Polar Vortex / Stratosphere Watch 2022 / 2023

[philglossop]

Well this has changed in recent days. EQBO here we come

[Don]

9 hours ago, philglossop said:

Well this has changed in recent days. EQBO here we come

Will it, won't it this time?!

[SqueakheartLW]

On 31/03/2023 at 15:29, Don said:

Will it, won't it this time?!

I think it should. No sign of any anomalous easterlies at 40hpa this time around. At least one thing that should be in our favour in winter 2023/24. Next one to look out for is the Atlantic SSTA tripole in May although I don't know how much truth there is in that theory.

[Don]

18 hours ago, SqueakheartLW said:

I think it should. No sign of any anomalous easterlies at 40hpa this time around. At least one thing that should be in our favour in winter 2023/24. Next one to look out for is the Atlantic SSTA tripole in May although I don't know how much truth there is in that theory.

Looking good so far!  Main issue for winter 2023/24 is ENSO where strong El Nino basin wide events tend to (along with climate change these days) override other teleconnections.

Edited April 2, 2023 by Don

[philglossop]

I have to say, given the weather in recent times - we’re unlikely to see all the stars Aline and give us cold winter. But you never know- a few outliers will always occur! 

[damianslaw]

11 hours ago, philglossop said:

I have to say, given the weather in recent times - we’re unlikely to see all the stars Aline and give us cold winter. But you never know- a few outliers will always occur! 

2009-2010 was a surprise hit, don't recall many long range forecasts going for such a cold winter, alas there were hints the atmosphere was changing somewhat in 08-09 and there was a marked shift in the jetstream - much more southerly summer 07, with a blip in the winter of 07-08.

December 2010 was a real outlier - an oddity, and I expect we may well see such outliers again.

Edited April 3, 2023 by damianslaw

[Don]

14 minutes ago, damianslaw said:

2009-2010 was a surprise hit, don't recall many long range forecasts going for such a cold winter, alas there were hints the atmosphere was changing somewhat in 08-09 and there was a marked shift in the jetstream - much more southerly summer 07, with a blip in the winter of 07-08.

December 2010 was a real outlier - an oddity, and I expect we may well see such outliers again.

The Met Office went for a milder than average winter for 2009/10.  However, I believe Netweather's long range forecaster at the time (Glacier Point) went for colder than average, need I say anymore??!!

Edited April 3, 2023 by Don

[Mapantz]

33 minutes ago, Don said:

need I say anymore??!!

Still waiting for that torpedo..

[Don]

7 minutes ago, Mapantz said:

Still waiting for that torpedo..

Winter 2015/16?

[Gray-Wolf]

So when was the 'Final Warming'?

 

[summer blizzard]

1 hour ago, Gray-Wolf said:

So when was the 'Final Warming'?

 

Not yet occured. 

[Rain All Night]

Hi strat watchers, I have a question. Why is it that although the weakening and eventual final warming of the strat polar vortex in the Spring lead to a weakening of westerly flows in the troposphere (as an SSW does), this effect expires in the Summer, months before the strat PV re-forms in the Autumn?

[Don]

1 minute ago, RainAllNight said:

Hi strat watchers, I have a question. Why is it that although the weakening and eventual final warming of the strat polar vortex in the Spring lead to a weakening of westerly flows in the troposphere (as an SSW does), this effect expires in the Summer, months before the strat PV re-forms in the Autumn?

Good question! 

[Eagle Eye]

10 minutes ago, RainAllNight said:

 

Likely because in Spring there is still some wave forcing parameters that link the Trop up to the Strat so Wavebreraking still occurs bringing down the Nino response in the Troposphere and it all gets rather complicated but a strong atmospheric Nino is accompanied by westerly wind bursts in the ENSO area with a retracting Pacific jet and a retracting Pacific jet results in an extending Atlantic jet. Wave reflecting is significantly less in the Summer and the Hadley cell naturally tends to expand anyway.

Edited April 16, 2023 by Eagle Eye

[Rain All Night]

1 hour ago, Eagle Eye said:

Likely because in Spring there is still some wave forcing parameters that link the Trop up to the Strat so Wavebreraking still occurs bringing down the Nino response in the Troposphere and it all gets rather complicated but a strong atmospheric Nino is accompanied by westerly wind bursts in the ENSO area with a retracting Pacific jet and a retracting Pacific jet results in an extending Atlantic jet. Wave reflecting is significantly less in the Summer and the Hadley cell naturally tends to expand anyway.

So in short, in Summer, it doesn't matter what the strat is doing because activity in the troposphere would dictate what is going on in that season regardless?

[SqueakheartLW]

Good news for snowy winter lovers although it doesn't guarantee this will be the case

I spy the start of the EQBO. At least we appear to have passed the test for the first time since 2014, we've had no failure of the EQBO and have seen a normal descent down to 30hpa.

Still can't believe it has been nearly 10 years since we last transitioned properly from a WQBO to an EQBO after the normal (approx. 1 year) of WQBO.

[StretfordEnd1996]

1 hour ago, SqueakheartLW said:

Good news for snowy winter lovers although it doesn't guarantee this will be the case

I spy the start of the EQBO. At least we appear to have passed the test for the first time since 2014, we've had no failure of the EQBO and have seen a normal descent down to 30hpa.

Still can't believe it has been nearly 10 years since we last transitioned properly from a WQBO to an EQBO after the normal (approx. 1 year) of WQBO.

I think mid 17 to mid 18 and mid 21 to mid 22 had EQBOs but I'm guessing the point (I think) you're making is that both of these came off the back of strange prolonged WQBOs (as was the case in 2017) or EQBO which never got going followed by a quick WQBO (2021).

[damianslaw]

2 hours ago, StretfordEnd1996 said:

I think mid 17 to mid 18 and mid 21 to mid 22 had EQBOs but I'm guessing the point (I think) you're making is that both of these came off the back of strange prolonged WQBOs (as was the case in 2017) or EQBO which never got going followed by a quick WQBO (2021).

When was the last El Nino east qbo combo?

[StretfordEnd1996]

9 hours ago, damianslaw said:

When was the last El Nino east qbo combo?

Last one would of been around 2014 through to 2015. 

EQBO began around June 2014, and persisted until around June 2015. El Nino conditions began around Fall 2014 and persisted for the duration of the EQBO, but this El Nino was very weak (eventually strengthening considerably after the EQBO). 

 

Prior to this, we had an EQBO from around June 2009 to July 2010, which coincided with a relatively moderate El Nino which persisted throughout a similar timeframe. 

And the one before this you then have to go back to 1991-1992 - which was very akin to 2009-2010 in terms of start/end dates of both the EQBO and El Nino conditions. 

86ish to-87 similar 

[summer blizzard]

Winter 1987 saw a moderate El Nino and -QBO. .

Winter 1992 saw a strong El Nino and -QBO. 

Winter 2010 saw a strong El Nino and -QBO. 

 

There were a few which got close or never coupled. 

 

Winter 1980 saw a weak El Nino and -QBO but both events were weakening.

Winter 1998 saw a strong El Nino and the -QBO event beginning but weak.

Winter 2003 and 2005 saw the weak El Nino events ending as the -QBO was beginning and weak. 

Winter 2015 saw a weak El Nino and strong -QBO event.

 

Note that the MEI index suggests that the 2015 and 2005 events were not coupled with the atmosphere (warm-neutral MEI value). 

 

 

13 hours ago, damianslaw said:

When was the last El Nino east qbo combo?

 

[damianslaw]

Thanks for that, so closest analogue for upcoming year is 2009-10 if we see a moderate El Nino at least.

I am seeing some similiarities with current synoptics and those of July 09. 

[bryan629]

Recretos published this earlier discussing the relationship with an El Nino and an EQBO this coming winter

A Stratospheric wind anomaly is developing over the Equator, expected to impact the Weather along the El Nino in the next Winter Season » Severe Weather Europe

WWW.SEVERE-WEATHER.EU

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Winter Weather in the United States, Canada and Europe will be influenced by the changing wind anomalies in the Stratosphere over the Tropics