[Scotland/Alba weather discussion - Autumn 2020 onwards]

Sustained snow here

[Scotland/Alba weather discussion - Autumn 2020 onwards]

1 hour ago, Penicuikblizzard said:

What is the most likely result going forward as I try not and jump on the bandwagon in the model thread as I’m keeping my feet firmly on the ground, are we looking at a possible BFTE later in January or into February? 

That is a strong possibility 

[Scotland/Alba weather discussion - Autumn 2020 onwards]

Lifting from EC /  Model thread, latest weeklies adding to the fun. It really is all going off this evening..

[Scotland/Alba weather discussion - Autumn 2020 onwards]

GO ON YE MIGHTY LAMP POST... You may be busy... !

[Model Output Discussion - Into the new year]

Oh go on then... don't think anyone here would complain...

[Model Output Discussion - Into the new year]

The filament at 120 > 156 really launches things at Greenland, last night 18z was similar.. General direction of travel reinforcing the blocking is there. A few different nuances ahead yet, that looks like a delicately poised solution.

[Stratosphere and Polar Vortex Watch 2020]

So much to look at just now courtesy of that record breaking W1 monstering the vortex - looking forward to the 2020/21 seasonal loop of the entire process as I think it will show just how disruptive the North Atlantic Wave Breaking and Blocking is in terms of being that 'one catalyst;' that wreaks havoc on the vortex. A couple of the retro charts today.. remember when we had this view and little else

Berlin view at 475K and the vortex getting mashed over to our side, again this was before we got superb resolution.

50hPa is my pick of the animations today as it's just so chaotic, the energy in the W1 driving from the Pacific side, the daughter vortice / filament dropping through Asia and of course the split structure.

Then in our locale the action in the Atlantic and the reinforcing of the breaks feeding the blocking regimes.

Tremendous viewing !

[Scotland/Alba weather discussion - Autumn 2020 onwards]

Newly installed light on my go to Lamp Post confirms SNAW !

[Model Output Discussion - Christmas and New Year]

Merry Xmas all - without a doubt the best season of model watching up until Xmas for many a year ( at least 10).

So many great contributions, and lovely to see loads of folks showing new interest too. Pro Tip - Be Kind, you were all there once !

Hope you have an lovely Xmas - get a chance to relax, reflect, rest and recuperate

Then - into January we have a tremendous bout of model watching ahead as the programmed SSW artefacts cascade into the modelling. Given our Trop Set up is tremendous, let's hope things fall good and double down on an already great season and keep us all chasing each run throughout Jan and beyond.

Have a good one !

 

[Stratosphere and Polar Vortex Watch 2020]

[Stratosphere and Polar Vortex Watch 2020]

Glosea on-board, properly.

[Model output discussion - The run up to Christmas]

11 minutes ago, Bartlett High said:

Even though I don't understand a single word of that ...it sounds very positive

It is.

[Model output discussion - The run up to Christmas]

There are wave breaks - then there are wave breaks.

Stunning synoptics, it's as good as it gets for poetry in this image.

The vortex clinging to it's climatological home with that furious filament, the inevitability of the Greenland break

combined with the Ural Torque and the Aleutian Low.

Vortex is toast.

 

[Stratosphere and Polar Vortex Watch 2020]

That vortex looks pretty toasted 

 

:)

[Scotland/Alba weather discussion - Autumn 2020 onwards]

Oh we will still get the BS around random energy or shortwaves blah blah or that run has nudged this 42.1km east /west etc.

That's par for the course for the GFS being available 4 times a day.

Simply put, if you don't look at tonight's ECM day 10 chart in awe and wonder and enjoy the evolution - then why are you actually here looking at charts?

Hope the UKMO verifies for Xmas Eve - like that for a lovely seasonal feel leading into Xmas Day.

[Stratosphere and Polar Vortex Watch 2020]

The dynamic tropopause breaks on the EC 12z tonight are things of beauty, especially across the Greenland plateau.

Appreciate this evolution is 10 days out and it's never a given with the nuances of these breaks. However that being said it is great to see this dream wave break uppercut evolution and cross model support to varying degrees dependent on how the residual energy in the vortex seeps into the CWB elements.

The Greenland 'nudge' or 'uppercut' is something that over the years we have seen the PV really responsive too, and following on from the EP assault it is positive to see again. It's probably the one most of us want to see live again. 

Fingers crossed we get that to verification, to witness the aftermath in what will be HD or UHD /4K vs 2009 Cathode Ray Tube view !

 

[Scotland/Alba weather discussion - Autumn 2020 onwards]

I don't see any toys needing to be thrown out of any prams for maybe some time..

[Stratosphere and Polar Vortex Watch 2020]

7 minutes ago, The PIT said:

Out of interest how reliable is it at time frame??

SSWs predictability is longer than one may expect... am thinking it's more about when in January vs not if in January... especially if we get anything like the amplification programmed on today's NWP output in terms of that Atlantic Ridging. Beyond that we can call in the Asian cavalry too...

[Model output discussion - Closing in on Christmas]

Who ordered the 1070mb block then - own up !

[Stratosphere and Polar Vortex Watch 2020]

[Model output discussion - Closing in on Christmas]

Lets call 144 from the 12z at the limits of the envelope for the GFS 12 z

There is the wave break and the resultant distribution of energy as the filament whips across NE US... let's see what the 18z does... EC had several clusters, hazard that it will take a couple of days for models to settle on resolution here.

[Scotland/Alba weather discussion - Autumn 2020 onwards]

Not teasing I promise, am enjoying this winter as it's severely random..

No SSW is a definite route to cold i.e. no one can say - Yay, SSW - Guaranteed we will benefit.. 

The post in the strat thread is around the upward wave activity disrupting the vortex, last year it beasted the entire winter going into absolute steroid mode leaving us at the mercy of endless crap synoptics.

This season the Troposphere and Stratosphere are disconnected, we are not subject to facing down the barrel of doom.

The chart attached shows Wave Activity Flux - EP Flux impacting the vortex, it's great to see a vortex which is already unsettled, be subject to more wave - driving. Simply put arrows pointing right mean that energy can impact the polar vortex as we see here at 50 / 30 hpa - Left graphic. Then arrows that are equatorward do not. 

In this plot we see clear signs of the EP Flux disrupting the vortex as the arrows are pointed poleward vs equatorward.

Why this matters more than most is that the vortex has a typical cycle where it will fire up and continue to fire up across winter, this is a VI period, Vortex Intensification. It spins and connects to the troposphere and - that's all she wrote, no matter what happens in the troposphere we get over-ridden by this climatological intensification period. 

It lasts 30 -60 days and varies in strength, it is one of weather's givens.

This year the stratosphere and troposphere are not connected at all, meaning what the Polar Vortex is doing way up high does not always translate down to the troposphere. And, we have signs ahead of continued disruption. 

This means we are not subject to winter is over or things going 'tits up' , quite the opposite. We can look forward to further changes, and looking at that flux chart this evening. An SSW is imo a strong possibility.

[Stratosphere and Polar Vortex Watch 2020]

Zac's site is really cool in terms of it's moved our visibility beyond the Berlin plots.

Have admittedly been obsessed with EP flux vectors for a wee while, and this looks again massively promising for TPV if not SPV disruption. Factor in EAMT in the post, MJO cycle in the post.. it's a great winter where our winter foe attempting as hard as it can to revert to climo - just isn't getting it's own way.

Am a big fan of this winter in terms of the variation happening.. it's pretty much the opposite of last seasons uniform - none shall pass.. into - proper chaos.

Yes, Jan you may say is another 'climo' pick statistically for a SSW to happen, however beyond the 'bookies shout' there is plenty of evidence that backs up that call, just a matter of when not if IMO.

[Scotland/Alba weather discussion - Autumn 2020 onwards]

Sorry @Hairy Celt a good two hours under the floor boards, then read again it will all make sense !

 

[Stratosphere and Polar Vortex Watch 2020]

Only way is up !!!