Model Output Discussion 29th December - Into mid-Winter.

[swebby]

8 minutes ago, nick sussex said:

Its really more about moving away from phase 8 as that's less favourable for western Europe in terms of cold. Phase 1 is more favourable but still depends on other factors.

Quick Qu for you nick or anyone else for that matter- I've seen ref to "COD" on this and the strat forum for the MJO plots which i understand to mean "cone of death" - i assume a ref for a phases(s) that are poor for HLB in the correct areas for cold weather to hit the UK.  What are the actual phases for this COD and does it depend/change on the month as i understood the NH pressure analogs for any given MJO phase are dependent on the time of year?

Cheers

S

[nick sussex]

2 minutes ago, swebby said:

Quick Qu for you nick or anyone else for that matter- I've seen ref to "COD" on this and the strat forum for the MJO plots which i understand to mean "cone of death" - i assume a ref for a phases(s) that are poor for HLB in the correct areas for cold weather to hit the UK.  What are the actual phases for this COD and does it depend/change on the month as i understood the NH pressure analogs for any given MJO phase are dependent on the time of year?

Cheers

S

Its circle of death! lol When the MJO is within that circle it will have little influence on the NH pattern. The phases that are more favourable for cold do depend on what winter month you're talking about.

Heres a link to the composites and you can see the different phases and their influence on the pattern. Bear in mind though that other factors can dilute the influence of the MJO.

Hope this helps

http://www.americanwx.com/raleighwx/MJO/MJO.html

[chris55]

That GFS is noteworthy, where has the zonal flow gone!! Of course the overall pattern doesn't bring in the real cold but whats more significant is the changes in the mid term, ECM first picked up this potential slow down in what looked like a nailed on zonal flow, so for me anyway the mid term is open to all sorts of changes/upgrades. The undercut will be the elixir we all would love to see and although that's not on the cards at the moment the balance of the pattern is not certain, thats for sure. UKMO144 highlights that sticking to the flatter pattern!

Here is GFS day 7 and 10, zonal flow never materialising.  

 

Also the more reliable part of the GFS run (up to 168) keeps us under a continental flow significantly longer than previous runs, Wednesday morning....cold!

[chris55]

some good WAA at 168 on ECM.... surely a healthy Scandi high to follow?

[SMU]

ECM still has all the hallmarks of an easterly down the line

[chris55]

More building than sinking at 192, nice high lat as well, could produce an undercut, slower but potentially good.

Looking at the 850s this could actually be a true high lat block setting up, enough to eventually deflect the Atlantic south?

At 216 the northern arm does its work with just to much energy heading north west, though with such inter run changes nothing is certain.

Edited January 18, 2017 by chris55

[Severe Siberian icy blast]

Just now, Steve Murr said:

ECM still has all the hallmarks of an easterly down the line

Charge ya phone Steve always in the red !!!

Yea great chart. Still waiting for the Atlantic IDO? Things beginning to reamplify again, I think with the trough in the Atlantic digging far south then that naturally encourages a high to go up the other side, just Hope the vortex don't squash it!

[Summer Sun]

Low pressure to the north west high pressure to the south so staying drier for longer here

Edited January 18, 2017 by Summer Sun

[northwestsnow]

Not a nice ECM as the Atlantic forces through and we are left with mild south westerlies-

Hopefully one of the milder solutions long term.

[geordiekev]

9 minutes ago, northwestsnow said:

Not a nice ECM as the Atlantic forces through and we are left with mild south westerlies-

Hopefully one of the milder solutions long term.

Certainly from the trends this Winter I wouldnt Underestimate the strength of the block if it does form as shown on ECM. 

Actually,  there are rumours Meto are thinking about naming the block as its been around so long. How about 'Jenny' 

Edited January 18, 2017 by geordiekev
Faux news alert

[chris55]

Take a look at how we have seen a marked change from the GFS in the last three runs...and this is for circa 144! A much sharper and more amplified pattern developing, until we get some consistency in the mid term and the new signal is a little more defined im not making a judgement either way.

00

06

12

[blizzard81]

1 minute ago, chris55 said:

Take a look at how we have seen a marked change from the GFS in the last three runs...and this is for circa 144! A much sharper and more amplified pattern developing, until we get some consistency in the mid term and the new signal is a little more defined im not making a judgement either way.

00

06

12

I agree. It will be very tempting for most members on here to be very dejected with the ecm day 9 and 10 charts. However, my advice is don't be  Why? Because the models clearly don't have a handle yet on the extent of amplification to our north east at days 5 to 7. Until this is resolved, all day 9/10 charts are pure fiction.

[Singularity]

A low from all the way over in Florida adds a lot of NE momentum to the jet from day 7 in the ECM 12z. Without it, I wonder if the mid-Atlantic trough could have disrupted against the block... something to watch out for, as with so much warm air firing poleward, relatively small adjustments in the orientation of the jet will have strong impacts on the way forward for the final week or so of the month.

[Zakos]

48 hours ago, the ECM operational and mean anomaly "guaranteed" a return to zonality

Now the forecast for the 25th shows a large anomaly to our NE, seemingly it has appeared out of nowhere.

If the ECM underestimated the block so much, there is surely scope for the forecast to further improve?

Not saying we will see a raging easterly, but I find it hard to believe we will see the atlantic come barreling through the block, without at least a snowy breakdown

The above chart is only 168 hours out, I would have thought there is good potential for a Scandi high to form... with a bit of luck.

 

 

Edited January 18, 2017 by Zakos

[Man With Beard]

1 hour ago, Summer Sun said:

Low pressure to the north west high pressure to the south so staying drier for longer here

The GEM has rarely got the mid-range wrong this winter and it's almost a carbon copy of the ECM at T240. 

[booferking]

17 minutes ago, Man With Beard said:

The GEM has rarely got the mid-range wrong this winter and it's almost a carbon copy of the ECM at T240. 

ECM mean agrees with all of the above for the phantom easterly. 

[Summer Sun]

 

[blizzard81]

6 minutes ago, Summer Sun said:

 

Indeed. I would advise people to look at the debilt ecm ext ensembles but only go as far as next Weds. Now compare the same time period from this morning's ensembles. Just look how much lower the temps are on tonight's suite for that time period. Because of this, I would advise people to look no further than day 6 at the moment.

[blizzard81]

Also remember that the only easterlies that are modelled at day 9 or 10 are the ones that never verify. They are only picked up CORRECTLY at around day 6, sometimes less than 6 days. They are notoriously difficult for the models to predict. For this reason I feel there is plenty of time for upgrades.

[Purga]

20 minutes ago, blizzard81 said:

Indeed. I would advise people to look at the debilt ecm ext ensembles but only go as far as next Weds. Now compare the same time period from this morning's ensembles. Just look how much lower the temps are on tonight's suite for that time period. Because of this, I would advise people to look no further than day 6 at the moment.

Yes and here they are to peruse

The mild shift is being shifted further out.

Shall we shift our expectations this evening??

[damianslaw]

Sticking to the reliable - it remains a very blocked set up, with the ridge to our east, becoming propped up by the azores high early next week, holding the atlantic well at bay, whilst longer term they all the atlantic rolling back in, the trend has been for the breakdown to continue to be put back and back... there is even the chance of some trough disruption should heights build sufficiently northwards, but the likelihood is a positively tilted trough pushing through , could be one of those cases when the trough is held back so long, it sharpens distinctly with a major temp contrast on either side, a quick SW shot followed by a potent NW shot.

 

[Dennis]

prepare for a few cold days : starting sunday

[Fozfoster]

The models This winter have been showing cold is coming, only to water it down nearer the time but to balance it out they have also been showing milder is coming only to water it down!!! Can we get just one decent cold spell this winter? I would sacrifice one mild spell for one!

[winterof79]

Battle ground forming with every run

Edited January 18, 2017 by winterof79

[karlos1983]

Nice trough disruption on the GFS gaining momentum with each run today. Interesting to see if that trend continues into the morning.