Autumn And Winter Lrfs

[Damien]

This is interesting. I've been following the discussion on a far away thread on a far away forum about precipitation patterns in autumn and colder winters. Well, even though the NCEP temperature forecast still continues to forecast a warmer than average September followed by a slightly cooler than average October, backed up by Ian Currie, this is what the NCEP CFS 6-month Precipitation chart has to say:

I think it's pretty self-explanatory. (But for those who don't know - a wetter than normal-looking September for Britain and indeed most of Western Europe, followed by a very "stand-out" and very dry-looking October, and above average rainfall also in November and December).

Again, not to add fuel to the fire....

The longer term is pretty obscure but it also seems to paint a similar picture only with the north and east much wetter than normal through this winter with substantially dryer than normal conditions to the south and west, and also over parts of France and Spain later. What could this specific pattern mean for the UK winter (this is not rhetorical question by the way - anyone in the know?).

[summer blizzard]

These are the charts from last saturday and today...

Here are the changes from last saturday...

July - Warmer and still above average

August - Warmer and still above average

September - Cooler but still above average

October - Warmer but still below average

November - Warmer but still below average

December - Warmer but still below average

As you can see, only September is forecast to be cooler than this time last week.

August to October - Warmer and still above average

September to November - Warmer and now above average

October to December - Warmer but still below average

November to January - Warmer but still below average

December to February - No change for England and still below average

January to March - Cooler but still below average

As you can see, while December has become milder but still below average, either January or February has cooled sufficiently so that the winter period has had no change and the January to March period has become cooler.

Edited July 15, 2006 by summer blizzard

[stormcloud]

Interesting reading guys!! I wouldn't normally show any interest in winter forecasting at this time of year but I have a new baby that cries and cries on the hot days, but is very settled when the weather is cooler. So for once, I wish summer was over and Winter was here!!

[Glacier Point]

The only problem is as Enforcer said even if it doesn't change much at all per day, think about how many days are in a 6 month period. The best comprasion i have is a winter model. They can keep forecasting a massive Greenland block but if the model hasn't spotted a developing low at say 48hrs out then the whole thing is wrong.

I must amdit though the long range models are something a long my own personal veiws...mind you when you compare my long range reasonings with someone like Steve Murr or GP and ther eis no comprasion, those two plus a few others on here are the ones who are more likely to be correct then the likes of me and other LRF.

So many different teleconnections, if you mess up on one of them then your entire forecast can go wrong. I think for now i'll stick to hurricanes...mind you if anything to try and forecast thier strength beyond 120hrs is even harder then predicting the temps for a month like December this far out, and I'm being serious as well!

(ps, look for hurricane Epsilon and see how many times the experts forecasted to die...and how long it actually lasted!!)

... and as a perfect example.... my summer LRF completely de-railed by a rampantly +ve AO - the second strongest June AO since 1950, bettered only by June 1994.

[kippure]

Quick question

When ever we get hot weather in europe why does greenland tempetures plunge ?

Its as if greenland goes into a deeper freeze?

Whats the connection, if any?

[Glacier Point]

Quick question

When ever we get hot weather in europe why does greenland tempetures plunge ?

Its as if greenland goes into a deeper freeze?

Whats the connection, if any?

Not a solid linear relationship but broadly the +ve states of the Arctic Oscillation and North Atlantic Oscillation favour high pressure at middle and lower latitudes and lower pressure at higher (polar) latitudes. This keeps Europe in a SW''y or S'ly flow hence the warmth whilst the low pressure over the polar region.

When the AO and NAO turn -ve, the reverse happens with warmer air aloft over Greenland turning things cooler over Europe.

http://www.washington.edu/newsroom/news/19...ve/k121699.html

http://www.cpc.ncep.noaa.gov/data/teledoc/nao_map.shtml

[kippure]

Thanks

[Damien]

I was going to post this yesterday but I never got the chance.

I am sorry to nit pick here folks and I am not a troll honest BUT come on its July the 15th and you are talking about the weather all the way to January 2007 already???

That's right, we're not really talking about the "weather" - we're talking about possible trends. NOAA base these on the current SSTs, as do the Met Office; and using this system can allow us to make, for instance, an NAO and general wind direction prediction for that period, and, as such, have a *guess* at what the actual weather may be for that month. And the forecast today on those NOAA charts is for cold.

I do'nt claim to know the science of it all - yet! - but come on honestly just how reliable are the long term models?

Encouraging as these charts are, they have forecast a cold winter before (albeit never for this long and to this sheer cold extent), and the Met Office "mild" charts are historically nearly always a much better indicator of the weather to come than these, interesting and worthy of consideration as these NOAA charts are. I listed my choice of "model" preference for this winter somewhere in the previous thread, and NOAA was not in the top 2.

That said the NOAA are still quite highly rated internationally though. Metcheck I think used to regularly consult them prior to the winter 2004/05 disaster.

In what way , that Ireland is a battle ground for the milder air coming up against the colder air?

Could you post the chart or provide a link

I don't think in terms of pathetic "mild-cold battles". I'm talking about long-term easterly winds and heavy snowfalls that go on for days. How this will pan out for the UK, and even an area like Ireland, in today's climate (and my area did quite well from late February 2005 but most other people especially in the South did not) I don't know, let alone if we even get an easterly at all! But heavy snow, light snow, cold and dry but with no snow at all like most of last year, or "mild-cold battles" are all a possibility from this kind of set up for Ireland. Especially if you live in the Southern bit.

Damien; what exactly are the success-rates of these forecasts that you say are a "bit of fun"

Correct me if I'm wrong, but I don't actually remember saying that. :huh:

Certainly you could look at inoffensive trend-spotting as "harmless fun" in trying to rationally and reasonably deduce what this winter might bring, as long as you know what you are doing, if you get my drift.

, then go on to describe as "locked in" at some point, months into the future?

Because that's what these charts are showing, however you view them or rate their accuracy.

It is a question you always skirt,

Mixed and constantly improving. They successfully forecast a mild winter for years like 2002/03 (I think) and 2003/04. They also forecast last November and December to be colder than average from quite early on, although not as cold as they initially foresaw, but they got the general trend of the period right. I think, given what they are currently forecasting, this next winter will be a real test for them and their current as well as to some extents future reliability.

no matter how many threads of this nature that you start.

Really? When was the last time I started a "thread of this nature"? The only thread on "winter" (which was actually on autumn and most of the latter part of this year) that I really started this summer to my knowledge was the thread on the June IRI forecasts, which incidentally became the first "Winter Thread". (By the way the IRI charts update next week, which should give us our first look at December 2006 though the eyes of the respected British Columbia-based meteorologists.)

Do you mean posts?

Amazingly enough, the forecasts don't change a great deal from day to day, because trying to forecast the weather in any particular month, 4/5/6 months in advance really is no better than guesswork.

Well the message has finally got through. But yes these charts are just predicted trends, based on the immediate outgoing SSTs, from which we can deduce such things as the possible NAO forecast and the possible general wind direction. But that is all they are - just possibilities, not predictions, based on the current trends in weather. They are not "golden". Even the Met Office's excellently good charts are not "golden" as anyone will tell you. However, as you rightly say, the NCEP has been fairly consistent for the last few months now, although others like The Enforcer are also right to say that this will mean nothing from a few days out. Hence these are just showing us the current trends and nothing more.

HP parked in the atlantic with pressure low over Scandinavia and europe with fronts toppling south east and affecting northern and eastern parts.??? Lots of northerly blasts by the sound of it! ??

Maybe I'm the one who's wrong, but I'm thinking more on the lines of frequent and hopefully "true" easterly blasts from that.

If, for arguments sake, it was true, doesn't sound like a plausible dominant set-up - although it could feature repeatedly if we got a cold zonal set-up with high pressure consisitently retrogressing to Greenland maybe?

Well, I am thinking in terms of the goal being a prolonged cold and snowy easterly, not some pathetic little 2003/04-type "northerly topplers", which brings us ultimately meaningless snow showers for some 3 hours before soon turning to rain. For someone as old as you who would have no doubt lived through at least the winters of the 1980s and 1978/79, not to mention even the mid-1990s winters were you in a favourable location, I am surprised to see you make such a statement.

And yes, such a set-up, be it frequent easterlies or northerly topplers, would be possible if, as last winter, there were consistent negative NAO conditions, high pressure in the right place, and of course the substantial cold and precipitation(?) in Europe to produce the goods for here next.

[Damien]

My statement regarding northerlies was not/is not a personal belief - I was simply making suggestions as to the possible synoptic set-up which could lead to wetter northern and eastern parts of the uk and a drier south west, which was the original post I replied to. Of course I would want it to mean bitterly cold and snowy easterlies! :huh:

Unfortunately (as we all know) we have not seen that sort of thing in any noteworthy intensity since 78/79 or a few of the winters of the early and mid 1980's with the possible exception of the very cold spell of Feb 91 and a few of the colder spells in the mid 1990's to a lesser degree. So, as easy and natural as it is for me to want to cold-ramp, caution and realism are still necessary (albeit reluctantly! ).

I agree with what you are saying, Tamara. Realism is fine - but perhaps, in this case, as I have so frequently been warned, so is altruism. "A few of the winters of the early and mid 1980s" seems to ignore factors such as December 1980 and January 1981(?). And as for the mid-1990s - well, where did you live at the time? I lived in the North-West, as I do today, and myself and many other people in this forum can verify that that was indeed a good time for snowier winters with heavy snowfalls commonplace, and long hot and dry periods in the middle of summer on the flipside of the coin. (That's why I find this "high pressure block - solar activity" theory quite exciting at this moment in time too: for the possible chances of another such period, not to mention hope for such periods and cold winters in the future, if we can get this winter.)

I should also point out with all due respects that expecting another winter like 1978/79 is folly in my view - the aforementioned winter was and remains a truly exceptional winter, that does not occur every year. It was a severe winter, never mind a cold one. And even a cold winter, in spite of the long period of wait that we've just gone though (and continue to go through), is *unreasonable*, given all we ask for is a return to the norm - our average. And if winters like 2000/01 are that average, then so be it, says I.

there is also time for the preliminary METO signal just issued to change as well - so need to reach for alarm buttons at all yet regarding winter potential.

Well I hope it doesn't, because a weakly positive NAO winter (like your mentioned example of 1990/91 was) with above normal precipitation sounds quite the potential and promising to me! Talk about a forecast being misread! (Did I also mention that lots of people are refusing to believe that this winter will be a positive NAO winter of any kind, and some are saying that the SST signs in fact point to an even more negative NAO winter that last time around! It's all true! )

Today's NCEP. Summer is still expected to be very hot, especially July. September is still very mild but now just slightly less mild yet as those small darker oranges over Europe just start to recede. A cooler October is still expected but now a just slightly less cooler one, which is good news as well IMHO. November is looking much colder yet again from the north and our near area of Europe(!), as is December, keeping us slightly below average again from Europe.

http://www.cpc.ncep.noaa.gov/products/peop...bT2mMonNorm.gif

http://www.cpc.ncep.noaa.gov/products/peop...bT2mSeaNorm.gif

The long-term scenario quite strongly backs up what today's NCEP short-range has said. January is still expected to be colder from Europe with the Atlantic still only digging in in Western Scotland and Ireland, but both of those months - December and January - look to be predominantly easterly months to me if this comes off. February is somewhat by contrast expected to see the Atlantic dig further into the West of the UK and Ireland, but North and East Scotland, Eastern England, and much of Southern England are still expected to be colder from Europe. If anything this is the only chart that has changed quite a *lot* over the last few days, and even then it has kept much of Eastern England and indeed all of England, per se, quite cold and under those North-continental or north-north-easterly winds.

Another noteworthy feature is that small blotch of -1.25--1.00°C air over Southern Europe in the JFM chart. Read into this what you will.

El Niño:

http://www.cpc.ncep.noaa.gov/products/peop...nino4SSTMon.gif

http://www.cpc.ncep.noaa.gov/products/peop...nino4SSTSea.gif

A weak El Niño expected for winter 2006/07. The last 2 days' charts showed a strong El Niño expected. Some of the other runs in the past 2 days have gone for a strong La Niña to develop again. Still no agreement on this issue from the NOAA models.

Edited July 16, 2006 by Damien

[johnholmes]

hi Damien

It may be me but your posts always run over the end of the page so I have to scroll back and forwards to read it. It does not happen with any other posters! Can you see if you are perhaps preparing your text in word(?) and then altering the width as it does affect what is seen on the page.

Hope you don't mind me asking.

John

[Damien]

hi Damien

It may be me but your posts always run over the end of the page so I have to scroll back and forwards to read it. It does not happen with any other posters! Can you see if you are perhaps preparing your text in word(?) and then altering the width as it does affect what is seen on the page.

Hope you don't mind me asking.

Sorry John. It's the El Niño charts. They are the culprits. :huh:

I'll just start posting the links in future as I find this annoying too. Just a sec., I'll edit my post.

Edited July 16, 2006 by Damien

[johnholmes]

cheers mate

j

[The Enforcer]

Another noteworthy feature is that small blotch of -1.25--1.00°C air over Southern Europe in the JFM chart. Read into this what you will.

A weak El Niño expected for winter 2006/07. The last 2 days' charts showed a strong El Niño expected. Some of the other runs in the past 2 days have gone for a strong La Niña to develop again. Still no agreement on this issue from the NOAA models.

Picasso's paintbrush slipped again?

My very limited weather knowledge suggests to me that until the models can pinpoint El Nino/La Nina, then the rest of the forecast will look rather shaky.

On reflection, I've been overly critical considering the time and effort you must be putting into this. There is an awful lot of information here. It's better to have it than not have it. Maybe one could get the most out of it if some sort of summary table could be compiled, which would provide a comparison between the LRFs of NOAA, NCEP, IRI, ECPC, METO et al. It could then provide an at a glance guide as to what trend each group is predicting for particular periods and/or a season overall. It could be kept up to date on a daily basis, as runs are updated. Having the key data in one place would act as an 'LRF hub'. This would present an at a glance overview for everyone, which would avoid the common problem of members/guests reading data independently and taking it as gospel (and then having to be corrected). Obviously, as soon as the majority of data sources start tallying we'll know we're onto something. Just an idea, it's up to the NetWeather Team, obviously.

Footnote: I guess Netweather's own official/unofficial LRFs could be stored in a similar way.

Edited July 16, 2006 by The Enforcer

[kold weather]

The one thing I'll say about El-nino and La nina is that actually its not amazingly hard to try and forecast, there tends to be quite a few signs that such an event is happening such as sub-surface warming and the trend sof the SOI teleconnection.

The problem with long range forecasting is simply because there are so many factors, if one goes wrong, the whole lot may well go wrong. I've not even began thinknig about winter in any sorts of depth right now because for the next 3-4 months the hurricane season will be in my mind!

[Stratos Ferric]

I answer to BFTP, I do entirely believe that detailed weather forcasting for six-/seven-months' time is (in terms of success rate) as near to guesswork as is guesswork itself...In fact, I'd imagine that the convergence of guess and 'science' occurs far sooner than that???

Only my opinion, of course, peeps.

Hear hear. Amongst all the rheotric of certain people talking up why this approach or that might be worthy of belief (as an aside, the main protagonists invariably seem to be enthusiastic for cold rather than mild / normal) so far as I am aware there is still absolutely NO robustness, for forecasting purposes, in ANY long term forecasts. There are plenty of people good at being wise after the event, but wasnt it ever thus...

I still tend to the view, PT, that the convergence point is not much beyond 5 days, let alone 5 months! Unless you lie in Shetland where the outlook is always wet and cool.

[West is Best]

Unless you lie in Shetland where the outlook is always wet and cool.

A surge of elation in the midst of a torrid time at home - SF is back posting on Net Weather!

[SMU]

Hear hear. Amongst all the rheotric of certain people talking up why this approach or that might be worthy of belief (as an aside, the main protagonists invariably seem to be enthusiastic for cold rather than mild / normal) so far as I am aware there is still absolutely NO robustness, for forecasting purposes, in ANY long term forecasts. There are plenty of people good at being wise after the event, but wasnt it ever thus...

I still tend to the view, PT, that the convergence point is not much beyond 5 days, let alone 5 months! Unless you lie in Shetland where the outlook is always wet and cool.

yawn- glass half empty as usual-

If it was such a fruitless task then bodies like the NOAA wouldnt be investing countless millions of dollars in Seasonal forecasting-

Sure, detail isnt the main emphasis- but that doesnt stop the field moving forwards-

If we all took the approach of it will never happen or cant happen i wouldnt be writing on this keyboard looking at TV-

They said the world was flat until it was challenged........- You do know the world is round SF- ??

yes West.... but it is a bit of a stuck record.........

With SF's unquestionable knowledge it could be better served than that....

In current LRF terms for the winter the only element to go on at the moment in term of a forecasting tool ( if you take aside the alleged pattern change) are the positive SST's across newfoundland- these generally contribute to a + nao winter.....

S

Edited July 17, 2006 by Steve Murr

[West is Best]

yawn-

S

Oh Stevie the heat must be making you grumpy! Lighten up! Stratos Ferric's posts are the perfect antidote to what even you must admit is the occasional wintertime cold ramp on this forum from certain notable cold spots* in the UK?

* Notable cold spots include, but are not limited to, Peterborough, the Shetland Isles and Sussex

Edited July 17, 2006 by West is Best

[The Enforcer]

* Notable cold spots include, but are not limited to, Peterborough, the Shetland Isles and Sussex

I thought you were going to put Bexleyheath on the list for a moment there, which would have been like a red rag to a bull.

It's all a question of balance. It is not so much an LRF that presents difficulties, more so the hype and hysteria that follows it.

Shuffling is a worse problem. Cooler temperatures and some wintry conditions started early last winter, but there were quite a few rumblings through late autumn and the early part of winter that January 2006 was to be the big month for a sustained cold/wintry spell. When this failed to materialise, February 2006 was almost immediately substituted.

[West is Best]

I thought you were going to put Bexleyheath on the list for a moment there, which would have been like a red rag to a bull.

lol!! And lol to SP too!

I'm backing out of this thread before I get flamed.

[SMU]

lol!! And lol to SP too!

I'm backing out of this thread before I get flamed.

LOL- Flamed from the continental high.........

I just dont see the point of coming in & contributing to a thread without anything of substance around the topic.....

S

Edited July 17, 2006 by Steve Murr

[Damien]

If it was such a fruitless task then bodies like the NOAA wouldnt be investing countless millions of dollars in Seasonal forecasting-

Sure, detail isnt the main emphasis- but that doesnt stop the field moving forwards-

If we all took the approach of it will never happen or cant happen i wouldnt be writing on this keyboard looking at TV-

They said the world was flat until it was challenged........- You do know the world is round SF- ??

yes West.... but it is a bit of a stuck record.........

With SF's unquestionable knowledge it could be better served than that....

Well said, Steve.

It was interesting to see your thoughts on the possible positive NAO winter pattern as well. You seem to agree with the Met Office on that one. A few other people, including some unbiased people and even some "mild rampers", are questioning the methodology used in this year's Met Office NAO forecast to come to the conclusion of a positive NAO winter forecast. But even if those people are wrong, 1990/91 was a weakly positive NAO winter, so all is still to play for I guess.

I thought you were going to put Bexleyheath on the list for a moment there, which would have been like a red rag to a bull.

Bulls aren't actually attracted to the colour red. They're attracted to all colours, as long as the presence is powerful enough.

Shuffling is a worse problem. Cooler temperatures and some wintry conditions started early last winter, but there were quite a few rumblings through late autumn and the early part of winter that January 2006 was to be the big month for a sustained cold/wintry spell. When this failed to materialise, February 2006 was almost immediately substituted.

Well, I must admit that that seemed logical last year. But who would have thought the Met Office could have got it so badly wrong? It was unprecedented. Whereas in 2004/05, when mid-January brought heavy downpours and mild temperatures, it was easier to give up on the Metcheck forecast, admittedly.

No NCEP today.

Edited July 17, 2006 by Damien

[johnholmes]

Well, I must admit that that seemed logical last year. But who would have thought the Met Office could have got it so badly wrong?

Damien if that is a comment about their prediction for last winter come off it you know fine it was the most accurate forecast issued by any of the big players. Why do you persist in sticking your head in the sand for your little part of the world?

If it is not about the 2005-6 winter my apologies.

John

[West is Best]

The Met Office forecast for winter 2005/6 was absolutely brilliant. How anyone can try to bend the facts otherwise beats me ...

[Dawlish]

The Met Office forecast for winter 2005/6 was absolutely brilliant. How anyone can try to bend the facts otherwise beats me ...

It wasn't bad; certainly the headline forecast looked good, but the error spread (two standard deviations, typically) did not actually include the outcome, therefore, technically, it wasn't a great forecast. The winter was actually milder than the Met Office NAO forecast predicted! Some of the coldest and snowiest weather occurred last Autumn, in November, which is not recorded as winter and this does seem to have clouded memories on the severity of the winter.

Paul

Edited July 17, 2006 by Dawlish