Winter 2023/24 - Discussions & Forecasts

[SqueakheartLW]

4 hours ago, summer blizzard said:

Regarding the SSW hunt, for those who want an early event like 2013 or 2021 its worth saying that the CFS is showing the next strong wave event in the Pacific passing between the 10th-20th December which should increase poleward heat flux. While the strength is not something i'd focus on with CFS, the timing should not be off. Given that we are early in the season though, we probably have to wait another ~month for the passage after but it's worth an eye on given that the vortex is already in some distress (or forecast to be) rather than continuing to cool and strengthen. 

I notice this is starting to be a constant signal for vortex weakening on the GFS

Maybe we won't have a raging vortex for much longer.

[Methuselah]

ooh er, the thot plickens: 

 

[Summer Sun]

Winter 2023/2024 Final Forecast: Cold arrives early across the United States and Europe and is likely to return as we head into the next year

 

Winter 2023/2024 Final Forecast: Cold arrives early across the United States and Europe and is likely to return as we head into the next year » Severe Weather Europe

WWW.SEVERE-WEATHER.EU

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Winter 2023/2024 start with early cold across the United States and Europe, with increasing seasonal influence from the strong El Niño event

 

[syed2878]

An interesting watch from gav's weather vids the 3RD and last moddle roundup for this winter.  Here it is.   

 

[sebastiaan1973]

An extreme cold Central European winter such as 1963 is unlikely but still possible despite climate change

Abstract. Central European winters have warmed markedly since the mid-20th century. Yet cold winters are still associated with severe societal impacts on energy systems, infrastructure and public health. It is therefore crucial to anticipate storylines of worst-case cold winter conditions, and to understand whether an extremely cold winter, such as the coldest winter in the historical record of Germany in 1963 (−6.3 °C or −3.4σ seasonal DJF temperature anomaly relative to 1981–2010), is still possible in a warming climate. Here, we first show based on multiple attribution methods that a winter of similar circulation conditions to 1963 would still lead to an extreme seasonal cold anomaly of about −4.9 to −4.7 °C (best estimates across methods) under present-day climate. This would rank as second-coldest winter in the last 75 years. Second, we conceive storylines of worst-case cold winter conditions based on two independent rare event sampling methods (climate model boosting and empirical importance sampling): winter as cold as 1963 is still physically possible in Central Europe today, albeit very unlikely. While cold winter hazards become less frequent and less intense in a warming climate overall, it remains crucial to anticipate the possibility of an extreme cold winter to avoid potential maladaptation and increased vulnerability. 

https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2523/

[raz.org.rain]

On 24/11/2023 at 13:07, summer blizzard said:

Regarding the SSW hunt, for those who want an early event like 2013 or 2021 its worth saying that the CFS is showing the next strong wave event in the Pacific passing between the 10th-20th December which should increase poleward heat flux. While the strength is not something i'd focus on with CFS, the timing should not be off. Given that we are early in the season though, we probably have to wait another ~month for the passage after but it's worth an eye on given that the vortex is already in some distress (or forecast to be) rather than continuing to cool and strengthen. 

Forgive me if my interpretation is wrong but wouldn't that point towards a SSW event occurring in winter rather than in early spring? From what I hear the expectation was for March.

[Catacol]

On 24/11/2023 at 13:07, summer blizzard said:

Regarding the SSW hunt, for those who want an early event like 2013 or 2021 its worth saying that the CFS is showing the next strong wave event in the Pacific passing between the 10th-20th December which should increase poleward heat flux. While the strength is not something i'd focus on with CFS, the timing should not be off. Given that we are early in the season though, we probably have to wait another ~month for the passage after but it's worth an eye on given that the vortex is already in some distress (or forecast to be) rather than continuing to cool and strengthen. 

EPS 200mb charts also suggest the same with regards to pacific wave passage . Uplift zones pushing towards the 7-8-1 orbit as early as 9th December. So should hit these key phases pretty close to mid month.

This is a little quicker than I expected meaning we get the next extra tropical impact in the North Atlantic around Xmas time, maybe a day or 3 earlier. Given the upcoming cold spell is extending in length as the ridge is propped up by jet angle, Atlantic SSTs and perhaps also the embedded cold over Scandy it may well be that the period of relaxation is rather short.

So - no change to the shape of things overall, but greater impacts of this early amplified period combining with swift MJO passage back towards phase 7/8/1 mean a colder December than expected. Blocked through until around Dec 8 with a short interlude of westerlies Dec 10 onwards for around a week, and then renewed blocking cycle.

EPS continues to see low pressure hammering through the North Pacific.

Regardless of what might happen in the Ural sector we are really cashing in here. Vortex shoved to the Scrussia side as a result and weakened by warmth fired vertically. No SSW for me in December now but the renewed pacific wave activity from mid December onwards may well be setting us up for SSW potential in January.

Very interesting to see this winter build forwards. Real cold weather potential lies within.
 

[summer blizzard]

9 hours ago, IrelandWeather said:

I'm curious why so many keep saying these are the best early winter charts for years/best start to winter. 

Was I hallucinating last year? It's been a year. One year since a good start to winter. And the model output for the above began in November too, and there were plenty of runs which showed potential of an even better spell of weather. The charts from last year rival nearly anything popping up currently, unfortunately we just did not get all the hoped embedded features so many didn't see snowy conditions. But still, you can't even argue that last years spell wasn't as good, because this years hasn't even happened yet and could end up even worse (or better, who knows). Some snow, prolonged cold, ice days...coldest spell of December weather since 2010. 

It's been tossed around so much the last week and it's a bit funny. I wouldn't say it (Dec 22 spell) was classic at all here in Ireland, but given nothing has happened yet it would be strange to say that this is the best start to winter since 2010. But hey, different strokes. 

 

This is a good point and i think it mainly stems from the fact that it was a snow poor event for many, especially given the southern bias from many. It's also worth saying that last year did not produce its sub zero daily mean until the 7th. It's somewhat like Feb 12 i suppose or winter 06 which are both rarely spoken of despite their statistical impressivness.  

[kold weather]

2 hours ago, summer blizzard said:

This is a good point and i think it mainly stems from the fact that it was a snow poor event for many, especially given the southern bias from many. It's also worth saying that last year did not produce its sub zero daily mean until the 7th. It's somewhat like Feb 12 i suppose or winter 06 which are both rarely spoken of despite their statistical impressivness.  

Also similar to Feb 86, outrageous cold but it doesn't get mentioned much due to the Snowy winters around it.

What last December needed was that big snow event, it did have snow but it was reasonably localised into certain regions. All the memorable cold spells (Jan 10, Dec 10, Feb/Mar 18, etc) have tended to have those near countrywide events.

But yeah, Dec 22 was actually temperature wise quite extreme, we nearly broke a cold record date mean (just missed out, ended up 2nd coldest for i think the 15th December), it'd have been the first since I think Mar 18.

[sebastiaan1973]

According to some the positive IOD can ruine our winter chances. This charts show the MJO from october 2019 till 2020. The last time there was a positive IOD.

You can see just in october and march a passage threw the Indian Ocean. Right now there is movement in that area, so it seems to me, that is an indication the IOD would be a problem. 

[Don]

6 hours ago, sebastiaan1973 said:

You can see just in october and march a passage threw the Indian Ocean. Right now there is movement in that area, so it seems to me, that is an indication the IOD would be a problem. 

Lets hope not!!

[CryoraptorA303]

On 26/11/2023 at 10:30, summer blizzard said:

It's somewhat like Feb 12

Feb 12 was quite localised but in the SE was extreme - If I recall correctly the lowest recorded temperature was -18.3C in Chesham, Buckinghamshire. Must've been the lowest southern England temperature in a long time, probably since January 1987. Here in Kent we had about 10cm of snow which is the most I've personally experienced lying in my life (although if I were living here and not in East London during December 2010 I would've seen considerably more here). Further north saw a fairly standard cold snap like the aforementioned January 87 due to it being caused by a Scandi high that clipped southern Britain. Once you're in Edinburgh it's almost shocking how unexceptional it was there. BFTE was a similar mechanism although storm Emma complicated it and led to extreme snowfall in the west. Even then the lowest temperature was at Faversham of all places at -14.2C and that was the lowest temp of all 2018. You wouldn't think it but the SE is one of the best places for cold snaps in the UK especially later in winter due to the proximity to continental airmasses.

[damianslaw]

Just 3 days left of November. I've not read many thoughts on winter ahead. Good to hear thoughts. 

[Dark Horse]

1 hour ago, CryoraptorA303 said:

Feb 12 was quite localised but in the SE was extreme - If I recall correctly the lowest recorded temperature was -18.3C in Chesham, Buckinghamshire. Must've been the lowest southern England temperature in a long time, probably since January 1987. Here in Kent we had about 10cm of snow which is the most I've personally experienced lying in my life (although if I were living here and not in East London during December 2010 I would've seen considerably more here). Further north saw a fairly standard cold snap like the aforementioned January 87 due to it being caused by a Scandi high that clipped southern Britain. Once you're in Edinburgh it's almost shocking how unexceptional it was there. BFTE was a similar mechanism although storm Emma complicated it and led to extreme snowfall in the west. Even then the lowest temperature was at Faversham of all places at -14.2C and that was the lowest temp of all 2018. You wouldn't think it but the SE is one of the best places for cold snaps in the UK especially later in winter due to the proximity to continental airmasses.

England does better in easterlies by being slightly further east compared to Scotland and this gives more of a likelihood of tapping into colder upper air from the continent but Scotland and Northern Ireland do better in northerlies owing to being closer to the Arctic air masses and north facing. Not sure about Wales though. Maybe the exposed north, like northern Scotland, can do good with a northerly I'd imagine. And the south from a rare channel low with the Midlands the usual northern extent.

Edited November 27, 2023 by Dark Horse

[summer blizzard]

49 minutes ago, damianslaw said:

Just 3 days left of November. I've not read many thoughts on winter ahead. Good to hear thoughts. 

Cold. I'm bullish for the first time in years

November has gone about as expected and I previously forecast a fairly average December and February with a cold Jan and March but it looks like December is coming in colder than expected. 

 

[LRD]

9 hours ago, damianslaw said:

Just 3 days left of November. I've not read many thoughts on winter ahead. Good to hear thoughts. 

I don't know about the actual weather but this is how I foresee the winter on here:

I predict the early winter will feature long bouts of optimism from fans of the cold*. There will be a good scattering of delusion and kidding-ourselves thrown in with some heavy, showery references to 1981 and, later in Dec, to 1963. If south-westerlies are raging in Dec there will be a blizzard of it's-still-early-in-the-season type posts

That will be followed by a January featuring frequent comparisons of 1947 spreading in from all directions to effect the whole of net-weather. This, despite the polar vortex raging away in NE Canada, Greenland and Iceland. However, 'winter is over' posts will become more frequent as we progress through the month, especially in the Winter Chat thread, which could get a deluge at times. This may lead to stormy encounters between different members of net-weather

In Feb a gale of panic will set in as, with hardly anywhere having seen a snowflake all winter up to that point and GFS, ECM, other models and the Met Office predicting westerlies as far as the eye can see, the tears of coldies could lead to some serious flooding issues, especially in areas experiencing a thaw of the optimism experienced earlier in the season. There may be thunderous storms of protest criticising seasonal weather models and the Met Office for daring to mention the possibility of a cold Feb. This could be accompanied by a torrent of I-told-you-so posts spreading in from smug parts

Late in Feb, a brief northerly will set in, leading to a few flakes on mountains in the north. This will lead to isolated predictions of the coldest March since 20,000 BC but they will soon clear as March settles down to a normal pattern of neither warm nor cold

By Easter, there will be a monsoon of posts lamenting where winter went wrong when it 'all looked so promising'

 

 

 

*of which I am one between early Nov and late Feb

 

[Matty88]

I showed optimism in early November stating what I felt was the obvious that after 3 months of westerlies and record LP's something was bound to change only to be shot down in flames at the time! It clearly wasn't misplaced optimism !! 

On a serious note I still believe Nothern Hem blocking HP's will be causing forecasters a few headaches and upsets running through the rest of December into the New Year... watch this space

[CryoraptorA303]

5 hours ago, LRD said:

This will lead to isolated predictions of the coldest March since 20,000 BC

Considering this would be going back to the last glacial period, I don't think this is all that likey Would be nice though

[CryoraptorA303]

3 hours ago, Matty88 said:

I showed optimism in early November stating what I felt was the obvious that after 3 months of westerlies and record LP's something was bound to change only to be shot down in flames at the time! It clearly wasn't misplaced optimism !! 

On a serious note I still believe Nothern Hem blocking HP's will be causing forecasters a few headaches and upsets running through the rest of December into the New Year... watch this space

Honestly, I'm really craving a December 2010 now. It's not going to happen, but I'd really like to see a notably cold and snowy December for some reason, even though January is the one we really want a notable cold snap in this year with the ENSO+/eQBO and not having a notable January cold spell since 2013. We're really overdue a notable January event by now while we only had a notable December snap a year ago. Yet I'd instinctively like to see it in December again

[cheeky_monkey]

very much an 80s kind of winter for the UK in my opinion..maybe a slightly less cold version of 1985

[raz.org.rain]

I can't claim to have any extensive experience in following the forecasts but having read through much of the commentary, it would seem that December and January will often trend towards the mild side with frequent cold snaps such as the current one. February will probably see a SSW, or maybe March? Sounds like March may be largely average though. It would seem that the back end of winter is the coldest period for these isles. After that, an early return of much warmer weather going into April.

[CryoraptorA303]

20 hours ago, raz.org.rain said:

I can't claim to have any extensive experience in following the forecasts but having read through much of the commentary, it would seem that December and January will often trend towards the mild side with frequent cold snaps such as the current one. February will probably see a SSW, or maybe March? Sounds like March may be largely average though. It would seem that the back end of winter is the coldest period for these isles. After that, an early return of much warmer weather going into April.

March SSW would translate to a late spring, so that's no good really. The PV is forecast to weaken throughout December so going off that we'll probably see SSW in late December or January now. ENSO+/QBO- seems to hit hardest in January, so that's where my bet is for 2023/24. I doubt we'll see much in December now although the 2009 analogue is interesting. Going off when they knew December 2009 was coming, if anything does happen this December, we'll know it's coming in about a week. February doesn't seem to be all that interesting in ENSO+/QBO- for the British Isles so I'm more or less ruling out an especially cold February. There is February 1978, so it's not entirely unheard of, but the overwhelming precedent for ENSO+/QBO- would appear to be January > December > February in terms of likeliness for a significant cold spell. October-November 2009 is still the best historical analogue for the same period this year in terms of hPa anomaly so eyes are definitely peeled for the December cold. I will note though that October-November 1977 is a fairly decent analogue for 2023, and the 1977 El Nino was coming off a triple Nina, so there's also quite a bit of historical analogy there.

Edited November 29, 2023 by CryoraptorA303

[raz.org.rain]

39 minutes ago, CryoraptorA303 said:

March SSW would translate to a late spring, so that's no good really. The PV is forecast to weaken throughout December so going off that we'll probably see SSW in late December or January now. ENSO+/QBO- seems to hit hardest in January, so that's where my bet is for 2023/24. I doubt we'll see much in December now although the 2009 analogue is interesting. Going off when they knew December 2009 was coming, if anything does happen this December, we'll know it's coming in about a week. February doesn't seem to be all that interesting in ENSO+/QBO- for the British Isles so I'm more or less ruling out an especially cold February. There is February 1978, so it's not entirely unheard of, but the overwhelming precedent for ENSO+/QBO- would appear to be January > December > February in terms of likeliness for a significant cold spell. October-November 2009 is still the best historical analogue for the same period this year in terms of hPa anomaly so eyes are definitely peeled for the December cold. I will note though that October-November 1977 is a fairly decent analogue for 2023, and the 1977 El Nino was coming off a triple Nina, so there's also quite a bit of historical analogy there.

I was hoping the potential for an SSW in March would be brought forward to be honest, it's far too late in the season for my liking. Midwinter would be more appropriate.

[CryoraptorA303]

14 minutes ago, raz.org.rain said:

I was hoping the potential for an SSW in March would be brought forward to be honest, it's far too late in the season for my liking. Midwinter would be more appropriate.

Indeed, SSW from late February onwards tends to be wasted on a simple cold spell during early spring. A split in late February can still produce a good cold spell in early March though. I don't see that happening this year however - cold Marches are almost exclusively an ENSO= thing. 1962, 2013 and 2018, all ENSO= and interestingly both 2013 and 2018 coming out of ENSO-. I think March 2008 was quite a cold one as well and that was also coming out of ENSO- into ENSO=. Going off other ENSO+ this spring is likely to start off average and overall be warm to hot, and dry. I'm sure you can find some weird example that was wet in year 19whatever but over the 21st century it has been almost unanimous - 2003, 2007 (signal is a bit weak with mild wet anomalies in central England but April 07 was the hottest at the time and also very dry), 2010, (2011 if you want to count it despite ENSO- as the whole year shared more similarities with a typical ENSO+ than ENSO-), 2016 was a bit of an outlier but we can chalk that down to Super Nino and weird QBO shenanigans, and 2020. 2024 is more likely to be like past Nino springs than not. June is likely to be a milder break and possibly wet too, and after that the year has some chance of staying wet (2007), but also about a 50% of going dry and warm again (2003, 2010 until August, 2016). 2020 somehow fits into both categories with June and July being a bit wet but also having some hotter days, and then August with the massive heatwave in the south.

Edited November 29, 2023 by CryoraptorA303

[raz.org.rain]

22 minutes ago, CryoraptorA303 said:

Indeed, SSW from late February onwards tends to be wasted on a simple cold spell during early spring. A split in late February can still produce a good cold spell in early March though. I don't see that happening this year however - cold Marches are almost exclusively an ENSO= thing. 1962, 2013 and 2018, all ENSO= and interestingly both 2013 and 2018 coming out of ENSO-. I think March 2008 was quite a cold one as well and that was also coming out of ENSO- into ENSO=. Going off other ENSO+ this spring is likely to start off average and overall be warm to hot, and dry. I'm sure you can find some weird example that was wet in year 19whatever but over the 21st century it has been almost unanimous - 2003, 2007 (signal is a bit weak with mild wet anomalies in central England but April 07 was the hottest at the time and also very dry), 2010, (2011 if you want to count it despite ENSO- as the whole year shared more similarities with a typical ENSO+ than ENSO-), 2016 was a bit of an outlier but we can chalk that down to Super Nino and weird QBO shenanigans, and 2020. 2024 is more likely to be like past Nino springs than not. June is likely to be a milder break and possibly wet too, and after that the year has some chance of staying wet (2007), but also about a 50% of going dry and warm again (2003, 2010 until August, 2016). 2020 somehow fits into both categories with June and July being a bit wet but also having some hotter days, and then August with the massive heatwave in the south.

It wouldn't surprise me if summer turned out to be very hot and dry next year, it feels like we're due a prolonged hot summer. I would assume it all depends on how dry Spring is, I think the 2022 record breaking high came out of a Spring drought.