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

[Liam J]

Despite the ECM OP not looking as good this morning it's still looking cold with plenty of snow more so up north (deeper than previous runs), the 00z is showing a foot of snow N England northwards with ice days just about possible, temps around -3c to plus 2c by day, further south around 3c to 6c. 

[johnholmes]

2 minutes ago, Greenland1080 said:

One for the experts.....Have the models we see missed the sub tropical low coming out of Bermuda, hence they are only now 4 days away getting a handle on this?....hence the big changes we are now seeing which the MO prob had in Glosea5 days ago....?

Sub tropical lows are well known for any model having great difficulty in dealing with them. Whether this is having an effect on the synoptic models I don't know, it may be. What eventual effect this may have on the cold spell starting Monday if not earlier further north is also unknown I would suggest.

[East_England_Stormchaser91]

Can't see what all the fuss is about to be quite honest. 

Look at the reliable timeframe first before fretting over what may or may not happen with the shortwaves and the Azores low. Through experience, Azores lows tend to be the catalyst for the real snowstorms. Winter 09/10, Jan 63 etc. with the Greenland high looking certain now, anything can happen. The main thing is will be the cold certainly heading in our direction. Anything more than 96 hours is subject to huge changes in these types of setups. 

[IDO]

...and despite the changes run to run, the GEFS mean has 9 days for London below seasonal average T850's from Tuesday, that would be a rarity if it verifies ( I am assuming the GFS op and C are over correcting), and of course all to play for from then, even if it is not a fabled GH:

 

This change was earlier than I was expecting only a week ago so we shouldn't complain.

[MR EXTREMES]

well all I can say is southerners forget the cold spell that I'm certain of.

secondly I think feb could deliver something more country wide if we can get real sustained northern blocking.

to be honest I'm absolutely disappointed!

but not surprised you could see the models over the last couple of days remove the block over Greenland and now removed with ease the vortex fights back to teach a lesson not to underestimate the mighty vortex.

still those to the north I'm sure your have some nice wintry weather.

 

[Bristawl Si]

Well, what a turnaround compared to 36-48 hours ago.

I thought a mid-Atlantic high was almost nailed with a chance of a Greenie High forming, then going on to produce an omega block.

Is that storm brewing off Bermuda causing the issues?

Hopefully GP's end January scenario is still on track.

[Day 10]

 

Still decent model output for coldies, still starting about the 12th and still slight variations on the cold theme early on.

Plenty of UK chances for snow from t96 onwards.

Wasn't it GP or Chino who mentioned a west best NAO to start with moving east with time?

[The PIT]

3 minutes ago, Bristle boy said:

Well, what a turnaround compared to 36-48 hours ago.

I thought a mid-Atlantic high was almost nailed with a chance of a Greenie High forming, then going on to produce an omega block.

Is that storm brewing off Bermuda causing the issues?

Hopefully GP's end January scenario is still on track.

Nothing is nailed at that far out time wise. It's still not dead but it's a case of watching how the models drift. If they keep drifting towards a less cold output then that will be the trend and the cold spell will be still born. At least we've lost the mild output for the time being.

[Wayneywoo]

Can someone post the stats for for various model accuracies please? 

[mulzy]

If truth be told, after the output we've had over the last few days, this is a rather disappointing Day 7 ECM ensemble mean chart.  Obviously a few clusters diluting this mean but you can pick up the warning signs of height rises over Iberia.

Edited January 8, 2016 by mulzy

[blizzard81]

4 minutes ago, mulzy said:

If truth be told, after the output we've had over the last few days, this is a rather disappointing Day 7 ECM ensemble mean chart.  Obviously a few clusters diluting this mean but you can pick up the warning signs of height rises over Iberia.

Overall, I would not call that a disappointing chart for cold lovers. GP did say there maybe a north/south divide initially but this should phase out as the neg nao kicks in and moves to a central based state.

Edited January 8, 2016 by blizzard81

[swilliam]

43 minutes ago, bluearmy said:

 

Sorry but the parallel ops are leading the way on the west based NAO and low upper cold not embedding so strongly beforehand.  Due to the Atlantic trough hanging back for too long. the most recent runs less favourable for lasting cold than the previous.  However, this is a snapshot in time and must be viewed as such. The ens give us an envelope to work within and the pendulum can just as easily swing back somewhat through the next few op runs.  tbh, we know the unreliability of ops post day 6. 

this is is a tricky evolution with the polar high and n American trough both of paramount importance in how plays out.  We should see the way forward with some reliability over the weekend. if we arrive at the 20th without a decent snow event on low ground somewhere over the UK then it will be a big surprise. 

Actually this was shown first on the 18Z GFS on Wednesday. I pointed out during the run that the initial ridge was too far W and thin which could lead to breakdown of the block at was then +240 (see below). This was the evening of the 1st stellar runs so I was then told by several people not to analyse every run, that the means were showing this etc. not to get upset (which I was not doing). All I did was point out what was shown and that we did not want this to become a trend. It confirms to me that no runs should be binned because we do not like what they are showing - just accept that they are one solution (especially beyond t120) which should be accepted as a possible if maybe unlikely outcome. the same applies when it is the other way round with everything showing zonal and then we start to see odd runs and ensemble members showing something different.

 

Back to the current and as I see it the problem with the initial ridge being to far W and/or thin is that the 2nd surge of WAA does not really happen because of the orientation of the 2nd low in the US. So this low begins to head more NE instead of NW and interacts with the Azores low. This basically comes under the ridge instead going NW into the US. It is pretty much game over then in terms of prolonged cold for us although we my get a big snow event,

However as has been said this phase is currently completely undecided and anything could happen at this stage so we will just have to wait and see. We can look at all the runs (good and bad) and see what the options are. But the main point I feel is that we want the initial ridge bigger and further E and then we want to see the 2nd low to rebuild the ridge rather than going underneath  it. Impossible to call at this stage but the trend has certainly been to move more towards the latter this morning but plenty of time for change to the former.

[MR EXTREMES]

the ecm retreats the Greenland block back west it was showing on other recent runs and was my concern and has always been a problematic thorn in the side of coldies.

as the ecm shows it retreats with ease and the atlantic onslaught continues the best model is ukmo going forwards for cold but even this is showing signs of a climb down of sorts although the outlook is cool in the south colder in the north so winter for awhile to our north as u can see the euro high is also trying to make a return.

disappointing very soon as I open my mouth about colder weather coming I'm made to look like a right plonker.

anyway knocker went against the grain shame hes not posted I'm missing his level head even if hes in the milder camp but his milder ramps give the forum a level playing field that stops disappointment.

but this don't mean the end of jan and feb march wont have another chance it was close to 09/10 rerun but no cigar although very wintry further north.

and nick Sussex well done mate as always you been keen to point out the worries and once again well spotted.

now we need to hope that the models are wrong if they can go from across the board model agreement of a real cold spell then hopefully they can be all wrong about the rapid removal of Greenland heights.

we shall see to be continued ...........

[coldcomfort]

Here's a quick question and I think it is relevant to the model output.

Who can honestly say they would not have taken the overnight model suite if offered it a fortnight ago?

I know I would have...and some!

[Bristawl Si]

1 minute ago, coldcomfort said:

Here's a quick question and I think it is relevant to the model output.

Who can honestly say they would not have taken the overnight model suite if offered it a fortnight ago?

I know I would have...and some!

What, cold rain?! No thanks!

[stewfox]

26 minutes ago, Minus 10 said:

 

Still decent model output for coldies, still starting about the 12th and still slight variations on the cold theme early on.

Plenty of UK chances for snow from t96 onwards.

29 minutes ago, emotional rollercoaster said:

well all I can say is southerners forget the cold spell that I'm certain of.

secondly I think feb could deliver something more country wide if we can get real sustained northern blocking.

 

 Job 1:21 Parallel Verses ... The LORD gave and the LORD has taken away;

Models seem to have flip over in 4 minutes to wipe off the rest of January ?

Having looked at the evolution upto T96 of the low presurres systems a 'messy afair'. I'm going to wait for a few more runs and worry about the phasing of the low south of us nearer the time. Frontal events can be epic but can of course lead to 'glad you got some'

Edited January 8, 2016 by stewfox

[IDO]

That LP system from Bermuda looks like it is definitely heading in our general direction and there is a 30% chance it blowing up by the middle of next week according to the warning issued:

 

 

[MR EXTREMES]

yesterdays 240 ecm

todays ecm 240

although we can take into consideration surface cold but still pretty dramatic changes

[No Balls Like Snow Balls]

Just now, emotional rollercoaster said:

yesterdays 240 ecm

todays ecm 240

although we can take into consideration surface cold but still pretty dramatic changes

The dramatic changes are because it's 10 days away LOL. Honestly nothing ever changes in this thread.

[joggs]

3 minutes ago, IDO said:

That LP system from Bermuda looks like it is definitely heading in our general direction and there is a 30% chance it blowing up by the middle of next week according to the warning issued:

 

 

Let's hope it takes a speedy south-easterly route

[Man With Beard]

Comparing the ECM spreads with the mean at T168, you can see they're still pretty happy with a Greenland High (indicated by blue shading on spreads chart over Greenland), but there is a uncertainty over how far troughing from the north gets towards Canada + tropical low getting north (green blobs in the Atlantic) and how far troughing over Canada gets towards Greenland (yellow blob off NE Canada). 

The presence of troughing between Shetland and Norway looks consistently modelled throughout the ens, as shown by the dark blues/purples in that location. Now I would say, for once, that this makes some sort of N/NWly feed over the UK more likely than not, as getting a pattern to avoid a northerly from this situation is actually quite complex.

[feb1991blizzard]

3 minutes ago, No Balls Like Snow Balls said:

The dramatic changes are because it's 10 days away LOL. Honestly nothing ever changes in this thread.

One things changed, i never expected to see Rafael Benitez take up model watching as a pastime so soon after losing his Job at Real, welcome to the forum anyway!!!!

[Liam J]

4 minutes ago, emotional rollercoaster said:

yesterdays 240 ecm

todays ecm 240

although we can take into consideration surface cold but still pretty dramatic changes

High moves in, cold air locked in at the surface at least. The day 10 2mT chart is showing a widespread frost & temps between 0c to -6c. 

[A.J]

I woke up 30 mins ago, poured myself a strong coffee and sat down to peruse the overnight output and more especially the overnight posting in this thread, and I'm impressed by the informative analysis by numerous members, most of which I understand, some of which is too complicated for the like of me...... 

What has impressed me more though, is the amount of soothsayers that we have in here, staggering, and a real asset!.....these soothsayers are trumpeting or moaning that the cold spell is over, the azores low is the spoiler that will allow milder atlantic weather to bulldoze through etc etc....astonishing! that this cold spell is over, several days before it has even started!........hey, 'soothsayers', wake up!....once you realize that mother nature is fickle and chaotic and doesn't rely on computer models, you will find that life becomes a lot less stressful.....in other words, don't write off events hundreds of hours before they're due to occur 

[Jayfromcardiff]

On 06/01/2016 at 11:17 AM, That ECM said:

What a rubbish run! Look at the warm air creeping back in to the SW. Cheeky smile with wink!!

Can someone tell me what time the next set of runs begin please? Also I still don't understand why people are so hung up on what models are showing over a week away when there are many changes every run.