Model Output Discussion - 05/01/2016 18z onwards

[Cloud 10]

LOL,the 18z NAVGEM has crumbled at day 6.

 

[swilliam]

45 minutes ago, johnholmes said:

 

Latest AO update from Cohen is available. Forecasting extended -AO and -NAO for 3-4 weeks +SSW + _ve temp anomaly so looks good for cold - depends how much faith you have in this stuff. 

http://www.aer.com/science-research/climate-weather/arctic-oscillation 

Looking at the ensembles even if we get a flat pattern later next week many of them re-amplify so I would expect something interesting to come in  down the line Best is P12 even though it is one the least promising at 120hrs

120

276

Edited January 11, 2016 by swilliam

[Tamara]

1 hour ago, TEITS said:

 

I will finally give some advice to newer members on here.

You will at times read some very technical posts on here referring to various teleconnections and how these may dictate the weather patterns in the medium/long range. However it does not matter how promising these signals are as they mean nothing if this does not show up on the actual model output at a sensible timeframe. I mention this because if I had a pound for every post I have read promising one thing only for the model output to show the opposite I would be a very rich man.

I will add if I had a pound for every E,ly I have predicted I would be a millionaire.

That applies to every professional organisation as well as any amateur on this site though. Working with the best information at the time and then making judgement based on the findings. Its easy to wait till such a close time period and judge retrospectively that somehow the reasoning was wrong, when it was completely valid based on previous consecutive datasets. Just today, the METO have stressed the uncertainty and the possibility that the upcoming cold could last beyond the 10 day period.

The teleconnections, as explained many times have underpinned a suggested outlook - based on an amplified pattern (for all the reasons stated) What it comes down to is the polar profile staying disorganised to take advantage of a poleward flux of waves from the tropics in such a way as to couple an amplified -AO state with a -NAO.  Such a profile making a huge difference to the possible outcomes of the accompanying jet streak that come simultaneously from upstream with it.

If the trop>strat relationship, as it *might* turn out to be, insufficient to provide an amplified or blocked enough pressure profile for long enough, that energy obviously will not disrupt and undercut. The end result looks wholly different to the reasoned outcome.

But based on some good ensemble data to support an amplified pattern, it has not been unreasonable to suggest greater sustained blocking .It certainly doesn't invalidate the teleconnections which after all act as signal indicators that the atmospheric circulation is pre-disposed to the possibilities in the first place

We would all be more than rich if we could second guess outcomes of millionth complex calculations that even super computers cannot give instant correct answers to

Edited January 12, 2016 by Tamara

[Trom]

27 minutes ago, booferking said:

I have a question is human input that more accurate than the models??

The basic concept is the models are deterministic i.e. they follow a set of algorithms based on past conditions.  So there is a fair bit of back fitting with the models.  Given this they will take the current base conditions and project it forward according to the models parameters.  The ensembles are what we see when we tweak those starting conditions.

What the models lack is common sense.  The skill that at present can't be replaced by pure equation at the current point in time.  Experience and the luxury to be able to focus on a specific area with greater available info than we see.

What we are also seeing is a hugel El Nino coupled with warm water in the pacific and indian oceans.  This is not a normal situation and as such not one the models equations know the bounds of the reliable future even a few days in.

[kumquat]

Seem to be more robust heights and WAA going north on th 00z as compared to 18z. Slowly coming around to the UKMO?

18z gfs  108hrs

00z gfs 102hrs

 

[Mucka]

Hope so but it seems to go one way and then the other.

Amazing how many mild sectors it finds as well, hopefully it is over complicating the trough and wrong on that too.

At least it gets enough cold air over us and enough energy sliding SE to give a snowy breakdown now.

Stunning UKMO 144

One word, "undercut."

Edit

LOL snap Kumquat!

Edited January 12, 2016 by Mucka

[kumquat]

UKMO 144 looking splendid!

Edited January 12, 2016 by kumquat

[Mucka]

Quite an obvious improvement within GFS ensembles by 96h so let's hope things are all going the same way now.

Just need GFS to keep improving and ECM to get on board.

We may never get things this far but this is what we should be aiming for.

Short ensembles central England - big improvement.

SE England

Edited January 12, 2016 by Mucka

[Captain Shortwave]

Day 6 charts

GFS/UKMO/GEM

         

It all pretty much comes down to how amplified we can get the pattern over the Atlantic and hence can we split the jet sufficiently to first undercut the ridge and secondly develop some low heights to our south. The UKMO looks good again this morning with an easterly following for a time. The other two are not good enough and conditions quickly turn milder from this point.

I won't give any favour to either solution apart from the most likely one will be the side the ECM takes this morning.

We need the UKMO to be right here to extend the cold or potentially very cold conditions well into next week.

Edited January 12, 2016 by Captain Shortwave

[Mucka]

Euro 4 still somewhat disappointing forecasting rain Wed night/thu morning

DP's still above freezing for England

[Ali1977]

Finally we have some agreement that it will still be cold till Atleast Sunday, if not Monday...GFS and now ECM falling more in line with the UKMO. Well done UKMO for sticking to your guns.

ECM at 120

UKMO

GFS.

UKMO still looks best to me, followed by the ECM

Edited January 12, 2016 by Ali1977

[Paul_1978]

Well the ECM has the Atlantic trying to get in and on our doorstep at T+120, but by T+168 it still hasn't made it.

Is that beyond FI - probably as things stand then yes. 

[chris55]

UKMO very cold this morning.

GFS and ECM both have frontal snowfall moving in off the Atlantic in the mid term via a disrupting trough.

Details academic really though, but as a general risk it is certainly a possible outcome. 

 

Edited January 12, 2016 by chris55

[mountain shadow]

What a roller coaster ride this is.

UK Met rock solid and no breakdown there.

[SMU]

Morning all

updating my post from last night ( & reinforcing what I said around 10 days ago when I said the models would flip - when they partially did ) is one of the biggest model failures ( or bias ) - especially the GFS is to move energy NE through a block - then as we approach real time so the final distribution often sees that replaced more & more By SE movement & the potential for prolonging the cold

The overnight model suite has seen fairly moderate model changes & fine tuning - but notable very positive moves ( a slight whiff of 96 in the air ) towards the colder solution ...

so,

UKMO has back peddled the least but ever so slightly reduced the northern extent of the blocking - but crucially gets enough of a trivial persuit size wedge in there that at 144 theres the majority of the atlantic energy is moving SE - delivering a dead cert snow event for the SW - ( if the low ever gets that far )

I would also say the East & SE is covered by the -10c isotherm at day 6 ( slight resemblance to Jan 85 in its most positive light ) & would see a continuation of the cold spell out well past day 6

UKMO ( the new anti global warming model )  -  A+

The GFS & ECM blend are less amplified & send a more even distribution of energy NE & SE allowing less undercutting - crucially though both models get enough SE to hold a cold SE flow into the front to see a snowy breakdown over the UK but eventually topple it all away -

B- which is a big swing to cold after yesterdays C-

 

In my experience where models are swinging to more energy going SE at day 6 against the block the trend for day 5 ( backing into day 4 ) shows the biggest continued trend of swinging to more energy SE so todays the day where if its going to happen the UKMO becomes the hero....

S

 

 

Edited January 12, 2016 by Steve Murr

[JoeShmoe]

1 hour ago, Mucka said:

Euro 4 still somewhat disappointing forecasting rain Wed night/thu morning

DP's still above freezing for England

So basically rain with snow on northern hills, temps a bit colder in the week but mostly dry with probability of it turning milder at the end of the week

[Liam J]

Took it's time but the GFS now extends the cold by a few days into the start of next week! More in line with the ECM which takes slightly longer, by T144 the UKMO is the odd one out whilst the GFS & ECM are in general agreement on a return to W/SW winds as we move into next week along with GEM. Be awesome if the UKMO was correct but with GFS & ECM against it then I have my doubts, remember the other week with the failed easterly drama and the UKMO always looked best for a potential undercut and it was the last one to back down - If you want the cold to last then start praying for the UKMO! 

[booferking]

13 minutes ago, *Sub*Zero* said:

Took it's time but the GFS now extends the cold by a few days into the start of next week! More in line with the ECM which takes slightly longer, by T144 the UKMO is the odd one out whilst the GFS & ECM are in general agreement on a return to W/SW winds as we move into next week along with GEM. Be awesome if the UKMO was correct but with GFS & ECM against it then I have my doubts, remember the other week with the failed easterly drama and the UKMO always looked best for a potential undercut and it was the last one to back down - If you want the cold to last then start praying for the UKMO! 

Yea but the GFS & ECM have only got back on the table to what ukmo has been showing for days is there not a chance they can upgrade run by run as it would be one hell of a flip to be the same at 144hr on one run?

[That ECM]

12 minutes ago, *Sub*Zero* said:

Took it's time but the GFS now extends the cold by a few days into the start of next week! More in line with the ECM which takes slightly longer, by T144 the UKMO is the odd one out whilst the GFS & ECM are in general agreement on a return to W/SW winds as we move into next week along with GEM. Be awesome if the UKMO was correct but with GFS & ECM against it then I have my doubts, remember the other week with the failed easterly drama and the UKMO always looked best for a potential undercut and it was the last one to back down - If you want the cold to last then start praying for the UKMO! 

Agreed. It would be some flip to turn this around and backed by the meto. 

Enjoy this week, then hope we see some changes towards the end of the month. More than happy to be wrong but it's odds against imo.

 

 

[mb018538]

However cold the UKMO output looks, the BBC don't seem too hyped....only really mentioning some higher level snow with a few flakes at lower levels. Nothing about any substantial snow at lower levels......yet. ECM and GFS both keen for the SW gunk to start reappearing at day 8 onwards, hoping that they are a bit progressive and that things don't move quite as quickly.

[terrier]

3 minutes ago, That ECM said:

Agreed. It would be some flip to turn this around and backed by the meto. 

Enjoy this week, then hope we see some changes towards the end of the month. More than happy to be wrong but it's odds against imo.

 

 

Don't know how u can say it's odds against when even the modes are flip flopping all over the place even this week. 

[bluearmy]

It really is like the twilight zone. For years and years, the UKMO has been the party pooper. Always signalling that we wouldn't get a cold pattern at day 6, when GFS and ECM had been touting it. I just can't get my head around the fact that UKMO is ALWAYS the model showing the coldest outcome. 

This mornings 00z run is potentially the most interesting yet with a sustained undercut on the cards. 

We live in strange times indeed (or does the old fella need an upgrade?)

[booferking]

I thought the UKMO has been solid for days now while the other 2 flip day to day i would have thought a solid performing model would have a good chance of being right as the other 2 trend towards it??

[johnholmes]

8 hours ago, The Enforcer said:

I hope it's OK to ask if you know why they never put the DAM lines on the 'Analysis' and T+24 fax charts?

sorry no I don't, that has always puzzled me

[Severe Siberian icy blast]

5 minutes ago, That ECM said:

Agreed. It would be some flip to turn this around and backed by the meto. 

Enjoy this week, then hope we see some changes towards the end of the month. More than happy to be wrong but it's odds against imo.

 

 

Completely misleading post , why are you using charts that's over 200hrs away to illustrate why the ukmo is on its own considering it stops at t144? 

The ecm especially has moved a lot closer to the ukmo this morning as it attempts to undercut the low to our southwest , it's only really once it gets to t168 it goes into ramp mode , the gfs also gives us slight trough disruption with a snowy breakdown , the ukmo in my opinion is on the money , why ?

1-its been rock solid this last 4 days and dragged the other models into line .

2-low heights into Europe already .

3-northern blocking already in place 

time after time this happens.  The models are almost always too progressive in moving the cold on and we see evidence of this already . Also once we have low pressure into Europe and the jet pushed south the other areas of low pressure usually follow suite .