Model output discussion - The Hunt For Cold

[Don]

Not a great long term update from the EC46 then.

[Allseasons-Si]

Am i aloud to post the ec 46

weeks 2-3

shows retrogression to me.

[feb1991blizzard]

3 minutes ago, blizzard81 said:

Thanks Feb. I know I shouldn't go too far out but I really do like the look of heights rebuilding to our north east again by week 6 - scandi high incoming. I say this because I have noticed since a very young age how weather patterns can often repeat themselves exactly a month later - certainly in winter. What a run up to Christmas that would be

I didn't even see week 6 even though all i had to do was move my mouse pointer a few mm lower on the screen, i saw week 5 was poor for cold, quite unusual for me as anyone knows i usually finish runs off right the way to 384 on the GFS no matter what!!

[bluearmy]

1 minute ago, Allseasons-si said:

Am i aloud to post the ec 46

weeks 2-3

shows retrogression to me.

You can from the Icelandic site as it’s not behind a paywall ...........

it might not show retrogression - could be progression ......... the global picture will be a little more revealing 

[Geordiesnow]

Problem with the Euro trough is that if it does not turn into a Scandi high then we do remain in the very mild air until the Atlantic breaks it down but on the flip side if it does edge further westwards then we will eventually get into a more continental airflow with fog and frost perhaps becoming more likely. I think despite the very mild weather, its a satisfying output who wants dry weather as next week does look drier especially as the week goes by. 

Also keep an eye on those weak heights around Svalbard, they might not look significant but it can turn out to be a building block to something that lead to more in the way of blocking. All in all though, a mild outlook with next week looking more and more likely to turn very mild with temperatures potentially into the mid-teens. 

[phil nw.]

I am always wary of Scandi blocks holding in November.The inevitable increase in Stratospheric zonal winds leading up to mid-Winter will usually be too much for the pattern to hold as the Atlantic jet ramps up..A much better chance of such a setup being more successful in the late Winter as the pv starts to weaken.

I remember reading something many decades ago along these lines but cannot recall the source now-it may have been in one of the editions of Weather magazine which was a monthly magazine i used to purchase back in the 60s.

[bluearmy]

9 minutes ago, bluearmy said:

You can from the Icelandic site as it’s not behind a paywall ...........

it might not show retrogression - could be progression ......... the global picture will be a little more revealing 

Looking at the big picture, it does look retrogressive from our perspective ..... weeks three and four show a mid Atlantic high and sceuro trough of sorts ...... not looking past week 4 as this is as far as I care to use the ec46. 

[feb1991blizzard]

The ECM eps clusters dont look great to me, cluster 1 (46%) does have well above average heights scandi but doesn't look like it would lead to much immediately, the other 2 clusters dont look great at all.

[Kirkcaldy Weather]

P15 the pick of the bunch  (plenty more have the high nearby or trying to get in a better position for us to get the cold, certainly not a zonal outlook at the moment)

     

[lorenzo]

As bits and pieces are discussing strat trop disconnect. This view helps show the massive difference between trop vortex and strat vortex, it also provides hypnotic animation of wave breaks if you like that. 

The developing rock in the tropospheric pond of the Scandi block is clear to see and way above in white the start vortex churns away.

http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

Heights

Temp

Forthcoming EAMT looks like more fun ahead in the trop..

[Interitus]

2 hours ago, lorenzo said:

As bits and pieces are discussing strat trop disconnect. This view helps show the massive difference between trop vortex and strat vortex, it also provides hypnotic animation of wave breaks if you like that. 

The developing rock in the tropospheric pond of the Scandi block is clear to see and way above in white the start vortex churns away.

http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

 

Maybe there should be some definition of a trop-strat disconnect because watching the animation in the link shows the linkage which exists between the two - the Scandi block is generating the wave 1 forcing which results in the strat Aleutian high pushing the vortex towards Eurasia. As the block weakens, so does the wave 1 forcing and the vortex returns to the pole.

[jules216]

Trend is your friend

[Cheshire Freeze]

Looks like we may have initiation at 228 hrs on the 0z GFS

Euro heights punching their way nicely N

Edited November 9, 2018 by CreweCold

[Cheshire Freeze]

...and by 300 hrs...

[GeordieX9v]

Not bad at all. Thought I'd be the only one here on my allnighter! Looking goood!!!

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=384&m

the coldies might  like it after 384 hr   are winter  could be coming!!!

[bluearmy]

2 hours ago, jules216 said:

Trend is your friend

If only it weren’t the cfsv2 jules ........

[jules216]

17 minutes ago, bluearmy said:

If only it weren’t the cfsv2 jules ........

Yes @bluearmy, very much aware of that caveat

[lorenzo]

4 hours ago, Interitus said:

Maybe there should be some definition of a trop-strat disconnect because watching the animation in the link shows the linkage which exists between the two - the Scandi block is generating the wave 1 forcing which results in the strat Aleutian high pushing the vortex towards Eurasia. As the block weakens, so does the wave 1 forcing and the vortex returns to the pole.

Good point ! I was hoping to illustrate how what's happening now in trop in terms of a strong block isn't exactly the same situation at 10 hPa.

When as you say what is happening now moves the strat vortex around. Could do with some defining! 

[bluearmy]

Eps days 9/11 getting close to cutting off that scandi upper  ridge ........ surface feature looking solid but quite what latitude it can achieve dependent on what undercutting  can get in from the east to prevent it ‘sceuroing’

[jules216]

16 minutes ago, bluearmy said:

Eps days 9/11 getting close to cutting off that scandi upper  ridge ........ surface feature looking solid but quite what latitude it can achieve dependent on what undercutting  can get in from the east to prevent it ‘sceuroing’

The cold anomalies do not even get as far as Germany, no sugar coating this is a downgrade from 12Z EPS suit, Scandi high does not migrate west towards Iceland or into mid atlantic ridge but rather shrinks and possibly becomes sceuro block, I am not sure how useful it will be in long run, but perhaps a zonal 2/3 of December looming behind +NAO

Edited November 9, 2018 by jules216

[mulzy]

15 minutes ago, jules216 said:

The cold anomalies do not even get as far as Germany, no sugar coating this is a downgrade from 12Z EPS suit, Scandi high does not migrate west towards Iceland or into mid atlantic ridge but rather shrinks and possibly becomes sceuro block, I am not sure how useful it will be in long run, but perhaps a zonal 2/3 of December looming behind +NAO

In my opinion, this morning's EPS are significantly better than last night's. The orientation of the Atlantic trough *hints* at undercutting is allied with the block being at a slightly higher latitude.  Sceuro block then sinker is definitely one of the options on the table but there are other options too.

Edited November 9, 2018 by mulzy

[bluearmy]

12 minutes ago, mulzy said:

In my opinion, this morning's EPS are significantly better than last night's. The orientation of the Atlantic trough *hints* at undercutting is allied with the block being at a slightly higher latitude.  Sceuro block then sinker is definitely one of the options on the table but there are other options too.

More in your camp than jules ... the Scandi ridge much more defined on this run - beyond day 10 is always going to offer options - clusters awaited in couple hours 

[feb1991blizzard]

20 minutes ago, bluearmy said:

More in your camp than jules ... the Scandi ridge much more defined on this run - beyond day 10 is always going to offer options - clusters awaited in couple hours 

Yes, cant talk about days 11-15 definitively as i don't have access, however, the D10 ens mean compared to yesterdays looks to me that its not possible that days 11-15 are less indicative of blocking and will stick my neck out that there is a clustering bringing cold uppers from the East on the London graph.

[BlueHedgehog074]

Looks to be further spells of wind, rain and showers for places in the UK for the next few days. Low Pressure taking charge to the North-West of the U.K. 00Z GFS used to illustrate this.

Compared to the last few days, the Atlantic Low that has been stalling in the Atlantic, does penetrate a little bit further East, pushing our favourite (or not-so-favourite) Eastern UK blocking High somewhat further East. The worst of the unsettled conditions being around North-Western parts of the U.K. and will be the coolest in those areas. Some brief ridges, especially next Tuesday as shown on the last chart above on the 00 GFS, will help bring some brighter breaks between the rain and showers. Though South-Eastern areas probably benefitting the most from this. And the area seeing more in the way of less-cool/milder conditions at times.

Then, this is where things start to heat up again. Using the likes of the GFS, ECMWF and GEM at 192 hours, the blocking comes back for revenge over and to the East of the UK. 

00Z GFS

00Z ECMWF

GEM

Around that time-frame, would say, generally, both the ECMWF and GEM have the Scandinavian High Pressure being the most influential towards the U.K. It would be dry and mostly settled, especially towards Eastern parts. And with the flow quite possibly being slack at times, some mist and fog at night too along with some frosty weather.

There are questions as to whether the Eastern UK block can migrate Westwards and become more concentrated directly over the UK, or just to our West in the Atlantic (or possibly around Iceland or Greenland - though don’t feel there is much confidence of that happening. At least not yet). Would help for the blocking to migrate as far North as possible over the U.K. or Scandinavian area. And the blocking High Pressure also being place favourably to bring lots of vertical Warm Air Advection towards the Pole via long drawn Southerly winds (bit like what some mentioned earlier) to give the Vortex a big smack! Otherwise, failure for the block to get far enough North and there could indeed be a risk of the Atlantic stamping out the block. 

Particularly should any Lows in the Atlantic fail to show much of negative tilt to them. Will depend how things continue to develop in the next few days or so.

For now though, it looks like a battle between the two forces will re-emerge next week.