these situations we await 7.00pm to see if it's been a total waste of money or money well spent!

[Seasonality]

6 minutes ago, legritter said:

Although the  gfs run as just changed its mind again ,look at the cold its only a stones throw away and at 7 days away it could easily flip back tonight with a stonker . Ecm of course critical but with todays met update in our favour its still looking good ,we all know good things take time ,are we approaching A knife edge situation ,that could be good seen it many times before in winters past ,stay calm gang  catch you all up later ,from behind settee 

I love your cheerfulness @legritter, would love to sit down to a stella and sausage bap with you one day lol. Look at the cold in Europe on this run, UK could tap into it as you say. At this rate the River Vistula is going to freeze over.  

[chris55]

3 minutes ago, mhielte said:

Well he can, and he did. However the GFS op is way out on its own after the 6th. Matt is a knowledgeable chap but he jumped the gun a little on this one!

Op an outlier at the end!

Also I read it like Matt was referring to the GFS OP as being lacklustre, not the full data set.

[Snowman.]

1 minute ago, chris55 said:

I think with a lot of runs churning out charts "against climatology" i.e these cold synoptics are not very common in more recent winters. Then i do wonder if inter-run inter-model changes has something to do with how all the data and leanings of the models in recent years may actually make them worse at picking out a proper cold spell.

UKMO seems determined to push everything back into a more "normal" pattern with that azores low doing its best to end up "where it should be".

Its probably rubbish, but i will sit back and reflect come the middle of Jan and see what has actually happens. 

I am fascinated to see where ECM ends up tonight.

It was something that was discussed a lot in 2012/2013. "Reverting to default" was what it was called unsure if it was proven but in times such as Jan 2013 (Ironically enough it was the UKMO vs all on our Jan cold spell) the models underplayed the block when its influence turned out to be stronger. 

[Singularity]

 

When it comes down to it, the upstream amplification is what really counts for the longer-term, and it will take a further substantial shift for the Azores low to cause enough trouble to prevent that from doing the job. UKMO might well be at that point which is alarming, though as implied earlier it has enough of a hang-down of lower heights to place an undercut of the high at just +168 hours on the table. Not something I'd bet on, but you never know - we should see what the run gets up to later this evening via that alternative view people have started making use of.

 

Regarding the Azores low strength in the mid-range, something I noticed with the 12z GFS was that there was much more wave development along the frontal boundary moving south 1st-2nd Jan. This tricky feature could be important for determining how much development potential then exists for the Azores low to work with. Further swings may be possible in the 24-72 hour range, which is unusually close in time,

Edited December 30, 2016 by Polar Maritime
To move discussion on.