Model output discussion - Winter has arrived

[SteveB]

2 minutes ago, throwoff said:

Lot of talk of 47' this year. I am not super familiar with it but I keep seeing it pop up all over the place.

Snowy 

[Skullzrulerz]

No News on ICON?

[Updated_Weather]

3 minutes ago, Skullzrulerz said:

No News on ICON?

Think I know why xD

[LRD]

5 minutes ago, Broadmayne blizzard said:

Euro heights building with a displaced and uncoupled strat vortex, worth looking in the wetterzentrale noaa archives for Jan 16th -18th 1947 to see what that can be a precursor for.........

1947 KLAXON alert!!!!!!!

Only joking BB! I agree that something might well be brewing. I hope anyway. The GFS spaghetti has been trending downwards slowly but surely in FI over the last day or two. 3 or 4 isolated pearlers too. Could be something. Could be nothing. I'm encouarged by some of the superb analysis by chionomaniac, Singularity and Catacol and others too and this is the most interesting period of winter model watching for a fair while

[Dancerwithwings]

6 minutes ago, throwoff said:

Lot of talk of 47' this year. I am not super familiar with it but I keep seeing it pop up all over the place.

Not familiar....shocking

http://en.m.wikipedia.org//static/favicon/wikipedia.ico Winter of 1946–47 in the United Kingdom - Wikipedia

EN.M.WIKIPEDIA.ORG

 

[bluearmy]

icon 12z shows the scrussian heights stronger than the 00z run by T180 … is that a surprise ?

[Methuselah]

5 minutes ago, throwoff said:

Lot of talk of 47' this year. I am not super familiar with it but I keep seeing it pop up all over the place.

Aye, Throwoff, it can get rather tiresome at times... But, we're not confined to 1947 reduxes -- 1963 looms large too!

To my 'expert' eyes, another '1947' is even less likely than Spurs winning the domestic double.. And, how likely is that!

[jules216]

13 minutes ago, chionomaniac said:

So, those who have been asking about the strat and disconnect need to understand that there are two forecast events occurring in the next ten days. One is wave 1 displacement that is propagating down from the top of the strat towards mid levels and the other is a secondary wave 2 split event propagating upwards ‘internally’ from the lower strat upwards.

 

The above upper wave 1 event can be described as a barotropic quasi stationary wave - ie the wave is in the same place as we drop lower into the strat with set areas of higher and lower pressure. This so far is dynamically fairly stable and may take time to evolve before we can see how the strat will be affected by it. The wave 1 displacement loses intensity as we head to the middle strat.

the next image above is at the tropopause - where trop and strat meet and shows a weak wave 2 event that is being directed from the trop directly. This type of chart and situation is of far more interest to us current, because the strength and size of the split can influence the severity and longevity of any associated mid lat trop cold outbreaks. However, because it relies heavily on trop conditions and forecast modelling of these, this type of split can be forecast one minute and be gone the next, so the further out timewise the far less reliable. 

The disconnect that we see is that rather than the upper and middle strat controlling the lower strat and then trop, both upper strat downward propagating conditions and lower strat upward propagation are ‘meeting in the middle’ . When the upper strat becomes dominant throughout the whole strat then we will see a return to more normal +AO trop conditions. Unless of course, an upper warming starts to affect the upper strat and weaken it significantly, and just perhaps we may be seeing that too.

A Well respected telleconnection expert from USA Paul Roundy uses a RMM regression map for use of MJO tropical/extratropical Wave response and is suggesting -NAO for last week of December and first week of January.This would still be away from NWP GEFS/EPS range.Now that would provide the Wave 2 split wouldnt it? Timing permiting.

 

[LRD]

6 minutes ago, Skullzrulerz said:

No News on ICON?

Well, the Russian High (which has out-stayed its welcome now - it might well have done a job in punching the polar vortex but I think its done its job now and can either do one or retrogess properly to Greenland and Iceland) almost becomes a well-placed Scandi High

But then doesn't

[Jason M]

2 minutes ago, SteveB said:

Snowy 

When 1947 gets mentioned I always think its game over. Its a bit like watching your football time enter injury time 4-0 down and saying 'remember that time in 1947 when they scored 5 goals in 3 minutes'.  

I think any mention of 1947 or 1963 should be banned 

 

[That ECM]

T120 ukmo and t144. Look at the pv

Edited December 7, 2020 by That ECM

[jules216]

Just now, LRD said:

Well, the Russian High (which has out-stayed its welcome now - it might well have done a job in punching the polar vortex but I think its done its job now and can either do one or retrogess properly to Greenland and Iceland) almost becomes a well-placed Scandi High

But then doesn't

Shockingly uppers on ICON 12z from Direct easterly showing positive values in my region.That for the middle of December!

[alexisj9]

6 minutes ago, bluearmy said:

icon 12z shows the scrussian heights stronger than the 00z run by T180 … is that a surprise ?

Not to me, does it slide both lows?

[SMU]

UKMO 120 + 144

Trough dropping into Svalbard

Better orientated high over SE Greenland...

Atlantic looking to go under...

[sheikhy]

Just now, Steve Murr said:

UKMO 120 + 144

Trough dropping into Svalbard

Better orientated high over SE Greenland...

Atlantic looking to go under...

Gfs 12z undercuts at 120 hours and further west!!better than 06z!

[chionomaniac]

4 minutes ago, jules216 said:

A Well respected telleconnection expert from USA Paul Roundy uses a RMM regression map for use of MJO tropical/extratropical Wave response and is suggesting -NAO for last week of December and first week of January.This would still be away from NWP GEFS/EPS range.Now that would provide the Wave 2 split wouldnt it? Timing permiting.

 

Yep. Saw that. The MJO needs keen watching as we may just have it playing to our advantage for once

[mountain shadow]

We are so so close to something special.

[LRD]

1 minute ago, jules216 said:

Shockingly uppers on ICON 12z from Direct easterly showing positive values in my region.That for the middle of December!

Agreed but it's the pressure pattern that I'm more interested in that far out. If the high places itself somewhere useful then the cold uppers will come. The 144 ICON is not that far from being a good chart if only the Russian ridge can detach from Kazhakstan and head to Norway and get cut off we'd be getting somewhere

[SMU]

GFS 24 hr change from 150 >>> 126 on the 12z

[Skullzrulerz]

12 minutes ago, Updated_Weather said:

Think I know why xD

Is it the beast from the east V2? 

Also includes a ton of hot air as a upgrade XD

[Updated_Weather]

Just now, Skullzrulerz said:

Is it the beast from the east V2? 

Also includes a ton of hot air as a upgrade XD

Spot on! How did you know?

[chionomaniac]

1 minute ago, Steve Murr said:

GFS 24 hr change from 150 >>> 126 on the 12z

Happens so often over the years at that timeframe

[jules216]

3 minutes ago, chionomaniac said:

Yep. Saw that. The MJO needs keen watching as we may just have it playing to our advantage for once

That was my thought as Well could we just for once have it reversed when it matters.For many many years now in a row we had pre Christmas warm up.time for a change

 

[Mucka]

Not sure why I can't post images again.

http://modeles.meteociel.fr/modeles/gfs/runs/2020120712/gfsnh-0-144.png?12

However GFS 144 chart is so full of promise.

The fly in the ointment of runs that don't give N blocking in FI is the lack of Atlantic ridging.

If we can get that and any link up with the arctic high we could see a pretty quick evolution to proper cold over the UK, within the 12 day range.

That is best case but I feel an Atlantic ridge would offer a reasonable secure root to some good blocking in the run up to Xmas.

[chionomaniac]

Don’t forget everyone that invisible brick wall I highlighted last night - the one that Atlantic systems cannot cross due to the split. They go under or north or dissipate 

Edited December 7, 2020 by chionomaniac