Winter 2023/24 - A Post Mortem

[MJB]

 northwestsnow Yes I appreciate that but we will have cold periods in our winters..........much more extremes Summer also. 

[jules216]

 Nick F that is why analog based forecast is the best in my opinion in Europe also including factors like SST,Legacy warmth from summer/autumn etc. The last time there was meaningful winter in central Europe it was after relatively cool summer and unsettled. i dont Remember when was last time that really hot summer was not followed by very mild winter. Anyway the best analogs like 1925/26, 2006/07 or 2015/16 performed very well and perhaps 2004/05 too,but the last one is not following cold February this year which is a shame. There was a very good signál of a cold spell 2 ND half of november which materialised then only really 1-2 snaps was anticipated which Also happened. So in my view also the GSDM/AAM/MJO is pretty useless as fórecasting tool because its Also a forecast of SST/tropical precipitation. There are múch better seasonal tools then MJO and they do verify ever since I am using them. There is too múch sucking on American tits here - trying to use fór Európe what they use fór USA there and its not working. Dont forget Also a lot on Americanwx like here on netweather just are so cold biased that they tried to use/flip everything that "might" have brought them cold winter and we know if didnt happen. There is múch better chance of cold winter next year when/if analogs like 1998/99, 2005/06 or 2016/17 would still hold merrit

[Met4Cast]

 MJB

I was speaking with James Peacock on Twitter and he thinks that the anomalous warmth in the SE Atlantic has propped up/strengthened Iberian heights this winter, given the link between climate change & an expanded Hadley cell it does make me wonder if this winter was a “real time” example of the type of winters we can expect in the future. 

Getting decent cold spells into the UK is becoming increasingly difficult. 

[Met4Cast]

1 minute ago, jules216 said:

There is múch better chance of cold winter next year when/if analogs like 1998/99, 2005/06 or 2016/17 would still hold merrit

We hear this every single year. “next year will be better”, it was said last year about this year. It was said the year before last about last year. 

Analogues categorically do not work anymore, last winter was a great example of analogues utterly failing. The climate is shifting too quickly for them to work, the baseline has changed, comparing winter to years gone past may have worked (somewhat) in the past but i’m firmly of the opinion that it doesn’t anymore, our climate isn’t the same as it was 20 years ago, let alone 50-100 years ago. 

[northwestsnow]

 Met4Cast I agree ..

I'll pop in here every winter but the tipping point has been reached for me now,there is only so many times you can chase cold and end up with nothing before logic takes over. 

Whatever combo we get ( nino nina qbo etc)  doesn't work for us..

The CC elephant is in the room.

[jules216]

 Met4Cast there was no analog in my list that was pointing to a cold winter this year or last year. You might be following biased forecasters analogs. Actually strong east based Ninos like 1925/26,2006/07 and 2015/16 verified very well. All 3 were super mild februaries in central Europe and Guess what we are on track fór oné of the mildest ever this year. I never understood from where a cold February notion here was touted so much prior to winter. 

[Weather-history]

 Penrith Snow

Point out that you mentioned a neutral ENSO, however 2009-10 was a moderate El Nino and 2010-2011 was a strong La Nina

 

[Met4Cast]

 northwestsnow

The fact this winter is likely to come out in the top 10 mildest winters is pretty telling. 

-QBO, El Niño, two, soon to be three SSW’s, weak strat throughout, declining IOD, on paper this winter should have been absolutely bitter. 

In reality? Not even close. 

[Bristawl Si]

Islands

Atlantic

Gulf Stream

A Maritime climate

The End

[jules216]

 Met4Cast -QBO is used fór Higher probability of SSW who's problem is that they presume relationship of SSW = cold. I have a lot of evidence where SSW "f.cked Up " good looking pattern in past and that is why scientists like Daniela Domeisen also try to match pattern at onset of SSW with post SSW outcome. Its so complex and I dont understand the bias again of using only the good SSW outcome and test/majority gets ignored. And of course you end up here where we are now scratching heads

[Derecho]

 Bristawl Si That logic wouldn't apply further into the past though. Between the 1740s and 1820s easterly winds were nearly as common as westerly winds during winter in this part of the world.

If we are to see colder winters again though, changes in ocean circulation are required IMO to overcome the expansion of the Hadley Cell. 2009 and 2010 show it is still a possibility.

 jules216 Agreed. I think the February 2018 BFTE resulted in too much confidence in the belief that an SSW = UK cold. Yes it can split the vortex but the pattern has to fall favourably for the UK to benefit.

[Met4Cast]

 jules216

-QBO does more than just increase SSW probabilities, it generally helps to promote a weaker sPV overall, which we have seen throughout this entire winter. 

But that’s just 1 variable, there were plenty of other variables favouring increased likelihood of blocking going into this winter, declining IOD should have helped the MJO gain more traction, that didn’t happen. 

What we did see is the anticipated rise in AAM/GWO to link the Nino base state with the atmosphere. We did see periods of fairly deep -NAO and -AO which was again, anticipated going into this winter. We did see a south shifted jet stream, most of the drivers talked about going into winter did “come off” and have the effects that were expected, from a UK point of view though it didn’t produce & i’m sure there’ll be lengthy discussions on why. 

For northern Europe it absolutely did produce, Scandinavia for example has been absolutely bitter as have many other Nordic countries. 

[Weather-history]

 Met4Cast

Unfortunately its not quite that simple.

Take 1978-79, that was wQBO, close to solar maximum and yet was a severe winter.  

We are told La-Nina winters are front loaded and yet the moderate La Nina winters of 1955-56 and 2011-12 had the coldest spells during the second half and 1995-96 had a wintry second half

Solar activity.  1911-14 was a very deep solar minimum but the winters were overall mild whilst the next severe winter to occur 1916-17 happened at solar maximum.  

[Met4Cast]

 Weather-history

Indeed, i’m not saying it’s quite that linear but we had more variables for a cold winter vs against this year and we still came out in the top 10. But then again the UK is a tiny island, difficult to upscale that.

Obviously it’s more complicated than A+B=C as this winter (and the winters you mentioned) show! 

In terms of solar activity - I think the link there is rather tenuous, it may help in some aspects but I don’t think it’s a driver of global weather patterns, at least not one that can dominate other earth based forcing! 

Edited February 10 by Met4Cast

[mulzy]

 jules216 Does AGW make using analogues unreliable as the base state is always moving?  

[Derecho]

33 minutes ago, Met4Cast said:

I was speaking with James Peacock on Twitter and he thinks that the anomalous warmth in the SE Atlantic has propped up/strengthened Iberian heights this winter

It's an interesting response but the winter months of 2010 saw the complete opposite. Warm air often moving into western Africa and southern Spain with anomalous warmth in the SE North Atlantic. So what made 2023/24 so different? 

[Met4Cast]

 Derecho

It might be worth looking at the MJO from that year & comparing it with this year, i’ll see if I can find the AAM from 2010 too, be interesting to compare the different variables & try to “diagnose” it, so to speak! 

I have to go to work now though so no time to do that today!

[jules216]

 Met4Cast but again there were lot of occasions where cold Scandinavia equaled mild central Europe and example being february 2007. Last mild month in Scandinavia really June 2023 was the last colder month here,almost inverse correlation.

[Penrith Snow]

 MattH I for one do not discount new research in meteorology or that teleconnections exist.

However, in science I was always taught that  you have to run an experiment several times with the same outcome to be sure the experiment was a success with cause and effect established.

Over the past few years many professional and amateur meteorologist have developed pet theories then promoted these like they are certainties when in reality the cause and effect correlation is close to 50% chance.

It's a problem throughout climate science, people jumping on unproven theories then promoting them as fact in order I  suspect to forward their own standing in the scientific community.

The days of rigid scientific research, in depth self doubt and continuous assessment seem to have gone.

[northwestsnow]

 Bristawl Si quite.

Except that list has aways been the same ,so what's changed?

And yes,things have changed ,dramatically ..

[jules216]

 mulzy generally we can add about +0.5/1 and also analogs with no 500mb height signal tend to verify with Higher 500mb anomally in the south of Europe.

[Earthshine]

Granted I know almost nothing about this, but it would be super interesting if there was a reanalysis study to see if MJO/AAM/etc. predictions do have some medium range skill and how good they are.  It would probably be a huge undertaking, but say we took the MJO forecasts from previous spells that preceded high latitude blocking events.  What kind of forecasting skill could we see?  I'm sure the vast density of information in the ERA5 could be used to create a pseudo forecast perhaps.  It would be interesting to try to quantify how useful these driver forecasts are in a historical setting, which might inform us on how to use them now.

[Frigid]

A lot of anger circulating around, and rightfully so. This is up there with one of the most disappointing winters I've ever experienced, not because it was mild and wet throughout but the background signals were all favouring a cold winter and yet we're set to get one of the mildest in living memory. For the longest time, Jan-Feb was looking to be quite cold. A month ago, the GLOSEA had the strongest signal for northern blocking I can remember for February but it's all come to nothing. Reminds me of last summer when July was looking quite promising for warmth, but what we got was the opposite. The MJO in a favourable position, very negative AO and weak jet yet we still get a mediocre month. I'm this close to giving up on winters in general, summer doesn't really interest me so it's either spring or autumn.. and we know how boring they can be. 

Hopefully we get a BFTE ending, or a cold March. Coldies have been deprived for years..

Edited February 10 by Frigid

[Scandinavian High.]

We have been very unlucky this winter before I started looking models 13 years ago didn’t realise how difficult it was for us to get a proper cold spell into uk December 2010 i didn’t realise how lucky we was I expected it to be repeated every now and then seems like there is barrier around the UK stops deep cold from reaching here now.

[northwestsnow]

 Frigid again I agree with everything you wrote.

CC has taken the fun out of the chase because 99% of the time the fabulous eps at day 15 turn out to be a mirage.

I don't feel angry , just defeated.