Autumn & Winter 2023---2024 Stratospheric Polar Vortex. Events, Analysis, Discussions AND Outlooks

[bluearmy]

12 hours ago, Mike Poole said:

Thanks, that is very interesting.  I presume the graphic (copied from the blog) must be from GloSea6:

It looks like a 16 member ensemble, which is few enough to identify the following clusters (give or take the odd one I’ve misread):

• 6 go for an early SSW (38%).
• 3 take the route I described in my post above, intensification followed by plummet (19%).
• 3 amble down more slowly and go mid Jan (19%).
• 2 reverse around end Jan/start Feb (one is a repeat SSW from the first cluster). 

Overall chance of SSW 13/16 (81%).

This is much higher than the ECM 46 is going for, which is interesting.  I think it also more fairly represents what we are seeing from the GEFS and GEPS, which look pretty bullish too although any SSW outside their range at the moment.  

That pretty much confirms the 30 dayer speaking about possible colder spell post mid jan is strat related. This isn’t a one off from glosea then. 

[bluearmy]

17 minutes ago, Andy8472 said:

Who's still the odd one out at 240? 

Btw the ecm at the end is the best yet although no split "atm"

Eps mean shows the spv very boxed in around ne scandi/ Barents Sea area and unable to extend towards e Asia as gfs op fi has been keen to show, run after run.  The mean must hide a variation of solutions though - shame we can’t see them in cluster form 

[Andy8472]

5 minutes ago, bluearmy said:

That pretty much confirms the 30 dayer speaking about possible colder spell post mid jan is strat related. This isn’t a one off from glosea then. 

As far as i know it is from Glosea but without a stamp can't be sure

[Don]

36 minutes ago, bluearmy said:

Eps mean shows the spv very boxed in around ne scandi/ Barents Sea area and unable to extend towards e Asia as gfs op fi has been keen to show, run after run.  The mean must hide a variation of solutions though - shame we can’t see them in cluster form 

Which wouldn't be so good for us I take it?

[bluearmy]

7 minutes ago, Don said:

Which wouldn't be so good for us I take it?

If we could lose the disconnect between weak strat and strong trop flow then it would be ok for us and potentially v good  (there are signs now as can be seen with more amplified NH profiles appearing) 

a vortex broadly in the scandi region is far better than one to our nw 

[Andy8472]

Finally, now will the core split later on?

[bluearmy]

2 hours ago, Andy8472 said:

Finally, now will the core split later on?

Ec and gfs are on a different page re the speed of the Asian warming 

it takes gfs 4 days to catch up to ec op profile and the gefs are pretty much the same as the ec op

so can’t really deduce much from the gfs until it catches up

it isn’t so different at 30 and 50 hpa so it seems to be an upper strat issue which is where ec really should be a better tool with its 137 levels at high resolution 

   

[BLAST FROM THE PAST]

From Spaceweather.

Three days in a row PSCs have been sighted in Norway and Sweden.

Widely considered to be the most beautiful clouds on Earth, polar stratospheric clouds (PSCs) are rare. Earth's stratosphere is very dry and, normally, it has no clouds at all. PSCs form when the temperature in the Arctic stratosphere drops to a staggeringly-low -85 C. Then, and only then, can widely-spaced water molecules begin to coalesce into tiny ice crystals. High-altitude sunlight shining through the crystals creates intense iridescent colors that rival auroras.

During a typical Arctic winter, PSCs appear no more than a handful of times, and the first sightings usually come in January. This week's apparition marks an early start, and may herald many more PSCs to come.

 

So would a SSW event be affected by this either way?  Is it a precursor or dampener?

 

BFTP

[joggs]

2 minutes ago, BLAST FROM THE PAST said:

From Spaceweather.

Three days in a row PSCs have been sighted in Norway and Sweden.

Widely considered to be the most beautiful clouds on Earth, polar stratospheric clouds (PSCs) are rare. Earth's stratosphere is very dry and, normally, it has no clouds at all. PSCs form when the temperature in the Arctic stratosphere drops to a staggeringly-low -85 C. Then, and only then, can widely-spaced water molecules begin to coalesce into tiny ice crystals. High-altitude sunlight shining through the crystals creates intense iridescent colors that rival auroras.

During a typical Arctic winter, PSCs appear no more than a handful of times, and the first sightings usually come in January. This week's apparition marks an early start, and may herald many more PSCs to come.

 

So would a SSW event be affected by this either way?  Is it a precursor or dampener?

 

BFTP

Would've thought a dampener with the colder temps

[Andy8472]

i wouldn't think it's either, it's just the core is v cold over that region at the moment -75/80 so it makes sense 

Edited December 20, 2023 by Andy8472

[DavidS]

10 minutes ago, Andy8472 said:

i wouldn't think it's either, it's just the core is v cold over that region at the moment -75/80 so it makes sense 

Correct, the colder temps at 10hPa are currently displaced from the typical home.

[Dignity]

3 hours ago, BLAST FROM THE PAST said:

From Spaceweather.

Three days in a row PSCs have been sighted in Norway and Sweden.

Widely considered to be the most beautiful clouds on Earth, polar stratospheric clouds (PSCs) are rare. Earth's stratosphere is very dry and, normally, it has no clouds at all. PSCs form when the temperature in the Arctic stratosphere drops to a staggeringly-low -85 C. Then, and only then, can widely-spaced water molecules begin to coalesce into tiny ice crystals. High-altitude sunlight shining through the crystals creates intense iridescent colors that rival auroras.

During a typical Arctic winter, PSCs appear no more than a handful of times, and the first sightings usually come in January. This week's apparition marks an early start, and may herald many more PSCs to come.

 

So would a SSW event be affected by this either way?  Is it a precursor or dampener?

 

BFTP

As others have alluded to, it shows a displacement of the strat vortex if anything. Interesting they were sighted over this neck of the woods.

I seen someone mention these on twitter, I've only ever seen them once and wanted to go have another look but there was no further detail on the sighting sadly.

[Andy8472]

You can see the lonely GFS op on it's own from this mornings 0z 

[Mike Poole]

2 SSW runs in the 6z GEFS:

 

[feb1991blizzard]

looking ar the recent charts you would think the SPV will move back over the pole, surely we couldn't see proper heat being fluxed right into the heart of the vortex to induce a split anytime before mid Jan......

 

OR COULD WE

[Norrance]

30 minutes ago, Dignity said:

As others have alluded to, it shows a displacement of the strat vortex if anything. Interesting they were sighted over this neck of the woods.

I seen someone mention these on twitter, I've only ever seen them once and wanted to go have another look but there was no further detail on the sighting sadly.

If those are the similar to nacreous clouds they have been visible both yesterday afternoon and today in Dundee. 

[Andy8472]

8 minutes ago, feb1991blizzard said:

looking ar the recent charts you would think the SPV will move back over the pole, surely we couldn't see proper heat being fluxed right into the heart of the vortex to induce a split anytime before mid Jan......

 

OR COULD WE

If we get something like this then probably

[Dignity]

8 minutes ago, Norrance said:

If those are the similar to nacreous clouds they have been visible both yesterday afternoon and today in Dundee. 

Cheers that what I was wondering if they were misidentified nacreous clouds, or are they the same thing?

I've had a horrific migraine today so looking out the window or being out and about hasn't been an option

[summer blizzard]

On 17/12/2023 at 17:49, SqueakheartLW said:

Bring those negative anomalies down to the trop please

Can't be too much to ask for surely

Just curious where the second U Wind anomoly chart can be sourced. 

[bluearmy]

27 minutes ago, Andy8472 said:

If we get something like this then probably

That looks to be the way that a ssw split would occur - seems isolated as an evolution at the moment with the displacement over the Kara/barents still favoured 

[Andy8472]

7 minutes ago, bluearmy said:

That looks to be the way that a ssw split would occur - seems isolated as an evolution at the moment with the displacement over the Kara/barents still favoured 

Yes i would agree with that atm, interesting few days ahead!

[BLAST FROM THE PAST]

It’s ‘unusual’ for sure…..in earlyness and numerically….let’s see what happens.  I think an early Jan SSW of some magnitude is plausible 

 

BFTP

[Daniel*]

Good to see geopotential heights this from ECM 12Z, wave 2 attack at the end pinching vortex. I personally think vortex is in serious trouble into early 2024 setting up for a major SSW.

[Andy8472]

Massive drop!

Edited December 20, 2023 by Andy8472

[Mike Poole]

4 minutes ago, Andy8472 said:

Massive drop!

Indeed.  Massive increase in the number going for the scenario I outlined yesterday - vortex intensification followed by a massive reduction and then reversal.  I reckon it was about 10 members yesterday, huge cluster today.