Winter 2017-18: Discussion

sryanbruen

The stratosphere right now is quite cold and if we look through the models, there is no signs of it warming up in the next two to three weeks. In fact, the GFS has the stratosphere getting even colder by the end of November. This would normally ramp up the Polar Vortex and in turn throw Atlantic depressions/very mild weather at us but the strange thing with this is the expected northern blocking and the crash in the AO.

Here's the current stratosphere (at 10hPa) situation:



Looks very similar to this point in 2010 if you ask me, although in 2010 there is some warming going on over in Asia:



The GFS as I briefly mentioned is going for even colder stratosphere temperatures at the end of November:



But again, bar some warming going on in Asia which could have had a major impact on the cold spell happening, this looks quite similar to that point in 2010 with it being very cold in the stratosphere over the Arctic. The AO was very negative at the same time - and was taking a similar crash to how it is now like you've seen.



So, more powerful Polar Vortex possible going by this but no model is showing us in a very zonal pattern.

Metmaster

Its forecast for wintry showers over high ground in the north for tonight.

Lumi

United road wrote: »

i am wondering if the original thread from boards showing that spell for say dec 2010 still exists.

If you start reading from HERE you should find everything you’re looking for - enjoy

Silverbling

sryanbruen wrote: »

The stratosphere right now is quite cold and if we look through the models, there is no signs of it warming up in the next two to three weeks. In fact, the GFS has the stratosphere getting even colder by the end of November. This would normally ramp up the Polar Vortex and in turn throw Atlantic depressions/very mild weather at us but the strange thing with this is the expected northern blocking and the crash in the AO.


I am a fascinated follower of weather but struggle to understand it, I hope you do not mind a stupid question but if the stratosphere is cold why would that produce very mild weather?

My assumption would be the colder it is up there, the colder it would be down here.

United road

Lumi wrote: »

If you start reading from HERE you should find everything you’re looking for - enjoy

Brilliant, thank you so much Lumi!!

sryanbruen

Silverbling wrote: »

I am a fascinated follower of weather but struggle to understand it, I hope you do not mind a stupid question but if the stratosphere is cold why would that produce very mild weather?

My assumption would be the colder it is up there, the colder it would be down here.

Cold air over the Arctic means that low pressure is over it. The cold is not descending into the mid-latitudes. This normally means that the zonal westerlies are intensified. The Polar Vortex, basically, is a ribbon of air high up in the atmosphere which is the boundary of the cold air / thing keeping the cold air in the Arctic from descending into the mid-latitudes. Sometimes, a sudden stratospheric warming (SSW) event where the stratospheric temperatures go up extremely quickly in a very short period of time, can take place and obliterate the Polar Vortex like in 2013. The effects of a SSW on our part of the woods can take up to a couple of weeks to take place. For example, January 2013's SSW event didn't truly affect us 'til March - although you could say it affected us about a week and a half later after the original occurrence on 5 January 2013 with the UK getting down to -13.6c. With the Polar Vortex obliterated, cold air can descend very easily to the mid-latitudes as there is no boundary to counter it then.

However, the cold air could go over to eastern Europe, it could go to us, it could go on the other side of the Atlantic at the eastern seaboard etc so it isn't as straightforward as a negative AO or northern blocking taking place and we will automatically go into a cold interval (as JCX BXC briefly said).

Hope that explains it simply enough for you to understand.

mickger844posts

Lumi wrote: »

If you start reading from HERE you should find everything you’re looking for - enjoy

I never grow tired of looking back through the posts from Nov. 2010. What fantastic charts they were and a real dream scenario for snow lovers.
I feel like this time of the year we do have great expectations for what may happen in the coming Winter. A lot of speculation for something late November but way too early to even remotely get excited.
From my own personal point of view i think its late November and into December we will see our best chance of a decent Wintry spell.
I had to chuckle a bit when looking back on a post i made on my Facebook weather page for Waterford in December 2010. We all remember that famous Satellite image with 95% of the country under snow and Waterford green. Snow is just never a given and i guess that's why it means so much when we do get some. Fingers crossed an exciting Winter season ahead which will deliver that white Gold

Silverbling

sryanbruen wrote: »

Silverbling wrote: »

The Polar Vortex, basically, is a ribbon of air high up in the atmosphere which is the boundary of the cold air / thing keeping the cold air in the Arctic from descending into the mid-latitudes.

Thank you that explains a lot

JCX BXC

Oh god fix those quote tags!

Met office haven't changed their 6-30 day forecast, still going with high pressure and cooler conditions.

Gaoth Laidir

ECMWF Winter forecast (NDJ), showing northern blocking promoting an easterly flavour. 850 hPa temperatures still a shade warmer than average, though.

squarecircles

Unfortunately,All gone tits up on 18z gfs.

Captain Snow

Our Eternal Winter........:D



Day After Tomorrow...lol

M.T. Cranium

So I was away for a few days (we are moving from the coast and the big city to a small town in the mountains, now I should really get time for research this winter).

There has been quite the little discussion going on, three points need maybe a bit of a comment from me, although I have learned to live with this sort of thing over many years.

(a) the most immediate, some discussion went back to some comment I made in mid-October about it taking a brave person to forecast a cold start to winter etc, that was just a throw-away comment embedded in my promise to get down to the task of making a winter forecast, not meant to be a fully researched forecast in and of itself. The forecast I did eventually post spoke about some milder weather to start off in December but you'll notice that I did not include November in the forecast and actually gave it little attention since winter is Dec-Jan-Feb. So not meant to be an excuse, you can take that any way you want, but in my mind it's a sort of false flag since I am sometimes in chat mode and sometimes in forecast mode.

(b) perhaps more serious, I don't appreciate any suggestions that there is some cult of personality or unwarranted respect brought about by any nefarious means, people here are fully independent thinkers who can form whatever opinion they want and I don't try to shape what opinion that will be. I have no interest in being the centre of any cult of personality, I would be hard pressed to demonstrate a personality at all.

(c) going on from that, there was some back and forth about comparisons of one individual (me or any other lone wolf forecaster) and national agencies. The irony there is that national agencies have made it pretty clear they do not consider monthly or seasonal outlooks to be all that credible and they would rather not be forced to provide them, but they will for high-level clients (the folks paying the bills). My attitude is somewhat similar, I keep mentioning each year that my methodology (maybe mythology was the right word) is a work in progress and you're just getting the latest from the lab so to speak. I'm sure it has been stated several times that I don't consider this work to be in some final almost-there stage, it's very much in an early stage of development but I do honestly think it has made some progress past just mere random guesswork, and I see some people posting that same impression. So thanks for your comments. I wouldn't claim to be "better" than anybody really, what motivates me is to try to solve this complex intellectual challenge and if somebody else gets there faster or more demonstrably then all power to them, I will be more impressed than anyone else because I know how difficult this is.

So that's about all I wanted to say, the November charts do keep hinting at some rather wintry synoptics but I keep noticing when I look back on my forecast package that they may have overstated a few cases already. This seems to be almost a routine default characteristic of the GFS model in recent years, but a pattern that I think many of us recognize is that eventually these false starts will be rewarded with a real event.

I will keep working on my research and will continue also to be very vigilant for good ideas "out there" including some that show up in these threads, it would be very limiting for anyone doing this sort of research to get too focussed on only one perspective or methodology. I've said this numerous times also -- in my opinion, this science won't score some huge theoretical breakthrough like the day Einstein wrote out his equation or Newton saw the apple falling, this is an empirical discipline and it will advance very gradually. Whoever is making the most progress will also have problems getting fully heard around the whole community, so you may not know when somebody has reached a sort of almost-there plateau of reliable results. I know that I am not there yet and so instead of getting peeved at anybody, my only useful strategy is to keep working. The only limitation on that is the natural span of life and the clock is ticking.

M.T. Cranium

Also, we'll have the annual winter forecast contest, then anyone is free to have a go at predicting the trends for the winter and whoever goes mildest and least snowy is almost sure to win based on the last six.

Snowbiee21

Any updates From the charts guys?

jaffusmax

When is the snow coming?

Donegal Storm

Snowbiee21 wrote: »

Any updates From the charts guys?

Nothing too interesting for the week ahead, just more of the same alternating between mild and cool

From around Thursday onwards it looks like it'll start to get colder but no real consensus on how cold. Likely some icy mornings at least

PokeHerKing

Should be a frosty morning tomorrow to start the week off

JCX BXC

jaffusmax wrote: »

When is the snow coming?

Nobody's saying snow is coming!

Oneiric 3

Gaoth Laidir wrote: »

ECMWF Winter forecast (NDJ), showing northern blocking promoting an easterly flavour. 850 hPa temperatures still a shade warmer than average, though.

Not necessarily. An inflated Azores high positioned a bit further north than normal (mid-latitude) would yield pretty similar results.

For what it is worth, the ECM showed a pretty similar seasonal forecast this time last year.

sryanbruen

jaffusmax wrote: »

If anyone has been following sunspot activity this year there has been a 25% number of days with no sunspots. Solar minimum has not even been reached yet.

Regarding predictions of any major cold outbreaks I will be placing my trust in established weather forecasting organisations like the UKMO. As generous as people are with providing short term weather forecasts the resources and data the UKMO have access to cannot compare to what is in the public domain.

I forgot to answer to this. On that second point, it don't matter if they have access to data that we don't. They can still be as inaccurate as us when forecasting the weather. Just to show you how bad they can be - as much as us - in 2009, they went for a BBQ Summer. It mostly certainly was not a BBQ summer. It was the wettest Summer on record for some parts, including Valentia Observatory with more than 600mm recorded for the season. It was the wettest July on record for England & Wales. If the inaccuracy couldn't be worse, they went for a mild Winter in 2009/10. May 2009 did not have a tripole or negative NAO and as a result, they said for 2009/10 to be a mild Winter..... oh boy were they wrong.

Anyway, the bottom line is what I said at the start of this post, it don't matter if they have access to data that is not in the public domain. They can be as inaccurate as anybody else. The atmosphere is ever changing and will always give us surprises. A qualification does not matter at all in this case of weather here. It's all luck based on forecasting 'cause as I said before here, long range forecasting is highly experimental. It is not a talent. It is not an art. It is very luck based.

sryanbruen

Oneiric 3 wrote: »

Not necessarily. An inflated Azores high positioned a bit further north than normal (mid-latitude) would yield pretty similar results.

For what it is worth, the ECM showed a pretty similar seasonal forecast this time last year.

I post on the GavsWeatherVids comment box all the time. He did his own interpretation videos of the ECM long range model for 2016 and 2017 (which I think some of you have posted on in this thread before), before access to it became public recently. Me and others frequently debate on the accuracy of this long range model. Gavin says himself that the ECM did very well for Winter 2016/17 with a block set up but not overly cold. However, others and I whom say otherwise. The ECM showed blocking up over Iceland which did not come to fruition at all. The block ended up over top of the British Isles than Iceland. Temperatures were also much milder than what the ECM was hinting at. In my opinion, the ECM did terrible but that is quite a debatable topic. As a result, the ECM long range model is not highly favoured to me but hey, what do I really expect from a long range model right? I'd be hypocritical of what I described in the above comment if I expected a lot more.

beefburrito

Sorry for going a bit off topic,has anyone a link to the build up to the cold spell in 2010

It's a book in itself I'd say

JCX BXC

beefburrito wrote: »

Sorry for going a bit off topic,has anyone a link to the build up to the cold spell in 2010

It's a book in itself I'd say

Go back a page! Lumi posted it.

Loughc

JCX BXC wrote: »

Go back a page! Lumi posted it.

That link just brings me to the weather forum. Not to the 2010 thread itself.

JCX BXC

Loughc wrote: »

That link just brings me to the weather forum. Not to the 2010 thread itself.

Strange, it has the page number in it too!

I found it myself before by going back several pages in the search function, perhaps you could do that? If not I'm sure someone may post it eventually.

Lucreto

JCX BXC wrote: »

Strange, it has the page number in it too!

I found it myself before by going back several pages in the search function, perhaps you could do that? If not I'm sure someone may post it eventually.

I am having the same problem but I think it's an issue on tablets and phones.

It is page 130 but I don't know the name of the thread.

Gonzo

found these from 2010, not sure if there is an earlier thread than this, but lots of memories can be found through both of these:

https://www.boards.ie/vbulletin/showthread.php?p=69272264

https://www.boards.ie/vbulletin/showthread.php?t=2056102350

Gaoth Laidir

Oneiric 3 wrote: »

Not necessarily. An inflated Azores high positioned a bit further north than normal (mid-latitude) would yield pretty similar results.

For what it is worth, the ECM showed a pretty similar seasonal forecast this time last year.

Not necessarily which part? I know pinch of salt and all that, but on average, there's a strong signal for high pressure anomalies to our north, with a weaker signal for low to our south. This would hint at an increased possibility of an easterly influence.

On the other hand, the UKMO and Méteo France show wildely different scenarios (nice NW blocking in the latter), which makes the multi-model average (last chart) highly uncertain.

ECMWF


UKMO


Méteo France


Multi-model average

Donegal Storm

Loughc wrote: »

That link just brings me to the weather forum. Not to the 2010 thread itself.

There were countless threads throughout the 2010 cold spells, it even got separated into regional and county threads at one stage as things were so hectic.

Lumi's link is to the forum in November 2010, if you keep going forward in pages you'll find the relevant threads