Polar Vortex / Stratosphere Watch 2022 / 2023

[mushymanrob]

15 hours ago, Ladyofthestorm said:

Any updates on the zonal winds graph ? 

Mondays and Thursdays, late...

[BLAST FROM THE PAST]

17 hours ago, summer blizzard said:

None. It's just symptomatic of the displaced vortex, it quickly takes control.

It’s too high up for the vortex to be the reason

 

BFTP

Edited February 1, 2023 by BLAST FROM THE PAST

[summer blizzard]

6 hours ago, BLAST FROM THE PAST said:

It’s too high up for the vortex to be the reason

 

BFTP

The stratospheric Vortex has been displaced towards the UK, hence the abnormally cool temperature in our locale at that height and subsequent clouds. We know this ends, with the vortex gathering strength until late FI. 

Edited February 1, 2023 by summer blizzard

[BLAST FROM THE PAST]

On 01/02/2023 at 17:36, summer blizzard said:

The stratospheric Vortex has been displaced towards the UK, hence the abnormally cool temperature in our locale at that height and subsequent clouds. We know this ends, with the vortex gathering strength until late FI. 

Interesting but the stratospheric pv alone doesn’t guarantee such clouds….but I see your point about their southward extent.

[BLAST FROM THE PAST]

Any latest update on the upcoming warming.   I anticipate it being of note with the March anticipated.

 

BFTP

[SqueakheartLW]

Such a big warming that the zonal winds are going off the scale in the negative direction at 1hpa

The GEFS are anywhere from a slow zonal flow right down to potential daily record negative zonal wind speeds with this warming.

10hpa peaks at -22m/s before ending at a decent -20m/s. Looks good but with that piece of vortex over NE USA then that could result in a bad outcome for coldies for the UK.

That's an impressive -56m/s at 1hpa but unlike at 10hpa the vortex starts to reform and by the end of the run we are back in positive territory again although at a weak 3m/s

[Weather-history]

Mike Poole posted the graphic of SSWs and Atlantic regimes in the above post and the thing that really stands out for me is the gap between the February 1990 SSW and the December 1998 SSW. That's quite a gap, any explanation why this was so? Just random chance? 

Edited February 8, 2023 by Weather-history

[Ladyofthestorm]

On 08/02/2023 at 08:39, Weather-history said:

Mike Poole posted the graphic of SSWs and Atlantic regimes in the above post and the thing that really stands out for me is the gap between the February 1990 SSW and the December 1998 SSW. That's quite a gap, any explanation why this was so? Just random chance? 

The 1990s were devoid of Easterlies. 

Plenty potent Nlys winter December 95 being one. 

I suspect climate forcing effects by CFCs perhaps? 

They were phased out shortly afterwards. 

Volcanic activity...  Such as Pinatubo it was a biggy 

 

 

[swebby]

48 minutes ago, Ladyofthestorm said:

The 1990s were devoid of Easterlies. 

Plenty potent Nlys winter December 95 being one. 

I suspect climate forcing effects by CFCs perhaps? 

They were phased out shortly afterwards. 

Volcanic activity...  Such as Pinatubo it was a biggy 

 

 

Was there not a super-nino event during this 90s?  No idea if that has any impact if there was - well beyond my understanding!

Edit - scrub that - misremembering! There were strong events for nino and nina but it was the very end of the 90's.

Edited February 9, 2023 by swebby

[Ladyofthestorm]

4 minutes ago, swebby said:

Was there not a super-nino event during this 90s?  No idea if that has any impact if there was - well beyond my understanding!

Edit - scrub that - misremembering! There were strong events for nino and nina but it was the very end of the 90's.

Absolutely 1989? 

[Methuselah]

5 minutes ago, Ladyofthestorm said:

Absolutely 1989? 

1998?

[Ladyofthestorm]

7 minutes ago, Ed Stone said:

1998?

1988 to 89 big la Nina , I knew it was one 

[IW Met]

On 09/02/2023 at 18:26, Ladyofthestorm said:

The 1990s were devoid of Easterlies. 

Plenty potent Nlys winter December 95 being one. 

I suspect climate forcing effects by CFCs perhaps? 

They were phased out shortly afterwards. 

Volcanic activity...  Such as Pinatubo it was a biggy 

 

 

There were some fairly decent easterlies in the 90s, for example Feb 4th - 12th 1991 with a Scandi high and huge snowfalls in some parts.
Nov 19th - 22nd 1993 that brought quite widespread snow.
Feb 12th - 15th 1994 with a scandi high and lots of snow in south and east.
Dec 4th - 16th 1995, Jan 21st - Feb 8th 1996, Dec 21st - Jan 10th 96/97 that brought snow to the usual areas and freezing drizzle to the IOW.
Dec 14th - 17th 1997, although it was fairly short lived but still brought plenty of snow showers followed by a very heavy transitional snow event to many places in the UK.
I would say no less than any other decade to be fair.  

I would love to see day by day strat charts for the dates above as I am sure there are probably splits and displacements driving some of them, as we know very well that even just minor warmings can occasionally influence the strat, especially if wave 2, although during the Neutral ENSO years I am leaning more towards trop driven blocking or at least lack of strat-trop connection for the early season Easterlies.

 

Edited February 12, 2023 by IW Met

[bluearmy]

Date record at -9.8 m/s. (Previous was 2018 9.1 )

[SqueakheartLW]

Wonder if there is any chance that this SSW ends up the final warming

16th Feb has 10hpa winds at -6.15m/s so 1st day of reversal but can we stay below 0 until it is no longer possible to get back above 0m/s?

Below are all of the years and the dates the final warming took place and the reversal to summer pattern.

The record earliest is 2016 on 5th March.

What I have noticed is that in general those years with no mid winter SSW are more likely to feature an earlier final warming. The fact we have waited until 16th February 2023 to get a reversal could potentially put us in the hunt to beat 5th March 2016 for the earliest final warming on the record.

Both the above charts seem certain that 16th February 2023 won't be the date of the final warming but there is another period of reversal predicted to happen from either 25th or 26th February 2023. Could that end up the date of the final warming?

It would take some doing but it can't be ruled out entirely.

[Blessed Weather]

Dr Amy Butler sounding a word of caution about any imminent sign of SSW impact downwelling from the strat to the trop in the forecast period:

 

[Blessed Weather]

Dr Simon Lee hinting that the second dip in sPV zonal mean zonal wind strength in a week or so could play a "crucial" role in bringing about the downwelling of SSW impact from strat to trop. Here's today's GEFS ZMZW forecast highlighting the second dip:

Source: http://weatheriscool.com/page11.html

 

[Mike Poole]

6 hours ago, Blessed Weather said:

Dr Simon Lee hinting that the second dip in sPV zonal mean zonal wind strength in a week or so could play a "crucial" role in bringing about the downwelling of SSW impact from strat to trop. Here's today's GEFS ZMZW forecast highlighting the second dip:

Source: http://weatheriscool.com/page11.html

 

It does seem from recent GFS runs, that a step change occurs lower in the atmosphere at the point of the second warming, or very quickly afterwards.  Today’s 12z (of particular interest given the trop evolution from exactly this time):

[Blessed Weather]

36 minutes ago, Mike Poole said:

It does seem from recent GFS runs, that a step change occurs lower in the atmosphere at the point of the second warming, or very quickly afterwards.  Today’s 12z (of particular interest given the trop evolution from exactly this time):

Latest update from Dr Amy Butler in the last few hours much more like it. GFS 12z suggesting lift-off in the first week of March.

 

[matty40s]

Very good explanation for the happening  here.

[bluearmy]

Another date record today and I suspect a few more to follow over the next week. 

[Gray-Wolf]

Was that the 'Final Warming'?

Not a lot going on at 10 HPa right now?

Is such early if it is the F.W.?

[summer blizzard]

No. The vortex has reformed in the upper levels and will over time seep down.

[Gray-Wolf]

On 14/03/2023 at 22:26, summer blizzard said:

No. The vortex has reformed in the upper levels and will over time seep down.

Still waiting here......

 

Or was it the 'Final Warming'?......

[summer blizzard]

8 hours ago, Gray-Wolf said:

Still waiting here......

 

Or was it the 'Final Warming'?......

Borrowed from the model thread but essentially we get light westerlies (probably stronger than normal during April as is common as the initial bounce back occurs).