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

[Chris.R]

Some very encouraging and interesting tweets from Matt this morning. Sorry can't link ATM but sure someone will.

[Seasonality]

4 minutes ago, Dennis said:

what you exactly mean ? Is it you like to see model output or something else?

Hi Dennis, thanks for the posts by the way, some interesting charts you are putting up. I am curious as to how GFS and ECM perform in terms of accurately predicting phases of the Madden-Julian Oscillation so I can have an idea which outcome is more likely when looking at the broad scale outcome for Europe.

[Summer Sun]

1 minute ago, Chris.R said:

Some very encouraging and interesting tweets from Matt this morning. Sorry can't link ATM but sure someone will.

 

[northwestsnow]

2M..temps,verycold..Europa@christmas...

[Dennis]

Just now, Seasonality said:

Hi Dennis, thanks for the posts by the way, some interesting charts you are putting up. I am curious as to how GFS and ECM perform in terms of accurately predicting phases of the Madden-Julian Oscillation so I can have an idea which outcome is more likely when looking at the broad scale outcome for Europe.

Hi at the moment you see GFS more blocked with high at the North of Europe and EC with more change of an SW ly - last days we see always this diff and between 15-20dec more will be clear i hope ; more details will need but there is an 70-90% chanche for cold weather to come 

Time will tell and ill show more coming days

[Chris.R]

Thanks SS :-)

[carinthian]

39 minutes ago, carinthian said:

Massive block over Southern Scandinavia for Christmas period on the run. A cold surface flow for many. Should cheer a few up on here at least!

Hi, I don't want to get your all too excited about snow on Christmas Day but it is possible on this run. I know its just one run but its there ! Of course there is no great depth to the cold but the 500mb- 1000mb layer thickness values do show potential for a bit of wintry mix as the chart below shows thickness values not far of the 528 dam values. The lower atmosphere temps will be close to freezing in that flow. Lets hope this is the trend, it has been here for a while, its just needs a lowering of heights over Southern Europe and cold advection can take place very quickly. Russia is under a lot of snow cover presently.

 C

[snowsummer]

2 hours ago, Devonshire said:

Hi SS - I started a thread on this a week or two back:

 

 

Thank you and @Yarmy for your replies.

[feb1991blizzard]

11 minutes ago, abbie123 said:

Just need push that high bit further north then we are in freezer. 

I'm probably not good or technical at explaining this but that flow would actually be ok if the frigid uppers were in a straight direct line with the flow, its all about timing, the shape of the high has to re-orientate just at the moment when the uppers are in the line of the flow, A south Eastern component in an Easterly can still deliver sometimes, on that chart if the frigid (and I mean really frigid as there would be moderation - circa -15 or less) uppers were much further South and West, then they would start to come towards us along the line of the flow.

[ITSY]

Something we should all be concerned about is the impending possibility of a nose dive in temperatures across the N/Eern Med region. The Canadian run this morning would bring snow and plunging temps across Syria at the worst possible time. -8 uppers in desert regions can be cripplingly cold, even with the added luxury of thermal clothing! This isn't the normal place for this and I hope the mods will allow it to remain, but we should take a moment to reflect on what the true impact of weather can bring to so many people. If anyone can help or donate anything in the festive spirit to the displaced children out in these war ravaged places, please PM me and I'll direct you to the right places. Let's be thankful that our lives can (for the most part) accommodate all the varieties of weather that nature can throw at us here at home  

Edited December 12, 2016 by ITSY

[karlos1983]

Let's not forget that this is one GFS 06z run, hardly renowned for being a trend setter! I am keeping my hopes well in check until this is repeated on the 12z and given some backup by the euros!

[Dennis]

Just now, karlos1983 said:

Let's not forget that this is one GFS 06z run, hardly renowned for being a trend setter! I am keeping my hopes well in check until this is repeated on the 12z and given some backup by the euros!

then pls also watch the para GFS 0z .....

[northwestsnow]

3 minutes ago, feb1991blizzard said:

Even if it is a trend setter, theres no guarantee of anything coming of it, it would probably be a trendsetter for zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

Very..cold..xmas...

[feb1991blizzard]

Just now, northwestsnow said:

Very..cold..xmas...

No precipitation though - warm pool aloft - agree better than mild though, sick of walking outside these last few days and my head itching because its too hot.

[Carl46Wrexham]

1 minute ago, northwestsnow said:

Very..cold..xmas...

I'll take that all day long. Remember Christmas last year? Dull, mild and wet. 

 

[karlos1983]

11 minutes ago, feb1991blizzard said:

Even if it is a trend setter, theres no guarantee of anything coming of it, it would probably be a trendsetter for zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

Ensembles don't scream cold HP to me...

[feb1991blizzard]

1 minute ago, karlos1983 said:

Ensembles don't scream cold HP to me...

What do you mean? theres only about 3 or 4 that suggest frigid uppers, the rest are either slightly below average or mild, if they were in a N-NW flow then yes because you could take a few degrees off them further North so some places would be in the genuine cold category.

[Methuselah]

Just as someone suggested above, three weeks' watching paint dry...My advice: don't let your 'emulsions' get the better of you!

[karlos1983]

3 minutes ago, feb1991blizzard said:

What do you mean? theres only about 3 or 4 that suggest frigid uppers, the rest are either slightly below average or mild, if they were in a N-NW flow then yes because you could take a few degrees off them further North so some places would be in the genuine cold category.

What I mean is if the high pressure was well supported we would see a tighter bunch of below average 2m temperatures. from how I read it, majority are going pretty mild, with only a few below average, suggesting not a continental feed? I could of course be completely wrong... 

i for one hope the high is correctly modelled for Christmas as nothing is worse than mild and wet in xmas day. 

[feb1991blizzard]

6 minutes ago, karlos1983 said:

What I mean is if the high pressure was well supported we would see a tighter bunch of below average 2m temperatures. from how I read it, majority are going pretty mild, with only a few below average, suggesting not a continental feed? I could of course be completely wrong... 

i for one hope the high is correctly modelled for Christmas as nothing is worse than mild and wet in xmas day. 

Right - yes I agree on mild. could be that a lot are modelling a high but some a cloudy high though, based on Matthew Hugo's tweet I would suggest high.

Edited December 12, 2016 by feb1991blizzard

[karlos1983]

The GFS 06z OP goes of the scale, but interestingly is not alone!

 

P5 Looks like it just jumped off a cliff on that chart 

EDIT: 955 low JFF

Edited December 12, 2016 by karlos1983

[Man With Beard]

13 hours ago, Mucka said:

If we get an Easterly by Christmas I'll run in the street naked.

And nobody wants that!

If I had a reputation, I would stake it on no Easterly.

I still think any small chance of cold for Christmas will come from the North and blocking to the West rather than from the East and a Scandi/Russian high. Even taking into account latest anomaly charts.

I would even happily accept the humiliation of being so wrong, should one crop up and give us a chance of snow at Christmas.

 

 

Since you did not specify a particular date "by" Christmas, I think the world is about to see you in all your glory, Mucka.

About 1000 miles of easterly from the Polish border to West Wales, just about including Manchester. 

[Tamara]

Indecision related to tropical convection persists related to "destructive" signal of further cyclone activity in the I/O - which continues to interfere with the low frequency (amplification) signal over Indonesia. Additionally there is now a watch in place for significant tropical cyclonic activity in the Western Pacific (a good thing)

.

http://tropic.ssec.wisc.edu/

The problem is that global models are not identifying these close resolution developments and hence the extra unreliability of the MJO model forecasts.

The latest 10 to 15 day model suggestions of a westwards shift of the hooligan vortex segment over Canada and removal of Aleutian High  (both combining to cause the cold pooling over NE US and steepened gradient downstream) ties in well to a section of my Saturday musings over how future seasonal wavelength changes could help augment blocking signatures into more ideal positioning over the longer term

On ‎10‎/‎12‎/‎2016 at 14:27, Tamara said:

If we consider that the models are programming another ramp up of energy in the Atlantic according to another low(er) AAM phase,, then I think it is significant that the long wave pattern has adjusted westwards(discontinuous retrogression) compared to November - and the storms and their secondary developments struggling to extend as far eastwards.

Assuming the atmospheric cycle can rebound again in terms of angular momentum and a return of the GWO to Phase 4/5, at the same time as the above Eurasian feedbacks seasonally beat a stronger drum imprinting stratospheric warming, then its not too difficult to see that height rises to the North and North East are quite conceivable as we head further towards and into January  - naturally helped by seasonal wavelengths adjusting the synoptic pattern favourably for us

Taking into account the painfully slow and highly uncertain evolution towards, hopefully, a better tropical signal eventually (in terms of downstream amplification) then it is conceivable to see how a better orientated block may appear -  resuming cold pooling to the NE in such a way that it may advect SW'wards on its southern flank - rather than southwards through eastern most Europe and towards Turkey and Greece.

In terms of the NAO - this is where a more concerted eastwards tropical forcing signal is required through MJO Phases 7 and 8 at the same time as another injection of poleward atmospheric angular momentum re-orbits the GWO back through Phase 4 and into (disconnected) Nino attractor phases 5,6,7. Notwithstanding what I said yesterday about the later timing of a higher amplitiude wave being into January, such a development into the New Year could still ultimately be a compelling -NAO signal in pulling cold air westwards on the northern flank of disrupted troughing heading into Biscay and Iberia- but as stated by some, the hardest part of the jigsaw to achieve.

Long term models struggle with blocking patterns as does shorter term NWP. GloSea5 might (currently) be jiving less than previously with longer term -NAO signals, but it can be seem how one *could* evolve. Also based on what is a truly a wildcard winter as Tony/Lorenzo so accurately captured at the weekend, this is one winter that doesn't have any inevitability about it - either way

It appears to feel like it to some, but we are not slow dancing in a burning room like we were this time last year. There is an abundance to keep us occupied 

 

Edited December 12, 2016 by Tamara

[Man With Beard]

The 1030mb high is still there by T360 on the mean - incredible!!

But given the vast range under 1020mb mean, I'm not sure it's too helpful in pinpointing where the block will be centred - could be anywhere within the 1020mb range, really, although most probably on the western side given the low heights to the east. 

[Methuselah]

8 minutes ago, Tamara said:

Indecision related to tropical convection persists related to "destructive" signal of further cyclone activity in the I/O - which continues to interfere with the low frequency (amplification) signal over Indonesia. Additionally there is now a watch in place for significant tropical cyclonic activity in the Western Pacific (a good thing)

.

http://tropic.ssec.wisc.edu/

The problem is that global models are not identifying these close resolution developments and hence the extra unreliability of the MJO model forecasts.

The latest 10 to 15 day model suggestions of a westwards shift of the hooligan vortex segment over Canada and removal of Aleutian High  (both combining to cause the cold pooling over NE US and steepened gradient downstream) ties in well to a section of my Saturday musings over how future seasonal wavelength changes could help augment blocking signatures into more ideal positioning over the longer term

Taking into account the painfully slow and highly uncertain evolution towards, hopefully, a better tropical signal eventually (in terms of downstream amplification) then it is conceivable to see how a better orientated block may appear -  resuming cold pooling to the NE in such a way that it may advect SW'wards on its southern flank - rather than southwards through eastern most Europe and towards Turkey and Greece.

In terms of the NAO - this is where a more concerted eastwards tropical forcing signal is required through MJO Phases 7 and 8 at the same time as another injection of poleward atmospheric angular momentum re-orbits the GWO back through Phase 4 and into (disconnected) Nino attractor phases 5,6,7. Notwithstanding what I said yesterday about the later timing of a higher amplitiude wave being into January, such a development into the New Year could still ultimately be a compelling -NAO signal in pulling cold air westwards on the northern flank of disrupted troughing heading into Biscay and Iberia- but as stated by some, the hardest part of the jigsaw to achieve.

Long term models struggle with blocking patterns as does shorter term NWP. GloSea5 might (currently) be jiving less than previously with longer term -NAO signals, but it can be seem how one *could* evolve. Also based on what is a truly a wildcard winter as Tony/Lorenzo so accurately captured at the weekend, this is one winter that doesn't have any inevitability about it - either wayIt appears to feel like it to some, but we are not slow dancing in a burning room like we were this time last year.

There is an abundance to keep us occupied 

Great post, T...The 'drying paint' is clearly not to be found within the models - it's only out of the window!