Winter 24-25 Thoughts, long range model musings

[chris888]

i know those ecmwf charts are not good for winter but it is also suggesting 2025 will be quite anticyclonic which will be a major improvement over 2023 and 2024

[nobble]

Winters are crap even when there is ‘potential,

 

So  you never know

[MP-R]

1 hour ago, chris888 said:

suggesting 2025 will be quite anticyclonic which will be a major improvement over 2023 and 2024

Unless next years anticyclones are like this one…

[chris888]

 MP-R  maybe in winter but in spring and summer the sun will be strong enough to burn off any cloud

[RJBingham]

 LRD Looks like Spring starts just after Christmas 

[Don]

If this was the summer thread in May and the long range models/teleconnections were going for a crap season ahead, any comments about wanting a cold autumn would cause uproar!

[E17boy]

 Don hi hope you are well,

A lot of comments from yesterday on the EC seasonal. Will someone be kind enough to show how the EC seasonal forecast has performed over the last couple of winters. I am just intrigued to find out as it seems of put a dampener on this coming season.

As I said in my post last week these seasonal models are just a general idea of what the basic pattern might be. If the EC is going for heights down south and above average temperatures, this does not by any means mean the whole three months will be mild all the way through, we could still end up with a weeks of freezing weather in all three months but the average may still be above normal if the rest of the period is very mild. I am sure a weeks of  cold  weather with snow in any of these months would be better than nothing in the climate we are today. 
 

So my conclusion is that fair enough if the seasonal forecast is going for mild, it’s not the end of winter we could still get our cold and snow but the total averages will still come out mild as explained above. I would not write any season of, there will be cold weather and there will be snow depending how the setup falls in line , we may come out lucky or we may not but it’s certainly best to compare the seasonal forecasts once we have seen winter through.

have a great day all

regards

[Froze were the Days]

I wonder if in my location I can get 12 consecutive January's with no noticeable snowfall lying...if ever you want an argument that GW is in full acceleration then this has to be it!

I'm expecting very little of this Winter (again)...people saying Spring is starting after Xmas but it feels like it hasn't gone away in October/November temperature wise, flowers out still cutting a vivid green grass regularly, not the yellowing and stunted growth that use to happen at this time.

[Don]

 E17boyHi there.  I don't have the stats for the EC, but it's one of the more highly regarded seasonal models.

[cheeky_monkey]

no consolation for you guys but for February 2025 the whole of Canada looks way below normal temps wise 

[Don]

29 minutes ago, cheeky_monkey said:

no consolation for you guys but for February 2025 the whole of Canada looks way below normal temps wise 

Thank gawd for travel....  A case of going from a dull, mild bore fest to a winter wonderland in 7-10 hours!!  

Edited November 6 by Don

[cheeky_monkey]

 Don you know what they say flights to Calgary leave twice a day 

[Don]

 cheeky_monkey Had better look to book one then!

[Jacob]

The GFS 12z looks slightly like the beginning of the 2022 December cold spell, but PV is disappointingly relocating to Greenland at 168h

[Jacob]

If we get this, but without the PV over Greenland then we could possibly get a very notable cold spell 

[TSNWK]

 Jacob looks better to my eye..vortex further east..

[LRD]

 Northern Sky All that high pressure anomaly in the Atlantic is showing is an inactive Atlantic as pressure will be higher than the usual, normally pretty low pressure there in winter

Check out the high anomaly in Europe. Grim if you dare to be of the persuasion of wanting to see some seasonal* weather in winter

 

*although seasonal is ceasing to be meaningful - in the traditional sense - in winter in NW Europe these days

[LRD]

 RJBingham Well, if the ECM seasonal is right, but leads to similar conditions we've had this past 10 days, then it won't be very spring-like and mother nature can stick it*. Although a lot of folk on here seem to like grey, uneventful nothingness

 

 

*where the sun don't shine... pardon the pun

Edited November 6 by LRD

[Jacob]

I just realised I commented on the winter forum instead of the model output discussion oops

[SqueakheartLW]

Someone here commented on how you could get the mildest and driest winter on record. I think the current pattern of stubborn cloud and high pressure could do the trick with maybe some daytime breaks in Feb to up the maxes whilst the cloud would keep the mins very high for winter

[WYorksWeather]

 Northern Sky That would be true if it were more of a circular high - you have to consider the shape. Essentially the winds would be flowing around the high  from almost straight west, because it's elongated.

Of course, it is a three month average - the details are always the interesting things. You can never rule out, for example, that in an otherwise mild winter, we have 10-14 days of notably cold and snowy weather. There's a big difference between a winter where it is consistently 1C above average, and one where it is consistently 1.5C above average, except say a two-week period where it is several degrees below average. Similar with the pressure chart - that suggests a mid-Atlantic high not far north enough, but could it get far enough north for a short period, even if that chart were right overall? Who can say.

[WYorksWeather]

 Don The ECMWF provides a value for the Anomaly Correlation Coefficient (ACC). This is for model runs starting in November, running over the winter, and is a 'hindcast' of the accuracy over 1981-2016. These should be interpreted as the square of the value. In other words, an ACC of 0.7 means that the model explains 0.7 * 0.7 = 0.49 or 49% of the variance in the outcome.

You can see that the performance over the UK is between 0.2 and 0.4, which means explaining between 4% and 16% of the variation. Pretty low skill level overall.

For 500mb heights, it's actually even worse! The UK is now in the grey area - essentially the model performance is zero.

This is ultimately why seasonal forecasting is so difficult - the underlying skill levels of the models are quite low. Hence, whilst I agree that the seasonal models are very poor this winter, they're not necessarily the be-all and end-all. There is a reason that accurate seasonal forecasting is very difficult - you can only really speak in terms of probabilities.

I would treat the poor seasonal models as another weight on the scale in favour of mild, in addition to the other factors such as global warmth, slow ice advance, etc., but there is no silver bullet. If there were, the Met Office and other agencies would be far more confident about issuing forecasts several months ahead.

As you can see from the contingency planner for November to December, they prefer to speak in probabilities, and with good reason.

 

[Don]

 WYorksWeather Thanks, that's very interesting and insightful 

[Penrith Snow]

I just don't buy the EC Seasonal, firstly the pressure anomaly indicates the main high pressure to the south West rather than south east of the uk so not a true Bartlett so combined with the core low pressure to the North East rather than Greenland would give a north westerly mean flow across the UK, hardly a 1989 revisit?

Secondly, if the EC is to believed virtually all of the NH will have a mild winter, that's highly unlikely, I can't imagine the US being so mild.

Looks like the EC seasonal model has had a large dose of AGW injected.

I don't buy it.

Andy

[Neilsouth]

I really think this winter is going to have a nasty bite to it at some point! It's way different than last year, there's no ooomph in the jet stream, and it was never this calm for so long!  I know we had a lot of rain previously with records being broken, but even that was because of the jet stream being rather slack and low pressure systems stuck over or near the UK. When was the last time we had storm after storm with gale force winds? Most of it has gone through the Med! It only needs the high pressure to be pulled towards the north west like some of the models are suggesting and winter comes

Edited November 7 by Neilsouth