Model Output Discussion - 31/10/2014 and Beyond

[Hocus Pocus]

I thought any pattern change to cold would be outside of the 10 day range anyway?

[radiohead]

Already identified by some posters, but just to reaffirm 00z EC DET (easterly) out at d10 considered outlier by UKMO M-R forecasters; and whilst 'not out of the question' it's considered only 10% PROB, with continuation of unsettled W/SW influence the favoured scenario into next 10-15d. Rain amounts are firmly the forecast and model-watch focus into forseeable.

 

Thanks Ian. Not too surprising really, though still worth keeping an eye on, perhaps for a more 'watered-down' version.

[Barry12]

Hi Ian, my observations of the EPS is that because of their lower resolution they are 24 hours late to the operational party.

 

I would say 75% odds on favourite for a block to the NE, 50/50 the cold getting to us.... either way it certainly looks a lot better than last year!

S

 

 

The Met Office vs Steve Murr, who will win!?

Edited November 8, 2014 by Barry95

[Hocus Pocus]

The Met Office vs Steve Murr, who will win!?

 

Let's hope Steve Murr.

 

We need to see the UKMO model get more interesting for the Met Office to increase there 10% probability.

I don't think its a case of that though. The MetO prime concern is for the relentless rains for the next week or so and any possible pattern change outside of that realm is still in its infancy so to speak. If the models start to continuously show a cold pattern from the NE/E over the weekend then expect some changes in the wording of the extended outlook.

[Snowy L]

I thought any pattern change to cold would be outside of the 10 day range anyway?

 

This, the possibility of a block is at least beyond 10 days and most likely in the 15-20 day range.

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2014110812/gfsnh-0-90.png?12

 

early doors on the GFS making all the right corrections in all the right places.....

S

[shaky]

And already at just 90 hours heights are stronger than the previous 2 runs!!what I dont understand is why does the gfs keep chopping and changing with the heights across greenland and then bring them back all of a sudden at a closer time frame!!

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2014110812/gfsnh-0-132.png?12

 

Could be the first GFS boom run of the season!!!

[Snowy L]

Upstream pattern looking much better with much weaker lows in Canada/West Atlantic.

[Dancerwithwings]

10%.......I'm sure at this stage the Met Office would of gave just 10% chance of an Easterly back in 2010.... Now't to worry about

 

[Snowy L]

This high pressure looks a lot more prone to being cut off from Russia, hopefully we get those lows to the west and North of Ukraine closing the gap in the rest of the run

 

http://www.wetterzentrale.de/pics/Rtavn1321.gif

[blizzard81]

Hi Ian, my observations of the EPS is that because of their lower resolution they are 24 hours late to the operational party.

 

I would say 75% odds on favourite for a block to the NE, 50/50 the cold getting to us.... either way it certainly looks a lot better than last year!

S

I must say that after the last 2 or 3 days output and not just this mornings ECM, 10% is very conservative, even by the mets standards. I would have placed it much higher than 10%.

[LomondSnowstorm]

Massive improvement on the UKMO 12Z as well over the last 24 hours, far more amplified pattern and more in line with the GFS parallel:

compared to yesterday's:

 

I suspect that 10% may well increase after the 12Zs if the ECM looks similar...

+144 is a classic impasse between the Atlantic and blocking:

Edited November 8, 2014 by LomondSnowstorm

[Winter Frost]

Well its better than last year but can't understand the fuss. Cold is going into Russia area.

[marksiwnc]

I don't think ian will reply to your comment.Steve as he has to sit on the fence. But by Monday I expect the 15-30 day forecast will have changed to say the chance of cold and wintry showers are possible.

[David Morse]

@Nick sussex, Captain Shortwave and Banbury: if the PV was better organised in January 2014; where did all that cold weather in the USA come from and why didn't we get ice boxed in? What is clear is that a disrupted PV does not inevitably lead to backing up Exacta Weather and Daily Mail / Express sensationalist headlines. We are only in November, sea temps are warm and current conditions simply make it HIGHLY unlikely that there will be ANY serious cold in the foreseeable future. SST's are so high that living on these islands they impact the surface temps so massively that no matter how strong a blast of cold we get; low altitude temps will always be too high for wintry precipitation until the end of November / early December. Instead I expect that the pressure charts will start to show up the development of some intense low pressure systems. There is NO aggregate signal in the ensembles for cold; but lots of signals for unsettled weather.

[phil nw.]

A few posts straying off the thread topic so can we keep to model discussion please all.

There are plenty of other threads where you can debate Winter prospects,UKMO forecasts and many other things. 

 

Thanks.

Edited November 8, 2014 by phil nw.

[The Eagle]

The Parallel run is a lot easier on the eye with much more potential.

[phil nw.]

@Nick sussex, Captain Shortwave and Banbury: if the PV was better organised in January 2014; where did all that cold weather in the USA come from and why didn't we get ice boxed in? What is clear is that a disrupted PV does not inevitably lead to backing up Exacta Weather and Daily Mail / Express sensationalist headlines. We are only in November, sea temps are warm and current conditions simply make it HIGHLY unlikely that there will be ANY serious cold in the foreseeable future. SST's are so high that living on these islands they impact the surface temps so massively that no matter how strong a blast of cold we get; low altitude temps will always be too high for wintry precipitation until the end of November / early December. Instead I expect that the pressure charts will start to show up the development of some intense low pressure systems. There is NO aggregate signal in the ensembles for cold; but lots of signals for unsettled weather.

Welcome to the forum David.

Perhaps put your location up please.

[ukpaul]

@Nick sussex, Captain Shortwave and Banbury: if the PV was better organised in January 2014; where did all that cold weather in the USA come from and why didn't we get ice boxed in? What is clear is that a disrupted PV does not inevitably lead to backing up Exacta Weather and Daily Mail / Express sensationalist headlines. We are only in November, sea temps are warm and current conditions simply make it HIGHLY unlikely that there will be ANY serious cold in the foreseeable future. SST's are so high that living on these islands they impact the surface temps so massively that no matter how strong a blast of cold we get; low altitude temps will always be too high for wintry precipitation until the end of November / early December. Instead I expect that the pressure charts will start to show up the development of some intense low pressure systems. There is NO aggregate signal in the ensembles for cold; but lots of signals for unsettled weather.

 

Because the PV descended far enough south to reach the Northern USA. That elongation meant that the USA got lucky (or unlucky if you don't like that sort of thing). When the PV did start to break up the bit that had reached that part of the US was strong enough to hang around for quite a while.

 

 

 

The GFS isn't half slow now but the added resolution up to 240 hours appears to be giving it greater consistency.

Edited November 8, 2014 by ukpaul

[SMU]

the 12z GFS(p) arrives at the same ECM party at day 10

 

http://modeles.meteociel.fr/modeles/gfsp/runs/2014110812/gfsnh-0-240.png?12

 

IF ***IF*** things align then day 10-12 could be when the flow gets into the right alignment will be the 20th of November- certainly a time where snow can fall to sea level & settle over the UK.....

 

S

[nick sussex]

GFS not that great as it doesn't detach the UK low from low heights over southern Greenland, the GFS P is much better and you can see the difference this makes.

 

This really is now the crucial component. The UKMO I don't find that inspiring as the high pressure is further south and theres no separation of trough energy at T144hrs.

 

Events over the ne USA are also quite important, do we get a shortwave to engage those low heights over western Greenland and help to pull some of that energy away to the nw, we really need to see some amplification to add a bit more sharpness to the downstream trough.

 

The sharper that is the better chance of the undercut and this can work in tandem with pressure rises to the ne to force a separation of that troughing near the UK.

 

Because of the set up its crucial to see a clearance of energy to allow the UK low to slip under the block.

[phil nw.]

My views on the UK and both GFS 12z Op runs in H.resolution are that they do show slightly more heights towards Greenland and the trough more dig se into Europe.

Small steps but the overall Atlantic pattern still means no change for us yet into the medium term.

[ukpaul]

Comparison ECM and GFS at 10 days (well, nine and a half days now) -

 

ECM

 

 

 

GFS

 

[snowking]

I think we need to bear a few things in mind here folks...

 

First of all with regards to the apparent shock at the Met Office figure of only 10% chance. The Met Office is a scientific organisation, and as such they will only generally comment upon what the data provided to them shows - sure, there will be a certain level of human input too, but at that sort of range their forecasts will be based upon what I would term Model Facts. In terms of this specifically, the 10% chance is not a figure that would have been arrived at randomly, it suggests that out of the suite of 51 ECM EPS members (whether there might be some integration with MOGREPS too I could not say), only 5 or 6 members show a scenario reflecting that of the operational run.

 

Now of course it is also true that the operational runs, running at a higher resolution, should in theory resolve features better than the ensemble members (I do not know whether perhaps operationals carry greater weight in probability statistics), and often we do find that to be the case, but the beauty of posting on an open forum, as opposed to forecasting to a scientific standard, is that we can play devil's advocate to a certain extent and theorise scenarios that might occur based upon previous experiences...but there is a reason ensemble suites are run at that range.

 

I would also caution, and I believe there was a post a short while ago from I'm Dreaming Of confirming this, that there has been a very noticeable trend over the past couple of years to raise heights in the vicinity of Greenland at day 9/10 incorrectly. I also usually find it concerning when the UKMO GM does not back a scenario whole-heartedly, particularly when it comes to blocking to our North and any sort of trough disruption accompanying this. So whilst the excitement is understandable, I would urge members to wait until such charts begin coming in to the 120 hour timeframe before lighting the cigars and bringing in the overweight contralto. You are probably sick and tired of me saying this, and I know my keyboard letters are getting worn out writing it, but just remember back to December 2012 and the trouble caused there even inside 144 hours.

 

Though to finish on a ramp, stratospherically things are certainly becoming interesting...

 

SK

Edited November 8, 2014 by snowking