Early run up to Winter 2021/2022 discussion

[damianslaw]

7 hours ago, Catacol said:

The strength of the Euro ridge appears to be strengthening in short and medium term modelling. Makes you wonder why we all gnash our teeth at 3 month average anomaly charts issued 2-4 months ahead of time, when the best model in the world cannot even get pressure patterns over the continent nailed at 5-7 days….

Anyway - this is good news if vortex disruption over the longer term is your thing. Sweet spot would be to see a U.K. trough stalling as it runs into a Euro/Scandy block in mid November. Cue stressed vortex when it really counts. One of my watching briefs moving in the right direction.

This is what happened in 2009. We ended up on the mild side of the jet for a time with the trough stuck to our west, in time it did move east at the end of November but something odd happened around 9 Dec.. sudden high pressure development over Norweigen Sea.. the azores high then did an odd thing and ridged N-S through UK and merged with Saud heights. Never seen anything like it since.. we were then locked in a cold period more or less for 3 months.. 

 

[damianslaw]

4 hours ago, Don said:

Yes, the biggest potential fly this year is if Nina develops into a strong central based event!

It's just one factor Don.. 

[Sunny76]

Someone posted about warmer than average winter months started becoming more common from December 1987. 
 

I feel this is where the U.K. climate started to warm, and was the first winter I remember where it felt really mild. 86/87 had mild spells, but never felt unusual, and cold weather came after Christmas.

December 87 ushered in the change, with a very mild springlike Christmas, and no cold weather in January and February 88. 
 

It was definitely the mildest winter since 1974/75, and one of the mildest on record at the time. This also followed the storm in October, so the atmosphere started to change around this time. Most of Northern Europe had less snow during 87/88 for the first time in many years.

Since 87, mild winters have become more common, and March has become warmer, but in recent years, the cold can bite at any time. 2013, 2018, and parts of last winter have shown that cold weather can still and will still feature. 

[andy989]

Any musings on the volcanic erruptions on going? The la Palma one not getting the media coverage it deserves, it's output is very impressive. I probably know the answer to the question " is it spewing enough particles to affect winter". Probably not, but Etna has just errupted too. It's a fact that volcanic eruptions can cool temperatures, 1991 erruptions in the Philippines a recent example. Any (non ramping) thoughts?

volcanic winter | Duration, Temperatures, & Facts | Britannica

WWW.BRITANNICA.COM

---

Volcanic winter, cooling at Earth’s surface resulting from the deposition of massive amounts of volcanic ash and sulfur aerosols in the stratosphere. Sulfur...

 

[Bradley in Kent]

Volcanic eruptions are the reason why one can never say we'll never get a cold winter again. It will happen, but when? Who knows!

[LetItSnow!]

Looking at recent output + the recent C.E.T. tendencies, it really wouldn’t surprise me if we flipped back to cold in November and or December, maybe sticking to January if we’re lucky. If you look at the pattern over the last year you can see this evidently clear 

July 2020 - Cool

August 2020 - Hot

Then swung cool into September and October before swing into mild into November.

Swung cold in January and first half of February before rapid swing to very mild. Then another rapid swing into cold into the spring before yet another rapid swing into a warm summer/autumn  

If this is to do with the jet being in what I’ve heard is a “meridional” state then I think there’s hope of a pattern shift occurring again and perhaps that may align with the winter months. Also, 2021 tought me something else too… I’m the eternal cold optimist but up until early this year I was starting to doubt in the ability to get a proper cold month but then April and May happened, notoriously mild months nowadays. I think there should always be hope going forward. Just like how no one in Apr. 2007 could have imagine the streak of cold spells that would have occurred during the next 6 years after such a disturbing year long freak warm spell. I think there’s a lot of reasons to stay hopeful about our climate in the future and that goes for the winter too. Here’s to a 1683/1684 redux!  

[sebastiaan1973]

In october of last year we saw a large area of too warm water in the Northern Pacific. This year it seems this will be less likely.

[url]https://www.weer.nl/nieuws/2020/winterverwachting-1e-versie-vroege-winter[/url]

Translation by google

All eyes on La Niña At sea, the eyes are on the La Niña, which is developing along the equator in the sea area between Peru and Indonesia. This means that the seawater here will be colder than normal for a while. It looks to be a medium to strong La Niña, peaking in the middle of winter. Such a La Niña comes in the fall with a negative NAO index in November, the month for which we now have the strongest evidence of high ocean pressure. Such a period can continue into December, but is often followed in high winter (January and February) - certainly if the La Niña does become strong - by a period with a positive NAO index. Something similar happened in 2010/2011 as well. After the cold December, the winter was over. If the La Niña is less strong than expected, those two months with a strongly positive NAO index will immediately be a lot less prominent on the map. Two other marine phenomena that attract attention are the warm seawater in the northern part of the Pacific and the warm seawater in the northwestern part of the Atlantic. [/b]Especially if the seawater in the northern part of the Pacific were to cool during the fall (and there are indications that this will happen, and it can go quickly) a combination is created that could cause the [b] negative NAO phase, as expected for November, also persists more easily in December[/b]. The chance of this seems to be 25 percent for the time being.

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I find it difficult to estimate the extent to which there is still heat in the N-Pacific. A lot less, but there is still a large area with too warm seawater.

[Catacol]

42 minutes ago, sebastiaan1973 said:

In october of last year we saw a large area of too warm water in the Northern Pacific. This year it seems this will be less likely.

[url]https://www.weer.nl/nieuws/2020/winterverwachting-1e-versie-vroege-winter[/url]

Translation by google

All eyes on La Niña At sea, the eyes are on the La Niña, which is developing along the equator in the sea area between Peru and Indonesia. This means that the seawater here will be colder than normal for a while. It looks to be a medium to strong La Niña, peaking in the middle of winter. Such a La Niña comes in the fall with a negative NAO index in November, the month for which we now have the strongest evidence of high ocean pressure. Such a period can continue into December, but is often followed in high winter (January and February) - certainly if the La Niña does become strong - by a period with a positive NAO index. Something similar happened in 2010/2011 as well. After the cold December, the winter was over. If the La Niña is less strong than expected, those two months with a strongly positive NAO index will immediately be a lot less prominent on the map. Two other marine phenomena that attract attention are the warm seawater in the northern part of the Pacific and the warm seawater in the northwestern part of the Atlantic. [/b]Especially if the seawater in the northern part of the Pacific were to cool during the fall (and there are indications that this will happen, and it can go quickly) a combination is created that could cause the [b] negative NAO phase, as expected for November, also persists more easily in December[/b]. The chance of this seems to be 25 percent for the time being.

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I find it difficult to estimate the extent to which there is still heat in the N-Pacific. A lot less, but there is still a large area with too warm seawater.

We await the 1Nov ECM ENSO update….but I’m not sure where this reference to “medium to strong” Niña comes from. MetO monthly forecasts don’t show it, this Aug1 forecast doesn’t show it. The signal last year for a potentially bigger Niña was much stronger. Worth discussing a year 2 back to back Niña statistically perhaps, but as a stand alone feature this does not look like a major Niña to me.

Mind you - I remember discovering last year that the definition of Nino or Niña is benchmarked against a much shorter timeline used to create the average than I expected. I can’t remember where I read it, but seem to remember it is an average created from the last 10 years? Perhaps someone with a better memory can confirm that. Given warming oceans it does create a headache when comparing the impacts of a 2021 Niña with ENSO conditions 20 years ago. Not easy to compare like for like.

Edited October 24, 2021 by Catacol

[Premiere Neige]

Signs of a tripole forming in the Atlantic possibly? North East Pacific continues cooling...

[Don]

19 hours ago, damianslaw said:

It's just one factor Don.. 

It is but we don't want it to be a too strong an event.  However, time will tell.

Edited October 24, 2021 by Don

[Summer8906]

On 23/10/2021 at 11:18, Ed Stone said:

Your post made me think of the 'front-loaded' winters I can recall, and I can't remember all that many: 1970-71(?), 1981-82 and 2010 come to mind. The rest (as far as I can recall) were either back-loaded, all-loaded, unloaded or even spring-loaded!

1996-97 is a very prominent one. Cold December, if not quite as cold as 1995, with some repeated if rather light snow towards the end. Very cold first 10 days of January. Rest of Jan average or mild, though dry. Feb mild, wet and windy.

2001-02 also. Cold, frosty and sunny December; mild dull January with a lot of Tm air; and changeable, westerly, mild Feb but with reasonable sun amounts.

I think you're right about 1970-71. I remember reading that for three consecutive years (1970/1/2)  January started cold, followed by a change to mild weather around the 5th. All three Januaries were mild, as were two of the Februaries, but Feb 1970 was apparently very snowy.

Edited October 24, 2021 by Summer8906

[damianslaw]

Yes 96-97 very front loaded.. similarities with 81-82 but not as severe.. 

01-02 this delivered a cold December but not especially so and the start to 2002 was very cold.. but by the 4th the mild air crept in and that was that for cold rest of the winter.

Back loaded winters include 04-05, second half of Feb and first part of March were cold.. not especially but very easterly. 85-86 delivered the exceptional February. I can't think of many others though. 

 

[sebastiaan1973]

22 hours ago, Catacol said:

We await the 1Nov ECM ENSO update….but I’m not sure where this reference to “medium to strong” Niña comes from. MetO monthly forecasts don’t show it, this Aug1 forecast doesn’t show it. The signal last year for a potentially bigger Niña was much stronger. Worth discussing a year 2 back to back Niña statistically perhaps, but as a stand alone feature this does not look like a major Niña to me.

 

 

It is a text from last year. I show it for the difference in warm water in the N Pacific.

[MattStoke]

23 hours ago, Premier Neige said:

Signs of a tripole forming in the Atlantic possibly? North East Pacific continues cooling...

I believe there was an Atlantic tripole formed when the NAO forecast for this winter was issued back in May.

[damianslaw]

2 hours ago, MattStoke said:

I believe there was an Atlantic tripole formed when the NAO forecast for this winter was issued back in May.

I think for an Atlantic tripole you need warm layer further north in the north mid Atlantic..  there is a sign of cooling in that region but not pronounced. The cooler waters further south are too far away.

I wonder how many negative NAO tripoles in May correlate to same base state in the following winter. I think last time was 2010.

Edited October 25, 2021 by damianslaw

[Simon M]

14 hours ago, damianslaw said:

Yes 96-97 very front loaded.. similarities with 81-82 but not as severe.. 

01-02 this delivered a cold December but not especially so and the start to 2002 was very cold.. but by the 4th the mild air crept in and that was that for cold rest of the winter.

Back loaded winters include 04-05, second half of Feb and first part of March were cold.. not especially but very easterly. 85-86 delivered the exceptional February. I can't think of many others though. 

 

2012-13 was a back-loaded winter, with a cold February and very cold March.  For my mind it's the best back-loaded winter in recent years.

[MP-R]

On 25/10/2021 at 13:43, Simon M said:

2012-13 was a back-loaded winter, with a cold February and very cold March.  For my mind it's the best back-loaded winter in recent years.

Technically not as late November and the first half of December was cold, as was the middle two weeks of January. An episodic winter, leaning towards longer lasting cold as it went on.

[Summer8906]

3 hours ago, Simon M said:

2012-13 was a back-loaded winter, with a cold February and very cold March.  For my mind it's the best back-loaded winter in recent years.

I'd call that one mid-loaded, with predominantly cold weather starting on January 10th with only brief mild interruptions thereafter.  January 2013 was, aside from 2010, the snowiest January since 1987 in the south of England and the only year aside from 2010 to produce a 'good' January snowfall in the south since 1987. (Perhaps at a pinch you could include January 2019 too though the snow fell right at the turn of the month and the heaviest snow was, I think, on Feb 1st).

It was also cold for two straight weeks, though mild start and end meant it was only moderately cold overall.

Edited October 25, 2021 by Summer8906

[Premiere Neige]

5 hours ago, MattStoke said:

I believe there was an Atlantic tripole formed when the NAO forecast for this winter was issued back in May.

I think there was yes.

[Summer8906]

18 hours ago, damianslaw said:

Yes 96-97 very front loaded.. similarities with 81-82 but not as severe.. 

01-02 this delivered a cold December but not especially so and the start to 2002 was very cold.. but by the 4th the mild air crept in and that was that for cold rest of the winter.

Back loaded winters include 04-05, second half of Feb and first part of March were cold.. not especially but very easterly. 85-86 delivered the exceptional February. I can't think of many others though. 

 

Also 1982/83 perhaps. From memory (which is a little vague given the somewhat non-descript nature of much of the winter):

December - mild to very mild and dry, though cold and frosty start

January - mild to very mild, cloudy but dry

February - cold spell of about two weeks, with one decent snow event and snow cover lasting about a week

1977/78 also? I can't really remember that one very well but looks like it was a mild to very mild December, average January and cold February. My earliest memory of snow was in this winter, sometime in January I think.

And at a pinch 2011/12 though the cold only lasted two weeks and was then followed by very warm.

Edited October 25, 2021 by Summer8906

[Summer8906]

18 hours ago, damianslaw said:

Back loaded winters include 04-05, second half of Feb and first part of March were cold.. not especially but very easterly. 85-86 delivered the exceptional February. I can't think of many others though. 

 

 

I do remember the first Sunday in March 05 really felt almost unnaturally cold for March, as it was very sunny as well as being very cold. Remember this was an era in which anything other than a mild March was decidedly unusual, and any colder ones were not intensely cold.

Perhaps a week, or two weeks, later it was 21C. A very sudden arrival of very warm air if I remember right.

[RJBingham]

Mild,  bit cool before Christmas maybe

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/business/public-sector/civil-contingency/3moutlook-ndj-v1secure.pdf

 

[Mike Poole]

7 hours ago, MattStoke said:

I believe there was an Atlantic tripole formed when the NAO forecast for this winter was issued back in May.

Yes, the tripole pattern appeared about 3 times over the warm season, then disappeared, the theory is that it can resurface into winter, so worth watching.  

GFS and GEM 12z again showing the 4 wave pattern with a high over the pole at T180.  

The models unravel after this, but it is definitely FI beyond that, but this looks an important timeframe, if we can get a surge into Greenland for example, there is a scenario where the NH pattern locks up shortly after this, not saying it’s going to happen, but I’m looking for what the models are saying when the current T240-T300 timescale comes into the reliable.  

[78/79]

Remember working outside during my apprenticeship during Dec 78 through to March 79, it was  ,,,,,kin cold I can tell you.  Your hands got so cold it almost brought tears to your eyes when they came back to life.  8 hours with that  E/N/E blowing on you  was no joke.  We had one good blizzard on new years eve.

87 was notable for the intensity of the cold around here, rather than snow fall.   The ground was frozen solid , we  couldn't work for about a fortnight, being self employed , no work = no money coming in.  It's  o.k for a week or so, but anything longer causes real problems for some people, especially the homeless I  shudder to think what it must be like for them.

 

[cheeky_monkey]

On 23/10/2021 at 12:05, Sunny76 said:

Someone posted about warmer than average winter months started becoming more common from December 1987. 
 

I feel this is where the U.K. climate started to warm, and was the first winter I remember where it felt really mild. 86/87 had mild spells, but never felt unusual, and cold weather came after Christmas.

December 87 ushered in the change, with a very mild springlike Christmas, and no cold weather in January and February 88. 
 

It was definitely the mildest winter since 1974/75, and one of the mildest on record at the time. 

 

actually there have been a lot of winters milder than 87-88..for example 88-89, 89-90, 94-95, 97-98, 98-99, 99-00, 01-02, 06-07, 07-08,..the list goes on