Model Output Discussion 01/09/17

[Jeremy Shockey]

3 minutes ago, Broadmayne blizzard said:

Bearing in mind that nothing was really looking like happening until the final week of November any way I,m quite happy with the ECM 240 northern hemisphere chart this morning. High pressure across the pole and Greenland and the jet digging south of the UK.

yes , lots of blocking potential still around this morning with high pressure across Greenland. Good chances of a brief Northerly on both GFS and ECM.

 Even the UKMO solution would probably give us a cold dry end to Nov with high pressure moving in.

[comet]

1 hour ago, northwestsnow said:

The pick of the big 3 at 144 is UKMO in my opinion.

Surely the only way forward from there is retrogression?

That said, and in the interests of balance im not sure how much stock im placing in UKMO at the moment, seems to be having wobbles.

Yes I would take the ukmo t144 chart over the other two without question. There seems little point looking beyond this time frame until the models can reach agreement.

[northwestsnow]

6Z driving snow showers into NW Scotland by next friday - looking at this stage like the colder air wont make it south of the border due to the Atlantic northern arm forcing the ridge towards the UK.

Certainly nothing like UKMO 0z- wonder if there are some problems with the UKMET model at the moment- seems out of kilter with the other big 2.

Edited November 12, 2017 by northwestsnow

[Summer Sun]

UKMO extended has low pressure to the west of Portugal whereas ECM and GFS have high pressure the result is UKMO has the UK settled whilst GFS and ECM have us unsettled

[northwestsnow]

Just now, Summer Sun said:

UKMO extended has low pressure to the west of Portugal whereas ECM and GFS have high pressure the result is UKMO has the UK settled whilst GFS and ECM have us unsettled

Yes good post Gavin- ukmo looks the more appealing at 144 but one has to question the UKMET model at present- as i posted above it seems way out of kilter at this time.

[bluearmy]

We will call the 00z suites a bit of a mess. with ukmo releasing a cut off low (from way south which must have some pretty warm air wrapped up in it) on day six to ec op which retrogresses an Arctic high into the n Atlantic day 7.  Yesterday morning I mentioned that the background direction of travel was undercutting of a n Atlantic ridge - not much has changed, in fact I'd say it's strengthened. given the glass half full perspective of the 12z suites yesterday, I'd say this morning has swung back a bit towards the coldies.. the ec extended control looks to be quite a snowy run so potential remains. 

there is no way anyone is taking their eyes of this just yet - even Crewe! 

[northwestsnow]

1 minute ago, bluearmy said:

We will call the 00z suites a bit of a mess. with ukmo releasing a cut off low (from way south which must have some pretty warm air wrapped up in it) on day six to ec op which retrogresses an Arctic high into the n Atlantic day 7.  Yesterday morning I mentioned that the background direction of travel was undercutting of a n Atlantic ridge - not much has changed, in fact I'd say it's strengthened. given the glass half full perspective of the 12z suites yesterday, I'd say this morning has swung back a bit towards the coldies.. the ec extended control looks to be quite a snowy run so potential remains. 

there is no way anyone is taking their eyes of this just yet - even Crewe! 

Yes- nice post Blue

I suspect METO will stick with their updates as it stands, 6Z trying to push the jet into Europe but its the mother of all battles getting rid of the heights across Europe (whas new)!!

I am really suprised to see UKMO model struggling like it has recently- although i much prefer that models solution at 144 this morning i have zero faith in it.

[Geordiesnow]

38 minutes ago, northwestsnow said:

Yes they are the mean charts as it says at the top of my post

Looks cold and mainly dry for most IMHO.

Certainly nothing to suggest Atlantic domination but NWP  seems very chaotic at the moment.

Oops sorry, clearly it's too early for my eyes to read properly! 

GFS06Z at least shows the initial trough trying to dig in which will bring some cooler uppers and decent convection it does seem to be backing away from the Atlantic ridge that yesterday's 06Z run showed. A lot of uncertainty still though.

[BLAST FROM THE PAST]

Great runs this morning.  Around the 20th is very interesting indeed and a period in mind is also 24-28 for potentially most active period.  If the real cold air is over as anticipated I suspect there’ll be a lowland sow event for many.  Yesterday showed how knife edge this situation is but currently I am very happy with how this is developing.  

06z following nicely

BFTP

[northwestsnow]

Well last one for me before heading out-

6z maintains the cold feed through next week ,suspect NW Scotland will see some snow showers before too long- and for the rest of us cold and mainly dry will be the theme- really enjoying the models at the moment- probably because there are no zonal + NAO runs on the menu- yet!!

Edited November 12, 2017 by northwestsnow

[northwestsnow]

Oh go on then one more- third week of Nov looks  on 6z- a few snapshots-

Lovely

[The PIT]

Suddenly a differing view between the models UKMO may follow ECM's lead but doesn't go out into FI land far enough. GFS now on it's own. I'd prefer the ECM run however it's looking like the models maybe thinking about a general change in the pattern. Anyway at least we've got some interesting charts to look at.

[Frosty.]

If coldies ain't satisfied with the Gfs 6z they should find a new hobby..it's still almost 3 weeks from official winter and overall the trends are looking good for those who are fed up with mushy mild dross!??

[Duane S.]

Surprised there is not more positive chatter about the 00z suite. Definitely a move back in right direction, assuming it is a decent cold spell you are looking for.

The ECM is certainly interesting. Never mind shortwave spoilers, it introduces a high pressure spoiler as a small cell develops smack over us just as the scandi trough starts to drive down some proper cold uppers! It's plausible looking also at the trough to our south west. What happens next would be my interest. This all will end up being fascinating viewing as we get into the last third of the month and towards December.

I get the concern over the lack of stratospheric 'assistance' here but at this time of year it is rare it does get that involved in terms of wavetrain influences (save that for later in the year). We have a disconnect and will for a little while yet, so there is a definite window of opportunity for a tropospheric driven cold spell in the offing.

Be cautious yes, as we will need a good dose of luck no matter what  but be grateful we even have a shot at a cold spell, as I suspect Mid December onwards for a few weeks thereafter we COULD be looking down the zonal / stormy barrel before we are right back in game later in January. Just my take on the winter of 17/18 (yet to even start, we do need to remind ourselves).

[Zakos]

The medium range output is excellent and full of potential IMO, just in time for us to see widespread snowfall.

The jet stream looks like its going to become progressively weaker and less organised as we head into winter proper,

Edited November 12, 2017 by Zakos

[blizzard81]

Almost an irresistible urge from the models this morning to bring in a north easterly around the 21st Nov. 

[Dancerwithwings]

4 minutes ago, Zakos said:

The medium range output is excellent and full of potential IMO, just in time for us to see widespread snowfall.

The jet stream looks like its going to become progressively weaker and less organised as we head into winter proper.

 

SVID_20171112_111412.mp4

Agreed, 06z GFS showing signs of that (weaker and less organised) jet stream late in Nov and also plenty of blocking potential.....Regarding trends for now, a zonal course is off the Menu 

[Zakos]

I can understand the skepticism of some posters regarding the upcoming cold spell

But the day 6 output screams potential.

I was an avid watcher of the anomaly charts last season, and I dont recall seeing anything like this within the medium range.

All to play for IMO

 

[MR EXTREMES]

6 minutes ago, Zakos said:

I can understand the skepticism of some posters regarding the upcoming cold spell

But the day 6 output screams potential.

I was an avid watcher of the anomaly charts last season, and I dont recall seeing anything like this within the medium range.

All to play for IMO

 

I was just about to post ao and nao charts if we can tank the ao by at least -4 or below that would be great.

Nao although neg not enough in my opinion meaning north Atlantic could well be more active.

Although perhaps Scandinavia greenland retrogression of coarse my money more on heights over UK the drifting slowly north so perhaps chilly settled in the southern half gradually getting colder and colder.

If the ao is correct then the vortex will be on the ropes.

So from now till first week of December is when we need to see further disruption to the polar vortex also would be nice to see the jet stream further south perhaps into spain.

2010 see the jet often in North Africa.

Charts today still show promise although looking at them confusion of timing of the low leaving the Eastern seaboard of the united states.

But this has always been a problem year in year out.

I'm adamant there will be stratospheric warming this year or early 2018.

Very interesting.

good thing east QBO seems to show promise although this is only one part of the Jigsaw puzzle.

So far I'm happy.

[bluearmy]

13 minutes ago, MR EXTREMES said:

I was just about to post ao and nao charts if we can tank the ao by at least -4 or below that would be great.

Nao although neg not enough in my opinion meaning north Atlantic could well be more active.

Although perhaps Scandinavia greenland retrogression of coarse my money more on heights over UK the drifting slowly north so perhaps chilly settled in the southern half gradually getting colder and colder.

If the ao is correct then the vortex will be on the ropes.

So from now till first week of December is when we need to see further disruption to the polar vortex also would be nice to see the jet stream further south perhaps into spain.

2010 see the jet often in North Africa.

Charts today still show promise although looking at them confusion of timing of the low leaving the Eastern seaboard of the united states.

But this has always been a problem year in year out.

I'm adamant there will be stratospheric warming this year or early 2018.

Very interesting.

good thing east QBO seems to show promise although this is only one part of the Jigsaw puzzle.

So far I'm happy.

none of the ens suites from the big three have taken the AO below -3 since Friday. the odd nao sub -2 but mainly now above -2.  The nao was never modelled much below there so that not a pull back but clearly the GEFS were very keen on a sub -4 AO for quite a few days earlier this week. 

the ec op this morning has trended back to sub -4 which is the first ec op run for a couple days to do so. all in all the trend  is a shallower phase than looked likely although the next op ec may be significant if again goes sub -4. 

[bluearmy]

For illustration, see the week from 15/11 on the eps from 3 days ago and today

 

[nick sussex]

What a mess!

I'm afraid we're back to the usual shortwave dramas that seem to be part and parcel of the UKs often tortuous route to cold set ups.

So just when you thought my shortwave obsession had been put on hold its back with a vengeance. To add to the uncertainty is the ECMs suggestion of a west based neg NAO by day 10 which as everyone knows I detest.

A pointless waste of blocking for us in western Europe!

So anyway perusing todays outputs we're still none the wiser as to what the weather on the ground will be because much depends how incoming shortwave energy phases with the troughing over the UK.

This type of set up can produce some fireworks for coldies if you have enough embedded cold but this seems a bit lacking at the moment.

However that might change but even before then the issue is getting strong enough heights to the nw to force the pattern sufficiently south.

The UKMO after backtracking towards the ECM/GFS now seems to have gone off on a mystery tour again which throws further uncertainty into the mix.

Overall lots of drama to come but don't bank on what the ECM/GFS show until the issue of that shortwave energy comes into the more reliable timeframe.

 

Edited November 12, 2017 by nick sussex

[ICE COLD]

Quite a few ens members flat lined going towards -10 850s from about the 21st . Always what you wanna see when looking for a cold spell . Let's hope it continues . 

Edited November 12, 2017 by ICE COLD
Spelling

[nick sussex]

In the GFS 06hrs run two shortwaves are ejected by the main upstream troughing, its only after the passage of the second one that colder air gets sufficiently south and even then we're not talking of anything really cold in terms of upper air. However we do see the development of a colder pool towards Scandi by day ten.

The ECM does have an initial better looking block to the north  but its move to a west based negative NAO is disappointing.

The GFS 06hrs run at least doesn't develop that and would save me from throwing my toys out of the pram!

I think what we're really missing is sufficient cold air to the ne and so in that sense the stakes aren't as high as they might be however I do like the look of that cold pooling over Scandi which could eventually work its way towards the UK.

Overall given what mild mush horror show could be on offer at this time of the year at least the outputs show some plausible routes to something colder, for the timebeing I wouldn't worry so much about the depth of cold but overcoming initial shortwave issues.

 

[bluearmy]

Nick - I wouldn't get too hung up on ec op day 9/10 showing a west based neg nao - mainly driven by phasing of Atlantic lows. With a euro trough of sorts consistent across all ext modelling we should get the southern arm taking enough flow to keep us on the cold side although whether that's cold enough would be the question