[Gaoth Laidir]

Originally Posted by lapua20grain

https://twitter.com/afreedma/status/...588467202?s=19

See, this is the type of hype I'm on about. It's "poised to bring...", as if it's set in stone. Pure clickbait.

[nacho libre]

yes, if only it were that straight forward:

Judah Cohen:
"For the #PolarVortex disruption to be impactful on the Northern Hemispheric weather the maximum positive anomalies needs to make its way down from the upper stratosphere to the mid-troposphere. This stratosphere "boomerang" will complicate things and may delay the full impact."

https://twitter.com/judah47/status/1346499533904236545

[Pangea]

Sky news article on the SSW

https://news.sky.com/story/uk-weathe...e-way-12180069

[Gonzo]

another fairly major warming could be on the way for 18th-20th January

[AuntySnow]

Originally Posted by Gonzo

another fairly major warming could be on the way for 18th-20th January

If that's where the tropospheric polar vortex ends up though,as is likely,the large blue near Greenland being the strat vortex,we'll just have a fired up Atlantic and a lot of cool wet and windy spells

[nacho libre]

If a third warming leads to a split, spring will likely be delayed, but it could be cold and wet, rather than cold and white. However with a split the chances of blocking in the right places increases. The problem with this current SSW is that it now looks increasingly likely a daughter vortex could end up in a position which inhibits GL blocking and fires up the jet stream. I really hope i'm wrong about this.

[AuntySnow]

Originally Posted by nacho libre

If a third warming leads to a split, spring will likely be delayed, but it could be cold and wet, rather than cold and white. However with a split the chances of blocking in the right places increases. The problem with this current SSW is that it now looks increasingly likely a daughter vortex could end up in a position which inhibits GL blocking and fires up the jet stream. I really hope i'm wrong about this.

A daughter vortex wouldn't take up situ in Greenland though would it,it would have to slide

[nacho libre]

Originally Posted by AuntySnow

A daughter vortex wouldn't take up situ in Greenland though would it,it would have to slide

You would hope so, but if i'm not mistaken after the SSW a couple of years back we ended up with a displaced section of vortex that stayed over the north atlantic which kept us cold and wet while colder air stayed out of reach on the continent. Hopefully this time if a part of the Vortex end up far enough west in the North Atlantic and another part in Siberia, we can manage a wedge of heights up north between the two.

[AuntySnow]

Originally Posted by nacho libre

You would hope so, but if i'm not mistaken after the SSW a couple of years back we ended up with a displaced section of vortex that stayed over the north atlantic which kept us cold and wet while colder air stayed out of reach on the continent. Hopefully this time if a part of the Vortex end up far enough west in the North Atlantic and another part in Siberia, we can manage a wedge of heights up north between the two.

Aidan McGivern spoke about the competing influences of la nina in the last third of yesterday's 10 dayer

[NMB]

Looking forward to an update on this thread in regards to the downwelling.

[bazlers]

To be honest ive read alot of different views of what happens next with alot of contradiction.

Sryanbruen seems to have a good handle on it though. Very complex affir with a third warming possible. All up in the air as they say : )

[sryanbruen]

Originally Posted by bazlers

Hi Sryanbruen, the SPV flipped westerly yesterday although quiet weak. Do you know if there will be further warmings soon?

Replying to this in the respective thread, yes there will be a succeeding warming that occurs later in the week and is reflected by a a drop back to reversal from this GFS forecast.

The latest GFS does show an eventual recovery in the SPV which you would expect. Warming events cannot go on forever. This is normal with mid-winter major warming events.



All eyes right now are on if tropospheric impacts will be felt now that the major SSW event was officially declared on 5th January. The likely route if we see any impacts is a mid-Atlantic ridge, North American trough and the main lobe of the vortex over Eurasia. This initially sounds all positive for a cold/snow lover but there are lots of complexities surrounding it. However, Iberian heights might prove an issue with depressions forming in the North Atlantic due to the vortex lobe over North America.

Models are on a rollercoaster at the moment with these stratospheric developments. They have no clue. Some runs show the likely route I mentioned whilst others show something completely different or nothing at all. This is definitely more uncertain than what happened in 2018 but even that event was not fully certain all the time with some rollercoaster moments such as models (notably the ECM) showing the high latitude blocking too far south to allow a direct feed of the severe cold polar continental airmass or the period of "lift off" would backdate on runs.

What is different this time to 2018 too is that we have high latitude blocking already or a weakened tropospheric polar vortex. Does the SSW prolong this blocking, does it intensify the blocking or does it give the atmosphere a bit of a shake to a different pattern?

Lots to keep a close eye on for sure.

[bazlers]

Thank you Sryanbruen, great insight there.
Alot involved indeed. Hopfully all the pueces of the puzzle will line up for snowy cold outcome : )

[Gaoth Laidir]

Interesting reading here on the predictability of downward propagation of SSWs. It's more the strength of the SSW, and not its morphology (split or displacement) or preceding wave-number (1 or 2) that's the strongest determining factor of whether it will propagate downwards. It compares the 2018 and 2019 SSW events.

https://agupubs.onlinelibrary.wiley....9/2019JD031919

[nacho libre]

A second minor SSW to take place in 3 or 4 days?