Model Output Discussions 06z 04/11/16

[SMU]

(zakos et al)

Ive not had much time to review over the last 24 hours

notes are :

ECM very volatile post 144 ( but yes 240 core of vortex to the east of the pole does no harm - rem late Nov 10 for second wave of cold )

GFS always eastward bias

UKMO very consistent - wanting to slide second system into the UK

- All models finally locating closed off low at 72 in the West / SW ( which is where UKMO placed it at 144 - GFS showing the most adjustments westwards as usual

- models now signalling snow from sider 1 which IIRC I mentioned the other day

- Record breaking -AO october...

 

S

 

Edited November 6, 2016 by Steve Murr

[swfc]

There seems imo a bit of model fatigue creeping in  already looking at some posts!!  Anyway the chopping and changing continues which seems reasonable given the upstream variables esp coming out of the esb.Instead of looking at day ten ete on anymodel id say stick to the ukmo and to an extent to the other models in the short term.Not sure but if its been asked or checked but has anymodel this autumn got near a correct ten day chart?? given the ao record maybe but just a thought.

Edited November 6, 2016 by swfc

[Frosty.]

The Ecm 00z ensemble mean shows the atlantic influence increasing through the run with trough, ridge, trough etc as the Azores high and lower heights to the nw / n ebb and flow with a wnw / ese aligned jet taking shape.

[SLEETY]

Messy looking models today,think they are really struggling with the different atmospheric pattern this AUTUMN

[bluearmy]

Tough to put any meat on any bones but broadly speaking, the upper trough is trying to get to our east in week 2 but the heights to our ne won't allow. This is nothing new thus far (has been the background for a while) but the additional energy in the northern arm is going to force the issue which currently shows the upper trough sinking across w Europe (from the nw) as a consequence.  Extended eps and GEFS not too dissimilar  which provides some added confidence for the 10/15 day period.  Deciding how any upper trough and low anomoly translates to surface conduitions re generally unsettled cold, cool or average unknown. 

I expect the theme of systems heading in on a nw/se axis will continue, interspersed with ebb and flow of the Atlantic ridge into the west of the UK 

as far as the AO for November is concerned, currently the GEFS are returning it negative such that the month would be able to return neg without any sig Arctic ridges popping up last third of the month. The eps and geps look more difficult in that regard and we could end up with a slightly positive number should the Arctic pattern stay the same post 20th. (My rough estimate of the AO for the 21/11 based on the 00z eps is approx -0.5). 

Edited November 6, 2016 by bluearmy

[pdiddy]

9 hours ago, weirpig said:

No but the Cfs is mild winters over 

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=1410&mode=0&carte=1&run=0

This CFS, you mean?

[Zakos]

Yes, the ECM does show atlantic influence for a time.

Blocking is weakest on the ECM at +120

However, within 3 days, the atlantic block reasserts itself... even stronger anomaly in the atlantic than we have right now.

Remarkably strong and stubborn blocking in the atlantic this autumn.

[phil nw.]

Good morning all.

Unfortunately a post with no model discussion has been removed.Any general chat about snow, incl.pics.,and general chat about Winter prospects should go into other threads.

Thanks.

 

[Banbury]

19 minutes ago, pdiddy said:

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=1410&mode=0&carte=1&run=0

This CFS, you mean?

That would do nicely

[Frosty.]

46 minutes ago, Zakos said:

ECM showing atlantic gaining ground??

 

The Ecm 00z ensemble mean certainly does

[bluearmy]

20 minutes ago, pdiddy said:

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=1410&mode=0&carte=1&run=0

This CFS, you mean?

most recent cfs runs show HLB averages across the winter months but whether that translates to neg NAO is uncertain. certainly looks like a any positive AO would be tough to achieve under those anomolys 

tbh, not a model I particularly like as runs four times a day and output can be fairly volatile as a consequence. smoothing out the averages should get you an indication but my anecdotal impression is that it's rarely accurate more than a couple weeks out at picking something away from the climatological average. 

[Zakos]

11 minutes ago, Frosty. said:

The Ecm 00z ensemble mean certainly does

Have to agree with you on that one.

Though the mean anomaly shows a fairly weak atlantic, and any mobility likely being in the form of a polar maritime flow - no sign of south westerlies.

Also, perhaps this is showing the core of the PV moving towards Scandinavia/Siberia. Steve Murr said this would lead to second cold shot in late November.

Im not an expert, but i believe we would probably have to experience a period of westerlies before this second cold shot potentially hits the UK if that were to happen

 

 

Edited November 6, 2016 by Zakos

[Ali1977]

The differences around Greenland at 180 are huge - this run looks better but hard to believe it's correct with such big changes. Top picture latest removing a substantial lump of PV

We could see a link of heights from Scandy to Canada here - Hopefully

and here as if by magic.

 

Edited November 6, 2016 by Ali1977

[Zakos]

00Z06z

PV lobe over Greenland has virtually dissapeared on the 06z

In my opinion, the GFS doesn't have a clue and is "defaulting" to the seasonal norm

I wouldnt look beyond +120 in terms of UK weather conditions.

 

Edited November 6, 2016 by Zakos

[booferking]

High pressure building to the north again most of the energy will go under beastly could be back.

[Allseasons-Si]

10 minutes ago, booferking said:

High pressure building to the north again most of the energy will go under beastly could be back.

Yup,going under and brutal cold in Scandi,

speculative at that juncture,but fun viewing though

Edited November 6, 2016 by Allseasons-si

[Frosty.]

Yes zakos, the ECM 00z ens mean looks more progressive from the w / nw whilst the operational looks completely different.

Edited November 6, 2016 by Frosty.

[fergieweather]

12 minutes ago, Zakos said:

PV lobe over Greenland has virtually dissapeared on the 06z

In my opinion, the GFS doesn't have a clue and is "defaulting" to the seasonal norm

I wouldnt look beyond +120 in terms of UK weather conditions.

 

Until the models (= all of them!) adequately resolve how the ridge out west (tied to low Rossby wave pattern) flexes in terms of weakening/strengthening, they will continue to flip dramatically as they try to synthesise what degree of propagation unfolds with the strong jet emerging from the US. We can see lately how both deterministic models and their ensembles are leaping around from one solution to another. This situation isn't some simplistic GFS v ECMWF v UKMO issue. The overriding fact is that limited confidence exists in ANY output beyond around d4. Moreover, ensemble means are viewed with caution: eg an ostensibly NW pattern may mask possible outcomes ranging from full westerly mobility to a less progressive/blocky northerly....

Edited November 6, 2016 by fergieweather

[Zakos]

5 minutes ago, fergieweather said:

Until the models (= all of them!) adequately resolve how the ridge out west (tied to low Rossby wave pattern) flexes in terms of weakening/strengthening, they will continue to flip dramatically as they try to synthesise what degree of propagation unfolds with the strong jet emerging from the US. We can see lately how both deterministic models and their ensembles are leaping around from one solution to another. This situation isn't some simplistic GFS v ECMWF v UKMO issue. The overriding fact is that limited confidence exists in ANY output beyond around d4. 

I see, thankyou for your expert input, most appreciated! 

I am an avid model watcher, but my meteorological knowledge is basic at best. Im very keen to start learning now that I have the time on my hands.

 

[swfc]

alluded to this earlier ian

just as a side note and in fi but even when the pv is destroyed and moves east the uk still manages to be in mildish sw winds !! 

shows heighths towards greenland and east based pv dont always equate to a cold uk in practice!

[bluearmy]

2 minutes ago, swfc said:

alluded to this earlier ian

just as a side note and in fi but even when the pv is destroyed and moves east the uk still manages to be in mildish sw winds !! 

shows heighths towards greenland and east based pv dont always equate to a cold uk in practice!

The dreaded west based -NAO

generally the final hurdle to pass in order to get real winter to our shores via a greeny/ n Atlantic ridge 

[lorenzo]

Lots of volatility and upstream shenanigans to work through, nice to see @fergieweather highlight not simply a case of the different models leaning to each other as overall the picture remains in flux.

Looking broadly at the anomaly profile day 0 to day 10 signature change is the loss of the Aleutian Low and a developing positive PNA pattern.

Wonder if the ENSO tilt will give way to neutral more Nina atmosphere..

Up above the strat continues to befuddle with the vortex sluggish.

Good model watching ahead

[swfc]

13 minutes ago, bluearmy said:

The dreaded west based -NAO

generally the final hurdle to pass in order to get real winter to our shores via a greeny/ n Atlantic ridge 

it was slightly tongue in cheek but he ho .guess the serious situation here needs me to step up to the mark eh!!

So a  case of wait and see beyond the 120 mark.not a bad outlook for early november either way.Also to note the continued lack of cold into canada which again is at odds with the norm.

Edited November 6, 2016 by swfc

[bobbydog]

Just to reinforce what Ian said above,

Day 10 on the ECM and GFS respectively-

Huge differences. None of which say 'zonal atlantic'

[January Snowstorm]

As Ian alluded too neither model is covered in glory at the moment. They all have their flaws and quite often a mix of the big 3 is more correct.

Re blocking: there a big difference in weather type between an azores ridge moving North and a high over Greenland.

Whilst blocking is favoured it's the dirty damp azores block rather than anything more favourable.

I will agree though that things still look good and v different this Winter. The vortex is certainly not happy at home right now

 

Edited November 6, 2016 by January Snowstorm