Model Output Discussions 06z 04/11/16

[karlos1983]

1 minute ago, mountain shadow said:

I just cannot fathom how we cannot get proper heights into Greenland given the complete absence of the Polar Vortex in that area, mind boggling.

Right now the NH is primed, we can't fail to get cold this year... surely..

a bit like Arsenal finally topping their champions league group...., but Real Madrid and Bayern Munich finish 2nd, 

the law of Sod ensues !!

[blizzard81]

1 minute ago, mountain shadow said:

I just cannot fathom how we cannot get proper heights into Greenland given the complete absence of the Polar Vortex in that area, mind boggling.

Maybe a lack of warm air advection into Greenland?

[Singularity]

If we are to see the poleward momentum transport cause a toppling of the attempted mid-Atlantic ridge, having that ridge hold its ground right over us would be dodging a wet and windy bullet, which I'm happy enough with doing for the time being. History does however feature numerous occasions where very mild air has swept north right through the UK on its way to disrupting the vortex (and yet not enough to deem it a reliable link).

You'd think the ridge would have trouble staying put given the vortex locating over Siberia - but ECM shows a substantial lack of connection between the stratosphere and troposphere over Asia. If that happens it will be another move in favour of vertical wave activity flux (WAFz) as opposed to a quiet period during which stratospheric anomalies propagate down into the troposphere (see J. Cohen's AER blog for some insightful words on the interplay than has been taking place in recent weeks, and how this may link to very poor model consistency...)

[Scandinavian High.]

6 minutes ago, blizzard81 said:

I must admit, that did catch my eye on today's meto update. For all the talk on here of a mid atlantic block and general blocking to our north west as Dec progresses, the meto mention high pressure especially to the north & east. Mmmm!

I can't see this high pressure to north west  occurring models keep pushing back or dropping all together I might be wrong. I really do think we  are in for a big  surprise  this winter- December  with higher pressure to the north east battle ground events may be wrong time will tell.

[I remember Atlantic 252]

or something like this, no PV near greenie, us mild

 

[knocker]

The 850mb temp and anomalies. Arh...................

[blizzard81]

5 minutes ago, abbie123 said:

I can't see this high pressure to north west  occurring models keep pushing back or dropping all together I might be wrong. I really do think we  are in for a big  surprise  this winter- December  with higher pressure to the north east battle ground events may be wrong time will tell.

That's certainly what the meto seem to be implying on the latest update

[Dancerwithwings]

40 minutes ago, Steve Murr said:

Is this the new ECM ?

looks like someone at ECMWF programming has hit the 'Northern heights delete' button...

To be fair it beat the GFS the other day when it was ridging to Greenland - lets hope its 1-1 come tomorrow eve-

At least ECM cold @ 240 trying to build a scandi High--

S

 

The 0z ECM mean at 216h Is very liking to the 12z GEFS mean at 216h

Will be interesting to see the ECM mean this evening.

Edited November 23, 2016 by Dancerwithwings

[bluearmy]

my eye looking through the GEFS memebers taken by two things and they are both in the n pacific

some wierd retrogressive pattterns being played out around the aleutians and a typhoon likely in the nw Pacific in two weeks - if that engages a kamkatchkan low then the AO could fall through the floor given the  predicted polar  profile at that timescale 

Amplification around the aleutians/kamkatchkan trough could be significant features re keeping the strat vortex under pressure late Dec  

[blizzard81]

12 minutes ago, bluearmy said:

my eye looking through the GEFS memebers taken by two things and they are both in the n pacific

some wierd retrogressive pattterns being played out around the aleutians and a typhoon likely in the nw Pacific in two weeks - if that engages a kamkatchkan low then the AO could fall through the floor given the  predicted polar  profile at that timescale 

Amplification around the aleutians/kamkatchkan trough could be significant features re keeping the strat vortex under pressure late Dec  

This is something GP has been mentioning these last few days. 

[pyrotech]

The chances of models showing a Scandinavian / Siberian high are elevated this year due to the Low ice cover, large snow cover and sunspots going into minimum. We also have MJO which has left phase 8 a week ago and weakening as it traverses 1 and 2. most likely to become weak in next few days. The weak la Nina  his another factor.

over last few months we have seen a prominent Scandi high and steady blocking, which would have been a delight for chartists if had happened in Winter. 

We seem hung up on this chart or that in Fi but as always its the trend we are looking for not the actual charts. We all know that the chart looks very different at day 8 when it comes around,  The polar vortex is always an interesting part of the puzzle, but its difficult to decide where the breakout disruption will occur, it so often happens in the states, when you consider the size of the Uk we have about 1 in 8 chance of being in the sweet spot. 

The First two weeks of December are ripe for being Zonal and the jet stream normally fires up and brings wet and stormy weather to the Uk, This is as can bee seen by the models a possibility as we enter December, however it takes very little for Scand high to drag cold air in and force low pressure below the Uk bringing what many here would want. 

The met office extended forecast hints at this scenario ( wetter ) and then a dryer second half of December, High pressure is likely to be in our vicinity but it may well sit to our North east. 

What we need to look for long term is signs of the Scandal high ( thats been prominent all Autumn) to establish its self again and again as we enter Winter and mean while the models constantly hinting at possible cold incursions show the possibility of something coming out of the blue (excuse the pun)

With a moderate warming already having disrupted the vortex and another warming expected the models will struggle to get hold of anything regarding heights and positioning until they are established. The GFS has probably played every card in regards to scenario's over the last few days and ECM  has not been overly consistent either, i suspect a cold model run for Fi in GFS for Nov 4th on the 18z tonight. The models predict a jet stream of some potency with us in the firing path  early in December, however with Northern Scandi high blocking, which is likely due to reasons mentioned earlier, that jet could be significantly further South and bringing the colder air from Europe more into play.

At least its on the cards this December as last December we had no signs of positivity at this stage and the forum was like quiet here

 

 

Edited November 23, 2016 by pyrotech
added what met o forecast said

[Singularity]

8 minutes ago, bluearmy said:

my eye looking through the GEFS memebers taken by two things and they are both in the n pacific

some wierd retrogressive pattterns being played out around the aleutians and a typhoon likely in the nw Pacific in two weeks - if that engages a kamkatchkan low then the AO could fall through the floor given the  predicted polar  profile at that timescale 

Amplification around the aleutians/kamkatchkan trough could be significant features re keeping the strat vortex under pressure late Dec  

I wonder if the unusual retrogressive outcomes could be linked to tropical convection being modeled to propagate in reverse over the coming 7-10 days or more. 

Thing is though, based on GP's expectations, I figure the observed line should head slowly but surely toward phase 6 over the coming week or so, as the current tropical wave over the maritime continent edges eastward. This being what in theory encourages a ridge to build poleward from the Pacific as part of a wave 2 attack (working with a mid-Atlantic ridge) - which will be a dramatic change of scene on the Pacific side if the current modelling signals are in the right ballpark for the run-up to that crucial mid-Dec period.

Tank the AO via a deep Kamchatka low, then build ridges from the Pacific and Atlantic sides to join forces in powerful cross-polar ridging scenario. What could possibly go... yeah, you know the phrase and that it's best not to say it! 

[Man With Beard]

Well it's not far off something more northerly there. Maybe we'll get a day or two of a cold shot out of this set-up.

[stewfox]

3 hours ago, Snipper said:

Not been able to view postings. Is everything still next week?

Hard to say  , shorty summary of current thoughts..........

Patience is the key

More runs needed

Short wave spoiler , will it be a spoiler ??.. so undecided

Up stream amplification undecided

no clean route to cold

T168 looks shaky 

30th Nov is key date

Matts said seasonal outlook

Ian said trouble accurately forecasting shortwave troughs at T+12 who gives a **** re T168 

Focus on ensemble forecasting

GFS set for epic fail

SM confirms 12Z GEM better then 12Z GFS

UKMO northerly outbreak seems plausible

Models are 'struggling' on output

Just make sure your PC is working for the 'pub run', mind wasn't yesterday

 

 

Edited November 23, 2016 by stewfox

[fergieweather]

1 hour ago, bluearmy said:

I think the high to the north east was glosea for mid Dec rather than early dec

the extended eps have consistently failed to support such a feature 

Correct. GloSea5 has repeatedly signalled this outcome. ECMWF prefers (weakly) +ve GPH/MSLP build to NW-N, but postage stamps show varied support towards GloSea5. Given the latter's performance strat-wise (=why Exeter were unconvinced re GEFS SSW debacle a few days ago), there's tentative support for it's evolution but we shall see where EC Monthly heads in update tomorrow.

[feb1991blizzard]

ECM ens mean looks to me like the extended could have more members with an Atlantic ridge.

[fergieweather]

Marked ENS spread again in ECMWF post-29th, in keeping with 00z suite. Magical mystery tour.... 

[Summer Sun]

 

[fromey]

4 minutes ago, Summer Sun said:

 

Sorry big amateur here but what does this mean?? And what effect would this have??

cheers

fromey

[Summer Sun]

GFS leading coldies up the garden path again?

 

[Frosty.]

14 minutes ago, feb1991blizzard said:

ECM ens mean looks to me like the extended could have more members with an Atlantic ridge.

Agreed, it looks similar to the 00z so I think it would mean generally below average temps and becoming unsettled from the NW after the upcoming anticyclonic spell. The mean looks better than the op at T+240 hours looking upstream.

Edited November 23, 2016 by Frosty.

[Methuselah]

4 minutes ago, fergieweather said:

Marked ENS spread again in ECMWF post-29th, in keeping with 00z suite. Magical mystery tour.... 

Well, from one who was a mere nipper, back in the days of Jack Armstrong, Bert Foord, Micheal Hunt, Michael Fish, Ian McAskill, Jack Scot - and so many others, I have only the utmost admiration for the Met Office...

Why are so many folk anti Met Office? The Met, together with computer models from all over the world, combine to give us all the best information available??

Be grateful?

[karlos1983]

 tomorrow's EC Monthly update is a biggy! (As ever)

Edited November 23, 2016 by karlos1983

[feb1991blizzard]

Just now, Frosty. said:

Agreed, it looks similar to the 00z so I think it would mean generally below average temps and becoming unsettled from the NW after the upcoming anticyclonic spell. The mean looks better than the op at T+240 hours.

You see theres slightly more of a kink in what I think is the 552 line in those charts you have posted, so very very slightly different to 0z, but a tiny difference like that could mean 10 or so more members showing cold by the end of the run, Ian says 'as you were though, I am not sure why the confidence has suddenly increased in the MO tex forecast when there is such a wide spread on bothe ensemble suites ive seen.

[feb1991blizzard]

Just now, karlos1983 said:

 tomorrow's EC Monthly update is a biggy! 

Yes in many ways its more important than the 15d ensemble suites for the time being anyway.